CORDIS - EU research results

Future RepAIR and Maintenance for Aerospace industry

Final Report Summary - REPAIR (Future RepAIR and Maintenance for Aerospace industry)

Executive Summary:
The goal of the RepAIR project with twelve partners from all over Europe and the US is the onsite maintenance and repair of aircrafts by integrated direct digital manufacturing of spare parts. Cost efficient and lightweight but robust reliable parts are obligatory for aircrafts. Additive Manufacturing allows completely new approaches for this requirement. The main objective of RepAIR is therefore to shift the ‘make-or-buy’ decision towards the ‘make’ decision by cost reduction in the remake and rework of spare parts and thus to improve cost efficiency for maintenance repair in aeronautics and air transport.
The project aims to reduce the Maintenance, Repair and Overhaul (MRO) costs with the help of the Additive Manufacturing (AM) technology as its crucial advantage is the flexible availableness allowing on-time maintenance. Through the integrated vehicle health management parts can be monitored constantly and thus the prediction of the remaining lifetime can be realized. Consequently, maintenance events can be harmonized with the flight schedule. When defect parts arrive at the workshop a multi-criteria decision support has been developed to compare different repair solutions on the basis of their costs, time and environmental impact. To adapt the AM technology to the needs of aerospace a high batch repair has been developed allowing the repair of a high quantity of identical parts such as turbine parts with an integrated in-situ quality system. In addition to that, a 5 axis Direct Metal Deposition machine and its control software has been engineered. It automatically determines the geometrical deviation between the existing part and its original geometry and reestablishes the required shape with multiple tools. To be able to provide high quality parts by AM extensive research has been put into testing of influence factors for surface, accuracy and part quality to determine optimized parameters. In this context a sample part has been topology optimized to fully exploit the technology’s potentials.
As a crucial requirement for the application of AM in aerospace is a defined QA and certification concept. Therefore, a quality assurance IT component has been specified and a certification procedure composed. Due to the fact that knowledge and experience are essential in this industry a knowledge management library has been prepared. As RepAIR aims for the direct digital manufacturing a constant IT support is the basic concept of the project. Hence, an existing MRO and CAMO IT system has been extended and significantly improved by the integration of the developed IT Components. So, the complete MRO process is supported by one integrated IT system architecture increasing the automation level and reducing lead time and costs.
The different research and development activities in the project have been evaluated and presented to a broad audience of end-users from various branches to receive feedback and determining the exploitation of the subsystems. The project’s progress and results have been published according to the dissemination strategy while the exploitation plan has continuously been synchronized with the individual exploitation plans of each partner.
New business models have been identified for this prospective technology. In order to achieve the project’s objectives a roadmap for the further progress and research needs of the considered technologies has been generated as further improvements of the technology are foreseeable.

Project Context and Objectives:
Additive Manufacturing (AM) (aka. 3D printing or Direct Manufacturing) promises optimal buy-to-fly ratio, flexible availableness, an omission of harmful chemicals and constant manufacturing efforts at an increasing assembly complexity. Due to the essential advantage for aviation to produce complex components with low weight, aircraft manufacturer and parts supplier currently employ this technology with less function important components. Improvements of the technology concerning the processing time, accuracy, further process improvements and costs are foreseeable. However, a holistic integration in the Maintenance, Repair and Overhaul (MRO) processes is not yet researched.
The aim of RepAIR is the shift from the "make-or-buy" decision towards the "make" decision by cost reduction in the remake and rework of spare parts. Decidedly for the MRO purpose, the process for cost optimised manufacturing of complex components by use of AM technology will be entirely researched. Starting with an analysis of defective parts, the geometrical 3D – scan of defective components to eliminate time consuming reverse engineering, the support for a cost optimised choice between purchase, reworking and new construction, having all relevant (cost) information available, and the following Additive Manufacturing (AM) up to the certification of the diverse parts and their assembly, the whole process will be explored. The specific purposes of different classes of parts and the derivable lifecycle lengthening characteristics out of this will be taken into consideration.
To get a holistic approach for the abovementioned main aim, the following objectives have to be achieved:
1) Reduce repair and overhaul costs of complex spare parts by 30% and the turnaround time by 20% through the use of a combination of innovative technologies
2) Increase the automation level for spare parts production processes by 20% through an integrated production and supply chain
3) Reduce scrap and toxic chemicals in the repair process by 80% and part weight by min 20% by the use of a new production technology
4) Increase the technology readiness level (TRL) of innovative repair processes for Aeronautics and Air Transport (AAT) to level 4 focusing on the AM technology
5) Develop processes to decrease certification effort for additive manufactured AAT spare parts in terms of cost and time based on an integrated quality control and process data monitoring
6) Reduction of inspection time by 30% by integrating continuous health management and usage based prognostics
7) Strengthen the business model of European MRO service provider in the world by integrating a complete production and supply chain for complex spare parts
8) Prediction of costs and future possibilities of AM technologies for MRO in 2020 RepAIR starts with an analysis of the conventional MRO production process for spare parts to understand requirements for an enhanced MRO using AM technology. Then several activities lead to the enhanced MRO process (topmost layer).
To get the highest benefit out of the process, two different levels of automation in every step of the MRO production are taken into account (Figure 1). Option A represents the introduction phase of the concept whilst Option B leads to the fully established process. As the quality requirements play a crucial role in every task and all tasks produce relevant documentation for the further certification, these issues will be treated in parallel to the production layer. The lowermost layer represents the cross cutting issues of costs, supply chain and the new workflows.
Special attention will be paid to IT support. A decision support tool will reliably pre-calculate the costs for both alternatives and gives correct advice. Furthermore, the enhanced MRO production process (Figure 2) can be easily managed by a production planning and control system. This will be developed to partly automatize the whole enhanced MRO process.

Project Results:
##1 Main Scientific and Technological results/foregrounds
RepAIR followed the layer approach shown in Figure 3. The four work packages WP3 to WP6 dedicated their research on different aspects of the enhanced MRO process in the topmost layer:
• WP3 carried out work to analyse all cost aspects.
• In WP4, the more precise prediction of part lifetime was elaborated.
• The concrete AM technology for MRO spare parts was developed in WP5.
• All the needed process steps to fully integrate the AM technology in MRO were integrated and carried out in WP6.
Strongly interconnected with every of the so far mentioned work packages were both the certification (WP7) and the IT management platform (WP8).
The whole work started with the methodical analysis of requirements out of the three categories ‘domain’, ‘stakeholder’ and ‘technology’. WP2 and WP9 packaged the entire project: All work packages considered requirements from WP2 while WP9 validated the results of WP3 to WP8 formatively measured against evaluation criteria deduced from the requirements.
The two activities project management (WP1) as well as dissemination and exploitation (WP10) supported the generation of significant and visible outputs. The project was supported by a list of Advisors, coordinated as an Advisory Board (Figure 4).

##1.1 List of deliverables
The following listing includes all deliverables created within the RepAIR project (Table 1). Public deliverables are available upon request via the project website

##1.2 Significant results from Work Packages
The work plan was structured in a way that all WPs envisaged significant results being transferred to foreground of the project. The following sections summarise these foregrounds based on WP specific perspectives.

##1.2.1 Requirements analysis and management
The goal of WP2 is laying the basis for work in the scientific and technological WPs, WP3 to WP8. It is divided into requirements analysis and requirements management. Significant results are several deliverables generated by the tasks of this work package. Work from partners in task 2.1 “Requirements analysis and management for the IT-Platform” led to a finished and delivered final version of ”Final Requirements specification of IT-System”. Mainly the IT Management Platform, the Central Node and all Internal Components supplied by other work packages have been described and specified. This information supports the work in WP8 and helps to reach overall objective 2. Task 2.2 “Requirements analysis and management for certification” dealt with legal requirements of repairing spare parts for aircrafts and components. This has been finalized based on an intensive study of all relevant legal aspects. Further key achievements are identified obligations of the MOA and DOA, a defined qualification procedure for manufacturing and repairing AAT spare parts with AM and identified parameters to monitor for process qualification assurance. These results mainly support overall objective 5. Work from partners in task 2.3 “Requirements analysis and management for Production Analysis” and task 2.4 “Requirements analysis and management of end-user repair and maintenance processes” specified the concurrent requirements for the production, supply chain and workflow requirements and process control system. Work done in this task finally results in 103 requirements (67 End-user Tree of Goals/Interviews, 10 literature factories, 9 literature MROs, 17 literature workshops) and 44 requirements from specification on different levels of abstraction with a sufficient quality to specify the production platform. The results are based on the approach defined in D2.5 and have been documented in D2.6. Furthermore a self-assessment of technologies using technology readiness levels has been conducted. In WP2 requirements on the sample parts have been identified and based on that parts for the project have been chosen.
After creating a basis for the following WPs, efforts in WP2 were directed towards continuous gathering and detailing requirements. This has been done mainly in tasks 2.3 to 2.5. Also, based on the status of considered technologies in RepAIR a TRL assessment has been conducted and a roadmap to progress in these areas has been developed (overall objective 4). Within this WP, specific scenarios for giving advice and support to development and evaluation have been prepared. Therefore, the most significant result of this work package is the finished and delivered final version of Deliverable 2.10 “Final specification of RepAIR scenarios”. The previously defined (D2.9) scenarios have been enhanced and detailed with the help of project information/deliverables or project partner interviews. One new scenario was established explaining the certification concept which is one of the major development topics in RepAIR. This scenario mainly supports overall objective 5. Based on the RepAIR scheme and the scenarios, a ‘story’ for disseminating the RepAIR concept (cp. WP10) and for preparing the first evaluation phase was defined in cooperation with all WPs (represented by WP leaders) and individual partners.

##1.2.2 Supply chain and lifecycle cost analysis for improving cost efficiency
While WP 2 defined the project runtime scenarios, in WP3 visionary scenarios for the further integration of the technology in aerospace. The deliverable D3.2 describes four scenarios how AM can be implemented in the MRO field at different stages. Depending on the development of the manufacturing technology there are different applications imaginable within the repair chain. It ranges from another repair technology to a vital part of aeronautics as a local on-demand production of spare parts. There are several influence factors that affect the extent of AM’s deployment. They are analyzed within the deliverable. As the development of the AM technology is also a matter of time the scenarios describe different time horizons on the basis of expected technology developments (cp. Figure 5). Those expectations are based on an expert survey conducted at UPB.
On the basis of the process analysis of WP2 the decisions that a MRO provider has to make to conduct a repair have been identified. They can be divided into operational decisions and strategic ones that have to be decided on a higher, more general level (for example, to invest in a special repair process). All decisions are cost relevant so that a detailed cost analysis is necessary to provide a decision support. In this context the reverse engineering process has been examined in more detail. The required process steps and cost factors have been identified. The development of a methodology to analyze the costs for the developed scenarios of MRO providers has been conducted. This is required to compare long-term decisions economically.
In cooperation with the project partners business models for MRO service providers were identified in WP3. Especially in the future Additive Manufacturing will become a necessary technology to be able to repair AM designed and manufactured parts that are currently developed and will be incorporated in the next aircraft and turbine generation. AM can be also applied for a standard part repair but competes with conventional technologies in its cost-efficiency. To support this strategic decision and to provide a tool to calculate an AM part repair or production, a prototype Decision Component tool has been developed in WP3. It is able to compute costs that arise during pre- and post-processing as well as the manufacturing itself and compares those with milling costs and the acquisition price (cp Figure 6). This easy-to-use cost estimation for AM is novel in its handling and evaluation. (Figure 7)
Manufacturing and repair processes can be enhanced by the application of AM. This highly depends on the part’s specifications and further process details so that a general statement whether an AM utilization is recommended for a specific type of products or a specific process structure, cannot be given. It furthermore has to be pointed out that in this process it should always be considered to identify further opportunities regarding supply chain benefits. Currently, a centralized AM production and repair is useful, based on only a small number of possible AM parts, high costs for AM machines and a high effort for post-processing. In the future it is imaginable that a decentralized production can be applied.
This enables the shortening of the supply chain, leading to less waste and costs having machines located at bigger hubs and producing spare parts on demand. The savings in warehousing and logistic are significant but cheaper machines and faster processes are required as well as a higher quantity of suitable AM parts.
The industry has a great potential as many aerospace parts are not state of the art as only the aircraft’s development phase already takes 10 years, followed by up to 60 years of production or operation. Thus, there are many parts that can be optimized in terms of performance and weight with the help of AM. A restriction can here be the certification effort for the new part design. New software tools enable the topology optimization and the constitutive CAD design for bionic structures, supporting the exploitation of the AM benefits. One is the environmental impact. Different influence factors have been analyzed for example the energy consumption during the process, which is currently higher for AM, but a reduction is expected when development resources are available for becoming more energy efficient. Therefore, no chemicals are used in the AM process and additionally the amount of waste is significantly lower than milling. Lightweight products can save fuel and CO2 emissions during the aircraft operation time. Ecological benefits of AM have been identified in detail and are mostly quantified. There are for example less to almost zero chemicals used for the AM process itself. Nevertheless, the amount of saved ones is difficult to determine as the variety of other processes and machines is too huge to be exactly quantified for each. Besides that, AM can generate a benefit due to lightweight design during the product life cycle. Several sources have been found in order to quantify this factor. A methodology has been developed in order to assess the benefits. The trade-off methodology compares a conventional design with an optimized one. Depending on the part size and volume the material consumption is calculated. It is further used to determine the weight difference. In combination with data for the costs of transporting 1kg 100km far it is then stated how much kerosene is saved for the optimized design. This directly affects the carbon emissions which can be quantified through the costs for an emission permit. Supply chain alterations are also taken into account: For different modes of transportation the costs per km and the emissions were found in literature and are calculated on the basis of the transport distance. Due to the fact that aircrafts have a very long life cycle and that prices usually change within that time frame the methodology is able to include price increases for kerosene and emission permits. The previously described methodology has been included into the Decision Component so that the ecological analysis is now also part of the tool. This enhances also the supply chain consideration within the tool as the ecological analysis can map the costs for two different approaches. The concept of the multi attributive decision methodology has been outlined in the deliverable and the different functionalities are described so that the document serves as a manual for the Decision Component. In order to enable the communication between the Decision Component and the Central IT Node the parameters have been fixed that have to be exchanged with the IT system. A way to exchange files has been developed in cooperation with ATOS and OGA to interlink the different IT systems fluently.

##1.2.3 Part monitoring and usage based lifetime prediction
The automatic communication between the different IT systems is of high importance as the increase in automation level is one of the main objectives in RepAIR. The part monitoring and usage based lifetime prediction targeted this, too. Through the constant control of parts and components their maintenance can be usage driven and start a work order automatically through the link to the other IT components. WP4 developed a methodology to monitor the part and to calculate the remaining useful life. In D4.1 and D4.2 the test rig requirements and design documentation has been stated. The completion of these deliverables involved choosing a part to work on that had the potential to yield interesting results in the areas of Integrated Vehicle Health Management and Additive Manufacturing. As a result, the differential used in Integrated Drive Generators (IDG) was chosen (see Figure 8).
The design and construction of a test rig to conduct experiments on rotating components produced using Additive Manufacturing (AM) technology was completed (see Figure 9). Deliverable D4.3 was submitted on time.
Web services have been used to read and write data which is then processed by software of the embedded analysis system. This could be extended by a successful communication with the central node, not only manual, but also automatic through the application itself. The development of a cost and downtime maintenance model to assess IVHM and new repair technology (AM) impact based on the capabilities of the IVHM system and the AM cost and times, studied in WP3, has been developed. This is based on the previous model, which dealt with a multi-objective optimization algorithm for part ordering: The algorithm assists the maintainers in real-time by providing the estimated cost and downtime of the repair alternatives when a problem arises, either triggered by the IVHM system, or detected on the ground. (see Figure 10 and Figure 11)

##1.2.4 Repair process related technology and integrated quality control for AM processes
When the part monitoring detects dysfunctionality of a component a work order is created and the part most probably has to be repaired. To exploit the full potential of AM technology further developments have to take place in order to adapt to the specifics of aerospace. This is why the development of a repair process for metal- and powder-based additive manufacturing and direct metal deposition (DMD) was envisaged. The former should be applicable for repairing a multitude of identical parts (Figure 13) and the latter for the processing of single parts with larger dimensions. The initial focus is on manufacturing system development within the project work and for both mentioned use cases. One of the mentioned objectives within [2] for this project is the increase in productivity by the factor of two (high level objective 4 acc. to [2]). Hence, referring to SLMG further developments concerning the manufacturing system are necessary. These are associated to the contents of task 5.1 Machine and manufacturing process developments for high batch repair and should lead to the application of this process for economically repairing parts (project partners performed the selection of specimen within WP2, see section 3.1). As a result of the project, SLMG presents the skin & core strategy as well as the application of the developed double laser technology in the following. Figure 12 is displaying a schematic sketch of a new process configuration by means of summarizing of both results.
Every single layer primarily consists of beam vectors for the powder solidification, which are covering the shape of the layer (skin) and vector information that comprise the interior layer area (core). Corresponding to this differentiation the new technology distinguishes also between the used heat sources parameters. Hence, it assigns a 400 W laser beam for the hull and a 1000 W source for the core. First is working with a focus of 100 μm and a Gaussian-shaped beam profile (already used in the past), whereas the latter works with a beam diameter of 700 μm and a top-hat profile. Hence, large parts or a high batch manufacturing of parts (as it is one of the use cases for RepAIR) is more economically producible by means of additive manufacturing. The usage of a 1000 W laser power is one of the reason for this statement. This configuration can result in the solidification of only every third or fourth layer (material-dependent) for the core layer sections, whereas in comparison the previous state of technology was not covering this feature.
Hence, the new procedure leads to the solidification of a whole layer compound instead of single layers. In contrast, only the hull vectors should be solidified every layer for avoiding a loss in surface quality. This procedure induces the enhancement of the build rate, especially when manufacturing a high amount of parts at the same time (as it is the case for the repairing procedure within this project), by the factor of five (material-dependent) compared to the previous technology level. Additional microstructure measurements of Niendorf et al. (2013) for the skin & core strategy demonstrate a higher anisotropy for the solidified areas of the 1000 W laser instead of the 400 W beam. The manufactured cubic specimen made of steel 316L powder showed also a resulting <001> texture in building direction. This reveals a quasi-single crystal microstructure according to the statements of Schwarze 2014. He mentioned also that comparable results have been investigated for other materials (e. g. Inconel or also CoCr alloys and Hastelloy® X). In conclusion, the double beam as well as the hull & core strategy result in a microstructure that is beneficial for high temperature applications and hence possibly for the aerospace industry addressed with this project. Furthermore, SLMG fulfilled the objective of enhancing the productivity.
SLMG was focusing on developing the in-situ quality system. This tool requires amongst other things the possibility of integration and usage in an established system concept. Further constraints are implementation into a current machine system as well as the upgrade of the QA system in existing systems of SLMG. In addition, the in-situ QA system is designed to work regardless of machine size and machine types, e.g. dual-laser systems or multi-laser systems. The optics design of a modular-built machine system of SLMG as a part of the whole machine concept is schematically shown in Figure 14.
The fiber tip of a diode-pumped single-mode CW fiber laser is coupled into a collimation unit, which is adjusted for the particular machine system. The collimated beam is led axially to a dynamic focusing unit, which allows a highly dynamic and high-precision positioning of laser focus along the optical axis. This unit was optimized for applications with high power densities in particular and replaces elaborate flat-field objectives. A scan system with digital control electronics is used for high-precision positioning and deflection of the process beam to the particular process plane.
The process radiation occurring from the exposure of several vector types and locally welded powder particles is a thermal signal which is diffusely emitted from the melt pool. It is utilized as input value in the QA system. A special beam splitter is applied to deflect the part of emitted thermal signals, which are back-reflected along the optical axis into the opposite direction of beam coupling. The beam splitter reflects all thermal emissions >1080nm at the rear interface seen from direction of the fiber. The upwards deflected wave lengths from primary optical axis are led vertically to the optical buildup of the in-situ QA systems. The signals are measured by a detection unit, synchronized and visually presented.
Figure 15 shows essential and necessary individual components for the integration of the in-situ QA systems into the SLM® machine system.
All components were designed based on the high degree of modularity and possible combination. In addition, the possibility of implementation into current and self-contained optics assembly groups of existing machine systems of SLMG is assured. Figure 16 shows individual integration steps of the integrated in-situ QA systems into the SLMG machine system, SLM 280HL-Dual.
Decisive results were also obtained for the software solution that is capable to control the machining process. Therefore, the system architecture of the MRO process at machine level as well as the software design for the 5-axis test rig has been finalized. Regarding a control unit for the motion control of the DMD process, AVAN has implemented low level control modules for the 5-axis test rig. As described in the DoW, another aim is the development of a software solution that is capable of automated generation of the tool paths for the Direct Metal Deposition as well as the finishing process, associating it with the parameters of the machining process and performing a collision test. For this purpose AVAN developed a prototype of a three dimensional slicing software.
Positional alignment:
In correlation to the description in Figure 10, SLMG has developed a MCS version with a new RepAIR functionality (see Figure 17 and Figure 18). The basis for this implementation is a so called software story board or user story. SLMG defined the requirements as follows:
Display camera image
• Features slice viewer that displays a selected slice
• Slice can be selected
• Snapshot button (only active if job is loaded and camera is connected)
• Unload snapshot
• Display snapshot image scaled to the build platform
• Image is rotated 90° clockwise
• Locked areas (drill holes) are visible above the image
• Virtual parts (from slm file) are visible above the image
• Transparency of visible parts can be adjusted from 0 (invisible) to 1 (opaque) using a slider
• If a slice was selected in the RepAIR-Tab this slice is passed to the build start dialog. It is then not possible to change the start layer in the start build dialog
• The initial exposure functionality works for the selected start slice (e.g. if start at slice 200 is selected then the 200th slice is exposed several times)
Scan Preview
• Scan preview functionality is available
• Scan speed + laser power for preview scan can be set

Material development
Within the material development of Haynes 188 it was concentrated on the variation of laser power P_L and scan speed v_s. These parameters are highly influencing the heat flow within the SLM process and hence are mainly contributing to the relative density values. (Figure 19)
For a better comparison with other experiments and pair of variates one can calculate a certain amount of distributed intensity by adding the information of layer thickness D_s and hatch distance Δy_s:
E_v= P_L/(D_s* v_s* 〖Δy〗_s ) (1)
Another important degree of freedom is the preheating temperature T_v. This value is governing the difference of temperature values between actual manufactured layer n and substrate plate n = 0 within the SLM process.
Microstructure and rel. density in dependence of preheating temperature T_v
The preheating temperature seems to increase slightly the relative density. For both cases a value above 99,8 % could be achieved. Taking a closer look towards the distributed intensities one can notice another correlation: The values for relative density decrease with lower distributed intensity.

Mechanical properties in dependence of preheating temperature T_v
The influence of the preheating temperature T_v on the mechanical properties can easily be seen in Figure 20. Within this figure one can see the two different levels - three samples each - of preheating temperatures, called H1 (200)...H3 (200) and H1 (HTH )...H3 (HTH).

Direct Metal Deposition Prototype and manufacturing process development
AVAN finalized the work for D5.4 (Realisation of the software solution for generating a three-dimensional area model and ascertaining the concrete need of repairs and integration of test rig in and final assembly of the DMD prototype).
AVAN completely assembled the DMD Prototype. Therefore, the electronic control unit for the Base machine has been assembled and the control software has been developed and debugged. The implementation of multiple tool-heads has been done. Besides that several health and security devices for the use of the laser head have been integrated into the DMD prototype (Figure 21).

It is able to compare the broken spare part with the original three-dimensional model in order to detect the damages of the spare part. This includes a solution for processing point cloud data, which is generated by scanning the broken part, into a more usable format capable of representing the surface of the part. Furthermore, the software modules for comparing the generated model with the original model and for the construction of the base surface for repair have been developed. Based on the results AVAN also finalised a software solution that is able to generate layers which get laid over the base surface to build up a structure that is congruent with the original model (the solution is called 3D-Slicer) and to generate the generic tool paths for this layers which is translated into machines specific g-code in an additional software module.

Experimental results

Process Distortions
Plugging of cladding head
In one of the first tests with AlSi10Mg one could observe different weld quality of single welding lines (see Figure 22). Within the “good weld”- picture one can identify the typical c-shaped weld seam whereas the “bad weld” shows no clear preferred melting direction.
This effect can be traced back to the plugging of the cladding head respectively one of the powder channels which can be seen in Figure 25.

Suction of environmental air
Another interesting effect which could be seen during the first experiments is the fact of suction of environmental air. It seems to be a correlation between the velocity respectively the volume of the inert gas stream and resulting turbulences with the environmental air. This observation can be also found in literature [16]. It is stated that there is a certain threshold velocity of an inert gas stream. After having exceeded this boundary value the effect of suction due to turbulences can take place.

Single welding lines
In Figure 23 one can get an overview over different single welding lines manufactured during the DMD-experiments.

From both figures (and Figure 23 and Figure 24) the following conclusions or observations can be derived:
• There is a correlation between welding line height and number of revolutions per minute of powder feeding plate N respectively powder flow rate. In both cases, f = 3,2 and f = 7,4, the weld line height is increased significantly by changing N from 4 to 5. The difference in weld line height for N = 5 and N = 6 is in both cases only marginal.
• There is a strong correlation between weld line height and scan speed v_s. The higher the scan speed v_s the lower the weld line height. This statement is valid for both cases (f = 3,2 and f = 7,4)
• There is no significant correlation between focal position and resulting weld line height and weld line width

Two other observations during these experiments which are not evident from figures are:
• There is only little correlation between welding line width and number of revolutions per minute of powder feeding plate N respectively powder flow rate (not evident in figures, but general observation)
• Working at the „real“ focus position (z = 0) was not possible during these experiments with AlSi10Mg due to strong laser back reflection effects. This state led to destruction of laser safety glass which results in process distortion (see Figure 25) and immediate process stop.

Walls on substrate
Within this section results regarding wall(s) on flat and cylindrical substrates are presented. Single parts, shown in Figure 26, representative for these experiments are analyzed by destructive testing method of metallography (for detailed description see chapter “Metallographic method”).

Results of metallographic analysis can be seen in Figure 27, Figure 28m Figure 29 and Table 2.
From these figures the following conclusions or observations can be derived:
• The test specimens achieved a rel. density of around 94%. This value is not varying significantly with the test specimen structure a), b) and c). Some of the detected imperfections are in a nearly symmetrical, round shape.
• The last applied layer (see Figure 27) is significantly thicker than the regular layers.
• A relatively flat solidification front can be observed
• In Figure 27one can observe a wedge-shaped layer formation which changes direction from layer n to layer n+1
• The lateral elongation (y-direction) of each layer is increasing with increasing number of layers (Figure 27).

The observed effects led to following assumptions which shall be discussed in the following passage:

• Regarding the rel. Density < 99,5%: The resulting maximum rel. density value strongly depends on the basic powder quality, relative powder humidity and shielding of the welding zone against ambient atmosphere (e.g. oxygen, hydrogen). For aluminum-alloys the effect of hydrogen-porosity is well known and often leads to unsatisfactory process results. One clear indication for having hydrogen-porosity within the workpiece are symmetrical, round shaped pores, like in the cross sections of Figure 27.
• Powder mass flow: If the powder mass flow is too low interruption of welding line, like no continuous welding line, appears. If the powder mass flow is too high the fusion rate could be unbalanced and loose powder is negatively influencing the laser radiation due to reverberation and scattering.
• Increasing lateral elongation of layers: The increasing lateral elongation of layers, like shown in Figure 27, could be the result of increasing heat affected zones and the accumulation of temperature during the processing of the aluminum powder.
• Wedge-shaped layer formation: The x-y cross section of test sample c) shows an untypical wedge-shaped layer formation. This effect could also be the result of cladding head-plugging. Having one of the four channels blocked the powder application is not homogenous respectively unsymmetrical. This could lead to that layer shape. Assuming a bi-directional strategy of scanning single layers can contribute to that alternating appearance of wedge-shaped layers.
• Flat solidification front: This kind of solidification front could be the result of a non-gaussian profile respectively intensity distribution.
Remarks to Non Destructive Testing (NDT):
NDT is reasonable as soon as one has achieved satisfying results regarding rel. density values > 99,5%.

DMD Software Concept

The DMD prototype provides the complete repairing process on bigger scale inside one platform. With its characteristics of handling bigger parts in an uninterrupted cycle from scanning, pre-processing, repairing and post-processing, it is the optimal platform for increasing the automation level for spare part productions. Besides that the DMD prototype enables to build up structures on uneven surfaces and even overhanging structures without needing support structures. As a result, this reduces build times and also build costs. Another result is the expected reduction of build material compared to powder bed based additive manufacturing technologies, which also reduces the build costs. So it addresses the RepAIR project´s Overall Objectives:
• Reduce repair and overhaul costs of complex spare parts by 30% and the turnaround time by 20% through the use of a combination of innovative technologies.
• Increase the automation level for spare part productions by 20 % through an integrated production.
The outcome contains the development of an overall Software solution that represents the complete process of repairing parts by the use of the DMD technology and the development Mechatronic Solution (DMD Prototype) as well.

A). RepAIR Software Solution
Especially with focus on the Overall Objectives, the importance of the development of a software solution that automates the process of repairing parts by the use of the DMD technology gets obvious. Therefore, a software solution was developed by AVANTYS that includes Software modules for different purposes, as described in the following, and combines them in an Overall Software Solution.
a). Software Solution for generating a three dimensional area model
A three dimensional area model is a collection of points in 3D space which are connected to each other using the primitive geometric entities like triangles, lines or curved surfaces etc. The CAD models for the spare parts are already available. But for the damaged or the broken part of an aircraft, a 3D model needs to be generated. This process of measuring an object and generating a model from its measurements is known as “reverse engineering”. Considering the capabilities and the limitations of all the types of scanners available, the triangulation based 3D laser scanners provide the maximum and optimal utility to generate a three-dimensional area model of the damaged or broken part. The data collected by the 3D scanner is in the form of a point cloud. A single scan can usually not capture the entire object under focus (Figure 42). So, the damaged part needs to be scanned from multiple positions and that too several times. These multiple scans are then aligned together in a common coordinate reference system to generate a complete and an accurate three-dimensional area model of the damaged or broken part (Figure 31). This generated model serves as an input for the software solution to ascertain the concrete need of repair.
The proposed software solution reverse engineers the worn out part from an aircraft and generates a three-dimensional area model. The process of reverse engineering is divided into several steps which are performed by independently operating components. These components form a pipeline i. e. a chain of components arranged in such a way that output of one component is the input for another.
The different functionalities of these components involved in this process are:
1. Scanning the broken part
2. Transformation of point clouds

b). Software Solution for ascertaining the concrete need of repair
Due to the mechanical uncertainties and abrasions, the model generated from the scanned part is different from the CAD data of the original part. The main purpose of this proposed software solution is to automate the comparison of generated 3D model data against the standard CAD model. This process helps in determining the missing portions and the locations of the object which need repair. The three-dimensional area model generated after processing the point cloud obtained from the scanner and the original CAD model of the spare part are the inputs for the software component for the comparison (Figure 32). The geometric topologies of the two models are examined under predefined tolerance to find the missing or damaged portions in the model generated. The final output of this software component is a new three-dimensional area model which represents the missing portions in the worn-out part.

c). Reengineering Software Solution
This software solution is again divided into multiple components operating independently in a pipeline. The different functionalities accomplished by these components are in the following order:
• Construction of base surface for repair
• Laying the layers over the base surface
• Generic path generation for the machine
• Machine specific g-code generation

By using the results of the comparison of the models, this software module is able to create a base surface over which the missing part will be laid by the means of additive manufacturing process. The base surface is the surface common to both damaged part and the missing part of the aircraft component (Figure 33).
The generation of a base surface is a starting point for determining the different layers which will be laid over each other by the additive manufacturing machine (Figure 34). Based upon the specifications of the additive manufacturing machine, the thickness of each layer to be added is 0.6mm. During the process of repairing the parts, each successive depositing layer of the material corresponds to a specific layer among the layers which will be generated in this process. The basic concept of this process is to fill the missing portions with the layers and to make an oversized version of original CAD model. Making it over sized is important as the extra size will be removed during the post processing after additive manufacturing.
The layers generated in the form of 3D models represent a layer of material to be laid down over the damaged part by the additive manufacturing machine. The software component for this process reads the layers and generates a generic path for the nozzle movement to lay a layer over the damaged part. This path is referred as a generic path because this path is commonly followed by all machines irrespective of the set of instructions that it uses to move the nozzle. This step is important as different types of machines might use different set of instruction sets guiding the movement of nozzle.
After that another software module is responsible for converting the path generated by previous component into machine specific g-code required to guide the nozzle to lay the material layer by layer.

B). DMD Prototype
Besides the development of Software for DMD automation purposes another aim was, to develop a prototype machine for repairing spare parts using the DMD technology. Therefore, in a first step a 5-axis test rig should be developed, which is capable to use multiple of tool heads. The intention for the development of the 5-axis test rig was, to enable AVAN to develop and test the software components, which had necessarily to be developed for controlling the machining process in a 5-axis DMD machine. Although there are first 5-axis DMD machines available (e.g. DMG Mori Seiki Lasertec 65 3D) on the market, there is still a lack of software that is able to automate the build processes, not to mention repair processes by the use of these machines.
The aim of the DMD Prototype development was not to use the powder bed technology, but to use the DMD technology, which means that the powder is applied exactly at the spot where it is welded by the laser in order to achieve a better efficiency. In order to build up and repair more complex spare parts than already existing Direct Material Deposition machines, the DMD Prototype that is developed within the RepAIR project is a five axis system. On the one hand this enables the machine to build up structures on uneven surfaces, which is the main use case in repairing spare parts. This leads to the fact that the effort for pre-processing of the broken spare part can be significantly reduced. Another advantage of the 5 axis machine is that support structures become unnecessary which leads to a reduction of build material and process time. The Base machine provides the complete repairing process on a bigger scale inside one platform. With its characteristics of handling bigger parts and uninterrupted cycle from scanning, pre-processing, repairing and post-processing, makes it an optimal platform for the desired application. Here Figure 35 shows the complete production cycle. The actual need of having all processes inside one closed chamber is because on industrial level, human involvement is quite undesirable to move parts between machines and compromise on performance and time of the entire process.
The Base machine consists of several electromechanical and software components, which are responsible for the controlled repairing process. The whole Base machine consist of three major parts, which can classified as an individual system
• Mechanical System
• Electronic System
• Control Software System

i) Mechanical System
The DMD Prototype is designed with the application oriented optimal dimensions, such that it can repair bigger spare parts from aircraft industry. The machine foot size of 1700mmx920mmx1800mm is enclosed by the cubical housing with the dimension of 2500 mm x 2500 mm x 2500 mm. The dimension of the machine enables to repair large parts of dimension up to 1000mmx250mmx250mm. Furthermore the DMD Prototype has been designed in a way, that it is scalable to even bigger dimensions. Handling parts of such big scale, will cause vibrations in structure, which can be harmful during the repair process. To address this issue, the weight of the DMD Prototype is kept almost 500 kg, such that it can absorb any possible vibrations from the structure. It is expected, that the precision of extruder based additive manufacturing systems is not like the precision of powder bed machines. To address this issue the DMD Prototype is designed in a way, so that it is able to use multiple tool heads. Therefore, it is equipped with a semi-automated tool changer and besides the extruder heads (laser head, plastics extruder) with a milling head. That enables to post process the generated structures, so that they match the industrial needs in terms of precise dimensions. It is possible to mill the generated structures already during the repair process, between the build steps. So it is possible to avoid collisions and also enables to process spots of the spare parts that are no longer reachable by a machine at the end of the repair process.
The Base machine is equipped with 5 axes, with 3 linear axes named as X,Y and Z and two rotational axes A and B, which can be seen in Figure. Every axis has its precision position feedback system, safety switches and brakes where it is necessary (Figure 36).
The linear X-axis attached with rotational B-axis which carries the tool is empowered with capability of a tool changing from the tool holder rack at the back side of the machine. As already described, the DMD technology is not able to achieve the precision, for example the powder bed technology based machines are able to achieve. This leads to a need for post processing, even in between the build steps. Concerning the overall objective of increasing the automation level for spare part production by 20 % through an integrated production, it would not be suitable to have different machines for building and pre/post processing. Therefore, the DMD Prototype is designed for being able to use multiple tool heads (Figure 37).
ii) Electronic System
The electronic system is the connective link between the mechanical system including all sensors and actors and the software system controlling machine movements and managing the overall production process (Figure 38). In a similar way the mechanical systems provides a generic interface to multiple tool heads, the electronic system provides generic electrical interfaces to adapt to additional electronic systems per tool head.
iii) Control Software Solution
The software system of the base machine takes the G-Code created by the path generator and executes it to repair a spare part. As some of the tool heads require a deep and complex integration into the controlling system (e.g. integrating Laser-Temperature-Control as a sixth virtual axis) an open-source machine controlling software was chosen to start with. This makes sure that there is an open API available to extend the controlling system with new modules or to change existing ones.
As mentioned above the DMD Prototype is designed for integrating multiple tool heads to meet the requirements that derive from the overall objectives of the RepAIR project. Apart from the fundamental need for pre- and post-processing of the spare parts to be suitable for the aircraft industry, there is supplementary need for post processing, which results from the lack of precision using the DMD technology for repairing parts. Considering these additional treatments have to be done in separate machines, the solutions would not only contradict the overall objectives of the RepAIR project but also not meet the industries requirements for such a system. Therefore a number of tool heads had to be integrated into the control Software of the DMD Prototype, as you can see in Figure 39.
For implementing and testing the basic functionalities of the Base machine and most importantly of the control software a synthetic material deposition device or plastics extruder was designed and engineered during the project and integrated into the DMD Prototype. This plastics extruder is able to mix all features that are required in DMD (Figure 40).
Besides the tool heads that are needed for the build and repair process, also any other necessary tool heads were integrated into the DMD Prototype. For process control purposes a pyrometer is used to control the temperature of the melt pool and adjust laser power according to the sensor output.
For Health and safety purposes the complete DMD Prototype is enclosed by a housing (Figure 41) with the dimensions 2500 x 2500 x 2500 mm, which is equipped with the necessary safety switches and a tower light indicator. To exhaust the weld fume that emerges during the process of welding metallic materials, a suction system is integrated into the DMD Prototype.

##1.2.5 Process and supply chain for repair and maintenance in AAT
Besides the technology development itself also the process chain and processing parameters have to be examined. Post-processing procedures for repair and production of aerospace components have to be analyzed. The foundation for the qualification is laid as test specimen are analyzed in order to assess the feasibility of AM.
For the comparison and optimization of Additive Manufacturing technologies for MRO an aerospace bracket has been selected to be the sample part for the comparison of SLM and EBM technology. Much work was put into designing a production platform so that a satisfactory qualification of the brackets could be made. In collaboration with WP7 the design of the platform was decided as shown in the Figure 42.
Three times this platform has been produced separated in time to test the reproducibility of the AM process.
The first Aerospace Bracket platform was produced with both EBM (@AIMME) and SLM (@DTI) technology.
Figure 43 shows the first SLM produced Aerospace Bracket platform when taken out of the machine. As can be seen on the picture there is a defective layer leading to a weak point in the part and it is therefore currently unsure if the parts can be used.
Figure 44 shows a page from the CMM report. After AM production parts were HIP’ed at BodyCote. See data from BodyCote below. BP2 produced at DTI with SLM technology. In the chemical analysis it was observed that there was too much iron (>0,3%) (see Figure 44).
The part will therefore not comply with the standard “ASTM F2924”.
Figure 45 shows a bracket being post processed.
Qualification parts and powder samples were sent to AIMME for analysis.
Aerospace Bracket BP2 and BP3 produced with EBM technology at AIMME. Results from the chemical analysis were OK.
The Aerospace Bracket has been optimized as shown Figure 46. This design has been printed in 316L at UPB to be used for dissemination purposes. This is however not based on topology optimization and can only be used as a demonstrator case. Topology optimization of the bracket has also been performed at UPB.
An example of results (Figure 48 and Figure 49) from the tensile test (Figure 47) (yield strength and tensile strength)
Results show that some parts are not within the limits specified in “ASTM F2924” – Microstructure analysis performed at AIMME and DTI according to the document “Ti6Al4V MICROSTRUCTURAL ANALYSIS PROCEDURE” made by AIMME. An example of results shown Figure 50.
Due to great variation in the thickness of the part CT scan (Figure 51) it is impossible to find suitable scanning parameters that will allow penetration of the thick parts while not burning through the thin parts. CT scan is thus not a good option for qualification of the Aerospace Bracket.
Chemical analysis performed on powder samples and support. (Figure 52, Figure 53, Figure 56, Figure 57, Figure 58)
Fatigue specimen produced with EBM and SLM technology
• Batch 1
o 40x”as build” with SLM
o 40x”as build” with EBM
o 40x”machined” with SLM
o 40x”machined” with EBM

• Batch 2 (bad results from batch1 “machined”
o 40x”machined” with SLM
o 40x”machined” with EBM

• SLM Fatigue specimen stress relieved
• 6x40 fatigue parts + 4x10 tensile specimen + SLM Aerospace Bracket BP3 HIP’ed at BodyCote
• 4x40”machined” sent to APR for post processing
• All fatigue specimen tested at UPB

Aerospace Bracket optimization: Figure 54
Interactive webpage - – D6.3
The webpage was created in order to give interested people an understanding of what was created and investigated in WP6. (Figure 55)

##1.2.6 Certification strategies / libraries / material tests
One of the major challenges for an AM application in aerospace is a qualification and certification concept. It takes the technology development and the process parameter investigation as a basis and defines the procedures that have to be undertaken to determine the feasibility of AM technology. Elements to ensure a verified and repeatable value stream for aircraft component therefore need to be identified (see Figure 59). Knowing these elements, all steps to be followed to consider an AM technology in the aircraft market could be drafted (see Figure 60).
D7.1 deals with the conceptual design of the new certification processes for AM implementation into the manufacturing and repairing of an aircraft component.
Concepts and workflows for complete parts and repaired parts are defined; and new certification frameworks and specific procedures for the different operations/strategies in the RepAIR process - based on direct manufacturing of identified geometries - are developed and described among the document.
It is included also the definition of the structure for a library of spare parts and build conditions compliant with the certification requirements. All concepts developed have been applied to two specific demonstrators defined by end users.
The document D7.2 deals with the definition of procedures and registers of the new certification processes for AM implementation into manufacturing and repairing of an aircraft component. In order to establish the basis of a Quality Management System (QMS) for a company which uses in its supply chain AM, all the relevant standard have been analysed. In particular, ISO 9000 EN 9100 Rev C, EN 9110 and EN 9120.
Nowadays, any aerospace company which provides services or products following the principles and requirements of those standards can be audited, and then certified by an authorized company. Due to the nature of the project, all the differences between EN 9100 Rev C and EN 9110 have been analysed in order to identify all clauses that can affect the certification of the QMS.
Effective implementation of EN 9110 in case of an MRO company or EN 9100 otherwise, will provide an organization with a good system to ensure safety, reliability and airworthiness.
Based on ISO 9001:2000, it contains nearly 100 additional requirements specific requirements to the aerospace industry such as:
Addresses civil aviation authorities and where in the standard that those requirements apply.
▪ Addresses definitions unique to the MRO industry such as, Maintenance, Technical Data, Human Factors & Release Certificates.
▪ Includes expanded requirements for personnel conducting MRO task.
▪ Addresses the qualification of new maintenance processes.

Also a Quality Manual Template which has been linked to the developed procedures has been created. This will facilitate the implementation or modification of a Quality Manual for a company which decides to implement AM in its supply chain.
New AM features are integrated in the current quality management systems. New procedures and documentation are defined for design processes, manufacturing and initial testing of build conditions.
Process qualification procedures and registers are defined and a manual is implemented that specifies a method by which the components processed as it has been specified are examined to ascertain if they meet the required specifications (qualifying criteria) in a repeatedly manner to be identified as qualified. An extensive set of data structured in registers for quality management systems and for process qualification.

D7.3 contains the specifications and electronic support to assure the quality process through the IT System. It specify the principals quality criteria, procedures, kinds of registers and how these elements will be managed and stored by the IT Platform across the Quality module.
The deliverable D7.4 deals with a pilot qualification of one process/material/application for a MRO business. In particular, the case study considered in this research is one aircraft component produced from scratch as spare part. This component was selected based on a bottom-up approach, therefore with a well-known geometry, high-margin of safety and non-safety-of-flight critical part.
The study was carried out based on the qualification method (QP) fully detailed in D7.2 and the test results gathered in D6.4. The qualification method has been developed within RepAIR project. The qualification method developed has been assessed by relevant entities responsible to safeguard air transport safety and airworthiness, such as EASA and MASAAG. Their feedback has been considered, not only for improving the qualification method but also for performing different statistical analysis from the test results in order to insure that the manufacturing/repairing process is reproducible. A very critical issue throughout a Quality Management System (QMS) would be the traceability. Traceability issues related the MRO sequences and its implementation through the RepAIR tool developed in WP8. Once the process is specified and some specimens are produced as it is specified, the corresponding results would permit to predict the mechanical behavior in the design stage, by implementing this data into the material database of the CAE tools. In addition, it has been developed QA templates in order to check the quality level in every stage of the process and finally to be implemented in the RepAIR tool.
All the requirements and results from the triplet Ti6Al4V/EBM/Bracket are developed and included in the central node as an example of qualified process.
A roadmap for AM QP development has been described based on the knowledge of the variables which rule the process, not only the AM itself but also its relationship with after melting processes such as surface and heat treatment; on the process specification; and on the data generated according to the process specified.
A guide for AM QP of Ti6Al4V using full-melt powder bed fusion has been specified, including procedures for the assessment of the variables among the manufacturing or repairing process and the corresponding results registered for taking decisions. This guide is based on new AM standards such as ASTM F2924-14.
This guide has been applied to a case study provided by an OEM as demo part. Component requirements and manufacturing plan for qualification have been specified. Assessment of the feedstock, bulk material and component properties are conducted along three build cycles. Finally, the results of the tests have been introduced. This guide could be considered as a reference for other metal alloys using full melt powder bed fusion, such as electron beam melting and laser melting. A QMS based on the results of the QP must ensure the process specification established along the time. QMS includes all the testing and qualifying criterion necessary to implement AM in the field, as well as to maintain their capability throughout their life cycle, specific procedures to manufacture or repair parts, work-flows and records amongst others. A novel AM QP is proposed and presented as a first step for including these technologies in this regulated market.
In D7.5 a description of the part library management is given. The part library can be considered as a component that feeds the different systems with the information to demonstrate the possibilities of the RepAIR project has as a whole. The part library is included in the Central Node, developed in WP8, and the proposed part data structure developed, representing typical aircraft parts, can be uploaded to the Central Node. All data are categorized in order to provide the option to filter according to certain criteria and relate them to the decision component developed in WP3. The structure of the library is explained, describing the technical, the manufacturing and the assessment parameters based on the shown structure in Figure 61.
An airplane is usually divided in structures: fuselage, wing, power plant, empennage and landing gear. Moreover, although the avionics and the electrical and hydraulic systems are not considered as structural parts, they are considered as a major group at the same level as the principal structures. By doing this, a fast classification of the parts of an airplane is allowed and not only the location can be figured out, but also the dimensions and the structural importance, which directly are described in the technical parameters.
Concerning the manufacturing parameters, the following three manufacturing methods are distinguished:
• Subtractive technologies
• Forming or shaping technologies
• Additive technologies
Subtractive technologies achieve the desired geometry by removing defined areas of a part’s material. Shaping technology models a given volume to the desired geometry by retaining the volume constancy. Additive Layer Manufacturing is characterized by a layer-wise production on the basis of 3D-CAD data without the need for shaping tools. There is a huge diversity of different technologies but the project RepAIR focuses on the SLM and EBM as well as on a specific Laser Cladding process.
The manufacturing criteria which are directly related to the parts, such as the original part price and the delivery time are described. Furthermore, some other criteria, not directly part related, are mentioned and explained.
The assessment parameters are related to both part and material qualification procedures and standards, as well as the part quality assurance procedure and standards have been taken into account.
Finally, the use of the part library during all RepAIR processes is described.
In WP7 it furthermore is described the entire cycle of 10 parts chosen to test the RepAIR concept. The entire cycle has been analyzed for each selected part and a detailed description is included in the document D7.6.
The part’s related documents are stored in the IT platform. It has been used to simulate the production of the parts. Due to the fact that the parts are not currently in production, there are several missing characteristics.

##1.2.7 RepAIR IT Management Platform
In order to integrate all single RepAIR approaches and to fulfill the objective of a high automation level, the various RepAIR components are integrated in one huge IT system. The main core of this system has been developed to be integrate with different systems such as MRO or CAMO. The modelling of the architecture of the platform has been developed to comply with the possible use cases included in the project. At the same time the platform architecture is designed to support a distributed and collaborative work environment among the partners, thus deal with the efficient management of information and maintain a repository of critical data. This allows studying possible improvements of the process and having a source of reliable and accessible data in case of temporary disablement of the system of one of the partners.
The design of subsystems of the IT Management Platform was documented in deliverable D8.2. The deliverable describes the components missions and how each of them helps to maintain an updated supply chain and avoid procurement problems on real time.
The most significant results due to the application development are related to the constant changes on data structure. Progress in the development of different work packages requires a constant readjustment of the communication needs of the different project partners. This adjustment causes small changes in the internal structure of ITPlatform development, requiring constant adjustment of its characteristics. This effect is significant in the sense that it brings the ITPlatform closer, step by step, to a more accurate and the needs of the project partners fulfilling implementation.
Coordination between all the actors involved in MRO (Maintenance, repair and operations) process through the platform. Thus mean a reduction of time in the fabrication/repairs of parts of an aircraft. Therefore, the control of the MRO Production process in “real time” is necessary and data security with failsafe mechanisms and data integrity had to be ensured. This includes also the user authentication and user profiles to determine system privileges and info access only for registered and rights owner user. Thus, it is possible of defining different access rights for each person/role. For those the Central Node provides production data to all partners to conduct their activities. The Knowledge DB and Part Library contains all information needed for RepAIR processes as described above. During the production processes the Platform allows the quality control over the processes: A process has been developed to decrease certification effort for additive manufactured AAT spare parts. The system informs about the next step and the control points to be validated. It makes sure that all steps in the repair process are signed and all information in the IT system (historical and logs information) is stored. The interfaces to do so are for all users easy-understandable and user-friendly. Additionally, the RepAIR IT-System leaves an open channel of communication via XML files which allows appropriate interchangeability of information with others such as external components MRO and CAMO. The complete system is built in a way that allows the IT Management Platform scalability for system expansion in case of new customers and more aircrafts.
Some pictures of the main screen of IT Platform are shown below.
Also some pictures of the Bridge component main screen. (Figure 62, Figure 63, Figure 64, Figure 65)

##1.3 Evaluation and Validation of project results
WP 9 dealt with the evaluation and validation of the project. Consequently, KPIs were established for the management platform and its subsystems. An initial evaluation of those KPIs has been conducted and afterwards they were reviewed and an updated strategy for the second evaluation has been set up. They were supported by field trials and the assessment of achievements based on requirements of WP2.
A preliminary evaluation of requirements for the overall Management Platform, including the subsystems is described in D9.2. A strategy was outlined for the review of the different WP approaches in order to improve efficiency of evaluation tasks. The field trials were then successfully executed. The Management Platform and communication with its subsystems has been successfully validated and described in D9.3. Finally, lessons learnt, final TRL assessment and a roadmap to TRL 7-8 in 2020 has been outlined.

##2 Exploitable results
As a result, the following list of exploitable results were identified:
The “Final Exploitation Strategy” is part of Work Package 10 “Dissemination and Exploitation”. As the name suggest the main purpose is to define the Final Exploitation Strategy for the RepAIR project results. The implementation of these methodologies is based in a full collaborative work among the Consortium members, which have helped to produce a complete model for the produced result.
In a first phase, the methodology of analysing assets uses information gathered through a series of questionnaires distributed to the RepAIR members of the project in order to identify the project results, start their description and classification. Using the information gathered, we can define the integrated RepAIR solution and its business model is constructed from Business Model Canvas. Previously, we used the SWOT analysis to examine the potential for a new business of integrated RepAIR solution. Also, in the correspondent deliverable, we determined the assets that are likely to be exploited. Finally with a quantitative analysis, we can evaluate the information received to help decide which are the exploitable results with greater possibility of commercialization.
With the methodology followed, we have obtained the assets that have the greatest potential for marketing and towards which shall focus the exploitation strategy once the project finished. These are:
• Validation and qualification procedures;
• Technologies for repairing
o High batch repair system based on SLM Machine;
o Multi-purpose 5 axis DMD system.
In Table 3, the main information of the validation and qualification procedures summarized in connection with the exploitation strategy:
Table 4 shows the main information of the Technologies for repairing (High batch repair system based on SLM Machine and Multi-purpose 5 axis DMD system summarized in connection with the exploitation strategy:

Potential Impact:
The main objective of RepAIR is to shift the “make” or “buy” decision towards the “make” decision by cost reduction in the remake and rework of spare parts and therefore improve cost efficiency for maintenance repair in aeronautics and air transport. This is done by establishing an enhanced MRO production process using the AM technology. This technology will foster cost efficiency, greening and safety related aspects and bring them to a new level in 2020 (compare Figure 66).
The expected impacts of the carried out project will be explained in the three categories cost efficiency, greening and safety. This is done in the two temporal dimensions directly after the project and in 2020. The dissemination and exploitation activities will be discussed below.
Cost efficiency
Having fully researched the new production process and integrated it in the whole MRO process, a high potential impact on the MRO service for all kinds of aircraft can be expected. At first, the costs for the process will be reduced through conserved material resources and the high level of automation. With this, European technology leading MRO service providers will be being both cost attractive while simultaneously mastering technology to repair complex parts. In the constantly growing market for MRO services, they will grab market shares (expected growth of 50% to 65 billion US$ in 2020 ) despite an intensified competition in a globalized MRO market. In the high wage economies in Europe jobs will be preserved and generated. MRO service providers, which do not apply the developed enhanced process, will disappear from the market.
A further impact in raising the cost efficiency will have the elimination of underutilization of spare parts. With more than 15000 commercial and transport planes being on duty and an estimated 5% extension of lifetime of wearing parts, a significant number of C- and D- checks will be shortened. This will be achieved as well through the increased usage of single piece assemblies, reducing assembly time and certification costs. This will reduce the overall maintenance costs and turnaround time of airplanes. The total material costs for the repair of complex parts will be dramatically reduced as less material may be needed (compare Figure 67) and as a very efficient buy to fly ratio can be achieved.
Simultaneously to the extension of lifecycle of parts, fewer of them will be needed. Resources will be entirely exploited und not wasted. Less scrap will be produced and less chemicals needed for the production processes. The possibility of a significant weight reduction of airplanes and a more functional design will lead to lighter and more efficient airplanes on the long run. Redesigns of sample aerospace parts have shown a weight reduction potential of up to 70 % of the original part weight . If the weight of an aircraft can reduced by 1 kg a year this saves $3000 in fuel annually . One can easily imagine what that means for the global greening and the cost efficiency of airplanes. In addition the fuel consumption of delivering spare parts through sophisticated supply chain systems will be reduced as the part can be manufactured at the gate.
The integrated vehicle health management approach of usage based part lifetime prognostics will be capable of increasing part lifetime (Figure 68). Especially in combination with the geometrical freedom the AM processes allows for the design parts. Additionally the high precision repair capabilities, even of high complex parts with undercuts increases the value of used parts. In combination with sensor monitoring the flights safety and the life of airplanes can be enhanced. The better knowledge about usage-based prognostics will help for the certification of parts as well.

In total the project results will lead to fulfill the following objectives by 2020:
1. Reduce repair and overhaul costs of complex spare parts by 30% and the turnaround time by 20% through the use of a combination of innovative technologies:
Implement a production and supply chain, which is mainly based on the workshop. This leads to a reduction of process and logistic steps. Furthermore, the use of innovative technologies and the integration of the certification processes reduce repair time. Investigation of the usage potential of different Additive Manufacturing technologies for certain clustered groups of parts.
2. Increase the automation level for spare parts production processes by 20% through an integrated production and supply chain:
Development of a self-organizing MRO process and information flow within streamlined technology chain. This starts with a component for decision support for cost efficient repair strategies leading to a more precise make-or-buy decision. Is a make decision taken, a central IT-System manages the fabrication process and following workflows. Spare parts specific production time and parameters will be supplied for on time assembly or delivery.
The RepAIR IT-System will take the three objectives costs, assembly or delivery time to the end-user, and repair strategies into account. Individual priorities for customer and MRO service provider in each specific constellation will be considered.
3. Reduce scrap and toxic chemicals in the repair process by 80% and part weight by min 20% by the use of a new production technology:
The integration of new production processes in MRO will allow major improvements in the buy to fly ratios of materials. Case studies of the RepAIR project on the optimisation of current parts will show a minimum weight reduction potential of 20% and therefore contribute to the reduction of aircrafts fuel consumption only by using differently produced spare parts. The airlines will automatically benefit without additional costs and will thus intensify their relation to the higher quality MRO service providers.
4. Increase the technology readiness level (TRL) of innovative repair processes for ATT to level 4 focusing on the AM technology:
Determine the technology readiness level (TRL) for AM in repair and overhaul in AAT and continuously improve it until the achievement of TRL on level 4. Therefore, a new AM machine will be developed for this specific field of application with special consideration of the certification processes in AAT. Processing speed of today’s AM machines will be increased by a factor of 2, aiming at a high batch repair process. Furthermore, the use of AM technology for repair will be introduced.
5. Develop processes to decrease certification effort for additive manufactured AAT spare parts in terms of cost and time based on an integrated quality control and process data monitoring:
Optimisation of the certification process for repaired or redesigned- / replaced parts for AAT based on integrated Quality Control and process data monitoring. By directly gathering information and material parameters out of the participating appliances and the whole production process, data for the extensive documentation are automatically available. They will be used to reduce documentation duty efforts and hence help to reduce cost and time of certification by 20%. To show the potential of the technology two function important parts will be certified during project runtime.
6. Reduction of inspection time by 30% by integrating continuous health management and usage based prognostics:
Increase of lifetime of parts with respect to safety of aircrafts. Eliminating of unscheduled maintenance and reduction of inspection time based on a smart on-condition maintenance system using integrated health monitoring and usage based prognostics.
7. Strengthen the business model of European MRO service provider in the world by integrating a complete production and supply chain for complex spare parts:
Several case studies to show capabilities for later products in exploitation and for the dissemination of AM in AAT will be elaborated. This will help to underline the technological leadership and put them forward for new technologies. In addition, it helps to reach a broad group of professionals on fairs and conferences. Furthermore, the project results will be validated on these case studies. Successful case studies will help to overcome on technological burden of the AM processes by spreading the knowledge about the possibilities of this technology for AAT in MRO processes.

Dissemination Activities
Dissemination and exploitation of the project results are important targets of the RepAIR consortium for ensuring the scientific progress beyond the state-of-the art in the course of the project and for a sustained economic yield after finishing the project. The whole consortium is fully engaged in creating public awareness, scientific interest and a new market. The project itself identified the following target groups:

• Science: Universities and other research institutes in the addressed or associated fields of re-search, Standardization bodies.
• Industry: Potential customers for commercial exploitation or partners for future developments.
• End-users: Emergency services (police, law enforcement agencies, fire and rescue services, medical services, e.g.)
• Public: Civil society, associations, ordinary citizen
• Education: Students attending lectures and workshops in the universities
• Government: European and national/federal legislative and executive authorities

Furthermore an advisory board with key technology stakeholder from academia and industry has been set up in order to advise with regards to project outcomes. They cover specific topics of the project – from enhanced transport capabilities as an overall objective to specific objectives like Supply Chain Management and Additive Manufacturing processes. Different workshops took place in ordered to disseminate the project results in the appropriate communities.

The following section will describe some of the key activities of the repair project.
First Repair Workshop:
Two major public workshops were scheduled within the lifetime of the project RepAIR in order to achieve wide impact on the target groups. The first took place at the Euromold, world fair for Moldmaking and Tooling, Desing and Application Development ( It was pondered as the best forum to organize the first of these workshops in terms of scope, audience and visibility opportunities. The first RepAIR workshop was organised in the format of an open forum as part of a series of workshops on ‘Additive Fertigung und Werkzeugbau” (English: ‘Additive Manufacturing and Tooling’). It was held on November 28th, 2014 in Frankfurt am Main, Germany. (Figure 69)
All parts of the projects were demonstrated along a ‘story’ – a kind of scenario which integrates all relevant scientific and technological topics. The envisaged software solution was used to visualise the storyline:
• “The RepAIR approach”: Rainer Koch (University of Paderborn, C.I.K./DMRC) presented an overview of the project and its current state.
• “Future use of Additive Manufacturing in aircraft MRO”: Gereon Deppe (University of Paderborn, C.I.K./DMRC) provided an insight into scenario based research on future applications of AM in aircraft MRO, possible business cases and applicable business models.
• “Software as an enabler for integration”: Ingrid Sánchez-Diezma Guijarro (O’Gayar Co.) introduced a draft dashboard user interface of the integrated RepAIR software solution based on Ogayar’s software for MRO services.
• “Condition monitoring and part lifetime prediction”: Adrian Cubillo (Cranfield University, IVHM Centre) emphasized the importance of integrated vehicle health management for an holistic approach to improve MRO processes.
• “Make or buy? Economics based decision support”: Gereon Deppe replaced Christian Lindemann (University of Paderborn, C.I.K./DMRC). He elaborated on costing aspects and derived knowledge to help decision making processes.
• “Integrated RepAIR technology for complex individual parts”: Alfred Schapansky (AVANTYS engineering) visualised the concept for a 5-axis Direct Metal Deposition machine to analyse defects, derive manufacturing data and actually repair the defect parts.
• “High batch RepAIR using Selective Laser Melting”: Toni Adam Krol replaced Dieter Schwarze (both SLM Solutions). SLMG presented a demonstrator for high-batch repair. The clamping device as an enabling part for this process was shown in a video presentation and at the SLMG booth.
• “AM: Key Enabling Technology as part of the supply chain”: Jeppe Skinnerup Byskov (Danish Technological Institute/DTI) reported about the project’s
• approach to design the future supply chain and work with actual parts in several research activities.
• “The final milestone: Certification”: Luis Portolés Griñán (AIMME) presented a key to utilise the AM potential – certification needs and constraints which were transferred into a concept and an overall quality management system.
• Throughout the whole workshop, moderated by Jens Pottebaum (University of Paderborn, C.I.K./DMRC) and organised by Eric Klemp (University of Paderborn, DMRC), the audience interacted with the presenters and other RepAIR partners like The Boeing Company, ATOS, APR and Danish Aerotech A/S.
The AB members contributed actively to the workshop in terms of questions and remarks after all presentations. After the workshop was closed, the consortium and the AB met for a closed session in order to discuss the current state of the project and the impressions that the AB members collected throughout the workshop. In this session, the consortium received very positive feedback but also valuable feedback regarding applications for airlines, key AM topics like materials research as well as partially weak integration of all aspects presented throughout the workshop.

Second Repair Workshop:
The 2nd RepAIR workshop was organised at University of Paderborn for several reasons. Firstly, the workshop was conducted the day before the opening of “Inside 3D Printing” congress, a well-respected AM conference in Germany and Europe. This enabled the attendants and presenters of RepAIR workshop to easily combine the attendance to the workshop and to the congress, which took place in Düsseldorf, only 2 hours by car or train from Paderborn. Secondly, the organisation of the workshop in University of Paderborn, gave the opportunity to visit the facilities of the DMRC and present production and testing facilities used during the project, including SLM high batch repair device developed. Besides, due to the closeness of AVANTYS Engineering headquarters, also a visit was organised to present developments of DMD prototype.
The second workshop was promoted over many different channels in order to achieve a wide participation of important stakeholders from the target groups. (Figure 70)
• Project Officer (PO)
• Members of RepAIR Advisory Board (AB)
• Faculty of mechanical engineering at Paderborn University
• Other project consortia, e. g. “Ersatzteil 3D”
• Relevant contacts and business partners provided by the members of RepAIR consortium
During the workshop, the participants were highly involved in all workshop sessions and contributed by asking questions and discussions. The different presentations during workshop followed a storyline conducted through a dashboard, a web page that showed, at each moment, the information on the speakers, the aim of the speech and the relationship with the complete RepAIR project scenario. It was useful to introduce and link each topic in a structured way. The Presentations can be seen in Figure 71.
During the workshop a tool for on-line questionnaires named “PINGO” was used to receive some feedback from the audience after every presentation. It is an open source tool that enables to ask questions to a numerous audience and to instantly receive responses/feedback. Find some examples in the following section.
Do you think that the RepAIR project can increase the competitiveness of Europe regarding MRO activities in Aeronautics?
In your opinion, to which industry the RepAIR concept could be transferred (total or partially) other than the aeronautic industry?
Would you be interested to know more details of RepAIR project results?
Do you think that the RepAIR project can increase the competitiveness of Europe regarding Additive Manufacturing technologies?

The 2nd RepAIR workshop offered a great opportunity for dissemination and presented a complete vision of the project objectives and the work accomplished during the time it has been running.
Many of the attendees showed their interest for this project, asked for further information and some were more than interested in an extended demonstration of the project results. Most of the attendees stated that the workshop had met their expectations: 80% much or very much.
From the analysis of the answers obtained in the questionnaires, the following statements can be obtained:
• The majority of attendees think that the RepAIR results/technologies that have higher potential for exploitation are those related to the Additive Manufacturing Technologies, Only 12% of attendees believe that full integration could be an exploitable result.
• The results of RepAIR could be transferred to others industries as railway, maritime and oil & gas
• The RepAIR project can increase the competitiveness of Europe regarding both MRO activities in Aeronautics and Additive Manufacturing technologies.
The majority of attendants think that their industry could benefit from 5-axis Additive Manufacturing approach developed in RepAIR. Also, they think project decision component.

The RepAIR Exploitation Plan uses several methodologies to identify the integrated RepAIR solution, the assets of the project, the potential market and the ways to reach the market. To make such analysis and identification the following methods were used: SWOT Analysis, Business Model Canvas Methodology and Quantitative Analysis.
The implementation of these methodologies was based in a full collaborative work among the Consortium members, which have helped to produce a complete model for the produced result.
In a first phase, the methodology of analysis of assets uses information gathered through a series of questionnaires administered to members of the project in order to identify the project results, start the description and classification. The following questionnaires have been used:
• Innovation Radar Questionnaire
The template was completed by each developer partner and collects information on their developed assets.
• Interview for key partners
The template was completed by the partners participating in the project and collects theirs opinions on the results that they consider more important with a view to the exploitation of the project.
• Diverse questionnaires were sent to a specialized audience before the end of the project, in order to get an idea of the generated interest in RepAIR (see D9.4 and D10.5).
In a second step, the exploitation team proceeded to interpret the information gathered. This step allowed to determine the assets that are likely to be exploited. In this phase a SWOT Analysis and Business Model Canvas have been used.
A SWOT analysis is a framework that can help to examine the potential of a new business or product. It is a simple tool that allows to understand the internal and external factors affecting a particular business or product. The SWOT analysis is an excellent tool for organizing information, presenting solutions, identifying roadblocks and emphasizing opportunities. Performing a SWOT analysis improves business strategies and decision-making. A SWOT analysis helps to build on strengths (S); minimize weakness (W); seize opportunities (O); counteract threats (T). Strengths, weaknesses, opportunities and threats are studied separately on individual blocks.
The deliverable D10.3 included a SWOT analysis for the integrated solution of RepAIR and in this deliverable a SWOT analysis is included for each of the assets considered.
The Business Model Canvas methodology is a methodology that covers a wide range of things that must be considered whenever a technology and its channel of exploitation have to be defined. This methodology comprises nine “building blocks” that help the exploitation team define the infrastructure management and its capability (blocks of Key partners, Activities and Resources), the definition of the service/product (the Value Proposition), the customer (Customer Segments block) and the interface thought it (blocks of Customer Relationships and Channels). Finally, it also provides a starting point of the financial aspects (Cost Structure and Revenue Streams blocks).
According to the study in D9.4 [ 3 ], the technology readiness level (TRL) of the assets are in a stage of pre-production. For this reason it has been decided not to include the information on the financial aspects within the Business Model Canvas of the assets identified.
Finally, the third step is a Quantitative Analysis that evaluates the information received to help decide which are the exploitable with greater possibility of commercialization.
The Quantitative Analysis is a methodology developed by Atos Research and Innovation (ARI) the R&D hub for emerging technologies and a key reference for the whole Atos group. This methodology allows the establishment of equivalent measures in order to facilitate comparison and detection of risks at the level of exploitable result and has been used successfully in several projects such as Mobiguide or Khresmoi . The full results can be found in the WP10 deliverables.

List of Websites:
Project Website:
Contact Person:
Prof. Dr.-Ing. Rainer Koch
Telephone: (+49) 5251 60-2258
Dr.-Ing Jens Pottebaum
Telephone: (+49) 5251 60-2234