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Multilaser Additive Layer Manufacturing of Tiles

Final Report Summary - MALT (Multilaser Additive Layer Manufacturing of Tiles)

Executive Summary:
Laser Additive Layer Manufacturing of heat shield tiles in various nickel super-alloys has been demonstrated at TRL4. Considerable investment has been made in developing materials data for the processes of record employed on the current generation of equipment, however this equipment is for general purpose prototyping and is not capable of high volume, low cost production of flight parts.

The objective of the MALT project was to develop a high volume, low cost Additive Manufacturing production equipment with a scalable concept that would be suitable for manufacturing flight approved components. The aim was to use the processes and materials validation data from the current generation of machines and increase productivity through the use of multiple lasers to address a larger build envelope. This concept could be used for to manufacture larger batches of small components or to allow large single components to be produced with an overlap of the scanner fields.

A prototype machine was developed, utilising four overlapping laser scan fields to address a build area of 400mm x 400mm. The machine was evaluated in a simulated production mode over a nine month period. Data was collected on geometrical accuracy and materials properties throughout the period. Reliability and maintainability metrics were also tracked throughout, as was the consumption and cost of all raw materials and consumables.

The MALT project has successfully demonstrated the concept for a high productivity, scalable machine, but further work is required to develop the machine concept to provide a reliable and robust machine for production environments.

Project Context and Objectives:
Laser Additive Layer Manufacturing of tiles in various nickel superalloys has been demonstrated at TRL4. Considerable investment has been made in developing materials data for the processes of record employed on the current generation of equipment, however this equipment is for general purpose prototyping and is not capable of high volume, low cost production of flight parts.

The objective of this project is to develop a second generation machine suitable for low cost manufacture while maintaining process equivalence to the current processes of record. This will be achieved by the use of multiple lasers to address a larger build envelope and will otherwise be in line with the capability requirements stated in the topic call.

The Participants will first agree the requirements for the machine with the Topic Manager. From this a functional specification will be developed, embodying the essential design concepts to be realised. A test rig will be constructed and operated in order to explore methods for controlling the overlap areas between laser fields. An alpha system will be designed, constructed and tested in accordance with the functional specification and incorporating the learning from the test rig. A subsequent prototype machine, being a development of the alpha machine, will be designed built & tested prior to installation in a representative production environment. Validation testing will be performed on this machine in order to establish (1) metallurgical equivalence to the current processes of record, (2) accuracy, in particular in overlap regions, (3) system reliability and (4) cost of ownership metrics.

Project Results:
Materials Solutions Limited (MSL), with input from the Topic Manager, developed a Requirements Document (RD) for the machine to be developed. This document is in the form of a procurement specification which outlines the performance requirements for the machine in terms of build envelope, dimensional accuracy, materials properties, reliability & maintainability and cost of ownership. It also specifies functional requirements in terms of both hardware and software features required for aerospace manufacture.

Based on the RD, EOS developed a Functional Specification, which maps the requirements into a form used within the EOS design process. EOS also developed an FMEA for each of the new sub systems which need to be developed within the project.

Also based on the RD, MSL developed a Validation Testing Requirements document which describes the validation testing which will be performed on the machine by MS later in the project.

EOS designed a new process chamber incorporating four lasers and scanning systems. Detailed CFD modelling of the gas flow within the chamber was performed. The chamber was constructed and incorporated within a test rig. Software was developed to control the four lasers simultaneously and various aspects of the system function were tested. Simple test parts were manufactured and some preliminary materials data obtained.

An Alpha Machine was designed and constructed by EOS, incorporating the learning from the test rig (above), based upon their existing M400 platform. This Alpha Machine was used to further optimise the design of the four-laser process chamber. Test parts were built and materials properties investigated. Further development of the control software was performed in order to optimise the treatment of the inter-field overlap regions and establish methodologies for linearisation and calibration.

Following finalisation of the chamber design, a Prototype Machine (for later shipment to MS) was designed and constructed.

In parallel with this activity, the control software has been completed to a user compatible state and initial user manuals have been generated and provided to MS.

A dedicated machine bay was designed and constructed at MSL. The Prototype Machine was completed at EOS, shipped to MSL and installed in the bay. The machine was then commissioned by EOS engineers and handed over to MSL.

MSL operated the machine in a simulated production mode for several months. Four different structures were built in cyclic fashion: (1) a geometric test pattern to monitor the scan field accuracy of the machine; (2) a materials test structure to monitor chemistry and mechanical properties; (3) a batch of representative small parts; (4) a representative large part requiring the combination of all four laser fields. Throughout this period, MSL monitored machine state and key reliability metrics. Consumable usage was also logged to feed into a cost of ownership model.

All operating data was fed back to EOS throughout the period. A number of hardware and software upgrades took place, enabling a continual improvement in performance and reliability.

All results have been reviewed and incorporated into technical reports in line with the Description of Work.

As of the end of the project, the Participants can confirm that the planned testing of the Prototype Machine has been successfully concluded and reported on, in line with the Description of Work. Despite various technical challenges, the project has been brought to a successful conclusion. All of the technical deliverables and milestones have been achieved.

A prototype additive layer manufacturing machine has been successfully designed and built by EOS. It has then been installed and operated in a manufacturing-realistic environment at MSL. Data has been generated regarding materials properties, part accuracy, system reliability, system maintainability and operating costs. This has been fed back to EOS in real time, allowing an acceleration of the time to market for M400-4 machine described below. The results of this project are therefore of great benefit to the Participants, to the Topic Manager and to the wider European aerospace industry.

Potential Impact:
Impact on Clean Sky

“The greening of Aeronautics and Air Transport calls for a quantum leap in performance through a consistent, coherent and holistic approach focusing on the integration of advanced technologies and validation of results in a multidisciplinary approach leading to full-scale ground and flight demonstrators.”

Clean Sky is sets out to achieve this quantum leap and is made up of 6 Integrated Technology Demonstrators; one of which is SAGE:

“Sustainable And Green Engines- will design and build five engine demonstrators to integrate technologies for... high efficiency, low NOx and low weight cores and novel configurations...”

This project addresses a Call within SAGE and seeks to enable the commercial application of additive manufacturing of lean-burn combustion chamber liner tiles.

More broadly it enables the application of this technology to complex 3D aerothermal geometries (for both combustion and turbine applications) for static use (liners, swirlers, nozzle guide vanes, seal hangers, acoustic dampers etc.) in aero and land gas turbines and nuclear (steam) turbines.

For example Additive Manufacturing enables effusion cooling holes to be placed as required by aerothermal design (rather than limited by the capability of laser/EDM hole drilling). The resultant improved cooling reduces cooling airflow requirement leading to improved combustion and emissions.

In addition to the lean burn demonstrator and ACARE 2020 and Flightpath 2050 targets there are specific impacts on the Topic Manager, Participants and the EU more broadly.

Impact- Topic Manager

In the call the Topic Manager has articulated their requirement;
“What is required is a future-proof production, multi-laser machine enabling low unit cost manufacture, scalable both in speed and build envelop size for higher volumes and part size without change in laser melt characteristics. It should demonstrate equivalence to best of breed additive manufacturing methods and demonstrate cost competitiveness and design flexibility.”
“Such a machine shall demonstrate high quality processes that are unaffected as speed and volume is scaled by the addition of further lasers and which demonstrates an at least 2x improvement in productivity over current known solutions whilst retaining existing materials integrity without revalidation.”

This project articulates a method of meeting that requirement and the outcomes from it.
In particular this project creates the conditions under which such a next generation metal Laser Additive Manufacturing machine is developed.

As a result the Topic Manager will be able to access knowhow and services that would otherwise not exist. This includes the capability to build demonstration engine parts in materials, at a cost and in a timeframe that would otherwise not be possible.

Impact- Materials Solutions Limited

This project will provide a next generation laser powder bed Additive Manufacturing machine for evaluation and testing, enabling continued relevance for its services to the aero-engine community.
Materials Solutions has demonstrated its competence and ‘open’ nature, providing World Class knowledge-based services on normal commercial terms to all customers since foundation in 2006. Materials Solutions provides aero-engine makers and their component suppliers in; Germany, France, Spain as well as the UK and outside the EU; Switzerland, Turkey, Japan, Canada and the USA.
1/3 of Materials Solutions’ employees were employed as new graduates (PhD or Masters degree). Materials Solutions sponsors post-graduate students and provides graduate student work placements. 2/3 of employees have a post graduate qualification.
This project will greatly assist in Materials Solutions’ continued growth and many additional jobs will be created directly within Materials Solutions at the rate of approximately 1 per €150,000 annual sales.

Impact- EOS

This project provided 50% funding for the development and beta build of a next-generation laser Additive Manufacturing machine specifically targeting a nascent market for novel combustion and turbine parts in nickel superalloys.
This market has high potential and a suitable machine is expected to sell widely- both within the EU and for export. These additional sales will lead to considerable jobs creation both within Germany, manufacturing these machines, and also more widely throughout EOS service and support network Globally.
Such a development has considerable financial and technical risks for EOS- the requirements for aero-engine production are extremely demanding- and this project enables EOS to take those risks by providing both grant assistance and technical de-risking.
Collaboration with Topic Manager and Materials Solutions both within this Project and subsequently will greatly assist future sales of the machine developed here.

Impact- EU Community
This project will directly contribute to meeting ACARE 2020 and Flightpath 2050 goals.
Knowledge based jobs in the EU are created directly by this project and indirectly through:
a) the use of the equipment produced in this project
b) the new business generated at EOS and its supply chain manufacturing, supplying and supporting these new machines on a commercial basis.
Exports from EU to its leading trading partners will be created by:
a) the sale and service support of these new machines by EOS
b) additional services supplied by Materials Solutions
c) existing EU customers of both Materials Solutions and EOS expected to commence or increase exports as a direct result of this Project. these include all the European aero-engine makers and their supply chains.
d)new customers of EOS and Materials Solutions who are able to commence or increase exports due to the technological advantage and cost reduction this Project generates.
In addition to the direct impact on the Participants, Topic Manager and the European aerospace industry, a high-productivity laser additive manufacturing machine is of benefit to many industries, improving life quality and employment opportunities. These include; medical devices, dental care, designer products, automotive, mechanical engineering and for producing tooling such as injection moulds.
Nickel super-alloys are also used for turbo machines in other applications such as power generation, CHP, and automotive turbochargers where they are dramatically improving efficiency and reducing fuel consumption and emissions.
Additive Manufacturing equipment that is economic enables the creation of customised products and could improve quality of life for many members of society.

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