A.dditive MA.nufacturing for T.iltrotor HO.using

Project Information

AMATHO

Grant agreement ID: 717194

DOI

10.3030/717194

Project closed

EC signature date 11 November 2016

Start date 1 December 2016

End date 31 August 2022

Funded under

• SOCIETAL CHALLENGES - Smart, Green And Integrated Transport

Total cost

€ 3 321 160,00

EU contribution

€ 1 749 999,50

Coordinated by

POLITECNICO DI MILANO
Italy

Periodic Reporting for period 4 - AMATHO (A.dditive MA.nufacturing for T.iltrotor HO.using)

Reporting period: 2021-06-01 to 2022-08-31

Summary of the context and overall objectives of the project

problem/issue being addressed
The main objective of AMATHO is to develop and manufacture the housing of the main gearbox of the novel tiltrotor adopting the additive manufacturing technology. The project is challenging as component is very big (not feasible via AM at the time of the proposal) and critical for the safety of fly.
The development implies to evaluate main production processes (SLM, EBM, DLD) and metallic powders available on the market and to identify the parameters able to optimize the final component.
The assessment of precursor materials and manufacturing technologies, together with the development of proper “design for additive” approach will allow the adoption of Additive Manufacturing Technologies to manufacture large components, suitable to be installed on flying platforms, like tilt rotors.

important for society
Additive Manufacturing of metal components is a novel technology that, in principle, could substitute oldest machining and casting technologies. At the present state of the art, it is possible to manufacture components not feasible with other technologies, but AM can’t be adopted for massive production, due to time and costs constraints

overall objectives
The objective of project AMATHO is to develop a novel tiltrotor main drive system housing produced by additive manufacturing (AM) technology. Such a development process will include evaluation and choice of viable production processes and precursor materials; testing of coupons and intermediate proofs of concept for assessing static performance and fatigue endurance; design for manufacturing, definition of optimised manufacturing process, experimental testing and industrial engineering of an appropriate number of full scale housings to support flight clearance on NextGenCTR demonstrator. The adoption of suitable numerical tools for design, optimization and structural substantiation of the AM housing will constitute part of the project’s activities as well

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

The POLIMI team explored both Powder Bed Fusion (PBF) and Directed Energy Deposition (DED) techniques (Figure 1). Three suitable AM methods were individuated in the two different classes, including:
- Selective Laser Melting (SLM)
- Electron Beam Melting (EBM)
- Laser Metal Deposition (LMD)
Furthermore, a review of currently available metal AM systems was performed, analysing features and performances of each of the off-the-shelf system

WP2, aimed to identify mechanical properties of components manufactured with AM, started the coupons manufacturing and their testing. The work is in progress, according to the plan.
WP2 is focused on process/material and it is 41 months long. WP2 is composed by four tasks, where task T2.1 is focused on the material/process investigation and characterization; task T2.2 on the prototyping of PoC and task T2.3 on the definition of design for AM rules, while task 2.4 is the joint concept review.
WP2 started with the manufacturing of ASTM specimens according to the outcomes of WP1 and continued with the mechanical characterization of these specimens (T2.1). Also the PoC prototyping (T2.2) and the definition of design rules (T2.3) have been concluded (see fig3).

In the WP3, the development of a methodology to carry out the redesign and optimization process of a tiltrotor gearbox was presented. After the definition of the design envelope, the topology optimization tool was used to obtain a preliminary load-bearing structure. This was then as a reference to carry out a more detailed design, which also embedded functional features. Structural analyses of the original and redesigned components was carried out, by performing a comparison between the two solutions. Finally, some insights on the design rules for AM and manufacturing strategies for complex large scale components were detailed.

Activities in WP3 have been focusing on designing and developing the novel DED system targeted to produce large scale AM components in Ti-6Al-4V alloy. Most of the activities have been focusing on designing the new system architecture, the laser source and powder deposition system, investigating the appropriate strategy for effective and efficient printing and developing novel solutions for monitoring and control the process for the large-scale target.

The WP4 have been split in further sub-tasks so to face better both the machine setting and the development of the prototype as final demo (see fig 4), while time has been rescheduled due to the pandemic situation that affected the activities on the machine.
During the whole period the Topic Leader has been frequently met by the Consortium, with formal and informal meetings

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

Activities were aimed not only to compare the three additive processes, namely SLM, EBM and LMD, applied to two materials widely adopted in aeronautics, aluminium alloys and titanium , but also to identify guidelines for the identification of precursors and their characteristics, the design and execution of experiments, and finally the qualification tests. Therefore, deliverables T2D1, T2D2 are methodological deliverables that also deliver guidelines and procedures for the selection of processes and additive materials at the sample level, once the final product specifications have been defined.

The static response of AM products has been deeply investigated, which is comparable, and can even surpass in performance, with traditionally manufactured parts.

A proper characterization of dynamic properties, such as fatigue, was performed. In particular, fatigue performances were determined and linked to typical defects of AM processes. Design rules for structural substantiation and for DED manufacturing of large components have been proposed as general guidelines to design and produce new components via AM

Design for AM (DfAM) rules to minimize needed supports, post-processing and maximize the mechanical properties of the final component were developed, with special focus on Directed Energy Deposition, resulting as the most promising solution for large scale metal AM.

A complete state of the art of in-situ monitoring in AM as viable solution for process qualification was presented to the topic leader, with a wide perspective on all the AM processes

PRIMA created a success story for the DED process in aerospace. This technology is not still mature respect to other AM processes like Powder Bed Fusion one. Nevertheless, PRIMA, together with other partners and AW, has shown as this DED process can be useful for large parts in Titanium alloys material.
POLIMI will foster initiatives exploring the potential advantages of AM for sustainable mobility in three different initiatives developed under the Recovery and Resiliance Italian Initiative under the EU NEXT GEN Plan (Cluster on Sustainable Mobility; Extended Partnership for Circular and Sustainable Made in Italy; Extended Partnership for Space Economy)

Manifold manufactured in EBM-Ti

The final demonstrator, here cut to facilitate NDT checks (tomography)

The second PoC, manufactured in EBM/titanium

AM manufacturing strategy of ASTM specimens

Aluminum ASTM specimens manufactured with SLM