Report

Teaser, summary, work performed and final results

Periodic Reporting for period 2 - EMUSIC (Efficient Manufacturing for Aerospace Components USing Additive Manufacturing, Net Shape HIP and Investment Casting)

Teaser

Introduction. EMUSIC was launched on March 31 2016 to assess the potential of several net shape processes for manufacturing components for aerospace. The 18 partners in the consortium, have the ability between them of manufacturing demonstrator components, of improving the...

Summary

Introduction. EMUSIC was launched on March 31 2016 to assess the potential of several net shape processes for manufacturing components for aerospace. The 18 partners in the consortium, have the ability between them of manufacturing demonstrator components, of improving the overall control of the processes via modelling, of assessing microstructure and properties and finally of assessing the cost for each process for the identified components.

Problem being addressed. Current manufacturing is focussing on net shape processes and the problem addressed in this project is to compare the quality and cost of a number of selected components, made using different net shape process routes, so that industry could make an informed choice of which route is most suitable for these components. The selected components are illustrated below, which were identified by the end users, who also defined the mechanical properties, the surface finish and accuracy of the components and the process-routes they wished to assess.

Importance to society. Efficient low waste manufacturing is of paramount importance today with the ever-increasing pollution associated with inefficient manufacture. Net shape manufacture is a very important approach to improve the environmental impact of manufacturing.

Overall objectives. To investigate a range of net shape manufacturing processes with the aims of reducing waste, improving properties and reducing cost of aerospace components.

Please see components in figure 1.

Work performed

During the programme teams were organised to work together to manufacture these components. The distribution of the tasks were:
Component (1). A guide groove to be Investment cast and produced by powder bed in Ti64 by BIAM, modelling of casting by Tsinghua and ESI/CALC and by Tsinghua of powder bed.
Component (2) An outer casing in IN718 to be produced
(i) via NNSHIP by IMR and by BIAM. Modelling by HUST and IMR
(ii) by blown powder by TWI.. Modelling by ESI
Component (3) A gimbal in Ti64 manufactured
(i) by NNSHIP by UoB– modelled by UoB
(ii) by laser powder bed by ILT – modelled by ESI and data from UoB and ILT.
(iii) by electron beam powder bed by BIAM – modelled by ESI, data from BIAM
(iv) by Wire feed AM by BIAM and BAMTRI – modelled by CIMNE, BAMTRI.
(v) by Investment casting by IMR and BIAM – modelled by Tsinghua and CALC
Component (4) Compressor casing in Ti64 manufactured by investment casting by BIAM. Casting modelled by Tsinghua and CALC and wax modelled by HUST.
Component (5). T900 frame connector in Ti64 manufactured by investment casting by IMR. Modelled by Tsinghua and CALC.
Component (6). Hub in IN718 manufactured by laser powder bed (at reduced size) by BAMTRI. Modelled by ESI.

Partners responsible for the different processes, worked closely with the partners who modelled each process used to produce the six demonstrators. The demonstrators were assessed by the processors and by the end-users. This assessment consisted of measuring mechanical properties, assessing surface finish and dimensional accuracy. The end-users were also provided with the processors’ costs of production, which they could compare with their costs using current technologies. In two cases (TWI and ILT) export control regulations limited the information that could be made public so in the case of the outer casing (component 2) made by blown powder by TWI no detailed information is available and ILT were not allowed to send the gimbal (component 3) made by laser powder bed to Collins for assessment.

Final results

The end-users reported that the mechanical properties generally exceeded specifications with two exceptions; although the stress rupture properties of the outer casing manufactured from IN718 for COMAC by both additive manufacturing (AM) and Near Net Shape Hot Isostatic Pressing (NNSHIP) were slightly improved by TWI who modified the heat treatment recommended by COMAC, the properties although improved did not meet specifications. The powder bed gimbal manufactured by ILT (assessed by ILT and not by Collins) distorted and did not meet the specified geometry. In other cases significant post-processing machining was necessary, which impacted on the costs.
The costs of all additive manufacturing (AM) processes and of NNSHIP were significantly higher than current costs and typically it was clear that in some cases machining from the solid would be less costly. On the other hand the investment cast components, produced by IMR and BIAM were either less costly than current technologies or in the case of component 4 (the compressor casing) the cost was identical to that of forging. These conclusions meant that although components could be manufactured, using AM or NNSHIP, the costs precluded the transfer to industry of these technologies for the selected components, other than investment casting. The underlying reason for this conclusion is obvious; the advantages of AM and of NNSHIP lie in the complexity of shapes that can be made and in the case of NNSHIP the additional ability to join different alloys by HIP diffusion bonding so that a component can be made with location-specific properties. Similarly AM can be used to add features to an already existing part and to repair components. The choice of the components by the end-users did not take advantage of the flexibility of manufacture using AM or NNSHIP and thus these technologies were not cost-effective.
Rolls-Royce in particular highlighted the important contribution that modellers had made to optimisation of investment casting of the components made by IMR and BIAM. The modelling of NNSHIP also was confirmed as being capable of producing components that required minimal machining. The difference in the properties of samples taken along the build direction or at 90 degrees to the build direction when using AM to manufacture components is a matter of some concern and as with all powder technologies the influence of inclusions and/or of regions that have not bonded during processing on the reproducibility of properties, was highlighted by end users – in particular by Collins.
Exploitation and dissemination because of the cost of all process-routes, apart from investment casting, the results obtained during EMUSIC will not be directly exploited. There was general support from all of those at the final meeting that we should attempt to build upon the work carried out in EMUSIC, where important cooperation between modellers and processors has been consolidated. If further work is to be done, there needs to be detailed consideration of the factors that could make AM and NNSHIP cost-effective. Complex shapes, adding features to large components and joining of different materials, thus reducing the number of welds required for many engineering components would be obvious areas, which are well-suited to these techniques. Any future research thus requires detailed discussions between end users and those developing/modelling these processes before attempting to put a research proposal together.

Website & more info

More info: http://www.birmingham.ac.uk/generic/emusic/index.aspx.