44: Industry in the Future: UTC an academic partner for enterprise

The ongoing digital transformation of industry is a major societal challenge. For UTC, accompanying a growing number of companies during the changes, the phenomenon represents an increasingly strategic field for studies. This Dossier zooms in on the university’s main activities and on the specific nature of its approach to the industries of the future.

44: Industry in the Future: UTC an academic partner for enterprise

Additive Manufacturing (AM): a field of knowledge worth exploring

‘AM’ represents a technological breakthrough and a new area of research for UTC. Initially, AF (aka 3D printing) was used for making prototypes. Now, production of polymer parts is a manufacturing possibility that interests industrialists when it comes to producing finished metal alloy parts. Provided we can overcome two hurdles. 

The underlying principle of Additive Manufacturing (AM) is to make a part – from a 3D model – by successively building up layers of matter in a print process. This could in time revolutionize the way metallic alloy parts are made. For the moment, the low productivity factor for the printers excludes moving to mass production levels. Likewise there is a high price tag for the printers and or the raw materials used, in our case metallic powders and consequently it may not prove attractive for production of simple parts. In contradistinction, it could prove very promising for small series of parts, especially when the latter are complex, or to make on demand spare parts which does away with storing spares. With AM techniques, production costs are far less correlated to complexity and quantities needed compared with classic foundry-machining processes.

Nonetheless, this breakthrough 3D printing technology totally calls into question the technical knowledge base acquired through classic processes. The main hurdle here is to ensure the control of product characteristics (geometry, tolerances, fatigue and corrosion factors …). It also depends notably on the quality of the metallic powders used, again a complex question and often varied from one delivery batch to another. And again thermal aspects must be taken into account during fabrication – each powder layer is heated by laser to close to melting point, then cooled and this generates mechanical stresses that can induce deformation of some of the finer geometry parts.


Certain part faults are difficult to anticipate

 “The key issue, notes Jérôme Favergeon, director of the UTC-Roberval Lab, “is that, to a large extent, we ignore the connections between raw material characteristics, process parameters and the quality expected of the final part produced in this manner. It simply is not possible, as yet, to anticipate faults that may occur in a parts produced; we only see them once the part has been made (printed). This can prove critical if we are making a very limited series of parts, because if we have to carry out preliminary tests lasting several months, then proceed by trial and error, then additive manufacturing is not really commercially worthwhile”.

Today, UTC is engaged in discussions with certain industrialists to carry out research on this difficulty and indeed, its academic multidisciplinary capability is an asset heretic-Roberval has specialist exports in mechanical engineering and material sciences & engineering and the UTC-TIMR Lab (Integrated transformation of raw materials) has a valuable expertise on the question of powder behaviours and applications of powder technologies. “For the moment”, says Khashayar Saleh, a TIMR powder specialist, “we have not yet carried out any specific research on additive manufacturing. But by analogy with other applications and via our knowledge base on process engineering, we have been able to identify the difficulties that might arise: notably the issue of powder ‘flowability’, unwanted clotting of particles when the laser beam traverses the powder layer, this leading to the difficulty to obtain clean-cut edges on the parts produced, or again, irregular dispersion of the particles when the powder layer is put in position. By we do have some paths to explore”. Last but not least, UTC-Heudiasyc Lab has an excellent expertise in data analytics (DA) (cf. p.10) that be used to obtain better part quality predictions.


A project on topological optimisation

The scope of research that UTC can undertake here is not limited to this field. Additive fabrication opens new horizons in topological optimization (optimizing the geometry of the parts produced and distribution of matter as a function of the expected mechanical properties. “Because AM allows you make increasing complex parts, it can be used to machine out les matter and lighten a part without degrading the structural limits of the parts”, notes Alain Rassineux, research scientist at UTC- Roberval. “But this implies that we adapt our tool, where possible, as used for topological optimization and compliant with the limits of the new AM process itself”. UTC Roberval has recently begun research on this question in the framework of an AM project financed by the Chinese National Research Agency, in an association with Northwestern Polytechnical University of Xi’an (China) and the Free University of Brussels (ULB), Belgium.