3D printing: a solution for long-gone industrial parts

Could you explain what 3D print­ing is and who uses it?

Fabi­en Szmytka. The sec­tors that use 3D print­ing (i.e., addit­ive man­u­fac­tur­ing) most are mainly the man­u­fac­tur­ing and trans­port­a­tion indus­tries, aerospace and motor­ised sports. These use 3D print­ers to make machines, robot parts, spare parts, machinery, casts, mod­els, etc. The most fre­quently used mater­i­als are still plastic poly­mers in dif­fer­ent formats (powder, thread, etc.). Only a small part of the mater­i­als used are metal­lic, ceram­ic or oth­er types.

In the auto­mot­ive industry, addit­ive man­u­fac­tur­ing was first used a way to make pro­to­types, but today it is also used to make mech­an­ic­al parts as well as ele­ments of design (car body, spoil­er, etc.). For instance, car man­u­fac­tur­ers like Honda have already built vehicles com­pletely prin­ted in 3D, although they are not yet marketed.

The aca­dem­ic world is also increas­ingly turn­ing to addit­ive man­u­fac­tur­ing to sup­port research. Many pro­jects use exper­i­ment­al pro­to­types made with 3D print­ing tech­no­logy. To this end, some labor­at­or­ies or research insti­tu­tions have equipped them­selves with their own print­ers, or even Fab Labs (fab­ric­a­tion labor­at­ory) like those, for example, of the Insti­tut Pas­teur (FLIP) or the Insti­tut Poly­tech­nique de Paris.

What are the main advant­ages of addit­ive man­u­fac­tur­ing in your field?

Nowadays, metal­lic addit­ive fab­ric­a­tion makes it pos­sible to cre­ate com­pon­ents with com­plex geo­metry. These would be impossible to make by using con­ven­tion­al meth­ods. For example, very small details would break dur­ing demould­ing in a clas­sic foundry. In some cases, weld­ing can be used to repair parts, but this tech­nique is very sens­it­ive to ambi­ent con­di­tions (air tem­per­at­ure, humid­ity) and very dif­fi­cult to auto­mate. You need many spe­cial­ised oper­at­ors, who require much long train­ing. Addit­ive man­u­fac­tur­ing thus makes it pos­sible, to some extent, to make up for the lack of spe­cial­ised workers.

What does your research on metal­lic 3D print­ing con­sist of? 

Our object­ive is to study metal­lic mater­i­als pro­duced by addit­ive man­u­fac­tur­ing. We use a spray­ing tech­nique based on metal­lic powder called “Dir­ec­ted Energy Depos­ition” to make our own mater­i­als. Their qual­ity depends on sev­er­al para­met­ers: powder com­pos­i­tion, power and speed of the machine. We then observe the effects of the vary­ing these para­met­ers on the micro­struc­tures of the mater­i­al. Finally, we test the res­ist­ance of this new metal­lic mater­i­al to mech­an­ic­al stress. For instance, we eval­u­ate the strain pro­duced by trac­tion, or meas­ure the effects of heat treatment.

In our labor­at­ory, we con­duct tests on com­plex struc­tures closer to the geo­metry of indus­tri­al parts, while stand­ard tests use a sim­pler geo­metry (plates, cyl­in­ders). Our research on metal­lic mater­i­als tries to meet the demands and needs of indus­tri­al part­ners. For example, they can ask us to devel­op a mater­i­al in com­pli­ance with determ­ined char­ac­ter­ist­ics for a spe­cif­ic use. We also lead research stud­ies on poly­mers in col­lab­or­a­tion with chem­ists from the CNRS.

In what fields are your stud­ies applied? And who are the final users of these materials?

One of the most prom­ising areas of invest­ig­a­tion is the use of these pro­cesses to repair dam­aged struc­tures. To devel­op applic­a­tions for these metal­lic mater­i­als, we work with the energy, trans­port­a­tion and aero­naut­ic sec­tors. For example, our part­ners EDF and SNCF use parts with very large dimen­sions. Their design some­times dates back to nearly twenty years ago and, as such, they are very dif­fi­cult to replace since they are not pro­duced any­more. Hence the need to find prac­tic­al and cost-effect­ive solu­tions to repair them.