Integration of printed electronics in rubber

A small team of high­ly qual­i­fied experts is tak­ing an impor­tant step toward the dig­i­tal future at Con­ti­nen­tal’s new loca­tion in Freiburg: test­ing, try­ing, rethink­ing. Short paths, lean process­es, fast results.

“It feels like being in a start-up. We are very flex­i­ble and can quick­ly devel­op and adapt our process­es; there is a great dynam­ic here. At the same time, we can build on the strength of the entire Con­ti­nen­tal Corporation.”

- Tim Wolfer, Project Manager

Here, for exam­ple, clas­sic rub­ber and plas­tic prod­ucts, which until now have only ful­filled mechan­i­cal tasks, are to be enriched with sen­sor tech­nol­o­gy, intel­li­gent sys­tems and actu­a­tor tech­nol­o­gy and thus dig­i­tized. Wolfer holds a doc­tor­ate in mechan­i­cal engi­neer­ing and has been respon­si­ble for research projects at the Druck­tech­nikum since fall 2020.

“My focus here is on the inte­gra­tion of intel­li­gent sys­tems and net­works. In par­tic­u­lar, we are look­ing at the inter­face of com­po­nents made of elas­tomers and the inte­gra­tion of elec­tron­ics,” says the engi­neer. A native of Bre­men, he pre­vi­ous­ly worked for five years as a group leader at the Pro­duc­tion Tech­nol­o­gy Cen­ter of the Uni­ver­si­ty of Hanover. There, among oth­er things, he estab­lished close con­tacts with his cur­rent employ­er, Continental.

The 36-year-old fam­i­ly man was already pas­sion­ate about tin­ker­ing and screw­ing in his child­hood and youth — and stud­ied mechan­i­cal engi­neer­ing for this rea­son. He came into con­tact with func­tion­al print­ing dur­ing his doc­tor­ate on addi­tive man­u­fac­tur­ing of opti­cal sys­tems. “Now I’m hap­py to be able to apply this knowl­edge in the research and devel­op­ment of a tech­nol­o­gy group,” adds Wolfer.

One of Wolfer­’s pio­neer­ing projects is the “sen­sIC” project: Inte­grat­ed sen­sor tech­nol­o­gy is used on the basis of print­ed elec­tron­ics in hose lines for elec­tric vehi­cles. Specif­i­cal­ly, hoses for the ther­mal man­age­ment of vehi­cle bat­ter­ies are equipped with inte­grat­ed tem­per­a­ture sen­sors. Con­ti­nen­tal is bundling such research projects in the print­ing tech­nol­o­gy cen­ter in Freiburg; sen­sIC will run for three years. The Ger­man Fed­er­al Min­istry of Edu­ca­tion and Research is sup­port­ing the project pro­por­tion­ate­ly with €2.9 million.

Project will be key to sensor technology and electronics in rubber products

Con­ti­nen­tal has high hopes for sen­sIC — above all, a wide range of appli­ca­tions for the tech­nol­o­gy and low­er costs in pro­duc­tion. “Print­ed elec­tron­ics we can the­o­ret­i­cal­ly use every­where. The prod­uct range is vir­tu­al­ly infi­nite and per­fect­ly tai­lored to Con­ti­nen­tal’s strat­e­gy: mak­ing prod­ucts intel­li­gent and using them to devel­op new busi­ness mod­els and mobil­i­ty ser­vices,” says Wolfer. “Hoses are just one exam­ple there. But if it works there, it will also work in air springs, belts, con­vey­or belts and tires, for exam­ple.” And that is pre­cise­ly one of his excit­ing main tasks: trans­fer­ring the tech­nol­o­gy to oth­er areas of Continental.

Industrial scale as a goal

“In this respect, the project has light­house char­ac­ter for us,” Wolfer empha­sizes. “In this project, we are using high­ly pro­duc­tive print­ing process­es to man­u­fac­ture the elec­tri­cal net­works. These process­es promise a very high through­put of processed area at very low cost.” What’s more, the elec­tron­ics must be absolute­ly safe, as they are increas­ing­ly being installed in auto­mo­biles and plant. For this rea­son, a par­tic­u­lar focus in the project is on safe­guard­ing the elec­tron­ic sys­tems against manip­u­la­tion and plagiarism.

“The great­est chal­lenge is not only to inves­ti­gate the nov­el tech­ni­cal sys­tems on a lab­o­ra­to­ry scale, but lat­er actu­al­ly to man­u­fac­ture them on an indus­tri­al scale at our col­leagues in Ham­burg,” says Wolfer. This is because, “Even on a small scale, the sys­tems in them­selves have an enor­mous com­plex­i­ty due to their fine and sen­si­tive struc­tures. For exam­ple, a spe­cif­ic sil­i­con chip will be designed and pro­duced for us as part of the project. But in the sub­se­quent pro­duc­tion in Ham­burg, we are then sud­den­ly con­front­ed with chal­lenges such as ther­mal expan­sion, sol­vents, high pres­sures and high tem­per­a­tures.” Right at the begin­ning of the project, Wolfer and Co. there­fore had to assess what tech­ni­cal require­ments await­ed them in the end, so that they could make a sen­si­ble choice in mate­ri­als and con­cepts from the out­set. “That was quite a chal­lenge, get­ting all the tech­ni­cal goals under one hat. But now the tech­ni­cal con­cept is in place and the project has ful­ly tak­en off,” empha­sizes Wolfer.

Freiburg as the perfect location

And why Freiburg? “Quite sim­ply, in order to cre­ate a cen­tral loca­tion for this tech­nol­o­gy, Con­ti­nen­tal has bun­dled its func­tion­al print­ing activ­i­ties here in a tech­ni­cal cen­ter. In addi­tion, the Freiburg loca­tion was par­tic­u­lar­ly suit­able because of the close coop­er­a­tion that already exist­ed with a local tech­ni­cal and sci­en­tif­ic net­work, such as Fraun­hofer ISE, the Karl­sruhe Insti­tute of Tech­nol­o­gy (KIT) or the ‘microTEC Süd­west’ tech­nol­o­gy cluster.”

A start-up atmos­phere, a strong local net­work, a new print­ing tech­nol­o­gy cen­ter and a pow­er­ful inter­na­tion­al tech­nol­o­gy com­pa­ny — the con­di­tions for the suc­cess of the sen­sIC project could hard­ly be bet­ter for Tim Wolfer and the project team.