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58 FLEX007 MAGAZINE I OCTOBER 2018 Printed Electronics from 2D to 3D Lately, stretchable inks have appeared, enabling the creation of stretchable electron- ics. These inks can survive deformation of 10–50%, and printing of these inks onto form- able substrates allows a deformation of the PCB without damaging the structure. Thin, comfortable electronics, that follow the shape of the surroundings, are created this way for integration into clothing and patches, for example. Clothing with integrated sensors, solar cells, and displays has already been dem- onstrated. Electronic clothing needs to be com- fortable in wear and survive washing tests at the same time. Overcoming hysteresis of the rubbers and building strategies for the inter- connects to survive stretching are research challenges in stretchable electronics. In an extreme form, these materials can also be used to create thermoformable or in-mould electronics. These electronics are created on pla- nar surfaces and then formed into the desired shape. The circuitry and graphical patterns are printed on substrates like polycarbonate. Again, the electrical components are assembled with traditional pick-and-place technology, and the whole piece is then formed into the desired shape, after which it may be die-cast to cre - ate the end-product. Thus, items such as dash- boards or consumer goods can be produced in a more cost-effective way (Figure 3). Lastly, the entire structure can be 3D printed. Multi-material printing allows conductive and structural materials to be combined and gives the ability to design electronics in three dimen- sions. Summarizing Printed Electronics The industry is requesting that smart func- tions be unobtrusively integrated into many products surrounding us. At the same time, the electronics need to be more cost effec- tive and produced at a higher volume to fulfill these demands, especially demonstrated in IoT applications. Printed electronics may be a key enabler for IoT because they provide the best of two worlds combined—printing and dis- crete component assembly on a conformable and flexible material produced on a roll. The next wave is from planar electronics to the third dimension. Stretchable electronics, thermo-formable electronics, in-mould elec- tronics, and 3D printing is already utilized to create 3D electronics. FLEX007 Corné Rentrop is a project manager at the Holst Centre, an independent R&D centre based in the Netherlands that develops technologies for wireless autonomous sensor technologies and flexible electronics. Since its beginning in 2005, the Holst Centre has been involved in flexible and large-area electronics. Figure 3: Thermoformed midconsole for automotive appli- cations, including capacitive touch, OLED integration, and NFC read-out. Figure 4: Circuitry printed on flat plate before thermoforming into a 3D product.