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16 The PCB Magazine • January 2015 and surface coating applications. All printing occurs without the use of vacuum or pressure chambers and at room temperature. The high exit velocity of the jet enables a relatively large separation between the print head and the sub- strate, typically 2–5 mm. The droplets remain tightly focused over this distance, resulting in the ability to print conformal patterns over three dimensional substrates. Despite the high velocity, the printing process is gentle; substrate damage does not occur and there is generally no splatter or overspray from the droplets. Once patterning is complete, the printed ink typically requires post-treatment to attain final electrical and mechanical properties. 3D MID technology (moulded interconnect devices) is another way to create an electrical interconnect inside a moulded plastic housing. An electrical conductive circuit is created by means of two-shot moulding or by laser activa- tion patterning. After this step the structures are metallized through an electroless plating pro- cess and become conductive. After the circuit- ry is created the conventional SMT machines (stencil printing, pick & place and reflow ov- ens) can make sure that components are added to the part. Things can get even more interesting when we change our conven- tional way of thinking! What if we first placed the components inside the housing and then printed the intercon- nects? In that case we would not need the reflow process either! It would, however, be beneficial to be able to print copper inter- connects without a post treatment. Plasma technology could be a good option in this case. This kind of tech- nology could revolu- tionize manufacturing processes for sensitive surfaces under atmo- spheric pressure. Cold active atmospheric plas- ma encompasses a multitude of applications in the industries like solar, semiconductors and could become a substitute technology for 3D MID. Plasma technology however still needs some extra attention to be able to create fine- pitch tight tolerance interconnects. What needs to be considered as well is the placement of the components. In case we create the electrical circuitry inside the housing and the shape is three-dimensional, we need to be able to place components in a three-dimension- al way. This also means that we need to be able to apply solder paste or glue in a e3D way as well. If we could first place the components and then print the conductive copper tracks, there might even be a need to change the design of certain components that have their connec- tions or heat sinks on the bottom side. What advantages can these changes bring the electronics industry? Besides having a prod- uct designed for purpose and not just to fit the electronics, there are some major cost advan- CAN THE ELECTRONICS INDuSTRy uSE 3D PRINTING? continues Figure 5: 3D printed copper tracks. FEaturE