Conductor tracks in 3D-printing
The plastic was fed in granulate form into a “freeformer”, ARBURG’s industrial additive manufacturing system, which uses a material preparation unit with a special plasticizing screw. After melting the standard granulate, the freeforming process, which uses no molds, followed: A high frequency nozzle closure discharged tiny plastic droplets, which could be precisely positioned with the aid of a movable part carrier.
In this way, the freeformer created three-dimensional components with cavities layer by layer, into which components could be inserted during the printing process. To make this possible, the freeformer automatically interrupted the process at each respective layer, so that the coil, circuit board and plug could be integrated very precisely. In a separate process, a dispenser was then used to produce the silver conductor tracks inside the casing. To complete the process, all that was needed was to overprint the cavities and then pot them in polyurethane.
The team produced more than 30 demonstration models of customized sensors in this way and then put them through their paces: the components had to be able to withstand temperature changes and vibrations, they had to be waterproof and pass an electrical insulation test. By optimizing the design and manufacturing process, the tests were ultimately completed successfully.
The “Electronic Function Integration in Additively Manufactured Components” research project ran for eighteen months. Stefan Pfeffer, who led the project at Fraunhofer IPA, is currently working with ARBURG on research into how conductive plastics can also be used in the future to tap into additional application areas.