Micro-components often involve macro-demands on mold design, manufacture and assembly. The top housing shell consists of a demanding hard/soft material combination. The hard component consists of PA12. A thermoplastic elastomer is used as a soft component. The part of the housing with little to no warpage meets tightest clearance requirements. toolcraft also manufactures a battery compartment and a push-button for the assembly. In this regard, Unitron makes use of the entire process chain, from 3D data customization, mold making and injection molding, through to quality assurance.
Special expertise in mold making
To ensure the economic efficiency of the application, the goal was to develop an extremely reliable mold for integrated molding process. In addition, the parts required extremely tight clearances for accuracy of fit as well as repeatable injection for smallest shot weights. Furthermore, a perfect alignment of hard and soft components was necessary. toolcraft had the necessary expertise in mold making. Nevertheless, the 20-week construction period proved to be a great challenge.
From concept to finished plastic component
The construction of a 1+1-component precision mold followed the development of automated manufacturing as part of the two-component injection molding process. Designing and programming the 2-component injection molding machine was the next step. The Arburg A470S 2K was outfitted with an integrated quality assurance system including a camera and a robot that sets down the parts on a conveyor belt. In so doing, the robot separates the trays so that expert personnel can then proceed with packaging. The concept was implemented as part of a close cooperation between the manufacturer of the injection molding machine and toolcraft’s engineering team, mold making and injection molding departments.
Challenges successfully tackled
Engineering such a complex mold, as well as the manufacture of parts with fine and small contours, proved to be demanding. Time pressure resulting from tight project planning was an additional incentive. Prior to mass production, the team had overcome all major and minor challenges. Since this time, the process is stable and large production runs have been ensured. Further activities in two-component injection molding are still being developed at toolcraft, including parts from the automotive sector as well.
Facts about Arburg A470S 2K
Ø cylinder 1 20 mm
Ø cylinder 2 18 mm
robot system KUKA KR16
part weight 0,5 g – 20 g