Injection Molding Machine for Mass Production of Microparts
The M3 microinjection molding machine presented for the first time at the K 2013 is ideal for producing very large quantities of plastics parts weighing only a few milligrams. The machine employs four compact modules, each of which holds 8 microcavities. This makes it possible to produce 32 injection molded parts per cycle. At a cycle time of five seconds, this translates into a production capacity of over 150 million microparts per year. Moreover, this approach provides the ability to mold eight different parts having different shot weights. This facilitates flexible and fast production of molded part families that are subsequently assembled to one another. The machine has been designed for use in a cleanroom, making it ideal for manufacturing medical components.
The clamping unit of the machine features a tiebarless design. Electromagnets generate the clamping force of 40 kN used to hold the two mold halves closed. The parting line is readily accessible from three sides. The standardized modular inserts for the cavities replace a conventional mold design, permitting cost-effective and rapid production of prototypes of microparts. Identical process parameters simplify and accelerate a smooth transition from prototype to mass production. In addition, mold costs are reduced significantly.
The plasticating screw has a diameter of 18 mm and can process standard pellets. The screw delivers the melt to eight separately controlled injection plungers. These inject the material into the cavities via a valve-gated hot-runner system. The material in the plasticating screw and injection plungers is kept at a relatively low temperature. It is heated to the processing temperature only upon entering the hot-runner nozzle. In this way, thermal degradation of the material during processing is prevented even when residence times are relatively long.