The requirements of medical technology when it comes to product cleanliness and quality are high. At the Swiss Plastics Expo exhibition (January 24 to 26, 2017, Lucerne Trade Fair, Switzerland), KraussMaffei will be demonstrating how a PX 50-180 SilcoSet can satisfy these requirements with high precision and productivity in the growth market of silicone. The new all-electric injection molding machine produces 0.03 g lightweight LSR (liquid silicone) diaphragms in a 32-cavity mold.
Flexibility is the key
The PX 50-180 SilcoSet is exemplary of the high degree of modularity and precision of KraussMaffei's new, all-electric PX series. "The modular concept of the PX is especially beneficial in the micro-injection of silicone, where extremely small shot weights, but also large platens are required," explains Bruno Schleiss, Managing Director KraussMaffei Schweiz AG. The ejector of the PX 50-180 SilcoSet is electric and encapsulated, so it corresponds with the strict clean room requirements of medical technology. The compact design provides lots of space for demolding and peripheral equipment and good accessibility.
Another highlight is a servo-hydraulically powered injection unit for the nozzle contact force, which guarantees reliable and leak-free injection of the low-viscosity LSR material through the open cold runner. The version with two pressure cylinders provides for even power transmission and high stability. Other equipment features of the SilcoSet machine at Swiss Plastics include a water-cooled cylinder, an electrically heated mold and a vacuum pump for mold ventilation.
High precision and greater stability
The production of LSR diaphragms weighing just 0.03 g and measuring just 0.2 mm thick in a 32-cavity mold requires particularly high precision. Unlike thermoplastics, LSR does not shrink in the cavity, but rather expands, meaning precision is primarily the result of accuracy during injection. Here, the PX series scores particularly well by being an all-electric injection molding machine. Another highlight is the plasticizing process, which has been specially configured for applications with silicone. It features a separate non-return valve with precise closing characteristics. The linear guidance of the moving platens also provides for precise, low-friction clamping movements, even with high mold weights.