Automatic Demoulding Aids in Injection Molding.

The development of pneumatic control and actuation elements has led to an increasing use of compressed air in the construction of injection molds. Several examples serve to demonstrate potential uses. Increasing use has been made during the last few years of the pneumatic sprue in the construction of single-cavity molds for shot weights of up to about 100 g; for it ensures the reliable release of the sprue cone, provided that this has been appropriately designed. Design details of molds as well as of a pneumatic driven auxiliary aid are given. The pneumatic actuation of ejector pins from the nozzle side is explained by means of a molding asymmetrically pin-point gated as an example. Compensation valves in the mold as inlets for compressed air have proven successful in direct pneumatic demolding. The inflowing air transforms the vacuum to overpressure, assisting in manual demolding.