Compression moulding plastic parisons - using press plunger with set of springs to compensate for shrinkage during cooling

摘要

In a compression moulding process for plastic material, e.g. to produce lids and caps of tubes and other containers, a heated parison is dropped into a mould and pressed to a moulding. A latch and notch maintain the plunger in contact. Several compression springs in a cap around the top of the plunger ensure that any shrinkage is compensated. ADVANTAGE - This ensures that sinks in the surface of the plastic moulding cannot occur and that a satisfactory smooth surface is achieved.