Injection moulding with quality control - uses system which draws gas from souce into compressors, then forces it into die, and compares parameters with standards to obtain quality indicator

摘要

An injection moulding process uses at least two different materials. of which one is a plastic and the other a pressurised gaseous material. The mould is charged with the gas when the mould temp. and the flow of the first material have been determined beforehand. In order to produce the required pressure for the gas concerned a moving part of a compressor is driven in a predetermined way under a constant (or nearly constant) power, and the path of its movement in a set time is compared with a target value; alternatively the time taken for a set movement is compared with a target time, so that any deviation from the target levels is a measure of the variation in quality of product. ADVANTAGE - The procedure makes is possible to ascertain the quality of a moulding during its actual production