Intelligent monitoring of the injection moulding process

Abstract

The quality requirements of injection-moulded components have become more stringent because of the growing s applications of plastics and increasing customer demands. The quality of the moulded parts depend on the processing conditions and this creates a continuous demand for developing advanced techniques for monitoring and controlling the process The current practice in industry is to adjust the parameters based on the product defects through trial and error, starting from information from the material supplier, mould designer, and, largely, on the basis of the moulding engineer’s (or setup person’s) own experience. Nevertheless, defects can occur in moulded parts due to, for instance, the variation in material properties (particularly when reground or biodegradable resins are used), the change in environmental conditions (e.g., humidity or temperature in the surroundings), and the machine characteristics (particularly those using hydraulic power). In this case, the process conditions have to be readjusted in order to re-establish the part quality targets. To overcome these difficulties, injection moulding quality control has been the subject of many off-line and on -line quality control studies. The purpose is to achieve automatic and adaptive quality control able to guarantee a stable and repeatable process, from the part quality point of view.[edited by author]