Introducing intelligent sensors in presses for plastic material injection

This paper presents some theoretical and experimental results concerning the introduction of advanced sensors in the design and development of a new generation of presses for plastic material injection used to produce washing machine tubs. The architecture of the control system for the presses is based on a distributed solution and relies on fieldbus communications to obtain a graceful migration path to the adoption of sensors of a new generation. This enables a dramatic decrease in both the cabling complexity and cost, together with a significant improvement in the performance of the whole machine. The adoption of the field network to connect sensors and actuators to the controller has been carefully evaluated by means of a preliminary theoretical analysis. Then, two test systems have been implemented to collect data and performance figures by carrying out experiments and measures on some of the real devices selected for the design of press control equipment.