Closed-Loop Control Applied to the Injection Moulding Process—An Industry 4.0 Refurbishment Case Study

Abstract

Injection moulding process stability is a key issue in ensuring suitable quality of plastic parts. External factors such as processing equipment malfunctions, environmental variations, or tool misuse require qualified professionals to handle the issue or diagnosing systems to detect them at an early stage to avoid production in unsuitable processing conditions. The process control system was developed to provide a solution to these problems, whether by introducing automatic self-corrections to processing conditions or providing key performance indicators (KPI) for operation, maintenance, production, and quality control, with a local or remote interface. The system gathers processing and operating data from the mould and from the processing equipment to provide an overall process view. The data collected are obtained from several sensors located on the mould, placed at strategic locations, and real-time information is provided by the injection equipment or its peripherals. These data are processed in near real-time by the process control system and corrections for processing parameters, if required, are transferred to the injection equipment to be implemented in the subsequent injection cycles. Preliminary results from this case study proved that this solution provided suitable responses to the imposed processing variations, resulting in optimized plastic parts.