By Xavier van Aelst, Director Food & Beverage, AVENTICS
A pneumatic solution from Aventics allows users to monitor the pre-blow molding process in the production of PET bottles online, in real time, and immediately make any necessary adjustments.
The new solution is based on proportional technology. By combining a proportional valve, control electronics, and software, the solution records the actual values occurring during the process and compares them with the set points. The set points for this step can either be stored in the electronics or transmitted via all common real-time Ethernet protocols and fieldbuses.
During a blowing period of around 200 milliseconds, enough control cycles are available to precisely control bottle formation. This allows process technicians to intervene as needed, for example, to reduce material consumption and fine-tune the formation of the bottle wall. Additional energy savings are possible by lowering the pressure level or reducing the furnace temperature.
Process data taken from the analysis can be used to derive continual improvements. At the same time, quality documentation is carried out in order to safeguard and track the process. In addition, trend analyses of the data enable the detection of wear before a failure can occur. Condition monitoring notifies maintenance early on to be able to carry out the necessary work in planned maintenance breaks.
The electro-pneumatic solution also meets new requirements in bottle production resulting from the trend towards more and more complex PET bottle shapes and smaller batches. As a software-based solution, the bottle formation process can be changed easily, without any mechanical alterations, and specific to each blowing station on the machine. The software can also automatically control process events, for example, reaching the yield point and target bottle volume, according to specifications, and keeping them constant, provided no wear limits have been reached. Once saved, parameters for a bottle type or specific material can be opened and activated at any time, significantly reducing waste during start of production. In close collaboration with product designers, the software developers validated numerous sample settings during the pilot production phase of new bottles.