The art of stable, consistent temperature control
United States - Today’s demanding moulding applications require precise, reliable, user-friendly hot runner controllers where the focus is on thermal and pressure balance within cavities for achieving consistent part quality. By Michael Schiele, Manager, Strategic Marketing Europe, Milacron.
When looking at standard control technology one of the advantages of hot runner systems with individual tip control is that the temperature controller automatically compensates for subtle gate-to-gate variations by adjusting the amount of power each tip receives, thus maintaining a consistent set temperature. The individual set temperatures can be continuously adjusted to compensate for varying material solidification from gate-to-gate and even better gate opening balance. Most temperature controllers on the market today do a reasonable job of controlling temperature. However, when it comes to controlling high-wattage, low-mass hot runner nozzles, the range and choice of sufficiently advanced temperature controllers are drastically reduced.
High-wattage, low-mass hot runner nozzles heat up and cool down very rapidly. Without a suitable high-performance temperature controller, the hot runner nozzle will experience undesirable temperature swings. Those temperature swings will cause non-uniform solidification of material in the gate area, and result in an unbalanced fill pattern. Because of the fast response of the nozzle heater, the controller’s logic needs to act faster than the nozzle in order to achieve a stable and consistent temperature.
State-of-the-art controllers are equipped to do just that. Through continuously optimised programming logic, the controller is able to identify the type of heater being controlled and automatically apply the correct algorithms to achieve precise and stable temperatures to the hot runner nozzles, thus achieving a more balanced fill of cavities.