Your end product could be the result of incorrectly designed thermocouples that measure the temperature process - see our solution that solved the challenge for a Slovenian plastic manufacturer
The user has noticed a difference between the displayed temperature and the actual temperature of the plastic, given the unsuitable (burnt) plastic products. After an internal repair, the ejection remained high and the line was stopped for urgent maintenance.
An incorrect choice of thermocouple design and partly incorrect preparation of the injection moulding tool were the reasons for the user’s problem. Both problems have been solved with specialised expertise and experience.
The set and actual values on the temperature controller displays were “uniform” throughout the process, with no more hot spots and no more hot spots. The quality of the product is perfect, no more rejections.
1. The surface on which the thermocouple was pressing was flat and the user was using a tapered design of plug-in thermocouples (118°). This resulted in a lack of proper loading at the measuring point and a lack of proper heat extraction from the measurement device (the plastic injection nozzle) to the measurement device (the thermocouple, which in this case serves as the temperature sensor).
|Plug-in thermocouple with tapered tip for 118° bores.||Instead of a bore hole, the tool design was prepared for surface measurement.|
2. The smallest nozzle on the plastic injection moulding tool was over-impacted due to the small mass of the gauge. Therefore, the effect of the heater on the thermocouple was greater than the effect of the heater on the tool (in terms of the mass of the gauge and the mass of the gauge). As a result, the temperature was lower in the larger plots and higher in the smaller plot (last nozzle).
|The smallest nozzle on the plastic injection moulding tool, with a plug-in thermocouple.|
|demonstration of the installed clamp-on thermocouple and comparative measurements with the special surface thermocouple TT-POV-TCK4.2x100R400x1000SS||display of the surface thermocouple on the TFN 520 thermometer and comparison with the display of the measuring system comparison: 176,8 °C measuring system 175 °C|
The advantages of working with the ELPRO Lepenik team, in this case:
The set and actual values on the temperature controller displays were “uniform” throughout the process, with no more hot spots and no more hot spots. The quality of the product is perfect, no more rejections. The inappropriate choice of thermocouple design has been resolved in this way.
Authors Rok Samec and Aleksandra Lepenik
Tel: +386 2 62 96 720.
They are always available for opinions and explanations: