Pressing of plastics is the process in which the heating form affected by heat and pressure, acquires the desired shape of the plastic product is gathered. The main parts of this process are pressing temperature, pressure and the time of hardening. High costs and time demands for the whole process can be reduced by pre-heating the plastic before pressing. This concerns an energy demanding procedure although due to this procedure, it is possible to significantly reduce the time of hardening, increase the fluidity of plastics, reduce pressing pressure by up to half and achieve a higher proportional character of the hardening. The Workswell ThermoInspector is used to inspect the temperature of pre-heated semi-products – an inspection system for contact-free monitoring, analysis and evaluation of temperatures developed by the Czech company Workswell s.r.o.
For example, in one of applications, the ThermoInspector TI160-25 system is used to inspect the temperatures of the pre-heated semi-products before pressing. The whole manufacturing-inspection process starts with the manual insertion of the semi-product into the mould and the semi-product is pre-heated to the required temperature of 130°C. The control area is monitored throughout the whole time by the Workswell WIC 336 thermal camera with 19mm lens and a resolution of 336×256 pixels. The working distance is approximately 800mm. The camera is compact and, therefore is easy to fix above the manufacturing line when handling products or during the movement of the press. The whole measuring process is controlled by a central unit that receives the signal from the operator that the semi-product has been inserted and starts to measure the temperature in eight points on the semi-product surface. If during the pre-heating before the pressing, the temperature reduces at any measured point below the level of, for example 75°C, the ThermoInspector sends a signal that the semi-product is unsatisfactory and the part is not transported into the press. In this case, the manufacturing line waits until the operator inserts a new pre-heated part, and then presses the button again so the inspection and production process can continue.