Characterisation of the Cooling System Performance of Additively Manufactured Thermoforming Moulds

Similar to the injection moulding process, the cooling step of thermoforming is the most complex one and will massively influence the productivity (cycle time) and quality of the finished products. In the case of plastic moulds, studied in this work, this step is even more essential, as cooling prevents thermal deformation and increases the service life of the mould. Based on some preliminary research and information from literature, a number of influencing factors had been studied, and the obtained results provided the baseline for the current research. However, further research on this topic is imperative due to the previous positive results, the fact that there are no rules defining the design constraints for cooling systems of additively manufactured thermoforming plastic moulds, the variety of materials available on the market and the different approaches that can be considered. Therefore, adequate experiments, based on statistical DOE- Taguchi L16 (45) plan, have been conducted to optimize and increase the performance of the cooling systems and to enlarge the knowledge in this underdeveloped field. The results showed that a 50% reduction of the mould temperature can be achieved after only 5 s and up to 70.3% after 25 s of cooling with pressurised air. Furthermore, the authors used FEM for Thermal Analysis to characterize the performance of the cooling channels and to compare the results with previous experimentally obtained ones.