Investment casting is one of the precise casting methods where disposable wax patterns made in wax injection molds are used to make a casting mold. The production capacity of precision foundry is determined by the time taken for producing wax patterns, which depends on the time taken for wax solidification. Wax injection molds are usually made of aluminum or copper alloys with the use of expensive and time-consuming computer numerical control (CNC) processing, which makes low-volume production unprofitable. To reduce these costs, the authors present a heat transfer analysis of a 3D printed wax injection mold. Due to the low thermal conductivity of the photopolymer resin, the influence of different cooling channels’ shapes was investigated to improve the time of the manufacturing process. Transient thermal analysis was performed using COMSOL software based on the finite element method (FEM) and included a simulation of wax injection mold cooling with cold air (−23 °C), water, and without cooling. The analysis showed that use of cooling channels in the case of photopolymer material significantly reduces the solidification time of the sample (about 10 s shorter), and that under certain conditions, it is possible to obtain better cooling than obtained with the aluminum reference wax injection mold (after approximately 25–30 s). This approach allows to reduce the production costs of low-volume castings.

The main method to improve the filling of the cavity by the polymer melt is to increase the mold temperature. Rapid temperature cycling (RTC) technologies have been used around the world for several years, improving the quality of injection molded parts with a slight extension of production time. The present work focuses on the application of induction heating technology in the injection molding process since it is the most effective and most intensively developing method of heating in modern RTC technologies. In this research, the application of the induction heating process for selected surfaces was investigated with particular emphasis on the dynamics of the process. The numerical simulations were used to study the influence of the number of coils, the distance between coils and cavity surface and the mold material was examined with and without the presence of a magnetic concentrator. According to the obtained results, several crucial conclusions were made: the efficiency of heating is directly correlated with the distance between the inductor and the mold surface, the presence of magnetic flux concentrator significantly improves the homogeneity of temperature distribution and heating efficiency, application of aluminum mold lowers the obtained surface temperature.

The use of selective induction heating of molding surfaces allows for better filling of molding cavities and has a positive effect on the properties of molded products. This is particularly important in the production of parts that include flexible hinges, which are thin plastic layers connecting two or more parts of the product. By using hinges, it is possible to expand the use of injection molding products and their capabilities. They are widely used in the production of parts for the electrical engineering industry and for packaging Fast Moving Consumer Goods (FMCG). The use of hinges also entails specific reductions in wall thickness. Increases in the shear rate can be expected, which can lead to the degradation of polymers and deterioration of mechanical properties of materials. This paper investigates injection molded flexible hinge parts manufactured with selective induction heating to improve their properties. To verify the efficiency of reduction of material degradation due to high shear rates, open/close tests of elastic hinges were performed. The linear relation between the number of cycles the hinges can withstand, mold temperature and injection time was identified, where mold temperature was the more significant factor.