3.1. Physical model, FEM analysis
Implementation of FEM analyses into development project was done due to authors’ long experiences with such packages and possibility to perform different test in the virtual environment. Whole prototype cooling system was designed in FEM
environment (see Fig. 5) through which temperature distribution in each part of prototype cooling system and contacts between them were explored. For simulating physical properties inside a developed prototype, a simulation model was constructed using COMSOL Multiphysics software. Result was a FEM model identical to real prototype (see Fig. 7) through which it was possible to compare and evaluate results.
FEM model was explored in term of heat transfer physics taking into account two heat sources: a water exchanger with fluid physics and a thermoelectric module with heat transfer physics (only conduction and convectionwas analysed, radiation was ignored due to low relative temperature and therefore low impact on temperature).
Boundary conditions for FEM analyses were set with the goal to achieve identical working conditions as in real testing. Surrounding air and the water exchanger were set at stable temperature of 20 ◦C.
Fig. 6. Temperature distribution according to FEM analysis.
Results of the FEM analysis can be seen in Fig. 6, i.e. Temperature distributi
through the simulation area shown in Fig. 5. Fig. 6 represents steady state analysis which was very accurate in comparison to prototype tests. In order to simulate the time response also the transient simulation was performed, showing very positive results for future work. It was possible to achieve a temperature difference of 200 ◦C in a short period of time (5 s), what could cause several problems in the TEM structure. Those problems were solved by several solutions, such as adequate mounting, choosing appropriate TEM material and applying intelligent electronic regulation.
3.2. Laboratory testing
As it was already described, the prototype was produced and tested (see Fig. 7). The results are showing, that the set assumptions were confirmed. With the TEM module it is possible to control the temperature distribution on different parts of the
mould throughout the cycle time. With the laboratory tests, it was proven, that the heat manipulation can be practically regulated with TEM modules. The test were made in the laboratory, simulating the real industrial environment, with the injection
moulding machine Krauss Maffei KM 60 C, temperature sensors, infrared cameras and the prototype TEM modules. The temperature response in 1.8 s varied form +5 up to 80 ◦C, what represents a wide area for the heat control within the injection moulding cycle.
4. Conclusions
Use of thermoelectric module with its straightforward connection between the input and output relations represents a milestone in cooling applications. Its introduction into moulds for injection moulding with its problematic cooling construction and problematic processing of precise and high quality plastic parts represents high expectations.
The authors were assuming that the use of the Peltier effect can be used for the temperature control in moulds for injection moulding.With the approach based on the simulation work and the real production of laboratory equipment proved, the assumptions were confirmed. Simulation results showed a wide area of possible application of TEM module in the injection moulding process.
With mentioned functionality of a temperature profile across cycle time, injection moulding process can be fully controlled. Industrial problems, such as uniform cooling of problematic A class surfaces and its consequence of plastic part appearance can be solved. Problems of filling thin long walls can be solved with overheating some surfaces at injection time. Furthermore, with such application control over rheological properties of plastic materials can be gained. With the proper thermal regulation of TEM it was possible even to control the melt flow in the mould, during the filling stage of the mould cavity. This is done with the appropriate temperature distribution of the mould (higher temperature on the thin walled parts of the product). 注塑模具电力驱动温度调节系统英文文献和中文翻译(3):http://www.youerw.com/fanyi/lunwen_33484.html