A 3D Numerical and Empirical Study on the Effects of Injection Pressure and Temperature on the Quality of Produced Mold

Plastic injection is a method in which by using an extruder plastic granules are injected in a hole with high pressure. Because of meeting the two flow fronts in this process, a welding line will be made. Along the welding line, the strength of produced part is low; therefore, the position of welding line and its clarity are very important. In this paper, analysis has been done with Fluent and Mold Flow softwares. In addition, verification of these analysis have been done with practical experiments in order to study the effect of injection pressure and temperature on the welding line and its clarity. The materials used in these experiments are ABS and PP. Results show that applying different injection pressures and temperatures affects the strength of the produced part. It is worth noting that both considered polymers are sensitive to pressure at high temperatures. For instance, pressure increase from 45 MPa to 65 MPa at 210 °C results in 35% and 45% reduction in plastic region, respectively. Temperature increase from 170 °C to 210 °C reduces the modulus of elasticity by about 16%. For the ABS polymer, the plastic region increases 13% at the injection pressure of 55 MPa and 65% at the injection pressure of 65 MPa. Temperature increase from 190 °C to 230 °C reduces the elastic modulus by 8%.