The injection molding process is difficult due to the phenomena such as contraction, production of parts with exact and respective measures. The contraction phenomenon is unavoidable in the injection molding processes and is the cause of defects such as warpage. Therefore although the injection process is superficially a simple process but in practice has specific complexities [1]. In consideration thereof, perusing the warpage of injection material and its prediction in design stage is very important. For this purpose, in continue the warpage value was calculated for two PP/PE materials based on the different composition ratio, cooling time, packing pressure, and injection pressure. The tests were carried out by experimentally and Taguchi method was used for selecting the number of samples. Upon comparing the results of analysis, it is concluded that packing pressure has the most effect on the warpage.
