Investigating the Effects of Forming Parameters on Molding Force and Springback in Deep Drawing Process of Thermoplastic Composite Laminates

Abstract

The automotive industry and research centers have intensified the search for innovative solutions in the field of material technologies and have recently accelerated their work on thermoplastic based composites in line with their requirements. Thermoform method is used for rapid forming of thermoplastics and composites. In this process, mold design and especially molding parameters are important for part quality. Thermoplastic composite sheets take the shape of their final form by spring back after they come out of the mold as in sheet metals. Therefore, springback is a parameter that should be taken into account in the manufacturing process and product design. In this study, preliminary research was carried out to design the forming process in thermoform mold. The experiments were done on Nakajima test setup and according to ISO 12004 standard. In the deep drawing of thermoplastic composite laminates, the effects of different holding pressure (0.4; 0.6; 0.8 MPa), punch speed (90, 120, 150 mm/min), specimen temperature (129, 159, 169 oC) and piece depth (20, 25, 30 mm) parameters on the molding force were examined and the spring back amount of deep drawn specimens was determined. As a result of the experiments, as the specimen temperature increased the molding force decreased. The molding force increased as the holding pressure increased. Increasing punch speed caused an increase in required molding force. As a result of the experiments, it was concluded that deep drawing can be made up to a depth of 25 mm.