Blow molding is a process in which air pressure is utilized to fill molten plastic into a mold cavity. Blow molding is a very important industrial process to make hollow plastic parts with thin walls including bottles and other type of containers. Since it is used very heavily, production of these plastic products is organized for high quantities. Blow molding machines operates in two basic steps: fabrication of a small tube of molten plastic also called parison, and inflating the tube to bring the final shape. Forming a parison can be done through extrusion or injection molding. A wide range of hollow parts such as plastic bottles are produced from different plastic materials through a blow molding process. However, there are three basic ones: stretch blow molding, extrusion molding, and injection molding. The products made through a blow molding machine can be made in a range of sizes and shapes. LDPE, HDPE, PET, PP, and PVC are the thermoplastic materials used in a blow molding machine to form molded parts.