PVC blow molding, also known as hollow blow molding, uses gas pressure to inflate a hot-melt preform closed in a mold to form a hollow product.
The process is usually an extrusion + blow molding process. The figure shows that the material is melted and extruded to produce a semi-molten tube billet. The tube billet is expanded and close to the inner wall of the mold by passing compressed air into the preform, forming the shape of a hollow product. After cooling, we can get a perfect PVC bottle or PVC shrink film.
Compared with blow molding, the process of PVC injection molding is simpler. Its process mainly includes 6 stages: mold closing, filling, pressure holding, cooling, mold opening and demolding.
PVC injection molding products are very common in daily life, such as PVC shoes, PVC auto parts, PVC pipe fittings, and PVC ball valves.