Blow molding inflates a heated parison or preform inside a cooled mold to form hollow plastic parts. Using HDPE, PP, PET, and multilayers with precision tooling, the process produces bottles, tanks, ducts, and packaging with controlled wall thickness and strength.
Blow molding is a forming process used to produce hollow thermoplastic parts by inflating a heated polymer parison or preform inside a mold. In extrusion blow molding, a continuous parison is extruded and captured between mold halves, then inflated with air to conform to the cavity. Injection stretch blow molding uses an injection‑molded preform that is reheated, stretched axially, and blown to achieve high clarity and mechanical strength—common for PET bottles. Typical materials processed include HDPE, LDPE, PP, PET, PVC, and barrier multilayer structures. Tooling consists of precision‑machined aluminum or alloyed tool steel or stainless steel molds with optimized cooling channels, pinch‑off areas, blow needles, and venting to ensure uniform wall thickness and rapid cycle times. Process parameters such as melt temperature, parison control, blow pressure, stretch ratio, and cooling rate influence part strength, transparency, and barrier performance. Blow molding is widely used for bottles, tanks, ducts, containers, fuel reservoirs, and lightweight packaging in automotive, consumer goods, food and beverage, and industrial applications.