6 - Blow Molding

Abstract

This chapter provides an overview of blow molding (BM). It is a process used to convert thermoplastics (TPs) into simple to intricate and complex shapes. The process is especially amenable to the goal of consolidating as much function as possible into making a single product. Like injection molding, the process is discontinuous in nature, involving a sequence of operations that culminates in the production of a molding. BM is a highly developed process with variant forms. Applications for BMs are used to contain many different products that include foodstuffs, beverages, household products, personal care products, medicine/pharmaceutical products, automotive parts, construction panels, tote boxes, trays, leisure items, and industrial parts. Blow molding can be divided into three major processing categories: extrusion blow molding (EBM) with continuous or intermittent melt producing a parison from an extruder, injection blow molding (IBM) with noncontinuous melt from an injection molding machine that fabricates a perform supported by a metal core pin, and stretched/oriented EBM and IBM to obtain biaxially oriented products that provide significantly improved performance-to-cost advantages.