Blow Molding is accomplished by vertically extruding a hollow tube of molten plastic. This tube is called a "parison" in blow molding terms. The parison is then clamped between two mold halves and expanded into the desired shape by inflating it with compressed air. After cooling, a hollow part emerges.
 

Process Characteristics
Part cost - moderate Tooling Cost - moderate Production rate - moderate to high Blow molding produces parts with the highest strength to weight ratio of any plastic process. Complex, hollow parts are formed with no internal stresses. Parts as large as 12 ft. x 4 ft. x 4 ft. can be formed
Examples
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