The Challenge of Injection/Blow molding

The Throttle Cuff

PPI, because of its expertise, was asked to manufacture an automotive part for a customer that had tried to do it themselves and were not satisfied with the results. The challenge was to produce a cylindrical part that required both a precise internal dimension and flexibility in its structure.

The first attempt to make the part, shown on the left, was with a blowmold process. The internal diameter (at the front of the picture) can be seen as molded but it failed to produce a consistent dimension of the required high tolerance.

The picture to the right shows the part after production in the combination mold. An internal seal ring (on the front internal diameter) was produced by a straight injection process in the injection side of the combination mold and can be seen at the front of the picture. The rest of the part, because it required flexibility, was produced in the other half of the mold, after being mechanically positioned in the blow molding side of the combination mold.


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