Preform test fixture and method of measuring a wall thickness

摘要

A preform test fixture for receiving a blow molding preform includes a structural base, a measuring device mount, a support arm, and a bar member having preform bores. The bar member is adjustable so that it translates up and down on the support arm, and is removably fastened thereto by a knob assembly screwed into a hole in the bar member. The system includes utilizing several bar members to enable the fixture to measure wall thicknesses of a virtually unlimited number of unique preform designs. The fixture also has a pivot device that enables the bar member to pivot on the support arm. The measuring device mount is adjustable on the base. The adjustment capability of the fixture enables uniform and repeatable wall thickness measurements, concentricity measurements at various locations, and preform tip wall thickness measurement proximate the preform gate.