Corner Thickness Measurement is a non-destructive test performed on flexible or rigid trays that have been produced by thermoforming. The test is done using a "Magna-Mike®
" gauge that consists of a probe and ball set-up whereby the magnetic probe and small steel target ball are placed on each side of the specimen to be measured and the thickness is determined by the measurement of magnetic flux. The technique is an improvement over using a standard micrometer as the area to be measured is curved, and the target ball is ideal for moving around the test corner area and finding the minimum thickness. Corner thickness is important to measure and control, as corners that are formed too thin risk producing holes in the package during distribution. Holes may be formed by abrasion, flex cracks and punctures, all of which become more likely the thinner the material. Corner thickness measurement may also be used in a designed experiment (DOE) as an output when studying thermo-forming inputs such as forming temperature, dwell time, vacuum, pressure, etc.