BUTTON RATCHET FIXTURES

I was approached by the metrology team at SMC with task of designing a fixture to suspend a manufactured part to allow for measurements to be taken. This part, called a button ratchet, was made of glass filled nylon and needed measurements to be taken on multiple planes by a vision measurement system that used a back light and camera to measure the outline of the part.

The first iteration of the fixture was my first test of fabrication at SMC. I was given a designed made by a previous co-op as well as all the materials necessary and was taught how to program a Bridgeport CNC. This design used springs to hold the part sideways while the measurements were taken as well as slots for the parts to lay face down on the back light.

The second iteration of this fixture was requested due o a change in the part that added slopes to the interior of the ratchet. My design included spring loaded plates with teeth to clamp the part in place. The teeth were added to create a contrast against the black molded part because the vision system was having trouble finding edges. Part of the issue was the glass in the nylon was creating reflections, making the software not consistently pick up the points selected for measurement.

The third design was made after the decision was made to change the measurement method to a CMM that uses a very sensitive pointer that touches the part and takes not of where in 3D space that contact was made. It uses magnets to clamp the part while a CMM takes measurements.