This fixture is used to hold a subframe part in optical measurement system. It is fully automated by a PLC. There are 4 clamping points and 2 retractable locating pins. When the part is loaded to the fixture by the robot, clamps close one by one according to customer specific clamping sequence. After all clamps are closed, pins are retracted from the part, to be able to get optical visibility of the locating holes.
After the first optic measurement done, one corner of the part is released both on clamping side and on bottom side and then the part is measured again. The results are compared and seen how much difference there is when part is fully clamped versus clamped with 3 points, which is called twist.
Twist tower. To release the part totally, firstly the clamp opens, and then the linear sliding assembly goes lower, which releases the part’s 4th corner. One key topic in this assembly is that the clamp is mounted on the sliding unit, so that it does not push the datum down when it clamps. This assures that the datum is at the exact nominal location.
4 points subframe clamping fixture overview with twist functionality.
Design of Machinery and Automation 