Effects of water flow rate on transparent window size for form error in-process optical measurement

In-process form error measurement provides feedback for precision control. There many existing studies on in-process roughness and size measurement but few on in-process form error measurement. Water beam based in-process form error measurement is proposed to solve the opaque problem of the commonly used coolant in precision machining. Factorial test results show that the water flow rate Q w is one of the five important parameters to give a reasonably acceptable transparent window size A t for the in-process form error measurement. In this project, both experimental and computational studies were conducted and the results show that transparent window size A t will increase with the water flow rate Q w and will decrease with the height of medium hm, coolant concentration c c , table velocity v t , and water channel diameter Φ w . Based on the results of A t (Q w ,h m ) and the results of A t (Q w ,v t ), the ranges of Q w ∈[0.65,0.75] ml/s, h m ∈[0.5,0.55] mm, and v t ∈[120,150] mm/s would give a transparent window size A t ∈[20,40] mm 2 , which is reasonably acceptable for the laser measurement currently for the tests. The results will be useful for design of the in-process sensor.