Comparative research on contact and non-contact measuring methods of 3D twisted blades in a torque converter

The contact and non-contact measuring methods were adopted to measure the twisted blades of the turbine in a casting torque converter. The curves were reconstructed using the B-spline and Bezier curve. Then the blade parameters were extracted based on the conformal transformation. Compared with the original data of the designed blades, measuring results of both methods were effective, while errors existed during both measuring processes including data missing error, measurement error and fitting error. Compared with the contact measuring method, the non-contact measuring method needed improvement because of its larger errors, which is mainly caused by the shrink and distortion of silicone rubber. But non-contact measuring method will be a trend in measurement system because of its own advantages such as expeditiousness, automation and the ability of acquiring relatively comprehensive information.