An approach on wheel position and orientation calculation for helical broaching tool sharpening

Helical chip gullets play a crucial role in the performance of broaching tool. Well-sharpened helical rake flanks, which require accuracy of rake angle, smoothness of rake flank, and the safety of operators, are significantly to maintain its broaching performance. In this study, a wheel orientation and position calculating approach was developed to the resharpen of helical rake flank by a ring-like grind wheel. With modeling the process requirements of helical rake flank sharpening as the constraints like single side contacting and desired rotation direction of grinding wheel, the enveloping theory-based contact curve identification helped the wheel orientation calculation approximate to a nonlinear searching problem for easily addressing by Newton-Raphson method. Then, the analyses of contact curves with different wheel orientations and a ground helical rake flank proofed the sharpening process requirement was satisfied, and the examined results of rake angle for both ground rake flank and simulated bars verified the accuracy of the presented approach. At last, optimal grinding wheel setup that has taken larger wheel size and practicable orientation was suggested based on the relationship analysis among wheel radiuses and orientations.