Laser machining and compensation truing of small concave-arc bronze-bonded diamond grinding wheels

Abstract

A laser can be effectively used as a “dressing pen” to dress super-abrasive forming grinding wheels. However, laser truing and sharpening methods are in their primary stages. Problems caused by poor dressing persist in the absence of a theoretical analysis of trimming, and there is no effective compensation algorithm to correct actual and theoretical deviations. A pulsed fibre laser was used to dress a small concave arc-profiled 230# bronze-bonded diamond grinding wheel in this study. The Canny-based sub-pixel edge detection algorithm was improved to effectively enhance the detection of circular edges. Experiments were performed on coarse laser dressing of profiling concave-arc wheels, and the regularity of the radius, angle and depth of the arc was investigated. An error analysis model for the laser profiling of small concave-arc grinding wheels was developed and used to determine the factors causing error and that the concave-arc grinding wheel produces a minimum roundness error of 34 μm under the considered experimental dressing conditions. A novel error compensation method for trimming was developed, the horizontal approximation compensation method (HACM). Compensated trimming experiments were performed with effective error compensation. The final trimming dimensional error was approximately 11.2 μm, and the roundness error was approximately 22.8 μm. The main external factors causing these errors were laser thermal effects and the burrs detected on the graphite plate.