Study And Experiment On Grinding Wheel Dressing Technology Of Modification Profile Form Grinding Of ZN Worm

ZN worm is also called straight sided normal worm. It usually needs modificationprofile in important applications, in order to improve meshing performance. Buttraditional worm grinder, which equipped mechanical grinding wheel dressing device, isoften difficult to achieve the modification profile grinding. In this project, the NCdresser of formed grinding wheel was researched for the modification profile formgrinding of ZN Worm.In the thesis, taking the left gear tooth surface of ZN worm as example, the theoryof form grinding was analyzed, and the tooth flank equations of worm was deduced,according to the principle of spiral face. The modification profile was calculated in thenormal plane of ZN worm. The parameters of modification ratio and depth were set upto achieve the precise profile of ZN worm. Then shape section of formed grindingwheel was calculated by space meshing theory. The obtained section contour ofgrinding wheel was a series of discrete dots. In order to obtain the smooth sectioncontour of computerized numerical control(CNC)-mechining, this paper proposed thedouble-arc fitting method for optimization approach of discrete dots.For the grinding wheel dressing of the formed grinding of ZN worm, usingdiamond dressing roller as the tool, the method of CNC-dressing of the formed grindingwheel was researched in this paper. With adjustable parameters, it is more efficient tocontrol the modification profile of worm by analyzing the process of grinding wheeltruing with parameters of diamond dressing size. Also, a pragmatic scheme for formedgrinding wheel dressing was proposed. According to the technological requirements ofgrinding wheel truing, this paper shows brief specification of the mechanical system andcontrol system.Considering the practical manufacturing condition, a dual lead ZN worm wasselected for the experiment of worm grinding and wheel dressing. While modificationprofile was calculated, the NC machining program of dressing was acquired afteranalyzing the process of one tapered side grinding wheel truing. The process of grindingwheel dressing was accomplished on the NC dresser and the worm grinding wascompleted on worm grinder in factory. According to the probable mechanical errorduring the process of grinding, this paper proposed a method of error-compensationanalysis based wheel dressing, which had been experimentally verified. After worm grinding, tooth shape detection and wheel dressing, the profile grinding accuracy of thedual lead modification profile ZN worm was achieved to6levels or above, whichproved the practical applicability of the grinding wheel dressing technology in thisproject.