Research And Developmeng On Auto-programming System For CNC Gear-hobbing

The gear is an important element in machine building,and gear hobbing is one of the most widely applied processing methods. The manual programming method of gear hobbing, which uses manpower to carry on processing procedure, computing , compiling programmings, inputing programmings, checking programmings and so on, usually leads to huge calculating work, high error rate and low efficiency. General CAD/CAM automatic programming software,such as Pro/E,UG and so on, needs the precise geometry modle of parts and then extract the geometry and process information to generate NC code. However,the precise profile of gear is hard to draw,so it does not adapt to CAD/CAM software to generate NC code.In order to solve this problem effectively, according to characteristic that the finite parameters determine the shape and size of gear, this thesis propose a suitable auto-programming method of gear hobbing. The core of the method is inputting a certain gear parameters, hob parameters, technology parameters and so on through people-machine interface, which automatically generate NC code of gear hobbing by parameter processing module in support of the operational and technology database.In this thesis, the research emphasis is put on auto-programming of elliptical gear and oval gear which is widely applied in non-circular gear. On the base of the processing theory of non-circular gear hobbing, the mathematical mode of machining elliptical and oval gears is established. According to the characteristic that finite parameters determine gear shape,the idea of auto-programming of the processing of gear hobbing is analyzed,on the base of which study the skeleton of the auto-programming system of the gear hob processing. Adopting object-oriented technology , people-machine interface is realized and parameter processing module, simulation module is designed. Because of the handicap that the cutting parameters depend on the experience of operators, the optimization of cutting parameters is studied and multi-objective optimization model for gear hob parameters is established. The programming system has the function of generating NC codes, parameters inputting and validation,the inquer of the technology parameters and optimization and so on.The auto-programming system of CNC gear hobbing, can avoid the shortage of manual programming, shorten the production period of gear, improve the utilization efficiency of CNC machines and decrease the professional technical threshold.