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Double milling CNC which is a newly developed kind of processing equipment,breaks the inefficiency and fussy situation of traditional machining units. It shorts the production period, cuts down the cost, increases the efficiency, and enhances competitiveness of enterprises, just by using double milling cutters working together. In this paper, the project bases on the theory of screw machining, researches how to form the helicoids, and how to insure the reposition accuracy of the cutters with the method of reverse backlash compensation.First of all, collect date—analyzing the current situation of the CNC miller and combining the needs of enterprises. Then, consider the whole design proposal and hardwares lectotype, mainly analyze the motion control system and CNC servo system.Secondly, study and analyze the hardware part of the double milling head efficient CNC. the design parameters and technical parameters of the screw, the milling parameters and the geometric element of the cutters.Thirdly, double milling CNC process the screw, for processing spiral frame of workpiece. When contour CNC milling, choosing the tool radius compensation function to realize the trajectory of tool.Fourthly, the formation of helicoid is on the base of the theory of engagement. The contact area between the cutter’s blade and the workpiece is a pair of conjugate surfaces, anywhen the two objects make relative motion, the two surface will always have a tangent line of engagement. The line can be interpreted as making from ample adherent points of fitting, every point spirals around the axis of the workpiece, getting the every helix of the helicoid, while the helix spirals making the helicoid. According to the research of the mesh surface, build the mathematical model, and make experimental analysis and processing by taking advantage of the software Matlab.Finally, it needed to repositioning the cutter at the very stop place, as the case of outage in the course of working. So the positioning accuracy will direct influence the machining accuracy of the screw. The knife will make a reverse clearance between feeding and retraction, which is a key factor of positioning accuracy. Make use of the software LabVIEW and write grogram about measure and offset of the gap, to achieve high accuracy.
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