Research On Dual-Cam Linkage Automatic Tool Change Technology

High-speed machining center is a typical product in high-speed machine tool. The development application of high-speed features has greatly improved the efficiency of cutting. With the shortening of cutting time, it is required to reduce tool change time. The speed of tool change has become an important indicator of high level machining center. Automatic tool change system, with relatively complex structure, must work accurately and reliably. It's difficult to increase the tool change speed. So automatic tool change technology has become one of the competitive focal points in machine tool manufacturing.Based on the study of domestic and foreign research and development about automatic tool change technology, the various types of tool magazine and tool exchange structure are discussed and compared. Dual-cam linkage automatic tool change techonoly is studied. The advantages and structural characteristics of dual-cam linkage mechanism are presented. With MDH horizontal machining center, the structural design and working principle of dual-cam linkage ATC are analyzed.Design the dual-cam linkage structure. Dual-cam includes a plate cam controlling tool bar movement and a composite cam (a slot cam inlaid on one side of a globoidal cam) controlling manipulator movement. The motion cycle chart of two sets of (three) cams is designed. The motion law of cam mechanisms is discussed, and modified sine (MS) curve and modified constant velocity (MCV) curve are chosen.A three-dimensional modeling method of globoidal cam is presented. Based on converse thinking, a modeling method is proposed. Theoretical profiles are built up on the blank model of globoidal cam combined with theoretical profile equations and movement laws, and working profiles are obtained by normal offset of the theoretical profiles and solid cutting operation. The accurate model of globoidal cam is completed after modification. A modeling example of the complex multi-head globoidal cam used in ATC of MDH horizontal machining center is carried out in Pro/E, and kinematics simulation is carried out. The result meet the design requirements, showing validity and feasibility of the method.Based on MDH horizontal machining center, the virtual prototyping of dual-cam linkage ATC is created, and simulation analysis is carried out. The displacement, velocity and acceleration measurements of linear motion of tool bar, linear motion and rotation movement of ATC manipulator match with the cam motion cycle chart and cam motion law design. At last, the problems of dual-cam linkage automatic tool change technology in practical application process are summarized, and recommendations and prospects are presented for the further work.