弧面分度凸轮通用数控加工的进给速度控制

Cutting Feed Speed Control for General CNC Machining of Roller Gear Indexing Cam

为避免实际切削进给速度的变化降低弧面分度凸轮的加工质量,从编程进给速度F指令的物理意义入手,分析了弧面凸轮在通用数控机床上加工时的编程进给速度与实际进给速度的关系。研究表明,由于在通用数控机床上加工弧面凸轮需要包括两个旋转运动的4坐标或5坐标联动,使两连续刀位点之间的实际移动距离与当量移动距离的不相等,是造成刀具的实际进给速度与编程进给速度不一致的根本原因。根据编程进给速度与实际进给速度的关系,在编程时给每个程序段都安排各自所需的F指令值,凸轮加工时的实际进给速度就可保持为常量,加工出的凸轮工作廓面无刀痕,表面加工质量明显提高。研究结果为弧面分度凸轮数控加工进给速度的控制提供了理论依据,有较好的应用价值。

In order to avoid the status that the changing of actual cutting feed speed debases the CNC machining quality of roller gear indexing cam,starting with the physical meaning of the programming feed speed F command,the relationships between actual cutting feed speed and programming feed speed under the situation,which the roller gear indexing cam was machined in a general CNC machine tool,were analyzed.The results show that the difference between actual cutting feed speed and programming feed speed is caused by the difference between actual distance and equivalent distance of two sequential tool center positions,because the general CNC machining of roller gear cam requires 4 or 5 coordinate axes simultaneous movement including 2 rotate movement.According to the relationships between actual cutting feed speed and programming feed speed,every CNC program block is arranged a various programming feed speed,so the actual cutting feed speed of CNC machining of roller gear cam can be keep a constant value and the machining quality of cam is improved obviously.The research results are worth applying to engineering.