等法向前角和等径向后角微细球头铣刀刃磨研究

Research on Grinding of Micro Ball End Mill with Equal Normal Rake Angle and Equal Radial Relief Angle

微细球头铣刀因其在制造复杂的曲面和零部件方面具有很大的优势而广泛应用于微机械加工领域。目前多轴数控磨削方法仍是实现微细球头铣刀批量化制造的主要方法,但是由于微细球头铣刀尺寸小,误差敏感性大,在刃磨过程中难以保证其制造精度和质量,因此迫切需要精确高效的刃磨方法来提高微细球头铣刀制造精度,降低其刃磨制备难度。为此,基于球面等导程螺旋线切削刃曲线,提出了用于等法向前角前刀面的刃磨模型。为了实现球部和圆柱形部分的后刀面的平滑连接,提出了等径向后角后刀面的刃磨模型。基于提出的刃磨模型和6轴CNC磨床运动原理,通过Matlab编程求解等法向前角和等径向后刀面微细球头铣刀刃磨过程中机床各轴运动轨迹。最后,通过磨削仿真和实验成功制造了直径为0.5mm的硬质合金微细球头铣刀,其最大几何误差不超过5%,从而验证了磨削方法的正确性和有效性。

The micro ball end mill is widely used in micro machining industry,with its great advantage in the manufacturing of complex surfaces and parts.At present,multi-axis CNC grinding is still the main method to realize the mass production of micro-ball milling cutter.However,due to the small size and error sensitivity of the micro-ball milling cutter,it is difficult to guarantee the manufacturing precision and quality in the grinding process.Therefore,there is an urgent need for precise and efficient grinding methods to improve the manufacturing accuracy of micro-ball milling cutter and reduce the difficulty of its grinding.So a mathematical model for manufacturing the rake face with equal normal rake angle is proposed based on the cutting edge curve.In addition,a mathematical model is proposed for manufacturing the clearance face with equal radial clearance angle to achieve the smooth connection of the clearance faces of the ball part and cylindrical part.And then,based on the proposed grinding model and the motive principle of Makino 6-axis CNC grinding machine,the kinematic trajectories of the machine tool in the grinding process of micro ball-end mill with equal normal rake angle and equal radial relief angle are calculated by Matlab programming.Finally,the cemented carbide micro ball-end mill with 0.5 mm diameters is obtained by grinding simulation and experiment,which maximum geometric error is less than 5%.So the correctness and effectiveness of grinding methods are confirmed.