凸曲面拼接模具球头铣刀的瞬时铣削力预测

在曲面模具拼接区域球头铣刀铣削过程中，刀具载荷变化大，瞬态铣削力有突变现象，影响模具拼接区域的加工精度和表面质量。为了预测拼接区域球头铣刀的瞬态铣削力，首先,建立考虑冲击振动的球头铣刀三维次摆线轨迹方程，得到瞬时未变形切屑厚度模型；然后,基于铣削微元的思想，建立凸曲面双硬度拼接模具球头铣刀的瞬态铣削力模型，该模型能够综合考虑拼接区冲击振动、硬度变化、刀具工件切触角度变化对瞬态铣削力的影响；最后,进行凸曲面拼接区域球头铣刀铣削加工实验。实验结果表明，预报的瞬态铣削力和实验测量结果在幅值上和变化趋势上具有一致性，在平稳切削时最大铣削力预测误差值基本在15%以内，验证了该模型能有效地预报凸曲面模具拼接区域球头铣刀的瞬态铣削力。

Prediction of the Instantaneous Milling Force of Ball End Milling Cutter for Convex Surface of Splicing Mold

During the milling of the ball-end milling cutter in the splicing area of the curved surface mold, the tool load changes greatly, and the transient milling force has a sudden change, which affects the machining accuracy and surface quality of the splicing area of the mold. In light of the prediction of its transient milling force in the splicing area, a transient undeformed chip thickness model is established based on a three-dimensional trochoid trajectory equation of the ball-end milling cutter considering impact vibration. Then, based on the idea of milling microelement, the transient milling force model for ball-end milling cutter of the convex curved surface and double hardness stitching mold is established. The model comprehensively considers the influence of impact vibration, the change of hardness and contact angle of the tool workpiece in the splicing area on the transient milling force. Finally, the milling experiments of ball-end milling cutter in the splicing area of convex surface is carried out. The results show that the predicted transient milling force and experimental measurements are consistent in magnitude and trend. The maximum milling force prediction error value is less than 15% during steady cutting. The experimental results verify that the model can effectively predict the transient milling force of the ball-end milling cutter in the splicing area of the convex surface of the splicing mold.