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针对复杂曲面恒定进给速度带来加工效率低下及表面质量差的情况,提出了基于切削力预测模型的铣削进给速度优化方法.首先,通过对刀位轨迹、曲面与刀具几何、刀/工切削接触区及动态切削厚度的分析计算,建立了多轴加工复杂曲面的切削力预测模型,从而得到了进给速度与切削力之间的映射关系.然后将给定的参考切削力与每个刀位点处的最大切削力之差的绝对值作为优化目标函数,通过Newton-Raphson迭代算法来调整原刀位点文件中的进给速度,以确保切削力的恒定以及机床系统的运行平稳.最后,以模型桨桨叶为对象,开展了相应的加工实验.实验结果表明:提出的优化方法使桨叶精加工的时间缩短了25%以上,表面残余应力和显微硬度得到增加,这对提高桨叶曲面的加工效率与改善加工表面质量具有明显的效果,从而验证了所提出的进给速度优化方法的有效性.
In view of the low processing efficiency and poor surface quality caused by the constant feed speed of complex curved surface, an optimization method of milling feed speed based on the prediction model of cutting force is proposed.Firstly, by optimizing the tool path, surface and tool geometry, Cutting contact area and dynamic cutting thickness, the cutting force prediction model of multi-axis machining complex curved surface is established, and the mapping relationship between the feed rate and cutting force is obtained.Then, The absolute value of the difference between the maximum cutting force at the knife point as an optimization objective function, through the Newton-Raphson iterative algorithm to adjust the feed rate of the original tool point file to ensure a constant cutting force and machine tool system running smoothly. Finally, the corresponding machining experiment is carried out on the model paddle blade.The experimental results show that the proposed optimization method can shorten the time for blade finishing by more than 25%, and increase the residual stress and microhardness of the blade, It has obvious effect to improve the machining efficiency of the blade surface and improve the machining surface quality. The validity of the proposed feed rate optimization method is verified.