Study on deformation and compensation for micromilled thin walls with high aspect ratios

Yang Li,Guangming Zheng,Lei He,Xiang Cheng,Siying Ling

doi:10.1007/s00170-021-07833-6

Abstract

In order to further improve the dimensional accuracy of micromilled thin walls with high aspect ratios, the machining process should be actively controlled. A device for active cutting force measurement and cutting parameter compensation is developed to realize the real-time measurement of radial cutting forces and compensation of radial cutting parameters in thin wall cutting process. Firstly, a mathematical model is established to calculate the deformation and cutting force of thin walls based on the cantilever beam deformation theory. The thin wall deformation in the cutting process is estimated by measuring the cutting force. Then, the obtained incremental thin wall deformation is to be compared with the compensation threshold, which is set at 0.5 μm. If the value of the incremental deformation is less than 0.5 μm, compensation will not be processed. Otherwise, the incremental deformation is used as the compensation value for iterative compensation, until the incremental deformation of the thin wall is less than 0.5 μm. At last, a contrast experiment is carried out. The experimental results show that the introduced device and compensation method are feasible. Machining quality of the thin wall has been obviously improved in dimension precision after the cutting parameter compensations.

Highlights

Thin wall parts with high aspect ratios are widely used in aerospace, electronics, die and other industries, the CNC machining method is generally adopted in the production of thin wall parts, among which high-speed milling is the most widely used one
3.1 Thin wall deformation model A stable cutting load is obtained by extracting the peak value of the cutting force of several successive cycles, which is applied as the concentrated load on the thin wall
In order to verify the reliability of the model and whether the dimensional errors are reduced after the cutting parameter compensation, the contrast experiments with and without compensations are conducted using the introduced device. 4.1 Experiment setup

Summary

Introduction

Thin wall parts with high aspect ratios are widely used in aerospace, electronics, die and other industries, the CNC machining method is generally adopted in the production of thin wall parts, among which high-speed milling is the most widely used one. Wang has proposed a numerical control compensation method for thin wall parts machining to reduce the errors generated by the elastic deformation of workpiece. In the multi-level cycle method, iterative calculation was carried out between the modified tool point, the cutting force model and the machining deformation until the machining surface error meets the given accuracy requirements [9]. Hou aimed at the problem of cutting deformation in the process of thin wall parts machining, a learning control method on machining error compensation was proposed. Based on elastic deformation theory, the nonlinear function relationship between machining error and nominal cutting depth was established, and a general model of machining error compensation for thin wall parts was constructed by using the compensation idea, that is the calculation method of nominal cutting depth in the cutting. The deformation value is used as the compensation value by the cutting parameter compensation device to reduce the dimensional error caused by thin wall deformation

Thin wall deformation mechanism and compensation device

Thin wall deformation model and compensation method

Contrast experiment

Conclusions