Optimal tolerance allocation for five-axis machine tools in consideration of deformation caused by gravity
- PDF / 1,395,614 Bytes
- 12 Pages / 595.276 x 790.866 pts Page_size
- 91 Downloads / 121 Views
ORIGINAL ARTICLE
Optimal tolerance allocation for five-axis machine tools in consideration of deformation caused by gravity Jinwei Fan 1 & Haohao Tao 1 & Ri Pan 1 & Dongju Chen 1 Received: 10 May 2020 / Accepted: 14 September 2020 / Published online: 23 September 2020 # Springer-Verlag London Ltd., part of Springer Nature 2020
Abstract Due to the effect of gravity on machine tools, the small deformations inevitably exist. The existing tolerance allocation methods are based on the rigid body assumption, which ignore the small deformations. It will make optimization results inaccurate and increase manufacturing cost. Therefore, a new optimal tolerance allocation method, which integrates the small deformations, is presented in this paper. The establishment of a geometric error model based on tolerance is involved at first. Based on this model and multi-body system theory, the mapping relationship between tolerance and volumetric error of the five-axis machine tool (FAMT) is formulated. Secondly, the small deformations of the FAMT are obtained based on finite element analysis. Then, the optimal tolerance allocation model is established by integrating the small deformations into the constraint conditions. Thirdly, simulation analysis is carried out with this model by using a genetic algorithm. Then, the optimal tolerance allocation scheme is obtained, and the total manufacturing cost after optimization is reduced by approximately 11.5%. Finally, the volumetric errors of the FAMT are calculated based on the two tolerance allocation schemes. The results show that the volumetric errors are within the permitted ranges. Therefore, the proposed method in consideration of the small deformation is feasible and effective. Keywords Five-axis machine tool . Rigid body assumption . The small deformation . Optimal tolerance allocation model . Total manufacturing cost
1 Introduction Five-axis machine tools (FAMTs) with clear advantages of higher material removal rate, fewer setups [1, 2], and higher machining efficiency [3] are extensively adaptable for the machining of sculptured surfaces [4]. The surface quality of the workpiece is significantly influenced by the machining performance of the machine tools [5, 6]. Since the machine tools’ machining accuracy is determined by the mutual coordination with the accuracy of machine tool components, improving individual components’ accuracy may increase the manufacturing cost instead of enhancing the machining
* Ri Pan [email protected] Haohao Tao [email protected] 1
Beijing Key Laboratory of Advanced Manufacturing Technology, Beijing University of Technology, Beijing 100124, People’s Republic of China
accuracy. Therefore, it is of great theoretical and practical significance to obtain an appropriate precision design scheme for machine tools cost-effectively while satisfying the desired machining accuracy requirement during the initial design stage of machine tools. As indicated by many engineering practices, a bad precision design scheme requires the component with extremely tight or l
Data Loading...
