Deformation Analysis and Fixture Design of Thin-walled Cylinder in Drilling Process Based on TRIZ Theory

Thin-walled cylindrical workpiece is easy to deform during machining and clamping processes due to the insufficient rigidi.Moreover,it’s also difficult to ensure the perpendicularity of flange holes during drilling process.In this paper,the element birth and death technique is used to obtain the axial deformation of the hole through finite element simulation.The measured value of the perpendicularity of the hole was compared with the simulated value to verify then the rationality of the simulation model.To reduce the perpendicularity error of the hole in the drilling process,the theory of inventive principle solution(TRIZ)was used to analyze the drilling process of thin-walled cylinder,and the corresponding fixture was developed to adjust the supporting surface height adaptively.Three different fixture supporting layout schemes were used for numerical simulation of drilling process,and the maximum,average and standard deviation of the axial deformation of the flange holes and their maximum hole perpendicularity errors were comparatively analyzed,and the optimal arrangement was optimized.The results show that the proposed deformation control strategy can effectively improve the drilling deformation of thin-walled cylindrical workpiece,thereby significantly improving the machining quality of the parts.

Variation characteristic of drilling force and influence of cutting parameter of SiCp/Al composite thin-walled workpiece

In this paper,the variation characteristic of the drilling force,and the influences of cutting speed,feed rate,and workpiece thickness on the drilling force,were eval・uated when drilling a silicon carbide particle reinforced aluminum matrix(SiCp/Al)composite thin-walled workpiece with a high volume fraction.Under the condition that the workpiece thickness was less than the drill tip height,three characteristic stages of drilling force variation were proposed.The results indicate that there is a sign币cant difference between the variations in the drilling force when drilling a thin-walled workpiece compared to thick-walled workpiece.When the chisel edge drills out the lower surface of the workpiece,there is an abrupt decrease in the thrust forces of the thin-walled and thick-walled workpieces.In addition,there is an abrupt decrease in the torque of the thick-walled workpiece,whereas that of the thinwalled workpiece increases.According to the thickness of the thin-walled workpiece,the instant of the abrupt decrease in the thrust force may lead or lag behind the theoretical instant at which the chisel edge reaches the lower surface of the workpiece without deformation.When drilling a thin-walled hole,the cutting speed has a slight influence on the thrust force,and there is a slight increase in the torque in accordance with an increase in the cutting speed.The thrust force and torque increase in accordance with an increase in the feed rate.When drilling a thinwalled workpiece with a thickness of 1 mm,the critical thickness of workpiece cracking decreases in accordance with an increase in the cutting speed,and increases in accordance with an increase in the feed rate.When drilling a thin-walled workpiece with a thickness of 0.5 mm,the concave deformation of the workpiece and the critical thickness of the workpiece cracking increase in accordance with an increase in the feed rate.However,the increment in the critical thickness of the workpiece cracking is less than that in the concave deformation of the workpiece.

热熔钻钻孔成型在空调管路件中的应用研究

为了实现简便快速、经济有效的薄壁工件联接,分厂开发出了一种无屑钻孔技术——热熔钻钻孔成型,应用于空调件管路件薄壁钻孔成型。它可通过一次性加工,在实现无屑钻孔的同时,利用加工部位的材料(紫铜)形成支承衬套。同时,工件表面形成一个凸环。紫铜相关管路件在钻孔成型的过程中存在凸环工艺要求,同步要求钻孔表面无毛刺铜屑,热熔钻钻孔技术能够完美实现以上三种工艺要求。它在空调件中的应用,使传统的紫铜薄壁工件联接孔位加工方式发生了根本变革。