面向装夹成功率的“一面两销”夹具精度设计

Precision Design of “One Side with Two Pins” Fixture for Probability of Assembly Success

为提高床头箱盖零件在机床上的加工效率、保证加工精度,在设计“一面两销”定位的专用夹具时,须在保证工件与夹具之间装夹成功率的前提下,优化定位元件(定位特征)的精度设计。考虑了定位销/孔的几何公差与公差原则,采用MATLAB蒙特卡洛模型模拟定位销/孔的实际加工尺寸与间隙分布情况。利用定位销/孔装夹成功率数学模型进行公差分析并进行优化设计。与传统的夹具精度设计方法相比,该方法能在保证零件与夹具定位精度的前提下,提高夹具与被装夹工件间的装夹成功率,从而提高工件加工效率。

In order to improve the machining efficiency of the headstock cover parts on the machine tool and ensure the machining accuracy, the accuracy design of positioning elements (positioning features) must be optimized on the premise of ensuring the probability of assembly success between the workpiece and the fixture, when designing the special fixture for “one side with two pins”. MATLAB Monte Carlo model is used to simulate the actual machining dimension and clearance distribution of the locating pin/hole, the geometric tolerance and tolerance principle of the locating pin/hole are taken into consideration as well. The tolerance analysis and optimization design are carried out by using the mathematical model of probability of assembly success of the locating pin/hole. Compared with the traditional fixture precision design method, this method can improve the probability of assembly success between the fixture and the workpiece to be clamped under the premise of en-suring the positioning accuracy of parts and fixtures, thus improving the machining efficiency of workpieces.