V形块槽半角偏差对工件定位精度的影响

Influence of half angle deviation of groove of V-shaped block on workpiece positioning accuracy

为探究回转体类工件在V形块上定位时V形槽半角偏差Δ_(α)对定位误差的影响,以注塑模具浇口套止转槽加工为例,采用极限位置法,分析了三种工序尺寸下单因素V形槽半角偏差Δ_(α)、工件尺寸偏差Δ_(d)和双因素Δ_(α)、Δ_(d)对工件定位和几何误差的影响,分别推导出了误差的计算公式,获得各因素下工件不同工序尺寸产生定位误差的特征。结果表明,单因素Δ_(α)时,引起各工序尺寸的定位误差均为0.122 mm,Δ_(α)引起的定位误差与工序基准无关,产生0.244 mm的对称度误差影响了加工表面的位置精度。双因素Δ_(α)、Δ_(d)综合作用产生的定位误差是各因素对定位误差产生影响在工序尺寸方向上的代数和。

This paper is aiming to study the influence of the half-angle deviationΔ_(α)of the V-shaped groove on the positioning error when the rotary part is positioned on the V-shaped block.The study consists of taking the injection mold processing of the stop groove for sprue brushing as the model,analyzing the influence of the three kinds of process sizes including the single factor of the half-angle deviationΔ_(α)of V-shaped groove,the work piece size deviationΔ_(d)and the combined factorΔ_(α)、Δ_(d)on the workpiece positioning error and geometric error by using the limit positions method;deriving the two error calculation formulas respectively as mentioned,which show the characteristics and rules of the positioning error caused by various factors on different process sizes of the workpiece.The results show that the positioning error of every process size is 0.122 mm caused by the single factor of the half-angle deviation,which is unrelated to the working procedure benchmark,and produces a symmetry error by 0.244 mm which affects the position accuracy of the workpiece surface.The comprehensive effect of the double factorsΔ_(α)、Δ_(d)on the positioning error is the algebraic sum of the positioning error caused by all factors in the process dimension direction.