A rmation of Enhanced Product Design using GD&T and Concept of Torsors in Tolerance Analysis

Abstract

Cost and quality of a product are prime drivers in manufacturing. It is important to optimize these variables for maximum bene t. It is to be noted that higher quality means a product which has lesser errors and thus more close to ideal product. The quality of product is associated with precision of manufacturing system but such machines are expensive. Therefore, a method of machine selection is devised based on tolerance range. Dimensional and geometrical tolerances are applied for manufacturing a quality product. In this work, a two part assembly is taken as a case study example. Tolerances are applied at three di erent conditions i.e. Least material condition (LMC), Maximum material condition (MMC) and Regardless of feature size (RFS). Then tolerance stack-up analysis is performed for all three conditions separately. The resulted minimum and maximum values for allowable variation range is compared which gives us an optimized method to design the product for manufacturing.It is followed by the torsor linkage model for case study parts in which e ect of Geometric tolerances on part precision and selection of machine to manufacture the part is analyzed. Standard tolerance classes have been used to de ne the parts under study. Part geometry is de ned in terms of form, orientation and position which are su cient to quantify the possible variations which might cause errors. Angle components of torsors for parallelism and perpendicularity constraints are controlled and evaluated at several standard deviations. The results are in compliance to proposed idea that a less precise machine can produce high quality product within a speci c tolerance range.