Knowledge-Based Tool for Assurance of Car Body Dimensional Quality in Design

The dimensional quality of the car body is built on quality management of form, fitment, and functional requirements. Each of these attributes reflects the final product quality and, therefore, needs to be ascertained quantitatively. Design intent and functionality conformance with specifications are paramount to performance, and thus quality. It is accomplished through optimal Geometric Dimensioning and Tolerancing of parts (GD&T), datum/Primary Locating Points (PLP) strategy, tricks/levers, and assembly design. Challenges stem from the complexity involved in the datum layout strategy and its optimization for desired deviations. Incorrect datum schemes in design prompt underconstrained fixtures, redundant datum, the sensitivity of datum layout, etc. and induce defects in later stages. The end effect is smoothing out the variation issues leading to compromise in quality. Hence, robust datum schemes and checks become imperative for high-quality standards, and keep components within tolerance. The article presented here provides a design aid for quality assurance of datum and assembly dimensional quality targets at the early stages of design. The methodology will be supported through the design and development of a knowledge-based tool containing the creation and validation of datum design parameters for manufacture and assembly for the first-time-right design itself. Based on the analysis, minimizing errors in the datum scheme in the design process such as underconstrained fixture, redundant datum, and inefficient datum layout and defects are contained effectively without affecting development cycle time, cost, and quality.