Virtual Locator Trimming in Pre-Production-Rigid and Non-Rigid Analysis

Paper in proceeding, 2005

In pre-production, during assembly of newly produced components geometrical deviations, caused by form errors of the parts, are discovered that can cause either functional or esthetical problems. One commonly used way of solving this is to reposition the components by adjusting their locators, also known as trimming. Traditionally this is done by assembling a number of components, measuring the deviations to surrounding parts, adjusting the locator points, reassembling the components and measuring the result. This is repeated until the result is satisfactory, and is a quite time and effort consuming activity. This paper presents a method and a tool that simplifies this process. Based on inspection data from the initial components all trimming activities are performed in the computer tool presented. After the locators are adjusted, the result is presented directly, which eliminates the need for physical inspection in order to verify the result of the trimming. The presented tool also includes optimization of the trimming. By formulating the problem of minimizing the geometrical deviations as a linear least square problem a general optimization package can be used. The optimization handles both boundaries on the allowed trimming and weighting of the different inspection features. By using the method of influence coefficients, also compliant (non-rigid) components can be handled.