Semi-automatic extraction of digital work instructions from CAD models

Abstract

Currently process engineers are using documents or authoring tools to bring the assembly instructions to the work floor. This is a time-consuming task, as instructions need to be created for each assembly operation. Furthermore, the engineer needs to be familiar with the assembly sequence. To assist the engineer, a tool is developed that i) uses a heuristic based on visibility, part similarity and proximity to semi-automatically determine the assembly sequence from a CAD model and ii) according to the computed sequence generates digital work instructions including visualizations and animations extracted from the CAD model. In essence, the assembly sequence generation works reversely: it determines the order in which components can be removed from the assembly, by evaluating whether the visibility of a component is obstructed by the remaining assembly. The reversed order is then returned as assembly sequence. During this process the engineer can modify the proposed sequence, add annotations and alter the vi-sualizations of the proposed instructions, i.e., images or 3D-animations. We illustrate that the developed tool effectively supports process engineers and speeds up the creation of digital work instructions by some industrial validation cases, e.g., the assembly of a weaving machine.