Recognition of interacting volumetric features using 2D hints

Abstract

Purpose

Recognition of machining features is an essential step in the development of efficient‐automated process plans from solid modeling data. This process represents the effective interpretation of the geometric data in a computer‐aided design (CAD) model to create semantically rich manufacture‐oriented features such as holes, slots, pockets, and others that may be exploited in downstream computer‐aided manufacturing/computer‐aided process planning applications. Most successful approaches towards feature recognition have been based on hint‐based procedures operating on a 3D B‐Rep model. The purpose of this paper is to propose an approach by which features are identified in a solid model that is built mainly using sweep solid modeling operations.

Design/methodology/approach

Part geometric model is queried for both 2D and 3D geometric elements. Feature hints are generated by an analysis of sweep operations and their 2D sketches, which are defined prior to building the solid model. These hints are then analyzed and validated by applying a two‐phase approach: 2D validation in the sketch geometry; and 3D validation in the final constructive solid geometry tree of the solid model. Valid hints are the basis for the creation of a machining feature model that can be input to a process planning module. In addition, interaction information for machining features is extracted from both 2D hints and their 3D validation. Feature interaction information is obtained by analysis of face/edge neighborhood and their geometric relations in both 2D and 3D spaces.

Findings

This approach provides a benefit of performing the majority of geometric analysis in 2D space which is much simpler and computationally more efficient than corresponding analyses in 3D space. Only minimal portion of the analysis is computed on 3D solid models. The approach is implemented in the Java‐based prototype system and is demonstrated and tested on several real‐world examples.

Research limitations/implications

The initial prototype implementation is limited to prismatic parts and linear sweep. Only hole and slot feature can be recognized due to the fact that pocket recognition appears to be trivial.

Practical implications

Motivation for this approach is in the fact that sweep operations from 2D sketches are very commonly used in the mechanical design process, so the approach may be applicable in practical applications of CAD.

Originality/value

This novel approach provides value to product designers and manufacturing planners since linear (extrusion) and circular (rotation) sweeps are very popular design engineer tools.

Citation

Šormaz, D.N. and Tennety, C. (2010), "Recognition of interacting volumetric features using 2D hints", Assembly Automation, Vol. 30 No. 2, pp. 131-141. https://doi.org/10.1108/01445151011029763