Algorithms for grouping machining operations and planning workpiece location under dynamic machining conditions

In this paper, algorithms are presented to develop an integrated system to generate machining groups for set-ups and to plan workpiece location layouts for fixture design. The objective of the proposed system is to overcome the deficiencies of existing set-up planning and fixture design approaches. Parts are described in terms of machining features that consist of attributes required for automation and integration. The approaches of machining feature-based design and precedence matrix algorithm are conbined to automate the process-planning task and to generate the machining groups for set-ups. An algorithm for selecting the locating and clamping positions of the workpiece is presented to configure the fixture in terms of modular elements. Fixture configuration verification analysis is carried out for time-varying machining forces to ensure that the workpiece will be held against cutting and clamping forces. The chip-removal effect is taken into account for stability analysis using finite-element analysis technique. An example is included to illustrate the application of proposed system.