Concurrent Cost Calculations With a Feature-Based CAD System

Abstract

The paper describes a procedure for calculating costs concurrent with the design process. The different modules of the computer program “IKF” are described. The modules include those for cost calculation, comparison and forecast. Form features are used for cost determination by classifying each feature and storing it in the detailed production plan. The production processes then follow from the list of stored features. The cost program takes the individual geometric data, e.g., part length, from the CAD program. The latter contains data sets, that describe the feature’s dimensions. The production time for the form feature is then calculated. From the time expenditures and the machine rates the program calculates the production costs for the given feature. Prior to developing the computer program a manual procedure was designed and developed. Upon testing, the group not using IKF took 40–50% more time and designed products that were about 80% costlier than the group using the IKF system. This procedure was then used as the model for the cost modules in a feature-based CAD program. Test cases dealing with sheet-metal design are described which demonstrate and quantify the advantages of this system.