Institute for Systems Research

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Author: search.filters.author.Zhang, G.M.Subject: search.filters.subject.flexible manufacturing

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    Building MRSEV Models for CAM Applications
    (1993) Gupta, Satyandra K.; Kramer, Thomas R.; Nau, D.S.; Regli, W.C.; Zhang, G.M.; ISR
    Integrating CAD and CAM applications, one major problems is how to interpret CAD information in a manner that makes sense for CAM. Our goal is to develop a general approach that can be used with a variety of CAD and CAM applications for the manufacture of machined parts.

    In particular, we present a methodology for taking a CAD model, extracting alternative interpretations of the model as collections of MRSEVs (Material Removal Shape Element Volumes, a STEP-based library of machining features), and evaluating these interpretations to determine which one is optimal. The evaluation criteria may be defined by the user, in order to select the best interpretation for the particular application at hand.

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    Implementation of an Integrated CAD and CAM System
    (1992) Chen, A.T.; Zhang, G.M.; ISR
    This is a progress report on a joint research project between the University and the M.S. Willett, Inc. The research focus is on the integration of a CAD system and a CAM system currently being used at the Willett.

    The development of CAD systems has revolutionized the process of preparing engineering designs and drawings. Likewise, CAM systems have significantly impacted the stop floor production process. Numerically controlled machines have improved accuracy and productivity in many applications. Integration of these two systems would tie the design phase of a project to the production process, and if done efficiently, could result in significant cost reduction and quality improvement.

    In this project, two computer programs have been developed to automate NC code generation directly from a CAD file, either in DXF format or in IGES format. These two programs have been successful in identifying the important elements of an integrated CAD and CAM system. The initial results also indicated how the Willett could shorten the time of product development cycle, low the production cost, and improve the quality of end products.

    This project has been supported by the Center for Manufacturing on the College Park campus.

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    Generation and Evaluation of Alternative Operation
    (1992) Nau, D.S.; Zhang, G.M.; Gupta, Satyandra K.; ISR
    This paper presents a new and systematic approach to assist decision-making in selecting machining operation sequences. The approach is to produce alternative interpretations of design as different collections of machinable features, use these interpretations to generate alternative machining operation sequences, and evaluate the cost and achievable machining accuracy of each operations sequence. Given the operation sequences and their evaluations, it is then possible to calculate the performance measures of interest, and use these performance measures to select, from among the various alternatives, one or more of them that can best balance the need for a quality product against the need for efficient machining.
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    Evaluating Product Machinability for Concurrent Engineering
    (1992) Nau, D.S.; Zhang, G.M.; Gupta, Satyandra K.; Karinthi, Raghu R.; ISR
    Decisions made during the design of a machined part can significantly affect the product's cost, quality, and lead time. Thus, in order to address the goals of concurrent engineering, it is important to evaluate the machinability of the proposed design, so that the designer can change the design to improve its machinability, To determine the machinability of the part, all of the possible alternative ways to machine the part should be generated, and their machinability evaluated. This chapter describes the techniques we have developed to do this automatically.

    The information provided by these techniques will prove useful in two ways: (1) to provide information to the manufacturing engineer about alternative ways in which the part might be machined, and (2) to provide feedback to the designer identifying problems that may arise with the machining.

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    An integrated Approach to Calibrate an Untended Machining System
    (1991) Parker, J.E.; Zhang, G.M.; Kirk, J.A.; Anand, Davinder K.; ISR
    This paper presents a new methodology for the calibration of an untended machining system. The methodology requires the calibration conducted under both static and dynamic loading conditions. The transformation matrix method was used to establish the mapping function between the performance measure of interest (input) and the control signal (output). A prototype system, building on an CNC machining center equipped with a magnetic spindle, was developed to demonstrate a strategy for monitoring the tool wear progress through the cutting force prediction. The effect of phase distortion due to the presence of time lag on the output prediction was studied. A performance index to characterize the phase distortion error was suggested for further improvement of untended machining.