Main Participants: Satyandra K. Gupta, Ramakrishna Arni, and Yusheng Chen
Sponsors: This project was sponsored by the National Science Foundation and the National Institute for Standards and Technology. We also received in-kind support from Galorath Inc. for this project.
Keywords: Manufacturability Analysis and Web-Based Services
Motivation
With the advent of high speed networking technology and recent advances in information modeling area, we are entering into a new era of a global manufacturing economy connected through Internet. In tomorrow’s marketplace, companies and individuals will be able to buy and sell manufacturing services on the Internet. The key technology to realize this vision will be a brokering technology that will provide match making services between manufacturing service providers and designers. Such services will register and manage manufacturing services—allowing designers to locate and access highly advanced manufacturing services. To ensure that the part being submitted is manufacturable, the brokering agency will need to provide manufacturability analysis service. Such a service will be used by designers to ensure that the proposed design can be manufactured by the selected process provider.
We need a framework for developing and deploying a variety of web-based manufacturability analysis services. These services will range from a service for providing manufacturability advice during design embodiment to a service for evaluation of detailed designs against specific processes.
Main Results and Their Anticipated Impact
We have developed two web-based manufacturability analysis services in this project.
A web-based manufacturability analysis service for solid freeform fabrication. We have developed a manufacturability analysis system that allows designers to analyze manufacturability of parts produced using Solid Freeform Fabrication (SFF) processes with flatness tolerance requirements on the part. SFF processes approximate objects using layers; therefore the part being produced exhibits staircase effect. The extent of this staircase effect depends on the angle between the build orientation and the face normal. Our service primarily serves two different types of users — process providers and designers. Process providers register their process’s capabilities and constraints with our service. Designers upload the geometry and tolerance information to our server and select a process from the list of registered processes and perform an analysis of the feasibility of manufacturing the part using the selected process. Our service also offers suggestions for improving manufacturability of difficult to produce parts. We use a two-step approach to perform the manufacturability analysis. We first analyze each specified tolerance on the part and identify the set of feasible build directions that can be used to satisfy that tolerance. As a second step, we take the intersection of all sets of feasible build directions to identify the set of build directions that can simultaneously satisfy all specified tolerance requirements. If there is at least one build direction that can satisfy all tolerance requirements, then the part is considered manufacturable. Otherwise, the part is considered not manufacturable. We also have developed an algorithm to formulate redesign suggestions that can propose suitable modifications to the part design so that a non-manufacturable part can become manufacturable. Our research is expected to help (1) designers in eliminating manufacturing problems and selecting the right SFF process, and (2) process providers in selecting a build direction that can meet all design tolerance requirements.
A web-based process material advisory system. We have developed a systematic approach to material and process selection during embodiment design of mechanical components. We follow a three-step approach to process and material selection. We first generate combinations of materials and primary processes. Then, we find the set of non-dominated sequences for each combination found in the first step by adding secondary and tertiary processes to meet detailed form requirements and pruning dominated sequences. Finally, designers can use our cost analysis functions to compare different non-dominated sequences to select the final combination of material and process sequence. We have implemented our approach and algorithms in a prototype web-based system called WiSeProM (Wizard for Selecting Processes and Materials). Our system demonstrates the following:
- It shows that it is possible to accounts for imprecision in design parameters in selecting material and processes. The effectiveness of our algorithm depends on how tightly various parameters can be defined during the embodiment design stage. If parameters have very large ranges, then very few solutions dominate other solutions and the pruning conditions do not work very effectively. If parameters have reasonably small ranges, then pruning conditions work effectively.
- It shows how to automatically generate process sequences to satisfy the form requirements when a single process cannot meet all the form requirements. Unlike previous approaches, there is no restriction on the number of processes used in a sequence. Therefore, it allows us to solve problems that require four or more processes.
- It shows how to construct an open architecture system in which databases and algorithms are completely separated. Therefore, as soon as new material and/or process information is added to the database, it can be immediately used in our system.
We believe that our system will allow designers to explore a large number of material and process options during the embodiment design stage and to select the most cost-effective combination. By selecting the material and process combination during the early design stages, designers can ensure that the detailed design is compatible with all of the process constraints for the selected processes.
Related Publications
The following papers provide more details on the above-described results.
- S.K. Gupta, Y. S. Chen, S. Feng, and R. Sriram. A system for generating process and material selection advice during embodiment design of mechanical components. Journal of Manufacturing Systems, 22(1):28–45, 2003.
- R.K. Arni and S.K. Gupta. Manufacturability analysis of flatness tolerances in solid freeform fabrication. Journal of Mechanical Design, 123(1):148–156, 2001.
- R.K. Arni, S.K. Gupta, and M. Kumar. A web based tolerance analysis service for solid freeform fabrication. In ASME’s Design for Manufacturing Conference, Baltimore, Maryland, September 2000.
- S. Rajagopalan, J. M. Pinilla, P. Losleben, Q. Tian, and S.K. Gupta. Integrated design and manufacturing over the Internet. In ASME’s Computers in Engineering Conference, Atlanta, GA, September 1998.
Some of these papers are available at the publications section of the website.
Contact
For additional information and to obtain copies of the above papers please contact:
Dr. Satyandra K. Gupta
Viterbi School of Engineering
University of Southern California
Los Angeles, California 90089-1453
Phone: 213-740-0491
Email: guptask [AT] usc [DOT] edu