M.S. Thesis Presentation by Bob Schmitt
Monday, October 4, 1999

(Dr. Shreyes Melkote, advisor)

"Design of a Flexible Fixturing System"


A fixture is a device which is used to locate and clamp a workpiece for machining and assembly operations during the manufacturing process.  Fixtures play a crucial role in the high volume production of automotive parts and can significantly influence development time and costs.  However, despite increasing pressure for more efficient production methods, modern fixture design has not significantly changed in decades.  To reduce production costs, manufacturers have identified the need for a flexible manufacturing system that is capable of machining more than one part without major retooling.  With the recent advent of CNC machine tools, this flexible manufacturing environment is partially realized.  However, there is still a need for a flexible fixturing system that is capable of fixturing a variety of parts so that a truly flexible manufacturing environment can be implemented.

The objective of this thesis is to develop a flexible fixturing system that is capable of fixturing a variety of parts for all machining operations.  In addition, this system should get rid of the need for datum features on the workpiece so that part design can be streamlined as well.  In this context, this thesis presents a methodology for the design and analysis of a flexible fixturing system.  Based on this approach, information regarding the design of a novel device, called the adjustable pin fixture, for fixturing a family of automotive parts is presented.  A review of the system’s performance with respect to the identified objectives is then given.

The results of this study show that the design techniques outlined in this thesis are effective in developing a flexible fixturing device which is capable of addressing the design objectives.  In application, the “adjustable pin”  fixture is capable of fixturing several cylinder heads for the vast majority of machining operations.  This fixture meets the meets the majority of the objectively specified requirements, and has potential application in a wide variety of flexible machining applications.