New technique advances carbon-fiber composites.
A new tool that allows faster machining of metal parts is helping the Ford Motor Co. reduce the time to bring a new automotive engine to market.
Developed by MIT engineers and colleagues, the Q-Tool is a shock absorber that damps the natural vibrations of cutting tools used to fashion metal parts. Such vibrations limit how quickly the metal can be machined and can cause variations in the surface finish of a part.
The new device "allows four times higher material removal rates while maintaining a high degree of surface finish," said Alexander H. Slocum, the d'Arbeloff Professor of Mechanical Engineering. Professor Slocum, mechanical engineering graduate student Gaurav Rohatgi, Dr. Kevin Wasson (MIT PhD 1996) of Aesop, Inc., and colleagues from Ford Motor Co. and Star Cutter Co. have won a 1998 R&D 100 Award for the device. This is Professor Slocum's eighth R&D 100 Award.
Named for the "Q" that is a measure of how well-damped a system is, the Q-Tool is a thin "sleeve" that grips the shank of a cutting tool. A layer of fluid, or damping material, is between the sleeve and the tool. "So as the tool trys to vibrate, the energy is dissipated on the damping material," said Professor Slocum, who is also President of Aesop.
The long, thin cutting tools required to reach into deep features of certain parts are especially prone to vibrations. As a result, these parts, which include dies for the automotive and aircraft industries, can take days to machine. The Q-Tool is changing that. "Experiments at Ford Motor Co. have shown that the Q-Tool can cut in half the time required to manufacture a large die," according to the inventors.
As a result, it is key to a Ford program in which the company hopes to produce a new engine -- from design to test engine -- in less than 100 days. "This is only possible if complex molds for engine castings can be rapidly fabricated. The Q-Tool will enable these production requirements to be met, and as a result it will directly help reduce the time to bring a new automotive engine to market," wrote the inventors in their R&D 100 application.
The Q-Tool was conceived by Professor Slocum and his former student, Kevin Wasson, during a summer barbecue. Later, Professor Slocum remembers, "Gaurav [Rohatgi] was looking for a design hardware thesis that had a high analytical content," and the Q-tool offered the perfect challenge.
"It required a great deal of analysis before the hardware could be made to work," Professor Slocum explained. "So Gaurav took the basic concept, which Kevin had developed, and created an analysis that enables a designer to rapidly develop designs [for the Q-Tool]." Mr. Rohatgi then worked with Dr. Wasson and the industrial partners to define, create and test prototype Q-Tools.
Work on the Q-Tool was funded by Ford, Star Cutter and Aesop.
A version of this article appeared in MIT Tech Talk on September 16, 1998.