Welding Automation Research
Welding Automation Research in the engineering school is largely focused on problems involving sensing, modeling, and control of welding processes, i.e., welding automation. Faculty and students from electrical engineering, mechanical engineering, and material science are involved in the welding automation research. The overall objective of this research is to provide both greater productivity and enhanced quality for welding in the manufacturing environment.
Welding generally involves the application or development of localized heat or pressure, or both, near the intended joint to produce a suitable bond between the parts being joined. The process is a continuum of closely coupled thermophysical phenomena, which must be controlled precisely to successfully carry out the weld joining operation. A wide range of disciplines and areas of expertise are required in carrying out research in welding automation. Past research by Vanderbilt faculty and students has resulted in many U.S. and foreign patents on automatic welding technology including: welding power supplies, welding torches, automatic pipe welding systems, and through-the-arc sensing. The research on through-the-arc sensing led to an adaptive robotic arc welding control methodology that is now used by virtually all arc welding robot manufacturers in the world. A statistical process control system developed by Vanderbilt researchers is manufactured commercially and used worldwide for weld quality control.
While most of the past research at Vanderbilt has dealt with the various electric arc welding processes, recent projects involve friction stir welding and laser welding.
Friction stir welding utilizes frictional heating combined with forging pressure to produce high-strength bonds. The material (aluminum alloy, for example) being joined is transformed from a solid state into a “plastic-like” state, and then is mechanically stirred under pressure to form a welded joint. Because of the large torques and forces involved, the process is currently limited primarily to flat parts joined with heavy-duty milling machine type equipment. Current research at Vanderbilt is largely focused on sensing, modeling, and control of the torques and forces involved. The objective is to broaden the range of applications to contoured three-dimensional parts joined with heavy-duty articulated robot manipulators with force-feedback control. Other interests include friction stir processing for enhanced material properties and defect-free friction stir welding starts and stops.
Currently, laser welding at Vanderbilt is being evaluated as a joining means for silicon components in micro-electro-mechanical-systems (MEMS). Vanderbilt's free electron laser (FEL) is being used for this research. The FEL offers the unique ability to vary the wavelength from approximately 2.1 to 9.8 microns. Although still an emerging technology, silicon bonding is already producing some commercial devices such as pressure sensors and accelerometers. With new developments, it is believed that laser joining can be used for packaging and assembly of MEMS made from silicon, glass, and polymers in conjunction with metals. Laser joining is also seen as a means of coupling optical fibers to optical chips or electro-optical components.
- Electric Arc Welding
- Friction Stir Welding
- Laser Welding