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This area will
conduct research in process development, modeling and control of various
welding and joining processes to enable the integration of lightweight and
dissimilar materials in automotive applications. These processes may
include gas-metal arc welding, laser welding, mechanical joining, adhesive
bonding, and hybrid joining processes (laser-arc, rivet-bonding, etc.).
Special attention will be placed on the joining of dissimilar materials.
Current Project
Network Process Monitoring for
Body Joining
Automotive body
structures are assembled by joining together a number of parts and
components using a variety of welding/joining processes. The commonly used
joining technologies used in the body shop include Gas Metal Arc Welding (GMAW),
Resistance Spot Welding (RSW), Laser welding (LW), and Self-Piercing Rivet (SPR).
All the welding processes are very complex because they involve the
electrical, thermal, mechanical process in a very short time. For example,
an RSW is completed in less than half a second, which include cold and hot
deformation, heat generation and conduction, metal melting and
solidification in a very tiny area. The SPR process is also completed in a
short duration, but with large deformation in the sheet metals and the rivet
in room temperature.
The quality of the
joints, to a large extent, determines the quality of the assembled body
structures. There are many unpredictable variations in the process that
influence the process stabilities and lead to joint quality variation.
These sources include variation from power supplies (electricity, air),
mechanical system, and electrical control systems. Thus, on-line monitoring
of joining quality is a key to consistent high quality products. Traditional
methods of monitoring joining processes and joint quality are heavily
dependent on the knowledge and experience of the operators. Therefore, it will be highly desirable to develop a system for on-line
monitoring and control of process stability by analyzing the signatures of
different joining processes
Based on the requirements of assembly production, quality monitoring and
controlling system comprises a central administrator or controller for a
workshop or a plant, line analyzer for different assembly line, cell
processor for different working cell and machine monitor for different
equipment.
In the past several
years, the GM/UM collaborative lab (1998-2002) has been working on the
monitoring of the GMAW process stability and has developed an algorithm to
assess the process performance for short circuiting GMAW process. The Lab
also had experience on the development of monitoring system for RSW process
and laser welding, and has facility for SPR joining process.
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Welding & Joining