MONITORING AND CONTROL OF WELDING AND JOINING PROCESSES

Abstract

An experienced skilled welder has highly sensitive sensors coupled with very significant processing capability, and can therefore accomplish a variety of important tasks, such as weld placement, weld joint tracking, weld size control, and control of the weld pool, among many others, with rel- ative ease. Using this feedback information, an experienced welder can assess the welding process with respect to its desired state, make minor changes in the weld parame- ters under his/her immediate control (e.g., weld current, voltage, travel speed and electrode orientation with respect to the joint path), and maintain proper torch orientation and distance in an effort to achieve the desired state of the weld. As human welders or opera- tors are relieved of the welding process control function in favor of computerized process control equipment, these process functions need to be evaluated to deter- mine if they can be automated to achieve the needed accuracy and reliability, as well as at what cost. Thus, sensors and computer processing equipment used to obtain, analyze, and con- trol the welding process must be durable and robust to be able to successfully perform in these environments. Welding process sen- sors obtain information about the welding process by converting physical phenomena from the input and pro- cess response variables into signals that can be utilized by monitoring or control equipment