Today, resistance welding takes many forms across numerous applications in diverse market seg-ments. While each company must decide the most efficient welding technology for its various operations, the parameters that govern such decisions often change, sometimes rather quickly over short time intervals. This means decision makers must constantly monitor welding processes to ensure the right technology is applied to each application and done so in a cost effective manner.
Process Control Yields
Cost Effective Weld Integrity
By Greg Reed, Contributing Editor, Design News
Orbitform 1600 Executive Dr. Jackson, MI 49203
www.orbitform.comA White Paper / 2008
Process Control Yields
Cost Effective Weld Integrity By Greg Reed, Contributing Editor
Today, resistance welding takes many forms across numerous applications in diverse market seg-ments. While each company must decide the most efficient welding technology for its various operations, the parameters that govern such decisions often change, sometimes rather quickly over short time intervals. This means decision makers must constantly monitor welding processes to ensure the right technology is applied to each application and done so in a cost effective manner.
Resistance Welding Technology Controlling such factors as proportions and Fundamentally, resistance welding combines material composition of the work pieces, elec-a set of processes that collectively produce a trode materials, electrode geometry, electrode coalescence of separate and distinct work pieces force, weld current, and welding time is vital to as a result of heat generated by the resistance of achieving structural integrity of the fused work work piece materials to the welding current (100 pieces. Figure 1 offers a look at the variables to 100,000 A) plus mechanical pressure (up to associated with resistance welding and a typical 30,000 psi). As the current passes through the welding cell where the activity takes place.work pieces, a molten fusion takes place at the Within the realm of resistance welding tech-connecting surfaces which is the point of high- nology, several distinct methods can be identi-est resistance. A stable fusion is accomplished by fied, each with its unique set of attributes that applying enough current to create a molten state govern which applications are appropriate for a while applying pressure at this weld zone while particular technology. Spot welding, seam weld-cooling takes place as the current is withdrawn. ing, projection welding, flash welding and upset The combination of current and pressure must welding are common methods used in automo-be sufficient to create a solid weld, but not so tive, industrial, aerospace and defense, medical, much as to create an expulsion of molten metal and many other applications across a broad spec-from the weld zone. trum of industries.Dan Shirkey, Lead Engineer (Orbitform Group, Jackson, MI) says, "A superior welding process control system must have inherent flexibility that allows users to match their unique process-ing methods with a standard process monitoring system. First, one must determine what process is optimal, and then one must determine how to optimize that process.
Welding Control ToolsFigure 1 As seen above, resistance welding technology Resistance welding process variables include heat, cur- assumes many forms. Engineering teams con-rent, resistance of work pieces, time, and heat loss. A tinually assess operations and then match the work cell offers localized resistance welding operation. correct welding solution to each situational During the welding process, many factors challenge. When the welding processes are impact the welding temperature which ultimately performed correctly and consistently, the man-influences the stability of the joined work pieces. ufacturer's efficiency is maximized. However,
Page A White Paper / 2008
an out of control process may result in wasted failure data in a meaningful way. The engineers raw materials, energy overruns, excessive worker performed admirably in collecting the data; downtime, and idle equipment. As a result, a however, a failure to translate the data into use-manufacturer could face substantial losses or ful and actionable information was the source severe fines when engaged in third-party con- of their downfall.tracts. In a worst case scenario, safety, accident, or injury situations could arise. Any of these RPAS for Resistance Weldingmay threaten the economic vitality of the manu- For manufacturers that rely heavily on weld-facturer, up to and including closing the plant ing operations, several vendors offer reliable doors. Clearly, a reasonable expenditure on the process control systems. One advanced system right system for monitoring with closed loop from Orbitform Group is the Resistance Process feedback provides a critically impo... [download for more]
