Resistance increase is a common phenomenon observed in medium frequency inverter spot welding machines. This article aims to analyze the characteristics of resistance increase and its implications in spot welding operations.
Heating Effect:
One of the main factors contributing to resistance increase is the heating effect during spot welding. When a high current is passed through the workpiece, heat is generated due to electrical resistance. This heat causes the workpiece’s temperature to rise, leading to an increase in its resistance.
Material Properties:
The resistance increase can also be influenced by the material properties of the workpiece. Some materials exhibit a higher increase in resistance compared to others due to their inherent electrical conductivity and thermal properties. For example, materials with lower conductivity or higher thermal expansion coefficients tend to experience a more significant resistance increase.
Contact Resistance:
Another factor that can contribute to resistance increase is contact resistance between the electrodes and the workpiece. Poor electrode contact or surface contamination can result in higher contact resistance, leading to an increase in overall resistance during welding.
Electrode Wear:
Over time, the electrodes in spot welding machines can undergo wear and degradation. As the electrode surfaces deteriorate, their contact area with the workpiece decreases, causing an increase in contact resistance and overall resistance during welding.
Oxidation and Contamination:
The presence of oxidation or contamination on the workpiece surface can also lead to resistance increase. Oxidized or contaminated surfaces have higher electrical resistance, affecting the flow of current and resulting in an overall increase in resistance during welding.
Resistance increase is a characteristic phenomenon in medium frequency inverter spot welding machines, primarily caused by the heating effect, material properties, contact resistance, electrode wear, and surface oxidation or contamination. Understanding these characteristics is crucial for optimizing spot welding processes and ensuring consistent and reliable welds. By monitoring and addressing the factors contributing to resistance increase, operators can maintain the desired welding parameters and achieve high-quality welds in their applications.
Post time: May-16-2023