Designing of Control Panel for Spot Welding Machine

In this paper we focuses on designing a customized special purpose control panel that can easily control and atomize the welding process. Microcontroller based system of spot welding machine controls the operation sequence of welding starting from squeeze time through Weld, Hold and off time. Welding current along with other parameters will be the input and output will control thyristor and solenoid. The system is build to reduce the size, cost and also increase the performance and reliability by precisely controlling the squeeze, weld, hold and stop time of welding machine. The system is used to atomize heavy industrial machinery. This system contains wide ranges of timings and current intensities so that it can weld different types and different thickness of sheets. To prevent our system from heating effecting and robustness and to improve the long life and efficiency of system we also incorporate the cooling system.

I. Background

During the invasion of industrial era the demand of reliable and efficient joining methods increased and different latest methods of welding invented after one another. Welding is basically a fabrication process that welds two metals which is usually done by the application of heat on the work pieces. Some major types of welding include gas flame, electric arc, laser, oxy fuel, electron beam etc. In industries, welding is done in various environments such as dusty environment, underwater, open air, outer space, it's basically depend on the nature of work which have to be performed. The main welding processes are heterogeneous, homogeneous and autogeneous. Our system is based on autogeneous welding processing in which we don't use any additional filter material for welding. The main welding which supports this autogeneous processing is resistance welding which we are using for our system. The main purpose of resistance spot welding method is to join two to four light gauge overlapping metal sheets, which can have thickness up to 3 mm[1]. During the RSW process, two or more parent sheet metals are pressed through upper electrode moving toward to the lower electrode by means of the electrode force, and heavy current is allowed to pass through both of the work pieces for fractions of time. Both work pieces melt and join together at the spot where the current is passed. Resistance welding is basically a pressure welding that's why for efficiency and precise welding of two metal sheets. Sufficient amount of heat is generated and applied to the required area and on the application of pressure the metal sheets are joined.