Capacitor Discharge Spot Welder Guide
What is a Capacitor Discharge Spot Welder?
Capacitor discharge spot welder is the fastest type of resistance spot welding machine. It is also known as a capacitive discharge spot welder or CD welding machine. Resistance spot welders, including capacitor discharge spot welder, are designed for joining multiple metal parts together, which are typically used for metal sheet fabrication. There are a large variety of welding methods, many of which require to be performed at high temperatures to melt the base materials for the welding process. General energy sources of these welding manners include but are not limited to frictions, electrical, electron beams, electric arcs, ultrasounds, chemical, and lasers.
Capacitor discharge spot welder is a type of resistance spot welder that can fuse two or more metal pieces together through applying pressure and heating the welding spot simultaneously. The welding process in capacitive discharge spot welder is a kind of electric resistance welding, where the heat is created and supplied from the resistance to electric currents. Capacitor discharge spot welders use capacitors to transmit the power within the welding machine. The capacitors in this type of resistance spot welder are charged with huge amounts of energy. The energy is released into the welding part at a high speed, which is within milliseconds. The electrodes work on the contacting welding spot on the metals’ surfaces where the pressure is also forced, then the permanent connection can be completed. Typical resistive metal includes low carbon steels.
Capacitive discharge spot welder features readily electrical energy source, portable system, simple and light welding equipment, low operating temperature, short welding cycle time, versatility. The spot welder can be utilized on metal thick materials in sheet form to produce high strength processed fasteners. Some common applications of capacitor discharge spot welder include projection welding, welding nuts and fasteners, welding high strength steels, coated steels, stud welding. With a wide range of applications, the capacitor discharge spot welder is preferred to be utilized in productions of automotive and aerospace components, metal furniture, or in medical, electronic, and rail industries.
How Does Resistance Spot Welder Work?
● Basic working principle of resistance spot welding
As mentioned, capacitive discharge spot welding is a type of electric resistance spot welding. In the resistance spot welding process, metal sheets can be fused together without inserting any filler. Spot welding typically uses electrodes made from copper alloys to transmit the currents to the welding spot on the sheets. The metals will then melt because of the heat as the energy is concentrated to a very small area which is simultaneously under pressure. By transferring a considerable current to the welding spot will effectively melt the materials and complete the weld. The sheets can be joined together at the time the currents are removed but the pressure maintains on that spot. After the molten materials solidify, the welding cycle is completed. In the case that the power is not enough to melt the sheets, the products will end up poor welds. However, if there is too much energy transferred to the spot, the heat is possible to make a hole on the welding area.
● Capacitor Discharge Process in Spot Welder
There are 4 basic stages in the capacitor discharge spot welding process: contacting, ignition, placement of the stud and closing the gap, completing the welding connection. The fastener is gripped by the stud gun which can regulate it to contact the metal sheets. The capacitor discharge gun will be triggered, and the stud tip on the end will be ignited. When the tip end melts, the welding spot under the head also melts due to the heat. Subsequently, the capacitor discharge gun will press the stud into the molten metals and enclose the gap between the metal sheets and the fastener. Eventually, the stud will be held properly while it connects together with the materials. This capacitor discharge spot welding process is also called a contact capacitor discharge stud welding process.
Why Use Capacitor Discharge Spot Welder?
Among various welding machines and welding methods, capacitor spot welder is versatile, reliable and significantly efficient. Easy set-up and maximum portability provide you with the needed electricity to perform the welding. Capacitor discharge spot welders have lower levels of the heat production, provide clean, high precision and rapid welding. Also, there are no risks of backside burning or distortion occurs on the welded parts. The finishes are clean, which provide additional benefits for the operators when they need the welded parts to have clean appearances.
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