An Introduction to Automotive Spot Welder

Posted on Jan 3, 2021

Automotive Spot Welder

Automotive spot welder fuses the auto body parts through the spot welding process, which is also known as resistance spot welding, a sort of electric resistance welding. By heating and applying the generated pressure onto the “spot”, multiple parts can be welded together.

What is the Welding Process?

Automotive spot welders are one sort of portable welding machine. The welding machine can be used for permanent metal fabrication, heating and melting the metal parts, and then welding them together.

What exactly is the metal welding process? The welding process is a classic and important metal joining method for a long time. There is a large range of welding methods that can connect both similar and totally dissimilar materials together. The materials we are talking about here include various metals, thermoplastics, and more, which can generally be fused together through the welding machine under high pressure. In most of the welding methods, the metals will be melted under high heat before the pressure is applied to the welding joint, like the focus of this article, the automotive spot welder. However, there are also several kinds of welding machines that work at room temperature, eliminating the melting procedure. These welding methods like friction welding, soldering, and more are called “cold working”, which are typically cleaner since there is no melting process for the materials.

In common welding applications today, the raw materials, which are mostly sheet metals, will be melted first and cooled down after the weld is completed. The typical energy sources of the welding applications involve electrical systems, electron beams, electric arcs, chemical sources, frictions, lasers, and so on.

Automotive Spot Welder

As mentioned, the automotive spot welder is the portable spot welding equipment that is specially used for fusing auto body parts together. The smart welder is also called a portable resistance spot welder or auto body spot welder. Now we know the function and basic knowledge of the welding process, we can easily understand what automotive spot welder is used for. Automotive spot welder fuses the auto body parts through the spot welding process, which is also known as resistance spot welding, a sort of electric resistance welding. By heating and applying the generated pressure onto the “spot”, multiple parts can be welded together. As the names imply, the automotive spot welder utilizes electric current and resistance to generate the heat in the system. Further details of how the currents and electrodes work will be discussed in the next section.

:: Read more: What is a Portable Spot Welding Machine?

Working Principle of Automotive Spot Welder

The smart automotive spot welder consists of the auto welding head, the double-acting gun, the control panel, and the water cooling system. When it comes to spotting welding, the “spot” is the welding point where the heat transfers to, and the heat in the spot welder is stably generated on the resistive materials due to the movements of the contacting copper electrodes working on the surfaces of the parts. At the moment, the predetermined pressure will also be conveyed and applied to the spot, forming the force which assists the welding process.

In the automotive spot welding machine, without adding any filler materials, the auto parts can be effectively and permanently joined together. The spot welders use the copper electrodes to deliver the electric currents toward the welding area and then the energy will be concentrated at the small spot, generating the heat to melt the materials. Once the current turns off and the metal melts, the automotive spot welder will, under the control, apply a large amount of pressure as the copper electrodes remain on the welding joint, fusing the metal sheets together. The weld is entirely completed after the parts solidify and cool down.

Typically, the material from which the electrodes are made is copper, which has great heat conductivity and lower electrical resistance. Thanks to the feature of copper, generated heat tends to work on the surfaces of metals rather than the electrodes. Not only the electric current, the magnitude, the resistance between electrodes but also the characteristics and thickness of the base materials can define the efficiency of the portable spot welders. The available thickness of the metal sheets ranges from 0.5 to 3mm.

:: Read more: Read this to understand Resistance Spot Welding!

Why Use an Automotive Spot Welder?

The spot welding process is the conventional metal joining method that is popular in the automotive industry for manufacturing, assembly work, and fixing for over a century. In addition to the industry, smart portable equipment is also used for welding in aerospace, shipbuilding, rail, medical industry, and more. The welding machine has numerous advantages for car manufacturers at all times.

For starters, automotive spot welders only take up little room in the factories, which is convenient yet effective especially when employing the automatic power system or robots, making it increasingly popular for automotive manufacturers. Another strong advantage of automotive spot welder is the rapid welding time where large volumes of energy can automatically complete the jobs. This allows the spot welder to achieve metal welding without excessive heating in other areas. Also, many smart automotive spot welders today can provide records and weld logs for the operators through wireless techniques, saving the time for the operators to monitor the process.

In general, thicker base metals are more challenging to handle for the portable spot welding machine since the heat may affect the surrounding area significantly. Among the steels, low carbon steels are better suited for spot welding because the material has lower thermal conductivity as well as higher electrical resistance than high carbon steels. On the other hand, stainless steel, nickel alloys, and titanium are also ideal welded materials for resistance spot welding. For some difficult weld materials like boron steels or advanced high strength steels, which are becoming popular material choices among automotive manufacturers, there are more and more automotive spot welders that are particularly designed to accommodate the challenging materials.

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