Spot welding machine | Advantages and disadvantages of contact welding machines

A spot welding machine is a type of resistance welding machine that is used to join metal sheets together by applying pressure and passing an electric current through the metal at the point of contact. This creates heat that melts the metal and fuses the pieces together. Contact welding machines, also known as pressure welding machines, are a type of spot welding machines that use a pair of electrodes to clamp the metal sheets together and apply pressure while passing an electric current through the metal.

One of the main advantages of contact welding machines is their high welding speed, which makes them suitable for mass production and high-volume welding applications.

Spot welding machine

Machines for resistance (spot) welding are quite widespread and are widely used both in enterprises and production workshops and in private workshops. The huge popularity of this type of welding equipment is due to the precision, speed and high quality of the seams that are made with it.

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What is spot welding?

If we have to define what this welding is, we can say that it is a type of resistant, contact welding. It is also called "resistive" because the process uses electrical resistance and the pressure it exerts on metals.

The technology of the welding process

Resistance welding is one of the oldest forms of welding, where two or more sheets of metal are welded together without the use of "filler" material.

The process involves applying pressure and heat to the weld area. This is done with the help of electrodes made of copper or copper alloys, which transmit the electric current to the metal elements being welded.

Electric current flows through the electrodes, creating concentrated heat to melt and fuse the two metal sheets in the desired area. During welding, the current works for a very short time , because after the metals are melted it is no longer needed, but the electrodes continue to apply pressure until the molten metal solidifies into a secure and strong joint.

The welds created by this process are usually between 3 and 12.5 millimeters in diameter, and their size affects the strength of the weld.

Materials suitable for spot welding

Due to its low thermal conductivity and higher electrical resistance, low carbon steel is best suited for spot welding. Besides it, stainless steel, titanium and nickel alloys and others are also suitable.

With materials such as aluminum, zinc, or copper alloys, spot welding is more challenging as they require higher current levels to perform well.

Spot welding machines

As with many other work tools, there are two main types of resistance welding machines:

● Portable, mobile devices

● Fixed, stationary machines

Mobile devices

Portable models, also called "apparatus" are small welding machines that, thanks to their compactness, can be used for spot welding of metals even in places with limited space.

Despite the greater ease of use, portable devices have limited performance, as their welding capacity is 2.2 mm +, which practically limits the ability to perform quality spot welds on materials of different thicknesses and structures. They also have a limited duty cycle , as the electrodes are not cooled.

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Stationary machines

Fixed welding machines, such as Metal Inn, are fixed stations that allow spot welding to be performed with great precision, accuracy and speed.

These kinds of machines are of heavy and imposing structure and are capable of making welds from 0.5 to 10+ mm thick. Their body consists of a generator and two mechanically, hydraulically or pneumatically driven arms equipped with non-fusible copper or copper-chromium alloy electrodes.

To prevent temperature rise during welding, the arms are cooled by the water that circulates in a closed system.

The arms and electrodes of fixed spot welding machines are interchangeable in order to adapt to the geometry of the desired welding point and the ergonomics of the elements to be welded.

Characteristics of the spot welding process

● This form of welding is characterized by great speed and accuracy. Joining (welding) time can be done within a hundredth of a second to several seconds.

● Performed at low voltage values ​​that are supplied to the welding circuit.

● It is carried out at very high values ​​for the working (welding) current, which can reach up to 1000 A and above.

● Involves a large amount of compressive force applied to the joining of the blanks. This effort can range from tens to thousands of kilograms.

Advantages and disadvantages of contact welding machines

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Advantages

● Through this type of welding equipment, flawless welds are achieved. With full responsibility, it can be said that in spot welding there is no unfinished seam or seam that requires a lot of additional processing.

● Since this type of welding uses an electric current that passes through electrodes, it is not necessary to use other consumables and materials in the process of joining the workpieces.

● Spot welding machines are capable of performing up to several hundred welding cycles (weld spots) per minute.

Disadvantages

● Resistance welding cannot be applied to all types of metals, which somewhat limits its application.

● The strength of the seam depends on the size and shape of the electrodes.

● The joint is formed only where the electrodes are in contact with both metal pieces.

● If the current is not strong enough or if the electrodes do not hold the metal workpieces firmly, the spot welding can be weak and easily broken.

Application of spot welding machines

Stick welding machines are used to make welds in a number of industries such as:

● The automotive industry

● Space

● The railway

● In the production of white goods

● In the production of metal furniture, structures and household items

● In dentistry in the production of equipment

● Electronics

● Construction and others

Because of the ease with which it can be robotized, this process of joining two or three metal blanks is used extensively in high-volume production lines such as assembly lines in the automotive industry and others.

Why choose a spot welding machine from Metal?

The company is known here and in Europe as one of the leading manufacturers of metal products, elements and components from solid and sheet material.

In order to meet even the most demanding customers, Metal Inn also has a high-performance spot welding machine.

The machine can perform spot welding both on metal blanks of low-carbon and stainless steel, and on details of aluminum, ferrous metals and others with a thickness of up to 3 mm.

Welds can be made both if the two metal parts are of the same thickness, and if they are of different thicknesses in a ratio of no more than 3:1.

Depending on the customer's requirements, the machine can be easily adapted according to the specific needs and according to the geometry of the materials that need spot welding.

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Spot welding with this type of Metal Inn equipment can help you in the following production processes:

● Joining details of metal household objects ( metal buckets, watering cans, agricultural tools and others)

● Welding of metal sheet structures for the automotive industry

● Connecting metal and aluminum pipes

● Welding of wire mesh

● Precision welding of garden metal furniture and decorations

● Connecting components of metal stairs

● Welding of stainless steel housewares and many more

The machine for sustainable welding that the company has is of high class and with extremely high productivity. The welds that your production process needs can be made in extremely short times and with great precision.

Conclusion

In conclusion, contact welding machines, also known as pressure welding machines, are a type of spot welding machines that are widely used for high-volume welding applications due to their high welding speed, ease of use, and reliability.

They are a popular choice for mass production and automated welding systems.

When choosing a welding machine, it's important to consider the specific needs of the project, the materials being welded, and the available equipment and expertise.

Contact welding machines can be a great option for certain types of welding projects, but may not be suitable for others.