Spot welding is often used to join pieces of sheet metal together. It's a simple process, but many things could go wrong if you don't know how to spot weld.
This detailed guide will teach you the basics of spot welding, including how it works, what kinds of things you can use it for, what types of materials work best, and what kinds of problems you might run into.
Spot welding is an electrical welding that uses heat and pressure from an electrical current to join two pieces of metal together. This method works best for sheet metals because a strong current removes resistance from the spot and makes fusing easier.
Spot welding is most often used in the design of cars, which requires the weld to be more flexible and last longer. Copper electrodes are often used for welding because they conduct heat and electricity better than other materials.
With the addition of robots to the assembly line, the industry is innovating the welding process. Resistance spot welding has become even more popular and is used more frequently as a result of significantly increased overall effectiveness and speed of the welding process.
Spot welding is a straightforward process. It works by putting a lot of high-voltage current on a small area under pressure. The electric current is strong enough to melt the metal immediately and start the fusion process. In this case, the pieces must fit together correctly. If you don't do this, the product might not work, and you'd waste the materials.
Pressure is another important factor that affects the quality of the weld. It has to be right because too little pressure would lead to a poor weld, and too much pressure could damage the base material. In essence, there are three main steps in spot welding. Here are the three main steps of spot welding:
● Step 1: Getting the pieces lined up
The welding process is not reversible. So, the workpieces must be put together with as much accuracy as possible. This would save time and money and ensure the results are always the same.
● Step 2: Put pressure on
The second step is to put pressure on it. Spot welding uses both pressure and heat from the flow of electricity. Pure refractory copper electrodes are usually the best choice for this because they don't oxidize even when there is a lot of pressure on them. This ensures that the workpiece has no flaws.
● Step 3: Flowing with the Current
After choosing the pressure and where to put the electrodes, the last step is to start the current. Most of the time, a foot pedal starts the circuit and lets the current flow. The current flows to a single point and melts it.
The thickness of the two pieces determines how long the current runs and how strong it is. After the fusion, the current stops, but the pressure stays the same so that the pieces fit together well.
Any resistance spot-welding product's quality and consistency depend on a lot of things, such as the following:
Weld time is the total time that the workpiece stays under the current. During the spot welding process, there is only one rule about this. The amount of time it takes to weld should be as short as possible. This will ensure the best quality.
But please remember that if you cut the time too much, the welds will be done too soon and won't fuse properly, which will cause problems later. Even though there is no standard minimum length of time, the AHSS Guidelines say that most times are about 1/5th of a second.
The hold time, also called the squeeze time, is the total time that the workpiece is under pressure before the current is turned on. By giving the piece more time to settle, increasing this time can greatly improve the overall quality of the weld. Also, the initial pressure causes the tips of the workpieces to change permanently without any heat, which is the best way to ensure quality and strength.
The squeeze time can make the weld better. There is a catch, though! Increasing the squeeze time can send costs through the roof because fewer parts would be made in the same amount of time. Just like any other parameter, the squeeze time needs to perfectly sync with the project's overall needs and provide the best balance of quality and production efficiency.
The forces between the electrodes are the amount of energy a certain metal alloy needs to melt together. The more current and heat energy a force gives off, the stronger it is. Too much heat energy can greatly hurt the weld's quality, so it's important to be careful with it.
The production of spatter is another important thing to know about the electrode forces. Since the most important factor in these forces is current, which is also the main cause of the spatter, it's essential to use the right combination of current and pressure, which directly affect the electrode forces. Note that the engineer or people working on the weld will choose the right combination. High current and low pressure is the best combination when you need results quickly and don't care about quality. In the same way, if you need very high quality for an application, you'll try to lower the current and increase the pressure/hold time.
There are a lot of different materials that can be used well for spot welding. Pure metals are not the only thing that can be used. Spot welds are used the most on steel because it is used so much in the auto industry. Generally, any metal alloy with high resistance to electricity can be a good choice.
Aluminum and galvanized steel are the most common materials that don't work well with the process. Both types of material need strong currents, making it harder for the weld to form.
Aside from the type of metal, it's also essential to ensure the sheet metal is the right thickness. Most of the time, a thickness of around 3 mm works best and gives the best weld. Also, for the best results, the two sheets to be fused should be the same size or have a 3:1 size ratio.
Spot welding is used in several industries for many different purposes. These are some of the places where spot welding finds use:
The auto industry often uses spot welding since sheet metal makes up most of a car's body. This welding method saves money, works well, and doesn't need any complicated setup. Because of this, it can be added to any assembly line, making it one of the best processes for automation.
Spot welding is used to ensure that components like circuit boards, gas sensors, and solar panels are high quality and can be made quickly. This welding method is also perfect for the most complicated electrical parts with many small details. The weld stays focused on a single point and leaves plenty of room for other capabilities and processes.
As has already been said, spot welding is the best way to make batteries. Batteries have several metal terminals that are all connected.
Spot welds are great for making nails. With automation, the welding process makes nails faster than with a pneumatic nail gun.
Spot welds are one of the best ways to combine two pieces of metal, but it's essential to do them right to ensure the best quality and consistency. Looking for the perfect partner for welding or making things out of metal sheets? Then Ares Prototyping is the best choice for you because our team is dedicated, and we have a lot of different kinds of experience.
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