Published on 22-Jun-2023

Mastering Spot Welding: Expert Tips and Techniques

Mastering Spot Welding: Expert Tips and Techniques

Image credit @machinemfg

Spot welding is generally utilized to weld objects like street metal and it is considered to be a straightforward procedure. 

But, there are a lot of ways in which things can not work right or as expected if you are not aware of the right parameters or do not have an experience in spot welding. 

In this article, we are going to explore spot welding in detail and also, and we have shared a few important tips to follow for effective spot welding! 

What Exactly Is Spot Welding?

In simple words, spot welding is a resistance welding method that is utilized to weld two or additional metal sheets concurrently. It is accomplished by applying electric current and pressure to the area of the spot weld. And the required heat is produced by the internal resistance of the metal to the electric current.

The pressure and electric current are put in an application by copper alloy electrodes and their tips are positioned on the opposite sides of the metal objects. So the heat generated helps in melting the metal and the pressure from the electrodes squeezes the melted metal in order to develop a weld. 

Moreover, it is named spot welding because this welding process helps in creating a small dot weld that actually looks exactly like a spot. The weld developed between the copper electrodes is also sometimes referred to as a nugget. 

What Are The Advantages Of Spot Welding? 

Today, spot welding has come to be the most preferred option in the automobile sector where aesthetics and functionality are exceptionally significant. This particular balance is the most crucial benefit of the spot welding process and it also sets it apart from several other methods like MIG welding and TIG welding. Here are the advantages mentioned below: 

  • Spot welding is a cost-effective process because it doesn't require filler metals or inert gasses. 
  • In the assembly line, robots can develop a spot weld because the method is quite straightforward. 
  • Spot welding can fuse numerous metal sheets at the same time. 
  • It is a clean, efficient, and quick process and mandates no post-processing requirements. 
  • Spot welding functions without any open flame, which is generally inefficient and risky. 
  • It also doesn't demand much training as it is quite simple & easy to understand.

Here Are A Few Tips To Ensure Tips To Ensure Quality Spot Welds

The consistency, reliability, and quality of multiple resistance spot welding products actually rely on a lot of factors. And the parameters that are mentioned below are some of the basic ones that are generally typical in each and every situation. Nonetheless, the authentic and significant factors are specified by the complications and the needs of a specific undertaking. 

1) Favorable Electrodes Forces

Here, the electrode forces are defined as the energy needs of a certain metal alloy in order to merge with each other. When the force becomes stronger, so will the thermal energy, and the current will be dissipated. Extra thermal energy can have quite a negative effect on the weld quality, which is why it becomes important to be more careful about this. 

2) Short Weld Duration

The weld time is actually the whole time a workpiece or an object has to remain under the application of the current to it. Plus, there is a rule associated with the spot welding process and that is the weld time must be kept extremely low as possible because this will help in ensuring the perfect quality. 

Regardless, you need to remember that keeping the duration as short as possible will result in premature welds that will not be able to merge appropriately and lead to certain difficulties in the future. Also, as there is zero or no accepted minimum time duration, the AHSs Guideline's general convention says that the usual times are nearly 1/5th of a second. 

Additionally, this is not set officially because several other factors such as the required strength, distance between the welds, properties of the materials, etc., can bring in alterations at a suitable time. 

Further Reading, Pipeline Isometric Drawings

3) Broaden Squeeze Time

Next is the squeeze or hold time, which means the total time that the object or workpiece stays under pressure before the current application. So, increasing the squeeze time can apparently increase the all-around quality of the weld because, in this way, the workpiece will have more time to stabilize. In addition, the pressure at the initial phase will result in enduring deformation in the workpiece's tips without any further heat, and this is considered to be the most effective way to make sure that the strength and quality have been kept intact.

The squeeze time can indeed help to improve the quality of the weld. However, if the squeeze time is increased, it can result in higher costs because the operational setup will develop fewer parts in an allotted time frame. Similar to other parameters, the squeeze time has to be in perfect sync with all the needs of the specific project and provide the ideal mixture of quality, integrity, and efficiency in the production. 

4) Correct Hold Time — Lastly, the hold time refers to the total time duration of the workpiece or object that stays under the pressure via connection with the electrode and this encompasses the time after the current application in order to enable the weld area to harden or solidify. And increasing the hold time enables the pressure to let the workpiece be stable, which has the ability to increase the overall joint quality. 

Nevertheless, if the hold time is increased, then it can create a lot of difficulties too. The heat might scatter towards the electrodes which can lead to possible wear & tear. Likewise, the material also has a vital role to play here! Friable selections such as carbon steels can develop cracks, and this can result in reducing the quality of the weld. 

Summing It Up

In conclusion, spot welding is a special technical procedure that is utilized majorly with sheet metal and is perfect for various applications. Spot welding can be simply automated when utilized with manipulation systems or robots. This makes it the perfect choice for weld processes in high-volume manufacturing industries. Spot welding has been the most preferred option as a joining process in the building of steel cars. Well, in case of any queries, visit our website OnestopNDT and feel free to reach out to us. 

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