What is pulse welding? How does it work and when to use it?

Last Updated on Apr 17, 2022

We know that welding is one of the best ways to connect metal and create something entirely new. But what type of welding is ideal for getting seamless, high-quality results? It turns out that pulsed welding offers some distinct advantages over traditional methods. This post will introduce you to pulsed welding and give you a few reasons it may be right for your projects.

What is pulse welding?

Pulse welding is a welding process similar to spot welding in which the welder is capable of controlling the amount of power and the duration of each pulse. It uses electric current to create heat at the tip of two electrodes, and then melts two distinct metal surfaces together. The electrode tips can get made out of any electrically conducting material such as copper.

Pulse welding is an efficient and economical way to weld metal parts together. While it has been around for years, it has only recently become popular among consumers because of its versatility in manufacturing environments.

Important Definitions

It is a method of welding in which the heat is concentrated on a small area for a short period with the arc pulsated at a high frequency. The process allows for more control over the weld, specifically greater penetration and less distortion.

The welder can control the arc in pulse welding by selecting three modes: short-circuit, globular transfer, and spray transfer. These modes can be switched between during the weld by switching from high frequency to low frequency. The benefit of this style of welding is that it allows for a better understanding of the heat input into each weld, which improves conditions such as lack of fusion or excessive penetration.

Pulse frequency

The pulse frequency on an inverter welder is the time it takes to go from the peak amperage to a primary current. It is usually measured in Hertz or cycles per second.

For example, if you have a machine set at 50 and it is welding at 100 amps, every second, it will pulse at high amperage and low amperage 50 times. If you set it to 1, then every second, it will pulse between high and low just once.

Pulse duty

The pulse duty setting on a TIG welder refers to the balance of time between peak and low current levels. When you weld in AC mode, the time your welder spends at maximum current and minimum current is always equal (50% each). Most TIG welders that allow users to control this set comes with a fixed set of 50% pulse duty.

You can increase or decrease the time your TIG welder spends at maximum current by changing the “duty cycle” setting on your TIG welder.

Gas post flow and gas pre flow

Gas pre-flow and post-flow are settings that adjust the time the welding gas is turned on before and after the weld cycle.

The gas pre-flow is the inert shielding gas released from the torch before the welding arc. The reason is to ensure that the weld pool is protected by an inert atmosphere from the very starting. If you do not have a pre-flow, the atmosphere around the workpiece can oxidize your material and trap contaminants in your weld.

The gas post-flow is released after the arc has been terminated. It ensures that there is still a blanket of shield gas over your weld pool when you stop welding. It helps prevent oxidation and other contamination until you have cleaned up and inspected your welded joint.

Where is pulse welding used, and why

Pulse welding is useful for welding thin materials that burn easily with a standard continuous welding process. It is also useful for welding dissimilar metals that may otherwise not be weldable.

Pulse welding can be used for fine-pitch, small-area joints, and high-speed, mass production of PCBs. Because it involves only a small amount of heat input, pulse welding helps reduce component damage from thermal shock and minimizes PCB warping. These properties make pulse welding ideal for joining devices with semiconductor chips, such as flash drives and other memory storage devices.

The main use of pulse welding is the higher quality of welded joints. The advanced technology allows maintaining low temperatures around the weld area to achieve high energy.

Pros and Cons of Pulse Welding

Pros

  • Pulsed arc allows for higher power levels at given currents and voltages, which is great for high deposition rates.
  • Precise control of heat input allows a lower thermal distortion, which can be critical in some applications.
  • Its lower residual stress due to less heat input results in higher weld quality and longer life.
  • Minimal spatter because less heat is being used.

Cons

  • Some jobs, such as stainless steel or aluminum, may require more heat than can be provided by a pulse welder and the weld bead might be too small.
  • Pulse welding requires a more complex power supply
  • Parts are more expensive because they need to be designed and manufactured specifically for welding.
  • Accessories such as water and air cooling systems, weld head assemblies, and wire feeders may get required.

Common Questions For Beginner Pulse Welders

Why should someone utilize the pulse technique?

Welding with a pulse can help you achieve higher-quality welds. Welding with pulse allows the welder to get more penetration weld into the metal, which results in stronger welds, less distortion, and an improved cosmetic appearance.

What is dual pulse welding?

Dual pulse welding is a technique used in laser welding to increase quality and speed. Dual pulse allows for more control over the weld itself and can make the process much faster than other welding techniques.