AC or DC Welding Machines: Which to Choose?

In this article, we will explain why some welding machines, due to the type of current they use, can have advantages over others.

Welding machines that use coated electrodes can operate on AC (alternating current), DC (direct current), or offer both current outputs.

Welding Machines with AC

The welding quality of machines that only use AC is not optimal, not due to the operator, but because of the nature of the current output. AC welding machines cause the current to alternate over time. Since the current is not constant, the heat delivery varies as well.

What does this mean for welding? In short, it results in uneven welding. You can achieve good welding points, but not long, consistent welds. These welds would be asymmetric, as the current alternates between positive and negative, which affects the electric arc and, consequently, the weld.

When the weld arc and heat delivery are not constant, the operator has to work harder to ensure the welding is done well.

Advantages of AC/DC Welding Machines

To address this issue, it is best to use equipment that offers both AC and DC outputs. DC provides a constant current, delivering steady power that results in homogeneous welds. With DC, you can achieve consistent, high-quality welds, making the welding process more efficient and effective.

DC Welding Machines

While AC machines are widely used by welders due to their affordability, they do not necessarily offer the best performance or results. Although the price difference between AC and DC machines is not substantial, investing in a DC welding machine can be beneficial for improved performance.

DC welding is a type of welding that uses direct current to create an electrical arc between the welding electrode and the metal being welded. The electrical current flows in one direction, from the negative electrode to the positive metal workpiece.

Benefits of DC Welding Machines

1. Welding Stability: DC welding machines provide greater stability, allowing for the creation of long, homogeneous welds. This reduces the likelihood of defects in the welding.

2. Heat Control: DC machines offer better control over the heat generated on the workpiece. This is because the direct current provides consistent and adjustable heat, enhancing precision in the welding process.

3. Versatility: DC welding machines can be adapted for various welding processes, such as TIG (Tungsten Inert Gas) welding or Argon welding. These processes are not feasible with AC welding machines.

4. Modern Technology: Inverter machines, which are popular today, use DC output for their numerous advantages. They offer ease of use, the ability to work at heights, and stable current, making them a preferred choice over traditional AC machines.

5. Historical Context: Older welding machines, such as those from the 1970s, used AC output due to the lack of technology to stabilize current. Modern DC inverter machines have since replaced these older models, offering superior performance and stability.

In conclusion, while AC welding machines are economical, DC welding machines provide enhanced stability, control, and versatility, making them a better investment for quality welding.

As a summary

For all these reasons the use of AC welding machines is not recommended, as they are obsolete in terms of use, quality and stability that the arc could present.

On the contrary, the DC welding machines result in better quality work and greater versatility of use.