Welding is one of the challenges the manufacturing industry faces. Spatter, rework, inexperienced welders, and a lack of skilled welders are among the problems. Using pulsed MIG welding can help you solve any of these problems.
For many manufacturing operations, pulsed MIG offers numerous benefits that can save them time and money. But when should pulse MIG be used?
Learn how pulsed MIG welding can improve welding results and how to switch to it. As a starting point, let’s discuss the different welding transfer modes. Understanding the different modes of arc transfer is helpful when welding with MIG or gas metal arc welding (GMAW).
· short-circuit transfer: It occurs many times per second when the welding wire touches the base metal. Amperages and voltages are lower in this mode.
· Globular transfer: During this mode, which is a transition between short-circuit transfer and spray transfer, large balls form on the wire tip.
· Spray transfer: This mode uses relatively high voltage and amperage values in order to spray tiny molten droplets across the arc. Once the arc is established, it remains on at all times.
· Pulsed-spray transfer: Also known as pulsed MIG welding, this is a modified spray transfer technique.
A conventional MIG welding power source can be used with the same wire for short-circuit, global, and spray transfer modes. The difference in modes depends on the shielding gas, voltage, and amperage being used. Pulsed MIG welding requires a welding power source equipped with pulse capabilities.
Pulse MIG Welding Basics
In pulsed-spray transfer, molten metal drops do not continuously move across the arc, as they do in spray transfer.
The welding power source switches rapidly between high peak currents and low background currents. For effective fusion, the peak current pinches off the spray-transfer droplet and propels it toward the weldment. Despite maintaining the arc, the background current is too low to transfer metal.
Welding in all positions on thin or thick metals is possible due to the slight cooling of the weld pool during the background cycle.
Considering pulsed MIG welding for your manufacturing operation could result in reduced spatter and rework.
Get a better understanding of pulsed MIG welding by watching this video.
The most effective tips for optimizing the results of pulsed MIG
While pulsed MIG systems with synergic control are designed to deliver optimal results right out of the box, there are some best practices to follow. To ensure a safe pulsed MIG welding process, operators should follow these tips:
Choose the right gas – Be aware that different base materials and transfer modes require different shielding gas blends.
1.Carbon steels – Pulsing and spray transfer typically require 80% argon content. It is very common to use a shielding gas that contains 90% argon and 10% CO2.
2.Aluminum-Never weld aluminum with CO2 blends. The most common gas shielding material is argon or an argon/helium blend.
3. Stainless steel using 98% argon and 2% CO2. To prevent sensitization, CO2 content in gas blends should not exceed 5%.
Watch stickout and technique – Welding techniques for pulsed MIG are the same as those for spray transfer. Keep a stickout of 5/8 to 3/4 inch, a 45-degree work angle, and a 10- to 15-degree travel angle. A push technique is usually recommended when using pulsed MIG — avoid using a drag technique. It is important to note that these best practices differ from those for short-circuit welding, which can use a push or drag technique and has a shorter stickout. Because pulsed MIG has a more fluid bead, operators changing from short-circuit MIG will need to adjust their technique.
It is fine to adjust the arc length according to operator preference. For less shorting, increase the arc length to get the arc off the puddle. Reduce the arc length for a tighter arc that increases puddle control.
Check the connections: Make sure all connections and grounding are tight and secure, and maintain clean clamps on the worktable or fixture. Coiled up weld cables can also affect the arc by causing a voltage drop.
It is important to know that pulsed MIG welding has many advantages such as lower heat input, better arc control, reduced spatter, porosity, distortion risk, and better directional control over the puddle, which makes it easier for welding newcomers.
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