Why use Pulse MIG ? 

Among other benefits, Pulse MIG is best known (or desired) because it offers;

• Lower heat = minimal distortion, reduced burn-through
• Reduced spatter: Spatter is significantly reduced, or even eliminated = Minimal cleanup
• Visually appealing welds = Added value to the finished product
• Higher deposition rates = Increased efficiency & faster travel speeds
• Tighter weld pool control = Ideal for out-of-position welding 
• Reduced welding fumes = Safer & cleaner work environment

What metals can you weld with Pulse MIG ?

Pulse MIG is ideal for metals and applications where controlling heat is difficult when using standard MIG process, and/or where high weld quality and appearance is desired. 

Pulse MIG welding Aluminium

Aluminium is a high thermal conductor (which means that heat is quickly transferred away from the weld pool), with a relatively low melting temperature. Pulse MIG process allows the operator much greater thermal control to apply enough heat for a successful weld, whilst avoiding distortion or burn-through.  

Pulse MIG welding with Bronze wires (MIG brazing)

Bronze wires are typically applied at a temperate that is lower than the melting point of the parent material - where the materials are essentially "stuck" rather than welded together - and are commonly used on thin materials (eg car body panels) where low temperature welding is essential to avoid distortion. Also commonly used on galvanised or zinc-coated steels (up to 2mm thickness) because the weld metal does not rust and the lower application temperature prevents disturbance (evaporation) of the zinc coating.  The ability to control and reduce heat makes pulse an ideal process for brazing wires.  

Pulse MIG welding with Stainless-Steel

Because stainless-steel is a poor thermal conductor, heat is typically 'trapped' close to the weld zone. This can result in expansion/distortion and rust contamination due to concentrated carbon in the weld zone. The weld pool is comparitively sluggish with poor wetting/flow into parent metal. The pulse process allows stainless wires to be applied at lower temperatures to minimise distortion and imperfectons. Pulse MIG is especially beneficial for welding thin stainless material where it is often extremely difficult, if not impossible, to avoid warpage/distortion with conventional MIG process. 

In all these applications, Pulse allows successful welding at lower temperatures with much better control of the weld pool. 

Pulse MIG welding mild steel

Mild-steel does not present the same "thermal challenges" as other metals like aluminium or stainless, and therefore pulse does not necessarily offer the same advantages. For this reason, conventional MIG (rather than pulse MIG) is still the best process for welding mild steel in many applications - especially in the material thickness range that is achievable with single-phase machines.

Pulse MIG can offer some productivity advantages for welding heavy steel, however this requires a high "peak" current which is available only from three-phase pulse machines.

For this reason single-phase pulse machines like the Weldclass Ultra 220MP don't offer a pulse mode for mild steel - although the 220MP does offer excellent results when welding mild steel in non-pulse modes, including welding of thin materials down to 0.5mm, thanks to the ATC (Advanced Thermal Control) technology. 

What is Double-Pulse MIG ? 

Also known as dual-pulse or pulse-on-pulse (PoP), this adds an additional pulse 'wave', where the current alternates (or cycles) between the main current level  and a secondary current level. This effectively multiplies the benefits of single-pulse, with even better thermal control, weld quality and appearance.

Pulse MIG vs TIG Welding

TIG is traditionally the go-to process when there is a need to weld materials to a higher standard (quality and/or appearance) than conventional MIG. Aluminium and stainless-steel are commonly welded with TIG, as these materials are often used in projects where the finish of the final product is critical - for example; boats & marine, architectural fixtures, food handling equipment, etc.

The disadvantage of TIG is that it is a comparatively slow & inefficient process, which increases cost and processing time. 

Enter Pulse MIG! Essentially, Pulse MIG offers;

• Weld quality and finish compariable or very close to TIG in many applications
• Superior speed and efficiency vs TIG
• Compared to TIG, typically requires less skill and is easier to learn, which reduces training time 

While the TIG process will always have its place, Pulse MIG is certainly replacing TIG as the logical choice for many applications, especially production work. 

What is the maximum thickness you can weld with a Pulse MIG?

This firstly depends whether the machine is 240V/single phase or 3-phase. With 415V of power to draw from, three-phase machines, are typically capable of welding up to 10-20mm thick material or even more (depending on their rated size). 

Single phase Pulse machines are typically able to weld up to 5-6mm maximum, if they are in pulse mode. Here's a few points to be aware of;

• Pulse mode requires higher output (amps) than non-pulse, which means that the 'maximum weldable thickness' will be less in pulse modes than it will in non-pulse modes. 
• The same applies to single-pulse and double-pulse: Single-pulse will typically allow welding of slightly heavier materials compared to double-pulse.
• In NON-pulse modes (essentially turning the machine into a conventional MIG), single-phase MIGs can weld 8-12mm material, depending on their rated size.
• The maximum thickness capacity can vary from one application to another. One important factor is 'heat sink'. Larger workpieces absorb more heat than smaller components (especially aluminium which is a very good thermal conductor), which means more/higher current is required, which then reduces the maximum weldable thickness.

Pulse MIG Options from keygree:

MIG-350DP-W/MIG-500DP-W