The Miller Plasma Cutter 625 X-TREME Review 2022

welder setting up plasma cutter

Welding Buddy Experts

January 1, 2022
Miller Plasma Cutter 625

A high-performance cutting tool is always welcome in any workshop. Plasma technology revamped the era of oxyacetylene cutting by providing the possibility for metal fabricators to cut through thin sheet metals and tubings with exquisite precision while simultaneously minimizing the need to grind and smoothen metal slugs.

Miller has always been at the forefront of providing quality solutions for welders and metal fabricators alike. Their Miller plasma cutter 625 is an excellent choice for your everyday metal fabrication needs.

How does a plasma cutter work?

The fourth state of matter is plasma. Plasma molecules are what you get when you heat gas at a high enough temperature. Plasma technology is commonly seen in neon signs and is naturally found in the sun. 

Plasma cutters use plasma energy by channeling an air source, usually oxygen, through a narrow opening with an electrode. The high-pressure movement heats the air molecules to a point where the atoms break apart, releasing vast energies in the form of a plasma jet stream, reaching temperatures of up to 20,000 degrees Fahrenheit, facilitating metal cutting via melting.

Should you buy the Miller plasma cutter 625 X TREME?

The Spectrum 625 X-TREME is a versatile machine that can perform light to medium industrial work. This compact machine can do anything between air plasma cutting and gouging. Here's a list of appropriate uses of the machine:

  • Light construction work
  • Home/DIY hobbyists
  • Owners of ranch and farms
  • Infrastructure workers
  • Metal fabrication and gouging
  • Artists engaged in metal artworks/building sculptures
  • Body shops
  • Boat/yacht makers


  • Applications: Air plasma cutting and gouging
  • Product weight: 21 lbs
  • Voltage and Hertz: 120/240 volts, 60 Hertz
  • Duty cycle: 60% duty cycle at 40 amps, 35% duty cycle at 27 amps
  • Reach capacity: 20- or 12-ft XT40 handheld torch and 12-ft power cord
  • Cutting capacity: Rated for 5/8-inch mild steel at 13 inches per minute and up to 1/4-inch at 64 inches per minute (presuming 240 volts with 40 amps) 
  • Severance maximum capacity: 7/8 inches at 40 amps
  • Air pressure requirements: 6.0 scfm at 90psi minimum and 120 PSI at maximum

Power and performance

The Miller 625 X-TREME is a flexible machine suitable for home and work use with its dual voltage capabilities. The Miller 625 comes with both 240V-50A and 120V-15A plugs, the latter being more appropriate for garage use. 

This machine is rated to cut easily up to 5/8-inch steel sheets at a steady, precise rate of 13 inches per minute. This rating is more than enough to meet or go beyond your daily cutting requirements, especially for light to mid-level industrial work. 

The XT-40 torch handheld torch comes in two options, the 12-ft or the 20-ft, with the 20-ft torch allowing you more flexibility around complex projects like metal sculptures. 

The torch set includes a complete array of 40-ampere consumables. The Miller 625 X-TREME also comes packaged with a robust work clamp and flexible cable that you can connect in a matter of seconds.

Another nifty feature of this light machine is the trademarked Wind Tunnel Technology and Fan-on-Demand. The Wind Tunnel protects internal electrical parts and PC parts from shop dirt, metal dust, and debris, significantly improving the parts' longevity and reliability. The Fan-on-Demand cooling system prevents any overheating of the unit.

Duty cycle

The X-TREME's output is rated at 40 amperes at 140 VDC with a 60% duty cycle and 27 amperes at 91 VDC with a 35% duty cycle. Depending on your project, most would consider those amperage outputs quite decent. At 40 amps, this welding machine is more than capable of cutting through 1/4 -inch mild steel at 64 inches per minute. 

The 60% duty cycle at max 50 amps is very respectable, designed to endure about 6 minutes of continuous work before it needs to cool down. Though 6 minutes seems slightly slow, you have to consider that the unit's portability and weight more than compensate for this limitation. 


This unit is genuinely built for portability, weighing only a meager 21 pounds. Plus, the shoulder strap makes it easy to lug the unit from one shop to another. You won't have to worry about dents and scratches with the X-TREME's protective X-CASE, with additional space for plug adapters, consumable kits, gloves, and other protective devices. 

The unit's LED display also features power, pressure, cup, and temperature indicators, allowing for quicker Miller Spectrum 625 plasma cutter troubleshooting and eliminating delays.


Safety is a combination of unit features that reduce fatigue and maximize efficiency. When you're less tired, you're less prone to making mistakes that could lead to a fatal injury. 

The X-TREME's trademarked Auto-Refire Technology provides for customer ease of use by automatically cutting off the pilot arc when cutting through expanded or multiple metal parts. The pilot arc switches in and out rapidly and adjusts power according to the metal thickness automatically. This prevents the need to conduct manual re-triggering, lessening user fatigue overall.

The XT-40 Torch features an ergonomic handle with a proprietary no-slip grip, guide for thumbs, and finger impressions to support a solid operator grip. The torch cables are also quite flexible, making maneuvering around your worktable an easy task. The XT-40 torch also comes with an Ultra-Quick Connect design that lets you start your work faster and more easily.

Pilot arc

A pilot arc start removes the need to touch the workpiece to start a plasma stream, helping prolong your consumables' lifespan. In contrast to high-frequency arc starts, the pilot arc is compatible with CNC applications. However, if you're investing in CNC machines, it's best to go with something other than a handheld torch.


Miller is famous for their TrueBlue 3-year warranty, which guarantees easy replacement and machine parts labor. The XT-Torch, however, is warranted only for one year, parts only.


  • For the steep price, it doesn't come with an air source compressor or bottled gas.
  • No weld leads

Accessories included

  • Spectrum 625 X-TREME unit
  • XT-40 handheld torch with cable
  • MVP adapter for 120/240 V
  • X-CASE 
  • Shoulder strap
  • Consumables: two electrodes, two tips (40 A), one tip (30 A), drag shield (30 A), deflector, and air fitting

Plasma cutter maintenance tips

Plasma cutters are a relatively new technology. For the cost, you'll want to preserve the parts and consumables for as long as possible. Here are a few tips to keep your X-TREME welding machine in pristine working condition.

  • Replace consumable parts as required. Consumables will degrade over time and need to be replaced. When your plasma jet stream starts to sputter or start poorly, your electrodes or tips might be worn out.
  • Correctly assemble the torch. A poorly assembled torch will result in the plasma cutter's poor performance and set the unit up for eventual damage. This might lead to preventable damages, which could cost quite a lot, especially for this brand's plasma cutter.
  • Use the right parts for the job. Make sure to study the Miller 625 plasma cutter manual before purchasing another set of consumables. Using the wrong consumables such as torch tips may lead to machine failure due to incompatibility, decreasing your machine's overall lifespan.  
  • Ensure appropriate gas and coolant flow. Make sure to do a daily check of the gas flow and coolant pressure. An insufficient flow will lead to inappropriate cooling of the parts and consumables, which might cause overheating. Incorrect gas pressure will result in a hard starting of the arc.
  • Clean the torch regularly. Hydrogen peroxide is a valuable chemical in keeping your handheld torch stain- and rust-free. Your torch must be sufficiently clean to maintain a smooth plasma jet stream.


With the Miller 625 X-TREME plasma cutter, you get a machine packed with many features that make metal cutting and gouging a safer procedure. Convenience is also paid heed to with flexible cables and nifty shoulder straps. The compact design will last you years, especially with its additional X-CASE protection. 

While there are certainly friendlier prices in the market, buying the Miller Spectrum 625 Plasma Cutter X-TREME gives you the ease of mind and stellar customer service essential for unexpected incidents. It's helpful to note that while the X-TREME provides a high value for many metal fabricators, heavy industrial work may call for a higher-caliber machine. As such, you should tailor your expectations of this unit to light to mid-level workloads or else risk overworking it. 

If you're dealing with steel sheets that aren't too thick, the Spectrum 625 will do you just fine. Happy cutting!

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