How to Improve Mechanized Plasma Consumable Life
Could you have imagined it, melting the stiffest materials with a gash of the brightest element? A plasma cutter makes it happen. It works more effectively than all other cutters out there.
Could you have imagined it, melting the stiffest materials with a gash of the brightest element? A plasma cutter makes it happen. It works more effectively than all other cutters out there.
Plasma cutters are so accessible and easy to use that we take the science behind them for granted. So, what is plasma, really?
Most of us learned in high school that there are three states of matter and as energy is applied to a substance it changes state from a solid to a liquid, to a gas. Well, that’s not where the story ends.
If a gas becomes superheated, the fourth state of matter (plasma) can occur. When this happens, electrons become stripped from protons and atoms forming an ionized gas and become free.
This allows plasma the potential to become electrically charged. Plasma will also produce and respond to magnetic fields.
These properties of plasma make it very powerful, but also very controllable.
Despite being relatively unknown and misunderstood by most of us, plasma is actually very common. How common? 99.9% of all mass in the universe is plasma.
As a matter of fact, Earth is one of only a handful of known planets where the other three states of matter even exist.
A lightning bolt is a large and powerful atmospheric electrostatic discharge that produces around a gigajoule of energy. That’s about enough to power the average US home for 9 days!
Lightning is visible in the form of radiant heat created through the rapid disposition of electrons in the atmosphere.
Most stars are formed entirely of plasma. They are so hot that atomic bonds will not hold, and molecules remain ionized.
Stars are the most powerful known examples of plasma, with the ability to project heat energy and electromagnetic radiation for hundreds of millions of miles!
Neon and fluorescent light bulbs use a gas sealed inside a tube or coil which is excited by the introduction of alternating current to emit light. If a strong enough electromagnetic field is present, these bulbs can even be illuminated without being plugged in!
Plasma TVs have largely been replaced by newer LED models, but they were the pinnacle of picture quality in the early 2000s. They work by using a series of tiny red, green, and blue light cells which are essentially tiny plasma spheres.
While still not fully understood, it is generally accepted that the Northern Lights are caused by solar winds carrying energy that interact with the magnetic field found near the North Pole of Earth. This ionizes atmospheric gas and creates a beautifully colored plasma that is visible for hundreds of miles.
There is also a Southern counterpart near the South Pole, however relatively fewer people live near the South Pole, so this event is lesser known.
St. Elmo’s fire is named after Saint Erasmus of Formia (a.k.a. Saint Elmo), the patron saint of sailors. It is a natural phenomenon when a tapered protrusion (often from a ship’s mast) reacts with nitrogen in the atmosphere under a very specific set of conditions to create a small blue corona of plasma.
Many of us have seen this toy as children without actually realizing what it was. A plasma globe is a glass sphere filled with various noble gases which has a high-voltage electrode placed conspicuously in the center.
When voltage is applied, the gases become excited and electrical filaments form amidst the plasma between the electrode and the outer glass insulator. It was invented by none other than Nikola Tesla, who called it an “inert gas discharge tube”.
If you are standing on the ground and touch one with your bare hand, the filament will become attracted.
Although lightsaber science has a foundation in the Star Wars universe and not our own, according to Wookieepedia a lightsaber consists of a plasma blade emitted by a kyber crystal.
Plasma cutting torches use the plasma to conduct an electrical arc from an emitter to the workpiece where it transfers massive amounts of heat energy to a precise point to melt the material being cut. The plasma is typically swirled to create stability, just as a quarterback would throw a football.
Think of a lightning bolt inside a tornado, all placed conveniently in the palm of your hand and ready to melt metal at the push of a button.
Want cleaner, faster cuts? Our cutters have a more stable plasma arc and electrodes that last 2x longer.
Additionally, our technology has the ability to reduce the usage of your consumables by 25% or more, increasing their lifespan and saving you money.
For more information on plasma cutting, take a look at ATTC’s selection of plasma cutting products.
Experiencing issues with your plasma cutter? Read our Plasma Troubleshooting Guide.
As your plasma cutting jobs progress, you may start to notice your cut quality diminishes. CNC plasma cutting is used for precise applications, so it’s important that you maintain your plasma consumables to extend the life of your torch.
In the world of modern metal fabrication, plasma cutting is ubiquitous. The low cost, ease of use, and capabilities of plasma cutting systems make them practical for a wide variety of everyday uses. That hasn’t always been the case, however.
Keep reading to learn the history of plasma cutting and what we are doing today!
Plasma cutting has come a long way over the years from its original creation in 1957. Which is lucky for us.
New technology has been invented and perfected to make plasma cutting more efficient and cost-effective.
In order to fully appreciate how far plasma cutting technology has come, we have to first look at where it all began. Back before there were cordless phones or even zip ties, Dr. Robert Gage invented plasma cutting.
(Plasma Cutting History Flowchart: click to enlarge)
As you can see, over the past sixty-four years, plasma cutting systems have become more capable, less expensive, and far easier to operate. Cut speed and quality are far above and beyond what Union Carbide could have imagined in 1957.
Cutting systems that once took up an entire room may now be slung over an operator’s shoulder and carried up a ladder. Technology that once only the largest of corporations could afford is now priced affordably to even the most price-conscious of consumers. Oxy-fuel torches, once a go-to, now collect dust in many fabrication and repair shops.
Our consumable technology is changing the game of plasma cutting tips by reducing plasma arc turbulence with a high-velocity configuration and stabilizing and accelerating the gas column.
Plasma cutting has never been easier with consumables and torches that allow you to produce ultra-smooth cuts with less than 2º bevel. Additionally, our current consumables are made to double the life of your consumables and torches to reduce downtime and save you money.
What will the future bring for plasma cutting technology? Nobody knows, but it is a safe bet to say that this shop staple isn’t going to disappear anytime soon.
Learn more about our plasma cutting technology’s unmatched capabilities and make the switch today!
There are many different types of plasma cuts and each one requires different processes and tools. If you do it wrong it can cost you lots of time and money, cutting into your profits.
In this article, we will explain the different types of plasma cuts and their proper tools, including the 5 different types of bevel cuts.
Let’s dive in.
Most plasma cutting is done with the torch positioned 90° perpendicular to the workpiece. This is called “straight” or “I” cutting. In this process, any bevel is considered undesirable and most operators will attempt to mitigate that by monitoring the performance of their machine and making sure all the parameters are properly set to get a square-edged cut.
Even under the best conditions, a bevel of up to 2° is usually considered acceptable, although it is possible to achieve a bevel of less than 1° using technology such as Clean Cut.
Sometimes, however, a bevel is required. If the part being cut is thick and must be fitted and welded, a bevel will assist with fit-up and ensure that the weld is able to fully penetrate the workpiece and achieve a proper joint.
Traditionally, this was done with an oxy-fuel torch, a grinder, or other secondary processes. Today, CNC plasma systems are capable of producing high-quality beveled edges at the same time that they profile the plate.
There are five types of plasma bevel cuts, represented by the letters A, K, V, X, and Y. These letters are a fairly accurate representation of the cross-section profile of the part after it has been cut.
An “A” bevel cut is the most common type of bevel. It requires only a single pass of the torch and leaves a cut edge that protrudes on top.
A “K” bevel is the most complicated profile to cut, as it requires three passes of the torch to complete. It is a combination of a top Y and a bottom Y which leaves a vertical land in the middle of the cut.
A “V” bevel is basically an inverted “A” cut. It also requires one torch pass. The cut will protrude on the bottom edge.
An “X” bevel is a combination of an A bevel and a V bevel where the mid-point of the two cuts meets in the middle of the plate, leaving an X shape. An X bevel cut requires two torch passes.
A “Y” bevel requires two cuts and comes in two varieties. Top Y will have a V bevel that does not extend all the way through the plate, leaving a vertical face at the bottom. A bottom Y cut will be the opposite, with the vertical face at the top and an A Bevel at the bottom.
Due to the large number of variables involved in plasma bevel cutting, programming can be difficult. Many times a “trial and error” process is needed to dial in a cut program that meets the requirements of production accuracy and quality of the finished cut part without crashing the torch into the workpiece or generating an excessive amount of dross. Special consumables are usually required for bevel cutting processes as well.
Contact American Torch Tip or your local welding supplier if you have questions about bevel cutting with your plasma system.
Looking to perfect your plasma cutting? The first step to improvement is deepening your knowledge.
In this article, we will discuss:
If you have used a plasma cutter, you have probably noticed that there is a difference in appearance between the two edges of the workpiece after a cut is made. This is due to the direction of the plasma gas swirl, as determined by the swirl ring (baffle), and the tendency of un-ionized gas atoms to be thrown to the outside of the gas stream due to their heavier weight.
The latter has a cooling effect on the nozzle, increasing its lifespan. With most plasma torches, the gas will swirl in a clockwise direction. This means the cut edge quality is better on the right side with respect to the torch direction of travel.
On some high-end plasma systems, swirl rings are available which swirl the gas counter-clockwise and allow for counter-clockwise torch motion, also commonly called “mirror cutting”.
This is typically used when two torches are present on one gantry. The torches are either on opposite sides when cutting the same program on two sheets simultaneously, or on the same side when slitting pieces out of a larger plate.
These systems typically also use a shielding gas or water injection system to further cool the nozzle and shield.
This means you are cutting a feature that is external to the finished part, the outside edge. When doing this you will want to cut in a clockwise path.
If you are cutting an internal feature such as a hole, you should cut counter-clockwise. Additionally, you need to cut with an appropriate lead-in and overtravel.
If your swirl ring becomes cracked or otherwise damaged, or if debris clogs any of the holes, turbulence may be introduced into your plasma arc. This can cause erratic cutting as the arc loses stability. You may notice a wider kerf, increased bevel angle, edge rounding, or other undesirable defects. Great care should be taken when installing swirl rings not to cause damage or clog gas ports.
Looking for quality plasma cutting torches to improve your cuts, increase your torches lifespan, and reduce downtime? We’ve got everything you need!
Schedule a FREE demo to learn more about how we can help you save money.
Dross is the nemesis of plasma cutting system operators everywhere. It ranges from a mild inconvenience to a downright pain in the you know what. Here are some tips for effective dross mitigation.
Both of these definitions seem very appropriate with regard to plasma cutting.
What’s better than easily removing dross? Avoiding it altogether. Our first three tips may help you do just that.
Anti-spatter spray is inexpensive, fast, and easy to apply and some formulas are non-toxic and environmentally friendly. This will help inhibit dross from adhering to the plate and make it far easier to remove. Anti-spatter spray can also be applied to torches, table slats, and anywhere else you want to keep clean.
Cutting too fast or too slow will cause the plasma arc to stretch and can result in dross that is both greater in volume and more difficult to remove. A few inches per minute (IPM) up or down can have a big impact here. Don’t be afraid to make an adjustment to dial in your program and find the sweet spot.
The nozzle in particular has a big effect on the shape of your arc. A worn or damaged nozzle can cause the plasma arc to become erratic and lead to lower quality cuts and increased amounts of dross. Nozzles should be replaced when the orifice becomes damaged or out of round.
Dross typically cools quickly and is easier to remove once it does. You also don’t want to be sending hot chips of metal flying around your shop and potentially igniting fuel sources. Letting it cool will also help you remove only the dross without damaging the plate if you are using power tools such as a grinder.
Here are some commonly used options:
Work smarter, not harder. If you find that the dross on your parts is very difficult to remove, you should consider what is causing it and if you are using the most appropriate tool to remove it.
30 seconds with a flap disc vs. 30 minutes of banging away with a hammer can save a lot of time, energy, and money.
Want to mitigate dross and have cleaner cuts? Visit our website or call 800-342-8477 to learn more about our efficient plasma cutting technology.
Handheld plasma cutting machines and oxy fuel cutting are both very common methods for metal fabrication and repair. Which technology is best? Here are some pros and cons of each.
Plasma is the overwhelming choice over oxy fuel on material under about half an inch in most cases. Oxy-fuel torches aren’t going away anytime soon, though. With the versatility they offer to do much more than cutting, we inevitably find ourselves wheeling them out from time to time for jobs where plasma just can’t cut it (pun intended).
Now that you know the pros of plasma cutting outweigh the cons, you may want to look at high-efficiency options for plasma cutting applications. At American Torch Tip well offer an unmatched line of plasma cutting torches & consumables with less than 2º bevel and minimal dross. For more information about plasma cutting, you can view our plasma cutting overview page to learn what plasma cutting products may be right for you.
If you’re new to plasma cutting, or just want to upgrade your plasma cutter, this guide will walk you through everything you’ll need to make an informed decision on buying a new plasma cutter.
If you’re coming from an oxy-fuel torch, you’ll be a bit ahead of the game. If you’re new to cutting metal, that’s ok too. We’ll walk you through it.
Will you be cutting mild steel, stainless steel, aluminum, or other materials? How thick? Most plasma cutting machines will be rated by material type and thickness, with mild steel being the most common material cut and therefore the most common rating.
You’ll need to know what the voltage, amperage, and phase ratings of your outlets are. Small plasma cutters typically run on 120 or 240 volt single phase power and require 10-30 amps of current. Some systems can automatically detect what voltage you have connected them to. There is also a wide array of NEMA plug styles and you’ll need to have one that matches the outlet you plan to use.
Unless you’re going to invest in a plasma cutter that boasts an onboard air supply, you’ll need a compressor and some method of drying and regulating the air once it is compressed. If you don’t have a compressor or are not sure if yours is up to the task, take a minute to read up on the list of air supply requirements for plasma cutting systems.
Check-in on some forums, blogs, and social media groups to see what other users are saying about particular models you’re interested in. Be cautious of reviews from marketplace sites as they are sometimes forged to boost the product’s position within the marketplace. Pay special attention to how the manufacturer handles complaints from customers. If a company displays prompt customer service and offers a viable remedy when problems are encountered, you may rest assured that you can get support when you need it.ƒ
In a perfect world, we would all have unlimited funds available to purchase tools with. In reality, we must balance our needs and wants against the resources we have available to purchase our new tools. It is generally recommended to follow the “buy once, cry once” mantra and purchase the best quality system that your budget allows, rather than settling for an alternative of lesser quality with a more attractive price point.
Just as important as the brand and model of the plasma cutting system you choose is where you choose to purchase it. Many manufacturers will not honor warranties for items purchased outside of authorized distribution networks. If you purchase online, do some due diligence and make sure that the seller is legitimate and will be there to assist you should a problem arise. If you are considering purchasing a second-hand machine, familiarize yourself with how to test it to ensure proper functionality and check to make sure that repair parts and consumables are still available. American Torch Tip provides a wealth of information on it’s products if you are looking for a reputable source for plasma cutting products.
If you follow these steps, you will likely find that you make an educated purchase and your plasma cutter will serve you faithfully (or at least you’ll have purchased it from a seller that will help you get it back to work).
There are a lot of ways to cut metal. Here’s why you should be using a plasma cutter.
Steel? Check. Aluminum? Check. Stainless? Also check. Your plasma cutter isn’t a picky eater. You can feed it almost any type of metal or alloy. Cut quality will vary (especially depending on the gases used) but your machine will eat it.
Next on our list of plasma cutter uses; you can use a plasma cutter when you need to finish a project quickly. With cut speeds exceeding 100 inches per minute, plasma cutting is very fast. The speed will decrease with material thickness, of course, but for most everyday materials, plasma cutting offers considerable time savings.
Plasma arcs can reach temperatures of up to 25,000 degrees Celsius. That’s almost five times hotter than the sun. That mind-boggling temperature is reached in milliseconds and will liquify metal instantly with no preheating. That means no waiting and no wasted energy.
If you wanted to cut various forms of metal (plate, tube, angle, beam, grating), you would need multiple different types of saws or shears. A plasma cutter can do it all. Some premium models even offer a continuous pilot arc mode that allows for cutting of expanded metal or grating with no loss of cut.
Not only can you cut with it, but you can also bevel, gouge, mark, and even weld! No other tool in your metalworking arsenal is so flexible.
There are few tools so capable as the plasma cutter that don’t require a formal education or at least detailed instruction and practice before using properly. With plasma, an operator with zero experience can pick up a torch and perform a high-quality cut in seconds. However, if you do have questions, we have the answers to your plasma cutting questions.
Most plasma cutting is done with compressed air. Nitrogen, argon, and even water are also used to assist with cutting. This is far safer than the acetylene, propylene, and other flammable and volatile gases used in oxy-fuel cutting processes.
In the past few years, a plethora of economical handheld plasma cutters in the 20A – 100A range have hit the market. Systems that once cost thousands can now be had for hundreds. That puts this technology within reach for even the smallest of fabrication and repair shops.
With plasma cutting systems being widely used in fabrication and repair, they have naturally become a go-to tool for cutting many different types of material. While plasma cutting systems are capable of cutting any electrically-conductive material, there are certain considerations that must be taken into account when attempting to cut stainless steel. Let’s start by looking at the practicality of plasma cutting stainless steel.
A plasma cutting is a great solution for cutting stainless steel. It is a relatively fast process and tends to be a more affordable method. There are a variety of plasma systems to select from to produce optimal results depending on your needs.
Now that you’ve selected a plasma cutter for your stainless steel cutting, let’s decide which gas to use when making your cut.
One of the primary factors in determining the cut quality and edge finish of stainless steel plate cut with plasma is the type of gas used. Ideally, a high-definition dual-gas plasma cutting system should be utilized when available for the best results, however, a single gas system will work.
Now that you’ve selected your gas, there are a variety of other factors to consider in order to maximize your cut quality, efficiency, and safety while plasma cutting stainless steel.
Heat-affected zone is a concern when cutting a variety of materials, but is of special concern when cutting stainless steel, as most grades of stainless will show drastic signs of temperature change that remain after the material has cooled. This may require secondary process pickling or passivation to remove the discoloration left from the heating of the material.
The edge quality of a plasma cut on stainless steel plate will vary and is highly dependent on three factors:
Compared to mild steel hole cutting on modern high-end plasma systems, where it is often possible to drop in bolts equal or larger in diameter to the thickness of the plate, precision hole cutting is more difficult on stainless steel plates due to the arc characteristics and dross accumulation. Operators may find it easier or necessary to drill bolt holes on a stainless plate or perform secondary processes to square or clean up holes cut with the plasma torch.
Polyethylene-coated sheeting is commonly used in food service and medical equipment fabrication to protect the surface finish of the material. Cutting PE coated stainless steel sheet is possible with plasma, however amperage must be kept low and nitrogen should be used as a shield gas.
Operators who are used to cutting mild steel will be familiar with removing at least some dross but may be unpleasantly surprised to find that dross is considerably more difficult to remove when cutting stainless steel plate. Reconfiguring the table slats may help alleviate this issue if it allows the pierce points to fall in between the slats.
If you’re welding stainless steel, there are a few additional things to consider.
Care must be taken not to contaminate stainless steel plates with carbon steel during dross removal, grinding, brushing, or other processes. This can cause rust pockets, staining, and other undesirable effects.
When consideration is given to the special requirements of plasma cutting stainless steel, the process can work very well and produce very high-quality parts. If you have questions about plasma cutting stainless steel, contact your local welding supplier or table manufacturer. If you’re interested in plasma cutting, you can read more about our plasma cutting products, to help you improve your cuts & increase efficiency.
Plasma cutting, while generally easy and efficient, isn’t always as easy as pull and cut. Here, we address some frequently asked questions about plasma cutting from our customers.
A: This process involves melting and expelling materials, such as steel, aluminum, or copper, from a cut using ionized gas. During this process, you establish an electric arc between an electrode and anode.
A: Yes! You can use a plasma cutter to cut through aluminum as well as many other materials.
A: Any electrically-conductive material including steel, stainless steel, and copper.
A: You emit an arc of electrical current from the electrode and combine it with swirling gas. Then a nozzle focuses and directs it to the workpiece. The jet of ionized gas is very hot and melts and blows away molten material from the workpiece.
A: No! An operator with minimal training may learn to use a plasma cutter in just a few minutes.
A: You should change the electrode when the emitter pit depth reaches 1mm (2mm for silver electrodes). You should change the nozzle when changing the electrode or when the orifice becomes out of round. The remaining consumables should be changed as needed when they become unserviceable.
A: You have exceeded the life of the electrode and the emitter has been depleted. The arc is now being emitted from the copper surrounding the emitter pit and the green color is oxidized copper. Stop cutting immediately and change your electrode and nozzle!
A: Absolutely not! The Magnuson-Moss Warranty Act prohibits companies from requiring the use of their brand of consumables in order to maintain warranty coverage.
A: According to your machine’s preventative maintenance schedule or when it becomes contaminated or electrically conductive.
A: That depends. Plasma cutting is easier to learn, safer, and faster on thin material. It can also cut materials that oxy-fuel cannot, such as aluminum. On thicker material, however, oxy-fuel often has a faster cut speed and can cut steel far thicker than plasma.
A: Yes. If your plasma cutting system has a continuous pilot arc mode, you’ll want to engage this feature to cut grating or expanded metal. If not, you’ll have to manually fire the arc each time you move between slats.
A: Yes, with the proper torch and consumables. Gouging is a slightly different process than cutting and not every manufacturer offers gouging torches and consumable options.
A: CNC stands for Computer Numerical Controlled. In CNC plasma cutting, a table and gantry are used and the torch movement and arc initiation is controlled by a program loaded into specialized computer software. CNC plasma cutting allows for the highest degree of quality and repeatability for high-volume part production.
A: Dross occurs when you melt metals and then it re-solidifies and is not ejected from the kerf. This can cause problems with the quality of your cut. But with the right plasma cutting processes, you can minimize dross.
To learn more about plasma cutting download our complete Plasma Troubleshooting Guide which discusses common challenges and their solutions as well as 7 tips to improve your cut quality!
If you have further questions about plasma cutting, feel free to reach out to us. We are happy to answer them for you!
So, you want to start plasma cutting? First, you’ll need to know the plasma cutting basics!
If you’ve ever done any metal fabrication, it’s almost a given that you’ve wished you had a plasma cutter. While oxy-fuel and saw cutting works pretty well for most purposes, the versatility and ease of use of a plasma cutter are enough to make anyone jealous.
Before you get started with this method of cutting, you should know the plasma cutting basics. Here are the 5 essentials you need to get started.
There are hundreds of options on today’s market for affordable, handheld plasma cutting systems. A small system in the 20A – 50A range can be had for under $500 which will be capable of cutting up to ½” mild steel. Some systems can run on 110V power or dual 110V / 220V power. Some weigh less than 40 pounds and can easily be carried around a shop or jobsite. Some even have onboard air compressors!
Most small plasma cutting systems don’t require much in terms of air, but you’ll always want to make sure that your air supply is clean and dry. Oil or water in your air will cause issues with your plasma cutter. At a bare minimum, you’ll need 80psi of pressure and 3.5scfm of flow capacity to run any plasma cutting system, but some systems may require 115psi and 6.7scfm. Do not skimp on a proper air compressor. Your plasma cutter won’t function correctly if you do!
The smallest handheld plasma cutters will run on 110-120VAC and draw 15-20A of current. As you go up in power, you’ll need 220V-240VAC with a 30A or 50A circuit. Many newer machines are adaptable for either voltage range, allowing maximum performance at higher voltage while still remaining versatile where only lower voltage input is available.
Just like any other tool, your plasma cutter will require an array of consumables to function. This may include electrodes, nozzles, swirl rings (baffles), retaining caps, shields, and other items. You’ll want to make sure that you have an adequate supply of these before you start cutting as they will need to be replaced periodically as they wear out or become damaged.
If you want to get the most out of your consumables, you should use high-quality products for better durability. At American Torch Tip, we have a full line of plasma cutting consumables that are built to last, saving you money on consumables.
You’ll want to protect yourself from injury while plasma cutting. To do this you’ll need shaded lens glasses, a face shield, gloves, and a bib or jacket to cover exposed skin and non-fire-resistant clothing. You may already have these things available but if you do not, be sure to get them before you begin cutting. ANSI and AWS recommend a minimum protective shade of 8 for plasma cutting in the 20-100 amp range.
In addition to the plasma cutting basics above, it also helps to have a straight edge or cutting guide to assist in making the straightest, highest-quality cuts possible, especially if your torch does not use a drag shield and you’ll be manually maintaining a standoff distance. Circle cutting guides are also available for a very affordable price to assist in cutting round shapes. For more information, visit our welding blog.
If you’re getting started with plasma cutting, we recommend taking a look at our wide selection of plasma cutting torches and consumables.
Plasma is a superheated ionized gas. In a plasma cutting system, you can think of this as a lightning bolt inside a tornado.
The electrical current (lightning bolt) contains a massive amount of heat energy. The gas (tornado) ionizes, controls the arc, and blows away the molten material. In order for a plasma cutting system to perform optimally, the gas supply must be clean, dry, and properly regulated. When using bottled gas, these factors are relatively simple to control. Since most modern plasma cutting systems rely on shop air for the majority of cutting processes, more variables are introduced into the equation, often causing performance and consumable life to suffer when the air supply is less than ideal.
Here we’ll discuss the three factors that contribute the most to the performance of your plasma cutting system, and how to make sure that your tornado can keep up with your lightning bolt.
Before we can discuss what a plasma cutter needs to breathe, we need to understand the design and operation of air compressors. A typical air compressor is comprised of a motor-driven compressor and a storage tank. The storage tank size will be represented in gallons or liters, with portable systems having tanks as small as 1 gallon and stationary systems having tanks 100 gallons or larger.
Flow rate capacity is a product of output pressure and storage tank size. The higher the output pressure is set, the lower the flow rate capacity will be. It is important that you are confident your compressor can keep up with the flow rate requirement of your cutting system when set at the required output pressure.
It is highly recommended that your plasma cutter air compressor be dedicated to running your plasma cutting system. If you plan to run other pneumatic devices simultaneously, you will have to add the flow rate requirements of all devices together to ensure that your compressor can keep up without exceeding its duty cycle.
Pressure is the force of the compressed air being fed to your plasma cutter. The value for gas pressure may be represented in pounds per square inch (psi), megapascal (MPa) or bar.
Air compressor system pressure is preset and is usually between 100 psi and 135 psi and output pressure is adjustable via the pressure regulator. Inlet pressures vary by system. For a small handheld plasma cutter running at 20-30 amps, you’ll need as little as 80 psi (5.5 bar). Larger, automated plasma cutting systems in the 130 to 800 amp range may require 115 psi (8 bar) or more.
Most commercial industrial air compressors for plasma cutters will be capable of generating pressures in this range. It is important to note that the inlet pressure at your plasma cutting system will be lower than the output pressure of your air compressor due to pressure drops between the two points which can be caused by leaks or restrictions such as undersized fittings or filtration units.
You may need to set your compressor’s output pressure slightly higher than the inlet pressure requirement of your plasma cutter to compensate for pressure drops. Consult your operator’s manual to determine the best pressure for your system.
Flow is the rate at which air is being fed to your plasma cutter from the air compressor.
The value for flow rate may be represented in cubic feet per minute (CFM or ft3/min), standardized cubic feet per minute (SCFM), cubic feet per hour (CFH or ft3/h), standardized cubic feet per hour (SCFH), liters per minute (l/min), or liters per hour (l/hr). The flow capacity of a compressed air system is largely determined by the size of the tank.
As a good rule of thumb, select a compressor that has a flow rate capacity of at least 1.5 times the consumption rate of the plasma cutter. You’ll also want to make sure that the hose or tubing in use is rated for the pressure the system will handle, large enough in diameter to handle the flow rate requirements, and will not corrode or cause excess moisture to develop inside the line.
Copper is preferable to steel and aluminum pipe. Lines shorter than 75’ should use 3/8” diameter hose or tubing. Lines longer than 75’ should use ½” diameter hose or tubing. If using a flexible hose, you should take care to make sure the hose is not pinched or kinked.
The orifice size of all fittings used should match the ID of the hose or tubing. Flow rate requirements also vary by system and you’ll need between 3.5 scfm (99 l/min) and 6.7 scfm (189 l/min) depending on your system’s requirements.
While inlet pressure and flow rate vary by system, filtration requirements do not. At surface level, it may seem that this makes filtration the simplest variable to account for.
In truth, filtration is the biggest gremlin in many air supply systems. It is often misunderstood and operators assume that because they have invested in the proper filtration equipment, they cannot possibly be experiencing a filtration issue.
The design and layout of a compressed air system can have a large impact on the amount of moisture that becomes trapped in the system, and where it ends up. Gravity can be your friend or enemy in this regard. Air filtration devices should be used to remove water, oil, and debris from your air supply and should be placed as close to the plasma cutting system as possible.
Under most conditions, a common coalescing filter with an automatic drain is sufficient. If cutting in a high humidity environment, a refrigerated air dryer should be considered.
Taking the time to ensure a proper supply of clean dry air to your plasma cutting system will provide you with better cut quality, less downtime, and longer-lasting consumables. If you need help selecting the proper air compressor or air system components, visit your local supplier for assistance!
If you’d like to learn more about plasma cutting, you should read our blog detailing how to properly replace your CNC plasma consumables.