One question we often hear when people come to us with projects is, “Should I use laser cutting or plasma cutting for my metal fabrication?” As a metalworking company, we have the knowledge and know-how to be able to give you our professional recommendations based on your budget, your needs, and your final project. Today, we wanted to take a minute to talk about what the differences are between laser cutting metal and plasma cutting, and what projects we would use these technologies on.
Most of us can picture what a laser looks like, but are unsure of what exactly it is. A laser cutter is essentially a concentrated beam of optic light (yes, a laser cutter is essentially a light saber). The high power beam rapidly heats, melts, and partially vaporizes the metal or other material that it comes into contact with.
Plasma cutting was actually developed before laser cutting and began to be used in the 1950s. Prior to this, metal was flame cut, which is exactly what it sounds like. However, some metals could not be flame cut, like stainless steel, aluminum, or copper, and so plasma cutting was invented. The plasma cutting method involves a highly concentrated channel of electrically conductive gas that acts as a vessel to transmit energy from a power source to the material being cut by means of moving through a plasma torch. Like a laser cutter, a plasma cutter ultimately slices through metal by melting it.
Comparing Laser Cutting And Plasma Cutting
- Lasers are typically more expensive to operate but offer a level of detail that plasma cutting does not. Therefore, lasers are great for engraving details or cutting out small shapes from the metal, whereas plasma is better for more simple cuts.
- Plasma cutters can cut through thicker sheets of metal. In general, a plasma cutter can cut through metal up to 1.5 inches thick. Lasers, on the other hand, can cut through half-inch thick aluminum, three-quarters-inch thick stainless steel, and one-inch thick steel.
- Plasma can only cut materials that conduct electricity, whereas lasers have been used to cut wood, plastic, glass, and other materials. This is because the plasma uses electrically conductive gas to create the cuts, rather than a beam of optic light.
- Lasers cannot cut highly reflective materials like copper, so plasma cutting may be the best option for materials like this. However, plasma can cut through any conductive metal, regardless of the surface.
- Laser cutting has a tighter tolerance of just .002 inches, making it ideal for precise cuts or parts that have intricate notching.
- Both laser and plasma cutters at our shop use CNC, computer numeric control, to control the machines. This means that your project can be completed quickly and accurately.
An Overview of Laser Cutting
One of the first instances where lasers were used for industrial purposes was back in the 1960s when a laser cutting machine was used to drill holes in diamond dies—a wire drawing die made of diamonds and used for drawing fine wire of hard metals. It wasn’t until the 1970s when laser cutting became a viable option for other industries, namely manufacturers of sheet metal and textiles. Additionally, because of its ability to produce reliable, clean cuts, the aerospace industry also took an interest in laser cutting around this time.
In the early days of laser cutting, materials had to be cut in a way similar to manual methods like shearing and sawing. This is because computer technology was not yet at a point where it could be utilized to guide cuts. As computer and technology became more advanced so did laser cutting, quickly becoming one of the most reliable and versatile forms of metal fabrication available.
Types of Laser Cutting
A number of industries utilize the powers of laser cutting and apply them to an array of materials, including wood, glass, stone, plastic, and sheet metal. Currently, there are three main types of lasers used in laser cutting:
- CO2 Laser
- Fiber Laser
- Crystal Laser
Additionally, there are many different types of cutting methods used to cut different materials. Some of these methods include the following:
- Vaporization Cutting
- Melt and Blow
- Thermal Stress Cracking
- Stealth Dicing of Silicon Wafer
- Reactive Cutting
Benefits of Laser Cutting
As we’ve said, laser cutting is one the most—if not the most—viable method for fabricators. So what is it about this process that makes it so valued by laser cut shops? Here are four reasons why it is the most relied upon method for metal fabrication.
- Precise Edge – when cutting with traditional methods, like a blade, it is not uncommon to see burrs or a rough finish that has to be buffed and smoothed out. This isn’t a problem when cutting with lasers.
- Exact Detail – laser beams do not wear. This improves precision. Additionally, because of the size of a typical laser and the fact that they are guided by high-powered computers, this allows for the creation of intricate designs that would otherwise be impossible to create.
- Low Maintenance – traditional cutting methods require routine upkeep and blade sharpening. Lasers don’t necessitate this sort of maintenance and can function for extended periods of time without needing servicing.
- Maximum Efficiency – whether you are making a prototype or pumping out full-scale productions, lasers do not need to be adjusted or retooled. This allows for optimal efficiency when fabricating.
- Variety of Uses – Laser cutting has the capability to cut a wide variety of materials and thicknesses.
- Quick Setup – Compared to other metal cutting technologies, laser cutting has a relatively fast set up time. It’s also much easier to make adjustments when custom fabrication is needed.
Quick Facts About Laser Cutting
- Laser cutting began more than a half-century ago.
- There are over 25,000 laser cutting applications.
- Laser cutting is extremely efficient and environmentally friendly.
- Oxygen cutting is cheaper than nitrogen cutting and is used for most mild steels.
- LASER is an acronym for Light Amplification by Stimulated Emission of Radiation, and it was first coined in 1959 by Gordon Gould.
- Laser cutting has earned a reputation for being extremely accurate (precision up to a billionth of a meter).
An Overview of Plasma Cutting
In short, plasma cutting is a technique used to cut through conductive metals, such as steel, brass, titanium, copper, aluminum, and more. Plasma cutting is not just done in metal fab shops using large CNC plasma cutting machines. It can also be done by hand using a hand-held plasma torch, or sometimes referred to as a plasma arc, plasma cutter, or plasma gun. However, as might be expected, since CNC plasma metal cutting machines use automation to guide the path of the torch, this cutting method is preferred in industrial applications where numerous and ultra-precise cuts are required.
How Does It Work?
Plasma cutting first came into use over 50 years ago when flame cutting wasn’t cutting it—literally, flame cutting wasn’t able to able to cut some metals like stainless steel, aluminum, and copper, which inspired the invention of plasma cutting. Plasma cutting works by sending a fast jet of hot plasma through conductive metals. This hot plasma is generated through the process of sending an electric arc through a gas like nitrogen or oxygen. When the plasma jet hits the metal, recombination occurs, causing the gas to revert to its normal state, thereby, emitting intense heat. It is during this interaction that a fourth state of matter is created. We call this state plasma.
Why Plasma Cutting?
Metalworkers prefer plasma cutting for a number of reasons. The following are just a few:
- Safer than using saws
- Can cut through thick metal (roughly up to 1.5 inches thick) and various surface types
- Offers extremely precise, quick, and repeatable cuts (when used with CNC machines)
Tips For Choosing the Best Plasma Cutter
- Determine its use. What materials will you be plasma cutting? What are the products you intend to produce from plasma cutting? Plasma cutters are amazing, versatile tools, but you need to make sure you buy one powerful enough to handle the jobs you will be doing. These questions will narrow down which plasma cutter is right for you.
- Consider the cutting speed. The cut rate will tell you how fast a plasma cutter can cut metals of varying thickness. Furthermore, one plasma cutter with higher amps will be able to cut metal faster than one with a lower current although both will get the job done. There are typically three cut ratings for plasma machines: rated, quality, and sever. This also tells you the thickness of the metal that the machine is capable of cutting.
- Consider how the plasma cutter will start. Most plasma cutters have a pilot arc that uses high frequency to conduct electricity through the air. The plasma cutter will start easier but the high frequency can interfere with nearby computers and equipment. High frequency cutters are cheaper and result in a more stable arc, but they are limited in the fact that they need to be started close to the metal with a scratch start.
- Weighing the costs of materials. Due to the nature of plasma, plasma cutting torches have many parts that need replacement routinely. If you are using a hand-held torch, you’ll have to replace the retaining cap, shield, nozzle, electrode, and swirl ring. All of these affect cutting performance once they begin to deteriorate. Logically, the less number of parts, the less parts you’ll have to replace, and the cheaper the overall costs will be over the long run. Some manufacturers give you an estimate on how long parts will last.
Not Sure What Type of Cutting Is Right for You?
When it comes down to it, no two projects are the same. Time and budget restraints can factor into whether or not we use our laser CNC machine services or our plasma cutting machine. Additionally, the thickness of your project, as well as the material and level of detail needed, will all play a role in how we get to the end product. That being said, one thing you can count on is that the final product will be just what you want! Contact the experienced fabrication team at Tymetal today and tell us about your next project!