Plasma cutting is a major requirement for the sheet metal industry. Plasma-cutting technology has completely changed the face of the sheet metal industry with its rapid reduction in uptime. Plasma-cutting technology is closely related to sheet metal fabrication and this technology is reflected in plasma cut parts.
Basically, sheet metal fabrication is the forming of sheet metal, referring to its parts. It goes through several stages of cutting, punching holes, bending, and other treatments on the sheet metal. Modern sheet metal fabrication uses machines and those machines are directed by certain codes which are converted from 3D CAD files. CNC machining-based fabrication ensures every cutting and shaping is done with extreme accuracy.
Sheet metal is used for a variety of purposes, one of the most common being for vehicle chassis. Sheet metal fabrication is typically intended for uniform high-volume production. Uniform here means uniform thickness.
What is plasma cutting?
Plasma cutting, also referred to as plasma arc cutting, is a thermal process that utilizes a jet of ionized gas with an exceptionally high temperature, reaching up to 20,000 degrees Celsius, to melt and sever various materials.
This ionized gas bursts with a temperature of thousands of degrees Celsius and is capable of melting almost any metal.
Essentially, plasma cutting involves directing a focused stream of high-velocity, high-temperature plasma toward a specific point to achieve precise material severance. As soon as the plasma jet hits the workpiece, the heat melts the metal and makes cutting easier. By compressing air, this plasma jet process becomes more effective with the ability to cut many types of steel with a thickness of 20 mm.
But how to choose the right plasma cutter?
This article offers a guide to choosing the right plasma cutter…
First of all, you have to know your cutting needs. It includes:
Determines the thickness of the sheet metal to be cut. Uniform thickness of the materials to be processed. The uniformity of sheet metal materials is the main key to the uniformity of the final result, apart from the machining efforts which are regulated by certain machine codes. In general, sheet metal materials that can be processed are in the thickness range of 0.9mm to 2.0mm.
Identify the types of metals commonly used in your fabrication projects. Along with the development of manufacturing technology, the variety of materials that can be processed is wider, but some of the popular ones are alloy steel, tool steel, stainless steel, carbon steel, and aluminum. Each type has advantages and disadvantages as well. For example aluminum. This material is lightweight, corrosion resistant, but not suitable for construction designed to experience consistent friction.
Consider the complexity of the desired cut. Desired cutting speed and precision are the next two factors that ensure the sheet metal fabrication process runs as planned. Of course, there is a range of speed and precision of sheet metal cutting.
Consider the volume and frequency of cutting.
Then you need to consider the balance between power and performance:
All plasma-cutting machines require a power source with high drooping and voltage characteristics. This has to do with the “conditions” to start the arc. Arc creation voltages can be up to 400V DC, although voltages for plasma supports are usually in the 50-60V range.
You should consider whether one power source option is better than another. There are several options, including electric power, and compressed air. If we take the average, the power output size of most plasma-cutting machines is 20-40 amps. To produce that value, it usually takes a power supply in the 13-16 amp range. Reliable machines can produce maximum output power even if supplied only by a 13 amp power supply. However, output power outside that range is also used, for example, 12 amps is capable of cutting sheet metal with a thickness of 1/8 inch and 60 amps is capable of cutting sheet metal up to 7/8 inches.
Know the required amperage range for your cutting needs.
Choose the cutting speed and adjust it to the cutting quality you want. The cutting speed of sheet metal fabrication is usually in the range of 30-500 IPM. As for “precision” it is usually denoted by a tolerance of ±0.005 in. If possible, ±0.001 in is preferable.
Evaluate the duty cycle of your plasma cutter. It will determine the continuous operation level of your cutting tool. Duty cycle and continuous operation are two interrelated things. What does the plasma cutting machine duty cycle mean? It is a measure of how long a CNC-based plasma cutting machine can operate without cooling. A long duty cycle contributes to a better continuous operation, and vice versa. For sheet metal industries with high production volume levels, machines with long-duty cycles play a role.
Now we move on to the third point. It talks about cutting capacity and efficiency:
You must specify the maximum cutting thickness.
Determine the thickness of the workpiece and its effect on cutting capacity. The thicker the workpiece, the slower the cutting speed. That’s the theory.
Determines the maximum cutting speed and its relation to different thicknesses. Basically, you should choose a stable cutting speed for different thicknesses.
The fourth point is about portability and workspace requirements:
You should evaluate the size, weight, and portability of your plasma-cutting machine.
Consider the power source you have, whether it is 110 V or 220 V, and its suitability for your project.
Don’t forget to also ensure the suitability of your plasma cutter for your workshop.
The size of the plasma cutting machine is determined by the size of the metal plate being cut, whether it is 4′ x 8′ or 10′ x 40′. Most plasma cutting machines are capable of servicing a wide range of sizes but the extreme size machines are intended for work on metal plates of “unusual sizes.” The size refers not only to surface area but also thickness. And to add, how much steel sheet is processed in one production cycle also determines how big the size of the machine is required. The number of rails and the machine width are considered interchangeably to determine the size, but more commonly used is machine width. How about portability? If the machine must be moved frequently to several places on a regular basis, of course, this factor becomes important. Usually, portable machines are more recommended for small-scale fabrication.
The fifth point is security features which include:
Checking security features such as thermal overload protection and automatic shut-off.
Evaluation of the air pressure regulator and moisture separator. The goal is to ensure a supply of clean, dry air.
Consider adding additional safety accessories such as protective gear and grounding clamps.
After all, regardless of the effectiveness of its work and also its operating costs, plasma cutting carries several risks that must be anticipated, for example, the risk of being splashed by an arc (users must use special protective glasses, fire-resistant clothing, etc.), the risk of electric shock (checking cable connections, the water content in the workspace). , etc.), and the risk of “compressed gas explosion” (choose an engine system with robust valve protection).
The sixth point is the ease of use and simplicity of maintenance:
The user interface, controls, and ease of operation are the three main factors that determine the ease of use of a plasma cutter.
Evaluation of the convenience of replacing consumables and their presence in your workshop area.
Consider whether there is any special certification or training before someone is qualified to operate a plasma cutter.
Consider warranty options and after-sales support.
And the seventh and last point is the consideration of price and comparison between plasma cutters on the market:
Before buying any plasma cutting machine, one should at least know the popular brands and their specifications. Comparing several machines is also highly recommended to minimize “buying errors”.
Make sure to read lots of reviews before settling on one plasma cutter.
Ensure the feasibility of the plasma cutter in terms of price, features offered durability, and satisfaction of the buyers (which you can find out by reading related reviews).
Ensuring that our purchase of a plasma cutter is not wrong must go through many considerations represented by the 7 points above. Maybe not always our choices can be as ideal as that, but at least following most of the points above will prevent us from making mistakes.