What is preferable? – plasma or laser cutting depends on the grade and thickness of the metals being cut, on the requirements for cutting accuracy, and on the financial capabilities of the customer.
Plasma vs Laser Cutting
Both technologies are eternal competitors although, under certain conditions, one will completely replace the other. However, there are cases in which preference is given to laser or plasma.
In a simplified view, laser cutting is carried out by a focused laser beam, which, in fact, is a cutting element. During continuous operation, it heats the metal, in the zone of its presence, to the melting point.
During sublimation laser cutting, under the influence of a laser pulse, sheet metal evaporates in the cutting zone.
In plasma cutting, the heat that melts the material is generated by generating a plasma arc. The removal of the melt also occurs due to the effect of the plasma jet on the liquid metal.
Due to the compression of a conventional arc and the simultaneous injection of a plasma-forming gas in a plasma torch, a plasma arc occurs.
The Main Difference Between Laser Cutting of Metal and Plasma
The main difference between laser cutting of metal and plasma is the accuracy of the perpendicularity of the edges and the thickness of the slots formed during the cutting process.
Thus, a focused laser beam cuts the line thinner. This means that a smaller area of the sheet heats up during the cutting process. This, in turn, explains the almost absent contour deformation of the resulting workpieces.
Laser cutting has a decent performance with the highest precision of the resulting parts. It provides perfect cutting of small but complex shapes and high accuracy of corners.
However, this technology is most effective when cutting sheets whose thickness is less than or equal to 6 mm. In this case, there is no scale on the workpieces, and the edges of the parts are perfectly smooth and straight.
When cutting thicker sheets, the edges are beveled up to 0.5 degrees. Therefore, the hole diameters obtained by laser cutting in the lower part are always slightly larger than those in the upper part. True, the quality of the cut and the shape always remain impeccable.
Laser and plasma technologies have the same field of application – cutting materials
Describing the advantages of a laser machine and a plasma cutter, in both cases, they resort to the same definition of their qualities – “high”. It refers to:
- performance resulting from high processing speed;
- accuracy of execution of elements, including parts with a complex configuration;
- edge quality, so there is no need for additional processing.
And the use of the CNC system, which allows for high-precision cutting of materials in automatic mode, further enhances the assessment of the advantages of the equipment.
To figure out which of the competing methods is the best, let’s look at the features of each. Laser cutting applies to a wide group of materials (non-metal and metals), and plasma cutting is applicable only to conductive metals.
Therefore, we will consider the operation of a laser machine and a plasma cutter under the same conditions, that is, their use in metalworking.
Laser Cutting Technology
In a laser machine, the cutting tool is a focused beam of light. The energy of the beam directed at the material causes heating of the material at a very small point, the diameter of which is fractions of a millimeter.
As a result of temperature exposure, the metal melts and evaporates or is blown away by a gas jet. As the laser head moves, the beam leaves a thin line of cut behind it.
The laser cuts thin sheet metal remarkably: aluminum and its alloys, copper, brass, bronze, low-carbon steel, stainless steel, and titanium … The cutting edges for straight figured cutting, making holes (regardless of diameter) are smooth, clear, and even.
The accuracy of cutting on a CNC laser machine is hundredths of a millimeter. Beam processing provides good cut quality when working with thin workpieces, but it decreases as the thickness of the metal increases.
The cut line receives a slight bevel, but the taper in any case does not exceed 1 degree. For example, when cutting steel sheets – up to a thickness of 4 mm, the cut is ideal, and at 6 mm it has a slight slope (about 0.5 °).
The maximum thickness of workpieces that can be cut with a beam depends on the properties of the material and the power of the source.
Depending on the features of the equipment (for different sources from 500 W to 6 kW), this value is:
- for ferrous metal – 6 mm … 25 mm;
- for stainless steel – 3 mm … 20 mm;
- for aluminum and alloys – 2 mm … 20 mm;
- for copper alloys -2 mm … 12 mm.
The advantages of laser technology include economical cutting of the material since due to the thin beam and the minimum temperature zone on the cutting plan, parts can be placed almost close to each other.
Plasma cutting: Operating Principle
Plasma Cutting Technology
In the process of plasma cutting, just as in the case of a laser action, the metal is heated and melted in the impact zone. Only in this case, the cutter is a jet of ionized gas – plasma. When passing through a narrow nozzle, the plasma flow acquires a high speed, which makes it possible to blow off the molten metal from the place of the cut.
It is worth noting that the diameter of the plasma jet is an order of magnitude greater than the thickness of the laser beam, so the cut line has a large width of 0.8 … 1.5 mm (against 0.2 … 0.4 mm for laser cutting).
This circumstance has to be taken into account when preparing the cutting layout, namely, to lay a certain distance between the contours to be cut. In addition, on thin walls, as a result of overheating, deformations can occur and burn out, so cutting openwork patterns with a large number of holes is not for a plasma cutter.
The deviation from the squareness of the edges also has a larger value and can range from 3 to 10 degrees. Therefore, a plasma cutter is used if there are no increased requirements for the quality of the edge, the geometry of the curved contour, and the holes. Good quality holes are obtained, the diameter of which exceeds the thickness of the metal by 1.5-2 times.
The advantage of a plasma cutting machine is its ability to work with thick metals while ensuring the normal quality of the workpieces. With thicknesses greater than 20 mm, plasma not only wins in comparison with a laser but is out of competition.
What to consider when choosing equipment?
If you need equipment for cutting sheet metal, when choosing equipment, proceed from the specifics of your particular production. For cutting thin metal sheets, the production costs of laser and plasma cutting are commensurate.
Laser cutting process
But the cost of a laser machine for working with metals of considerable thickness, combined with energy costs, is several times higher than the cost of a plasma cutter and its operation.
Get your plasma or laser-cutting part
Choosing between plasma or laser cutting is not always easy, Do you need a hand?, Proleantech is a Chinese – based rapid prototyping service provider that provides a quality-focused Laser cutting service we offer materials such as aluminum Brass Copper Steel and Stainless steel. For several industrial applications.
For cutting thin sheet metal, CNC laser equipment, which is characterized by excellent quality and high performance, will be more effective. Such equipment will ensure the accuracy of cutting and the quality of the profile in the absence of thermal deformations, and hence the cost of additional processing.
The laser can be entrusted with complex contour cutting with a large number of various holes, including small-diameter ones.
It is optimal to use a laser machine for cutting metal up to 6 mm thick. But to work with thicker material, it is necessary to increase the beam power, and, in order to provide the desired performance; you will have to use more expensive equipment. And this is not always advisable.
The plasma cutting machine is chosen for a wide range of metalworking industries. The plasma cutter is excellent for cutting both galvanized sheets of small thickness and steel parts with a 30-40 mm profile. But still, plasma cutting is extremely rare for thin materials; this technology is more advantageous for thick workpieces.