What is preferable? Plasma or laser cutting depends on the grade and thickness of the metals being cut, the requirements for cutting accuracy, and the customer’s financial capabilities.
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 is, in fact, a cutting element. During continuous operation, it heats the metal to the melting point in the zone of its presence.
During sublimation laser cutting, sheet metal evaporates in the cutting zone under the influence of a laser pulse.
In plasma cutting process, 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, which 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, the workpieces are not scaled, 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 more significant 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.
The use of the CNC system, which allows for high-precision cutting of materials in automatic mode, further enhances the assessment of the equipment’s advantages.
Let’s examine the features of each competing method to determine which is the best. Laser cutting applies to a wide range of materials (non-metals and metals), while 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: their use in metalworking.
Try Prolean Now!
Laser Cutting Technology
In a laser machine, the cutting tool is a focused beam of light. The beam’s energy directed at the material causes heating of the material at a tiny point, the diameter of which is fractions of a millimeter.
Due to 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 cut line behind it.
Laser Cutting Technology
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-figure cutting, making holes (regardless of diameter), are smooth, precise, and even.
The accuracy of cutting on a CNC laser machine is a 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 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 material’s properties and the source’s power.
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 material cutting. 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
In plasma cutting, just as in laser action, the metal is heated and melted in the impact zone. However, 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.
Plasma Cutting Technology
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, laying a certain distance between the contours to be cut. In addition, on thin walls, overheating can cause deformations and burnout, 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 more significant value and can range from 3 to 10 degrees. Therefore, a plasma cutter is used if there are no increased requirements for the edge’s quality, the curved contour’s geometry, 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.
Try Prolean Now!
What to consider when choosing equipment?
If you need equipment for sheet metal cutting, 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
However, the cost of a laser machine for working with metals of considerable thickness, combined with energy costs, is several times higher than that 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 quality-focused Laser cutting service and Plasma cutting service. We offer materials such as aluminum Brass Copper Steel and Stainless steel for several industrial applications.
Summing Up
CNC laser equipment, characterized by excellent quality and high performance, will be more effective for cutting thin sheet metal. 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 various holes, including small-diameter ones.
Using a laser machine to cut metal up to 6 mm thick is optimal. However, to work with thicker material, the beam power must be increased, and more expensive equipment is required to provide the desired performance. This is not always advisable.
Plasma-cutting machines have been chosen for a wide range of metalworking industries. The plasma cutter is excellent for cutting galvanized sheets of small thickness and steel parts with a 30-40 mm profile. However, plasma cutting is extremely rare for thin materials; this technology is more advantageous for thick workpieces.
0 Comments