Sheet metal products are almost everywhere in our daily life such as computer housings, cell phone cases. laser cutting is widely use during the sheet metal manufacturing process due to its advantges. but what is laser cutting and how does it work? today, in this article, we will provide a comprehensive introduction of laser cutting process.
What is a laser？
Laser stand for Light Amplification by Stimulated Emission of Radiation. it produce a a narrow beam of coherent light through an optical amplification. All These lights have very similar wavelengths which result in a high engery. it is widely used in various industires.
What Is Sheet Metal Laser Cutting?
Sheet metal cutting use beams of light to cut sheets of metal and get the desired shape with computer numerical control(CNC) technology. this process is one of the most cutting technique used for sheet metal.
Types Of Laser Used in Sheet Metal Cutting
There are 3 types of laser: CO2 laser, Fiber laser and crystal laser ( Nd: YAG or Nd: YVO). they use different ways to stimulate the laser.
CO2 laser is the earliest laser used in market, it is to use charged CO2 gas generate beams of light emission through electrical discharge. CO2 laser can output high power beam of light to cut thick metal at high speed. However, CO2 lasers are bulky, take up more space, and consume more power.
CO2 Laser has high power, the general power is between 2000 ~ 4000W, can cut the full size of stainless steel, carbon steel and other conventional materials within 25mm, as well as aluminum sheet within 4mm and acrylic sheet within 60mm, wood sheet, PVC sheet.
Fiber laser cutting machines use fiberglass for cutting, it is easy to maintain, fast and can cut stainless steel and carbon steel within 12mm. it belongs to a family of solid-state lasers and mainly used high accuracy and efficiency requirements.
Crystal Laser (Nd: YAG/Nd: YVO)
Crystal lasers generate their beams from either Nd: YAG (neodymium-doped yttrium aluminum garnet) or Nd: YVO (neodymium-doped yttrium ortho-vanadate, YVO4) crystals. it cut aluminum sheet, copper sheet and most non-ferrous metal materials which can not be cut by other types of laser. Crystal Laser solid laser wavelength is not easy to be absorbed by non-metal, so it can not cut non-metallic materials.
How does laser cutting work?
Laser cutting is a thermal cutting process. it use laser beam to hit a spot on the surface of metal sheet and increase the material temperature at the spot area qickly. the material will be vaporized and form a hole at the spot area. As the laser beam move, it can create a narrow cut around 0.1mm wide.
3 Types of sheet metal Laser cutting process
Laser Fusion Cutting
Laser Fusion Cutting is to partially melt the workpiece and then use airflow to blow away the molten material in a liquid state. The gas itself does not participate in cutting. Laser Beam Fusion Cutting uses lower power than Sublimation Cutting, and its laser power is between 104W/cm2 and 105W/cm2, but its cutting speed is faster. Laser fusion cutting can produce oxidation-free cuts on iron and titanium materials.
Laser vaporization Cutting
During the laser vaporization cutting process, the material vaporizes at the cutting seam. In this case, very high laser power is required, generally greater than 108W/cm2. This processing is only suitable for use when there is no discharge of molten material, and is actually only used in few materials such as iron-based alloys. This process cannot be used with wood and some ceramics because thicker cuts are needed in these materials.
Laser Flame Cutting
The difference between Laser flame cutting differs and laser fusion cutting is that it uses oxygen as the cutting gas. The chemical reaction between oxygen and the material will further heats the material. For the same thickness of steel sheet, this method can achieve higher cutting speed than fusion cutting. However, this method results in poorer cut quality than fusion cutting.
5 Advantages Of Laser Cutting Sheet Metal
1. High Precision and Accuracy
Because the laser spot is small, and with High power and fast cutting speed , the laser cutting can obtain better cutting quality. The dimensional accuracy of the cutting parts can reach ±0.05mm. At the same time, the cutting surface is smooth and beautiful, the surface roughness is only tens of microns.
2. High Cutting Efficiency
Laser cutting machines are equipped with multiple CNC worktables, allowing for full CNC automation. By modifying the CNC program, different-shaped parts can be cut, enabling both 2D and 3D cutting.
3. Fast Cutting Speed
Cutting 2mm thick low carbon steel with 1200W laser power, cutting speed can be up to 600cm/min, which is fast compare to other cutting method. The material does not need to be fixed in the laser cutting, which can save the fixture and save the auxiliary time of loading and unloading.
4. Non-Contact Cutting
Laser cutting has no contact with the workpiece, and there is no tool wear. Processing parts of different shapes, do not need to replace the tool, just change the output parameters of the laser.
5. Versatile Material Compatibility
Laser cutting can cut metal, leather, wood and fiber. However, for different materials, due to their thermal physical properties and different absorption rates of laser, they show different laser cutting adaptability.
Disadvantages Of Laser Cutting Sheet Metal
- High cost: Laser cutting machines are usually expensive, especially for high power and high precision machines.
- Deformation: Heat is generated during laser cutting, the workpiece may have deformation due to the heat.
- Safety: laser beam may cause damage to the eyes and skin, so operators need to wear protective equipment.
How To Ensure Quality During Sheet Metal Laser Cutting
Achieving the highest quality laser cut parts needs to have careful consideration of cutting parameters. These key factors include:
- Material Thickness: when the material thickness is thick, high leser power is needed, So set a proper laser power is critical before cutting.
- Surface quality : If there are rusted areas or oxide layers on the surface, the cut outline will be irregular and there will be many defects.
- Alloy composition: The alloy composition affects the strength, specific gravity, weldability, oxidation resistance and acidity of the material. The higher the carbon content (0.8% carbon), the more difficult the material is to laser cut.
- surface reflectivity: Some aluminum alloy, copper, brass and stainless steel sheet have high reflectivity. So, When cutting these materials, the focus position need to be adjust before cutting.
Alternatives to Laser Cutting
If you’re considering options other than laser cutting for your sheet metal needs, here are alternatives:
- Waterjet Cutting: Waterjet cutting is a manufacturing technique that uses high pressure water to cut through materials effectively with a low cost.
- EDM (Electrical Discharge Machining): It can provide a superior surface finish and minimal heat-affected zones. EDM is particularly used for cutting hard materials.
- CNC Cutting: CNC cutting use rotating cutters to carve and shape workpieces where laser cutting relies on laser beams to melt or burn out the desired shapes.
Laser cutting requires skilled operators to operate the machine to get a good cutting result. KUSLA provide sheet metal cutting service with decades of experiences. besides sheet metal cutting, we also can provide sheet metal bending, stamping, welding services. we can cover all your needs for sheet metal fabrication.
How accurate can you make the sheet metal laser cutting?
we can make a laser cutting accuracy within ±0.1mm and the cut width can be as narrow as 0.1mm, this is depending on the laser power and material thickness.
What thickness of sheet metal can you cut with laser cutting?
Generally, we can cut the metal sheet with thichness from 0.5mm to 25 mm. this depends on the materials. Above this thickness, need to cutstom cut with a higher price.