CLOSED SHUTTLE WORKTABLE LASER CUTTING MACHINE
Laser engraving machine

How to choose the nozzle correctly for laser cutting

Laser cutting is currently recognized as one of the most efficient, high-quality, and high-precision metal processing methods. There are many factors that affect laser cutting, and nozzles are also one of them.

The nozzle is located at the lower end of the cutting head, and both the laser beam and auxiliary gas act on the cutting material through the nozzle. Its main function is to gather auxiliary gas and form high pressure, which is released onto the surface of the cutting material and the cutting seam, blowing away the melted and vaporized base material generated during the cutting process, leaving a clean cutting seam; At the same time, it prevents pollutants such as slag and smoke from rebounding upwards, thereby protecting the internal lenses.

The impact on cutting quality when the center of the nozzle is not aligned with the center of the laser beam:

1. The cutting gas is sprayed from the center of the nozzle, and the center point of the nozzle is the center point where the sheet needs to be cut. If the laser is not at the center of the nozzle, there will be a deviation between the laser action point and the actual cutting effect, resulting in a significant discrepancy between the actual and expected cutting results.

2. If the laser is not in the center of the nozzle, the beam will hit the inner wall of the nozzle during normal operation, and in severe cases, it will burn out the nozzle, affecting the actual cutting effect.

To verify whether the laser beam and nozzle are concentric and coaxial, the following steps are required for testing:

1. Stick transparent tape on the nozzle mouth, completely overlapping the circular edge with the tape;

2. Adjust the device power to around 100W and use a spot shooting mode to irradiate the transparent tape with laser;

3. Remove the transparent tape and observe the position relationship between the circular edge and the laser perforation.

Selection of nozzle types:

The nozzle is divided into single-layer and double-layer nozzles. Single layer nozzles have relatively slow gas flow rates and are commonly used for cutting metals such as stainless steel, aluminum alloys, copper, etc. Nitrogen gas is often used as an auxiliary gas.

The double-layer nozzle has a fast gas flow rate and is suitable for high-speed cutting. It is commonly used for cutting carbon steel and oxygen is generally used as an auxiliary gas. The cutting surface usually turns black due to oxidation.

Selection of nozzle size:

The size of the nozzle aperture determines the gas flow rate acting on the cutting material, thereby affecting the removal of molten material. The larger and faster the airflow entering the incision, the stronger the ability to remove molten material by spraying.

In theory, the thicker the sheet, the larger the nozzle should be used. However, the larger the aperture of the nozzle, the higher the chance of sparks from the molten material splashing upwards during cutting, resulting in a shorter lifespan of the lens.

When the nozzle deforms or there are molten stains on the nozzle, it will affect the cutting effect. Therefore, the nozzle should be placed carefully to avoid collision or deformation, and any molten stains on the nozzle should be cleaned in a timely manner.