Overview
Laser cutting is a versatile fabrication process that is becoming increasingly popular in the metalworking industry. By using a focused beam of light to cut metal, it allows for precision cuts of complex shapes and patterns with a relatively low cost. However, it is also possible to produce uneven surfaces or unacceptable levels of surface roughness when using laser cutting.
Therefore, it is important for fabricators to understand the factors influencing the quality of the cut surface in order to minimize defects and produce an acceptable surface finish. This paper will discuss the factors affecting the quality of a laser cutting surface and how to improve the surface finish.
Factors Affecting the Quality of Laser Cut Surfaces
The quality of the cut surface is determined by a number of factors. These include the power of the laser, the speed of the cut, the type of material used, the type of finish applied, and the quality of the gas used.
1. Laser Power: The amount of laser power available is the most important factor influencing the quality of the cut surface. If the laser used to cut the material is not powerful enough, the cut will be too shallow and the edges may not be smooth or precise. On the other hand, if too much power is used, the cut may be too deep and have unacceptable roughness levels.
2. Cut Speed: The speed at which the laser beam is moved over the material can also influence the quality of the cut surface. If the speed is too slow, there will be more heat applied to the material, leading to an uneven cut surface. On the other hand, if the speed is too fast, the laser beam will not have enough time to penetrate the material and the results may be unsatisfactory.
3. Material Type: The type of material being cut will also have an impact on the quality of the cut surface. Different materials will have different levels of thermal conductivity and/or reflectivity, both of which can affect the results. It is important to use the correct setting when cutting various materials.
4. Finish: The type of finish applied to the material can also affect the results. A dull finish can cause the laser to concentrate its energy in certain areas, leading to an uneven surface finish. Conversely, a reflective surface can scatter the laser beam and lead to an unsatisfactory result.
5. Gas: The type of gas used to cut the material can also influence the quality of the cut. Different gases are best suited to different types of materials, and using the wrong gas can lead to poor results.
Improving the Quality of Laser-Cut Surfaces
There are a number of steps that can be taken to improve the quality of a laser-cut surface. These include:
1. Adjusting the Power and Speed of the Laser: Adjusting the power and speed of the laser can help to optimize the surface finish. The laser should be set to the correct power and speed for the material being cut to ensure a smooth cut.
2. Changing the Type of Gas Used: Different types of gases are better suited to different types of materials. Changing the gas can help to optimize the surface finish. The following are some of the most commonly used gases:
• Nitrogen: Most commonly used on non-ferrous metals, such as stainless steel and aluminum. Nitrogen is inert, so it does not react with the material being cut and helps to reduce the risk of oxidation.
• Oxygen: Used on ferrous and non-ferrous metals. The oxygen helps to improve the cutting speed and surface finish. However, it can also lead to oxidation of the material.
3. Reducing the Amount of Heat: Reducing the amount of heat applied to the material can help to reduce the risk of warping. This can be done by ensuring that the laser is set to the correct power and speed and that the correct type of gas is used.
4. Applying a Protective Coating: Applying a protective coating to the surface after the cut can help to reduce oxidation and improve the cut quality.
Conclusion
Laser cutting is a versatile fabrication process that is becoming increasingly popular in the industry. In order to guarantee a satisfactory cut surface, it is important to understand the factors influencing the quality and how to optimize them. By adjusting the power and speed of the laser, changing the type of gas used, reducing the amount of heat applied to the material, and applying a protective coating after the cut, it is possible to improve the quality of the cut surface.
