Around the 1970s, laser cutting technology was first used in modern industrial production. In the next 50 years of development, this technology has gradually been applied to the cutting production of sheet metal processing, wood, leather, plastic, and other different materials, gradually replacing traditional cutting machines as one of the indispensable processes in industrial production.
As we all know, the accuracy of the laser cutting machine will directly affect the quality of the cutting. If there is a problem with the accuracy, the product may be unqualified. In general, the factors that affect the cutting quality mainly include these aspects: the position of the focus, the cutting speed, the thickness of the workpiece, the laser output power, the quality of the parts, and so on.
Emit Laser has been committed to improving the cutting accuracy of laser machines, and to provide customers with the best quality laser cutting machines and engraving machines. So, how can we improve its accuracy? Next, Emit will take you to understand these factors and methods to improve accuracy.
1. Focus position
The focus position is an important factor that affects the processing quality of the laser cutting machine. Relative to the surface of the processed material, after the laser beam is focused, the focal point is the focal position. The focus position will affect almost all processing parameters such as the width and slope of the slit, the roughness of the cutting surface, and the cutting speed. The smaller the focal depth of the focusing lens, the smaller the diameter of the spot at the focal point, so effective control of the focal position can improve the cutting quality.
The choice of lens focal length is an important issue. After the laser beam is focused, the spot size is proportional to the focal length of the lens. Using a short focal length lens to focus, the spot size will be small. But its disadvantage is that the focal depth is short, the adjustment margin is small, and it is usually suitable for cutting thinner materials. Since the long focal length lens has a wide focal depth, it can be used to cut thicker workpieces as long as it has sufficient power density.
After determining the focal length of the lens, the focal position should be determined. Since the energy is high at the focal point, in most cases, the focal point should be just on the surface of the workpiece. The distance between the surface of the workpiece and the laser head is usually about 1 cm. In the whole cutting process, ensuring the constant relative position of the focus and the workpiece is an important condition for obtaining better cutting quality. Sometimes, due to poor heat dissipation and poor cooling during operation, the focal length changes, so it is necessary to adjust the focal length and change the focal position in time.
On the other hand, the quality and transmittance of the lens will also affect the accuracy of cutting. The better the quality of the lens, the better the light transmittance, and the higher the cutting precision. If the machine is used for a long time and does not pay attention to frequently wiping the lens, dust will accumulate on the surface of the lens for a long time, causing the light transmittance of the lens to become worse and worse. This will not only make the cutting accuracy lower and lower but also make the laser break the lens.
2. Laser output power
The laser output power is the output energy of the laser system. In the cutting process, the laser output power is a parameter directly related to the melting capacity of the processed material. In actual operation, setting a higher power can achieve a higher cutting speed to cut thicker materials.
We can judge whether the used precision light output power is appropriate according to the spark situation during processing and the cut surface after processing. If the laser output power is larger than the standard value, the heat-affected area around the incision will increase, and the edges will be burnt. If the laser output power is smaller than the standard value, the phenomenon of not being able to cut through the sheet will occur. And during the cutting process, sparks lag behind the direction opposite to the advancement of the laser head.
After long-term use of any equipment, some parts will deteriorate. The laser is the core component of the laser cutting machine. After long-term use, the power will drop. At this time, it needs to be replaced with a new laser
The size and pressure of the auxiliary gas will also affect the power of the laser cutting machine. The most commonly used auxiliary gas is oxygen or an inert gas such as nitrogen. If the thickness of the non-metallic plate is large or the cutting speed is slow, the air output can be appropriately increased; when cutting the metal plate, the air output is generally fixed. If the plate thickness is large, the cutting speed can be reduced or the laser output power can be increased.
3. Cutting speed
The power of the laser will affect the speed at which the machine cuts the workpiece. Generally speaking, the cutting speed of the material is proportional to the laser power, that is, increasing the laser output power can increase the cutting speed. In the case of certain laser power, there is an optimal cutting speed range, too fast or too slow will affect the final cutting result.
When the cutting speed is too fast, the contact time between the laser beam and the material is short, which may fail to cut successfully, resulting in the inability to cut the plate in time, the cutting section shows a diagonal stripe, and the lower part produces melting stains.
When the cutting speed is too slow, the contact time between the laser beam and the material will be longer, resulting in over melting of the cut sheet, and the cutting section will be rougher. The cutting seam will become wider, causing over-burning in the details, which will not achieve the desired cutting effect. In addition, lower cutting efficiency will affect production capacity.
Supplement: The method to judge the reasonable cutting speed is to observe the spark and the cutting surface. Cutting sparks should spread from top to bottom, the cutting surface should be smooth, and there should be no slag at the bottom.
Therefore, to improve the accuracy and quality of cutting, when cutting plates of different thicknesses and materials, you should select different parameters and adjust the cutting speed.
4. The thickness of the workpiece
Generally speaking, the greater the thickness of the workpiece, the lower the cutting accuracy; the thinner the thickness of the workpiece, the more helpful it is to improve the cutting quality. Because the laser beam is tapered, the slit is also tapered. The diameter and size of the slit will directly affect the cutting accuracy. Under the same power and cutting speed, the thickness of 0.5mm material is much smaller than the gap of 2.5mm, so the cutting precision on 0.5mm material is higher. Of course, different materials will also have a certain impact on cutting accuracy. So before cutting, pay attention to the material of the workpiece and whether it can be processed with a laser cutting machine. (Read more: https://www.emitlaser.com/laser-cutting-manual/)
5. Nozzle design and airflow control technology
When the sheet metal is processed, oxygen and a focused laser beam will act on the material being cut through the nozzle to form an airflow. The basic requirement for airflow is that the airflow entering the incision is large and fast, so that there is enough oxygen to react with the material exothermic, and there is also enough airflow to blow away the slag. Therefore, the nozzle design and airflow control technique should be optimized.
6. Cutting and perforating technology
Cutting and perforation technology should be optimized. In most cases, laser cutting machines start cutting from the edge of the sheet. Since the laser cutting machine is a thermal processing machine, it is necessary to penetrate a small hole in the metal sheet first, and then the laser beam starts cutting from the small hole. The smaller the hole, the higher the cutting accuracy afterward.
7. The quality of accessories
The quality of some parts in the laser cutting machine will also affect the cutting accuracy, such as the motor, worktable, and lens. The better the quality of the motor, the higher the accuracy of cutting; if the accuracy of the worktable is improved, the accuracy of cutting will also increase. Therefore, the quality of parts is also an important factor to measure the accuracy of the laser generator. Before buying a machine, it is necessary to find out the quality and source of the parts of the merchant’s machine.
The above are 7 factors that affect the processing accuracy of laser cutting and engraving machine sorted out by Emit for readers. It is precise because these factors have been mastered that Emit Laser can effectively improve the processing accuracy of the company’s machines, and customers can buy with confidence.