How To Cut Galvanized Sheet With Laser Cutting Machine

Galvanized steel sheets are widely used in the manufacture of automobile bodies due to their excellent corrosion resistance. They are also commonly used metal materials in industries such as home appliance manufacturing, filing cabinets, and daily necessities. In order to ensure the accuracy and quality of product molding, galvanized steel sheets are cut out. At this stage, laser cutting is the most commonly used process method. It is a processing method that does not touch the material, so it will not damage the surface of the plate, and there will be no burrs on the cut surface. It is a processing method that can greatly reduce the subsequent processes. However, there are few reports on systematic research on the laser cutting process of galvanized steel sheets.

Since galvanized sheet is a coated steel sheet, it has always been recognized as a material that is difficult to laser cut. Today, the most mainstream equipment for laser cutting is fiber laser cutting machine, which has great advantages in cutting cost and maintenance. So, what are the better solutions for fiber laser cutting machines in cutting galvanized sheets?

As we all know, the function of galvanized steel plate is to protect the carbon steel inside through galvanizing on the surface. It is a plate that is not easy to rust after long-term use. Although this kind of plate is slightly more expensive than ordinary carbon steel plates, it is still cost-effective in terms of the cost of the entire product because there is no need for subsequent processes such as spraying for rust prevention.

During the processing of galvanized sheets, auxiliary gas needs to be added. The purity and pressure of the auxiliary gas directly affect the cross-section quality of the cutting sheet. The purity of the oxygen used for cutting should be above 99.6%. When the purity of the oxygen used for cutting is higher, the cross-section of the galvanized sheet will be cut. The higher the roughness and quality, of course the cutting cost will also increase. The purity of nitrogen during cutting should be above 99.5%. Increasing the purity of nitrogen can ensure that the color of the seams does not change during the cutting of galvanized sheets.

From the perspective of auxiliary gas, there are generally three cutting processes for galvanized steel sheets, namely air cutting, oxygen cutting and nitrogen cutting. Let's first analyze the advantages and disadvantages of these three cutting processes:

First, air cutting: The advantage is that the processing cost is extremely low. You only need to consider the electricity costs of the laser itself and the air compressor. There is no need to incur high auxiliary gas costs. However, the cutting efficiency on thin plates can rival nitrogen cutting. It is a An economical and efficient cutting method. But the shortcomings on the cut surface are also obvious. First of all, the air-cut section will produce bottom surface burrs, and the laser-processed products must also undergo secondary processing such as deburring, which is not conducive to the entire product production cycle. Secondly, the cross section of air cutting is easy to turn black, which affects the quality of the product. Therefore, the advantages of laser processing without subsequent processing cannot be reflected. Therefore, many companies are unwilling to choose air cutting when processing galvanized steel sheets.

Second, oxygen cutting: This is the most traditional and standard cutting method. The advantage is that the gas cost is low, and in sheet metal processing mainly made of carbon steel, there is no need to frequently switch auxiliary gas, which facilitates factory management. However, the disadvantage is that after oxygen cutting, a layer of oxide scale will remain on the surface of the cut surface. If such products with oxide scale are welded directly, the oxide scale will naturally peel off over time. This is one of the reasons why welding of galvanized sheets is easy to cause false welding.

Third, nitrogen cutting: Use nitrogen for high-speed processing. Since the role of nitrogen is different from the oxygen used to support combustion, it plays a protective role, so the cutting section will not produce oxide scale. Many companies are interested in this advantage, so they often use nitrogen for cutting galvanized steel sheets. But the disadvantage of nitrogen cutting is here: because there is no protection on the cutting section, the product is easy to rust. In order to prevent the product from rusting, it had to be sprayed again. As a result, the galvanized sheet purchased at a higher cost did not show the characteristics of its galvanized layer, which is quite a pity.

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