A laser cutting method for improving the quality of an aluminum nitride cut surface

Abstract

The application discloses a laser cutting method for improving the quality of an aluminum nitride cutting surface, and other steps include the following steps: (1) selecting appropriate alignment base points according to the shape and size of the aluminum nitride ceramic substrate to be cut, and determining the position of the aluminum nitride ceramic substrate in the actual machining platform through the alignment base points; (2) calculating the repeated cutting frequency F according to the actual thickness of the ceramic substrate; (3) determining the cutting depth each time; (4) fixing the aluminum nitride ceramic substrate on the bearing platform of the laser cutting equipment, and repeatedly cutting along the cutting path by using a low-power laser; and repeatedly cutting the cutting path by means of slow walking of the low-power laser. The method can be used for the aluminum nitride ceramic substrates with different thicknesses of 3 mm to 8 mm in the low-power mode to adopt a layered and repeated cutting method, the optimal cutting speed is adjusted according to the cutting depth of each layer, the cutting surface roughness is effectively reduced, the cracks on both sides of the cutting surface are less, and the cutting surface quality is significantly improved.

Claims

1. A laser cutting method for improving the surface quality of aluminum nitride, characterized in that: It includes the following steps: (1) Select appropriate alignment points according to the shape and size of the aluminum nitride ceramic substrate to be cut. Determine the position of the aluminum nitride ceramic substrate in the actual processing platform by using the alignment points to provide a reference for the laser processing path. Draw the cutting path in the CAD software with the alignment points as the reference, and confirm the cutting part and direction. The thickness of the aluminum nitride ceramic substrate to be cut is H. (2) Calculate the number of repeated cuts F based on the actual thickness of the ceramic substrate. The calculation formula is F=[H]-[(H-2) / 2]-[(H-2)%2], where [] is the integer symbol and % is the remainder symbol. The thickness H of the aluminum nitride ceramic substrate to be cut is 3-8mm. Based on the relationship between the number of repeated cuts and the thickness of the ceramic substrate, the number of repeated cuts F is 2-5 times. (3) Determine the cutting depth for each cut. Taking the maximum value of F, 5, as an example, the first cutting depth is H1=35%H, the second cutting depth is H2=30%H, the third cutting depth is H3=20%H, the fourth cutting depth is H4=10%H, and the fifth cutting depth is H5=5%H. When F<5, the first F-1 cuts are the cutting depths corresponding to each cut, and the Fth cut is the ceramic substrate thickness H minus the total depth of the first F-1 cuts. (4) Fix the aluminum nitride ceramic substrate in the carrier platform of the laser cutting equipment, and use a low-power laser to repeatedly cut along the cutting path. The cutting path is repeatedly cut by using a low-power laser slow-moving method until the cutting is completed. In step (4), the cutting power and cutting speed are determined each time, and the cutting speed without stripes on the cut surface can be determined based on the ceramic substrate cutting mechanism. In actual cutting, the temperature at the cutting edge remains constant, simplifying the formula to: , To achieve the optimal speed-power quotient, For stripe-free cutting speed, Density of aluminum nitride ceramic material, where P is the laser cutting power. The laser absorption rate of the material being cut. The heat absorbed per unit mass of material during laser cutting. Let H be the average diameter of the laser beam over the material thickness range; In step (4), when the low-power laser cuts along the marked trajectory, an auxiliary gas is applied to the cutting trajectory. The auxiliary gas is a side-spray type, which is at a certain angle to the ceramic surface. The gas direction is blowing towards the processed area, and the side-spray angle is adjusted according to the cutting depth. When a low-power laser cuts, the surface of the ceramic substrate vaporizes. An auxiliary gas is applied to the cutting path. The auxiliary gas is side-sprayed, which blows away the vaporized material and removes any incompletely vaporized residue from the cutting groove, keeping the cutting groove clean. When the low-power laser moves, it can be directly emitted to the surface of the ceramic substrate, avoiding interference from residual impurities, speeding up the cutting process, and carrying away a large amount of heat to prevent overheating and cracking. This improves the quality of the cut surface and protects the unprocessed ceramic surface area.

2. The laser cutting method for improving the surface quality of aluminum nitride according to claim 1, characterized in that: The fiber laser has an average power of 150W, but the actual cutting setting is a low-power mode with an average power of 40-50W.

3. The laser cutting method for improving the surface quality of aluminum nitride according to claim 1, characterized in that: The auxiliary gas is ejected at an angle of 35° to 60° to the ceramic surface.

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