A method to improve the quality of laser metal 3D forming parts
A forming part, laser technology, applied in the direction of improving energy efficiency, process efficiency, additive manufacturing, etc., can solve the problems of difficult to avoid sticking powder, inability to accumulate thin-walled parts, low energy density, etc., to reduce surface roughness, The effect of surface roughness reduction and quality improvement
Active Publication Date: 2018-02-13
苏州柯莱得激光科技有限公司
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Problems solved by technology
However, there are still problems with this method: it is still difficult to avoid powder sticking on the outer surface of the formed part; it is not possible to stack narrow thin-walled parts; stacking efficiency etc.
[0005] In the traditional optical external coaxial powder feeding structure, the laser scanning energy has a Gaussian distribution, and the energy density on both sides of the melting channel is low, resulting in uneven cladding layers on both sides, easy to shrink and crack, and powder adhering to the surface is not easy melt
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[0025] The powder material is selected as Fe313, the particle size is 75μm-106μm, the laser power is 600W, the powder feeding volume is 8g / min, the scanning speed is 7mm / s, and the protective air pressure is 1.5bar. The parameters of the selected hollow laser cladding nozzle are: s=18mm, α=20°, . The negative defocus amount f is adjusted to 3.5mm, and the measured β value is about 5°. According to the expression D=f×2tan(α) of the outer diameter of the spot, the expression of the powder spot diameter Φ Thus, D:Φ=0.7635>0.7 can be obtained. The average surface roughness of the molded part was measured to be Ra=1.195 μm.
[0026] The present invention adopts the hollow laser internal powder feeding cladding nozzle, the laser beam is distributed in a circular focus, and its scanning energy distribution is saddle-shaped, which is more uniform than the Gaussian distribution, the cladding layers on both sides can be fully melted, and the surface roughness is reduced; The powd...
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Abstract
The invention discloses a method for improving the quality of laser metal 3D formed parts. A hollow laser internal powder feeding cladding nozzle is selected. The cladding nozzle is provided with a powder tube in the middle of the laser beam and a collimation protection gas tube located on the periphery of the powder tube. The laser The beam is distributed in a circular focus, the powder beam is centered, and a collimated protective gas curtain is formed around the powder beam, so that the annular focused distribution of the laser beam, the collimated protective gas curtain and the powder beam are coaxial; the parts are placed in negative defocus Position, the laser beam acts on the surface of the part to form a molten pool, move the cladding nozzle along the Z-axis direction, adjust the negative defocus of the laser beam, so that the outer diameter D of the spot at the molten pool is the same as the diameter of the powder spot at the molten pool The ratio of Φ is greater than 0.7. Using this method, the laser scanning energy distribution is more uniform, and the edge of the cladding layer can be fully melted, which can greatly reduce the amount of powder adhering to the side of the formed part, reduce the surface roughness of the metal formed part, and improve the quality of the metal formed part. the quality of.
Description
technical field [0001] The invention relates to the technical field of laser rapid prototyping, in particular to a method for improving the quality of laser metal 3D forming parts. Background technique [0002] Laser metal rapid prototyping technology is based on laser cladding technology and rapid prototyping technology. Generally, the laser cladding nozzle is clamped by a moving mechanism, and the laser is used as a heat source to synchronously transport the metal powder / wire, which is rapidly melted and cooled at the molten pool on the substrate. Slice the 3D CAD model layer by layer, plan the motion path, and then use the above laser cladding method to stack layers into a solid body. It has the advantages of no mold, short forming time, capable of forming complex structures, capable of forming gradient materials, unlimited forming size, metallurgical bonding between layers, and uniform and dense microstructure. It has wide application in aerospace, national defense, med...
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IPC IPC(8): B22F3/105B33Y10/00B33Y30/00
CPCB22F3/003B33Y10/00B33Y30/00B22F10/00B22F10/36B22F10/32B22F10/25B22F10/38B22F12/53Y02P10/25
Inventor 石拓金朝龙石世宏
Owner 苏州柯莱得激光科技有限公司