METHOD FOR COMPOSITE ADDITIVE MANUFACTURING WITH DUAL-LASER BEAMS FOR LASER MELTING AND LASER SHOCK

Abstract

A method for composite additive manufacturing with dual-laser beams for laser melting and laser shock, includes the following steps: 1) performing cladding on metal powder through a first continuous laser beam by thermal effect, and performing synchronous shock forging on material in a cladding region through a second short-pulse laser beam by shock wave mechanical effect, so as to perform the composite additive manufacturing; and 2) stacking the material in the cladding region layer by layer to form a workpiece. The method has the characteristics that the two laser beams make full use of the thermal effect and the shock wave mechanical effect, and synchronously work in a coupled manner, so that defects such as pores, incomplete fusion and shrinkage in a cladding layer are eliminated, and the performance of the workpiece is obviously improved. The method is high in manufacturing efficiency.

Claims

1. A method for composite additive manufacturing with dual-laser beams for laser melting and laser shock, comprising the following steps: performing cladding on metal powder through a first continuous laser beam by thermal effect, and performing synchronous shock forging on material in a cladding region through a second short-pulse laser beam by shock wave mechanical effect, so as to perform the composite additive manufacturing; and stacking the material in the cladding region layer by layer to form a workpiece.

2. The method for composite additive manufacturing with dual-laser beams for laser melting and laser shock according to claim 1, wherein a temperature of the first continuous laser beam is monitored and controlled online through a temperature sensor according to different characteristics of machined metal materials, so as to enable the metal materials to be in a temperature range that is most favorable for plastic forming after the metal materials are cladded and then cooled, and the second short-pulse laser beam performs the shock forging; and the temperature of the first continuous laser beam is decreased/increased to form closed-loop control if the metal materials deviate from the temperature range that is most favorable for plastic forming after the metal materials are cladded and then cooled resulting from extreme high/low temperature of the first continuous laser beam.

3. The method for composite additive manufacturing with dual-laser beams for laser melting and laser shock according to claim 1, wherein forging parameters of the second short-pulse laser beam are monitored and controlled by a light beam quality detector or apparatus; a pulse width of the second short-pulse laser beam is determined according to a thickness of the material in the cladding region, so that the material along a depth of the cladding region is fully and thoroughly forged; a forging frequency and a light spot size of the second short-pulse laser beam are determined according to an area of the material in the cladding region, so as to ensure that moving speed of laser shock forging is matched with a laser cladding speed and ensure that a temperature in a forging region is always in a temperature range that is most favorable for plastic deformation; and the moving speed of the first continuous laser beam is reduced to form closed-loop control if the area/thickness of the material in the cladding region exceeds a preset limit of the second short-pulse laser beam, and vice versa.

4. The method for composite additive manufacturing with dual-laser beams for laser melting and laser shock according to claim 1, wherein a coaxial powder feeding amount is monitored and controlled by a powder feeder; the coaxial powder feeding amount determines a thickness and an area of the cladding region, and also affects moving speed of the first continuous laser beam and forging parameters of the second short-pulse laser beam; and the moving speed of the first continuous laser beam is decreased/increased to form coupled control if the powder feeding amount exceeds/does not reach a preset amount of the first continuous laser beam.

5. The method for composite additive manufacturing with dual-laser beams for laser melting and laser shock according to claim 1, wherein parameters of the composite additive manufacturing with dual-laser beams are detected and controlled online; the second short-pulse laser beam is capable of performing the shock forging on a front surface or side surface of a cladding layer at any angle between 15 to 165 degrees or in any position, has circular light spots and square light spots or randomly exchange therebetween, and is capable of treating cladding-formed parts having different structural characteristics.

Description

DESCRIPTION OF THE DRAWINGS

[0013] In order to make the technical solutions in the disclosure or in the prior art described more clearly, the drawings associated to the description of the embodiments or the prior art will be illustrated concisely hereinafter. Obviously, the drawings described below are only some embodiments according to the disclosure. Numerous drawings therein will be apparent to one of ordinary skill in the art based on the drawings described in the disclosure without creative efforts.

[0014] FIG. 1 illustrates implementation steps of a method for composite additive manufacturing with dual-laser beams for laser melting and laser shock provided by the present disclosure; and

[0015] FIG. 2 is a microscopically structural schematic diagram of a cladding layer. In the figures: 1: cladding layer; 2: molten pool; 3: metal powder; 4: continuous laser; 5: short-pulse laser; 6: plasma; 7: shock wave; 8: defect such as pores, shrinkage and incomplete fusion; 9: fused metal crystal; and 10: variable angle of short-pulse laser.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0016] In order to make the objects, technical solution and advantages of the present disclosure more clear, the present disclosure will be further described in detail with reference to the accompanying drawings and embodiments below. It should be understood that embodiments described here are only for explaining the present disclosure and the disclosure, however, should not be constructed as limited to the embodiment as set forth herein.

[0017] Referring to FIG. 1, FIG. 1 illustrates steps of a specific implementation mode provided by the present disclosure:

[0018] Step 1), performing cladding on metal powder through a first continuous laser beam by thermal effect, and performing synchronous shock forging on material in a cladding region through a second short-pulse laser beam by shock wave mechanical effect, so as to perform the composite additive manufacturing.

[0019] The step includes a process parameter detection and control process as follows, and as shown in FIG. 2.

[0020] The thermal effect of the first continuous laser beam 4 generates a molten pool 2 according to different characteristics of machined metal materials, and a temperature of the molten pool is monitored and controlled online through a temperature sensor, so as to enable the metal materials to be in a temperature range that is most favorable for plastic forming after the metal materials are cladded and then cooled. A second short-pulse laser beam 5 performs shocking to generate plasmas 6) and the plasmas 6 penetrate through a certain depth of a cladding layer 1 by means of shock waves. Under the action of a shock wave mechanical effect, defects 8 such as pores, shrinkage and incomplete fusion are closed, so as to achieve the aim of equivalent forging. Parameters are adjusted to decrease/increase the temperature of the first continuous laser beam molten pool 2 to form closed-loop control if the temperature of the molten pool 2 is extremely high/low and results in such a phenomenon that the clad and cooled materials deviate from the best plastic forming temperature range, namely under the action of the plasmas 6, the material temperature shall be in the best plastic forming temperature range.

[0021] Forging parameters of the second short-pulse laser beam 5 are monitored and controlled by a light beam quality detector or apparatus. A pulse width of the second short-pulse laser beam impact wave is determined according to a thickness of the material in the cladding region 1, so that a depth material of the whole cladding layer is fully and thoroughly forged. A forging frequency and a light spot size of the second short-pulse laser beam 5 are determined according to a material area in an acting region of the plasmas 6, so as to ensure that the moving speed of laser shock forging is matched with a laser cladding speed and ensure that a temperature in a forging region is always in a temperature range that is most favorable for plastic deformation. The moving speed of the first continuous laser beam 4 is reduced to form closed-loop control if the area/thickness of the material in the cladding region exceeds a preset limit of the second short-pulse laser beam 5, and vice versa.

[0022] In the method for composite additive manufacturing with dual-laser beams for laser melting and laser shock, a coaxial powder feeding amount is monitored and controlled by a powder feeder. The coaxial powder feeding amount determines a thickness and an area of the cladding region, and also affects moving speed of the first continuous laser beam 4 and forging parameters of the second short-pulse laser beam 5. The moving speed of the first continuous laser beam 4 is decreased/increased to form coupled control if the powder feeding amount exceeds/does not reach a preset amount of the first continuous laser beam 4.

[0023] Parameters of the composite additive manufacturing with dual-laser beams are detected and controlled online. The second short-pulse laser beam is capable of performing the shock forging on a front surface or side surface of a cladding layer at any angle between 15 to 165 degrees or in any position, has circular light spots and square light spots or randomly exchange therebetween, and is capable of treating cladding-formed parts having different structural characteristics.

[0024] Step 2), stacking the material in the cladding region layer by layer to form a workpiece. Since each layer of cladding-formed metal undergoes continuous laser thermal effect forming and short-pulse laser shock wave effect forging, the mechanical property is obviously improved, and the metal may reach a level of a forged part.