WO2017050226A1

WO2017050226A1 - Method of laser-forming aluminum

Info

Publication number: WO2017050226A1
Application number: PCT/CN2016/099546
Authority: WO
Inventors: 段宣明; 陈勇; 曹洪忠; 王林志; 王国玉; 范树迁
Original assignee: 重庆塞拉雷利科技有限公司
Priority date: 2015-09-22
Filing date: 2016-09-21
Publication date: 2017-03-30

Abstract

A method of laser-forming aluminum, the specific steps thereof comprising: step 1, utilizing a computer establishing a geometric model and generate a forming track; step 2, prepare a vacuum or a protective gas machining environment; step 3, provide a raw material to a machining region, and utilizing a laser having a wavelength of 700-900 nm, melt the provided raw material; step 4, determine whether or not machining is complete, and if not, enter step 3 and scan a next layer, and if so, enter step 5; step 5, clean and recover an excess of the provided raw material; step 6, remove a product. The method fully utilizes the high absorbance of aluminum, aluminum alloys and aluminum-based composite materials with respect to a laser having a wavelength of 700-900 nm, reducing as far as possible the reflection of the laser by the aluminum, aluminum alloys and aluminum-based composite materials, resulting in a high energy utilization efficiency of the forming process, rapid forming, and high forming accuracy, realizing faster 3D printing.

Description

Laser forming method for aluminum

Technical field

The present invention relates to the field of three-dimensional manufacturing technology, and in particular to a laser forming method for aluminum materials.

Background technique

Laser rapid prototyping technology is based on the development of laser multi-layer cladding technology in the late 1970s. The technology is a typical digital manufacturing and green intelligent manufacturing technology by adopting computer design digital model and computer intelligent control to form materials layer by layer, and finally realize solid parts with three-dimensional complex structure. The current laser rapid prototyping technology mainly includes stereolithography technology, layered solid manufacturing technology, laser near net shaping technology, selective laser sintering forming technology, selective laser melting forming technology, etc. Among them, laser rapid prototyping of metal structures mainly depends on Laser near net shaping technology, selective laser sintering forming technology, selective laser melting forming technology, etc.

Because of its low density, high strength, low temperature resistance, good electrical conductivity, good thermal conductivity and good ductility, aluminum has been widely used in various aspects of the national economy and the national defense industry. The laser rapid prototyping technology currently developed for aluminum, aluminum alloy and aluminum matrix composites mainly relies on selective laser sintering and selective laser melting forming technology. The laser sources used are mainly fiber lasers and Nd:YAG lasers. . Because aluminum, aluminum alloy and aluminum matrix composites have higher reflectivity during laser forming, their research on laser rapid prototyping lags behind other metal materials. Therefore, it is urgent to develop suitable for aluminum and aluminum alloys. Laser rapid prototyping method for aluminum matrix composites.

Summary of the invention

The present invention is directed to the deficiencies of the prior art, and proposes a laser forming method for aluminum materials by using a laser having a wavelength of 700 nm to 900 nm, and fully utilizing aluminum, aluminum alloy and aluminum matrix composite materials for lasers having a wavelength of 700 nm to 900 nm. The high absorption makes it more efficient in energy utilization and forming efficiency in 3D printing, and the forming is more precise. The specific technical solutions are as follows:

A laser forming method for aluminum material, characterized in that: the specific step is

Step 1: use a computer to establish a geometric model to generate a forming path;

Step 2: manufacturing a vacuum or protective gas processing environment;

Step 3: Supply raw materials to the processing area, and use a laser with a wavelength of 700-900 nm to melt the raw materials.

Step 4: Determine whether the processing is completed, otherwise, go to step three, scan the next layer, and then go to step 5;

Step 5: Clean up and recycle excess raw materials;

Step 6: Take out the product.

In order to further achieve the present invention, preferably, in the third step, the raw material is a powder material having a particle diameter ranging from 1 nm to 1 mm, and the powder material is supplied by a nozzle directly to the processing region.

Preferably, step 1.1 is provided between step 1 and step 2, specifically preheating the shaped substrate;

The specific method for manufacturing the protective gas processing environment in the second step is

2.1 The vacuum is extracted from the closed processing chamber, and the gas pressure ranges from 1×10 ^-5 Pa to 1×10 ⁴ Pa;

2.2 adding a protective gas to the closed processing chamber;

The specific steps in the third step are:

3.1 feeding a powder raw material having a particle size ranging from 10 nm to 500 μm into the forming chamber;

3.2 using the powder laying device to carry out the powdering operation of the powder raw materials;

3.3 Turn on the laser with a wavelength of 700-900 nm to melt the powder material. The method of adding a protective gas after first vacuuming is simple in operation and easy to implement.

Preferably, the powder raw material is aluminum, or an aluminum alloy, or an aluminum-based composite material.

Preferably, the step 3 is specifically:

3.1 supply of raw materials to the processing area;

3.2 Turn on the laser with a wavelength of 700 to 900 nm.

Preferably, the step 3 is specifically:

3.1 Turn on the laser with a wavelength of 700-900 nm;

3.2 Supply raw materials to the processing area.

Preferably, the specific method for manufacturing the protective gas processing environment in the second step is to blow a protective gas to the open processing region. The processing area can be open and is not limited by the shape and size of the processed product.

Preferably, the supply raw material is a wire-shaped material having a cross-sectional diameter of 10 μm to 5 mm; or a strip-shaped material having a cross-sectional width of 10 μm to 10 mm and a thickness of 10 μm to 5 mm.

Preferably, the laser having a wavelength of from 700 nm to 900 nm is a continuous laser, or a pulsed laser, or a quasi-continuous laser.

Preferably, in the fourth step, the specific way of scanning the next layer is to raise the focus of the laser beam by one layer after scanning one layer, or to lower the processing area by one layer.

The invention has the beneficial effects of fully utilizing the high absorption of aluminum, aluminum alloy and aluminum matrix composite materials for laser light having a wavelength of 700 nm to 900 nm, and minimizing the laser light of aluminum, aluminum alloy and aluminum matrix composite materials. The reflection makes the energy utilization efficiency in the forming process high, the forming speed is fast, and the forming precision is high, which realizes the rapidization of 3D printing; the whole processing process is in the environment of vacuum or protective gas The processing parts are not in contact with the air to ensure the quality of the processed products; the laser forming with a wavelength of 700nm-900nm makes the application materials and feeding methods various, which makes the application range of 3D printing technology more extensive and convenient. The rapid application of 3D printing technology.

DRAWINGS

1 is a flow chart of Embodiments 1 and 2 of the present invention;

2 is a schematic flowchart of Embodiment 3 of the present invention;

3 is a schematic flowchart of Embodiment 4 of the present invention;

Figure 4 is a laser absorption spectrum of a laser absorption spectrum of pure aluminum powder;

Figure 5 is a laser absorption spectrum of AlSi10Mg aluminum alloy powder;

Figure 6 is a laser absorption spectrum of an aluminum-based composite material (AlSi10Mg/CNT) powder;

Figure 7 is a surface top view of an AlSi10Mg aluminum alloy molded part;

Figure 8 is a test chart of surface roughness of an AlSi10Mg aluminum alloy molded part;

Figure 9 is a microstructure diagram of an AlSi10Mg aluminum alloy molded part;

Fig. 10 is a graph showing the hardness test results of the molded article of AlSi10Mg aluminum alloy prepared by the present invention.

detailed description

The preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings, in which the advantages and features of the invention can be more readily understood by those skilled in the art.

Embodiment 1: As shown in FIG. 1 , a laser forming method for aluminum material, the specific steps are: Step 1: Using a computer to establish a geometric model of the aluminum structural device for forming, and layering the geometric model of the design Plan the formed scan path and select reasonable forming parameters;

Step 2: Vacuuming the closed cavity in the closed working chamber mechanism, when the vacuum pressure reaches 1×10 ^-5 Pa to 1×10 ⁴ Pa, the vacuum is stopped, and the protective gas mechanism is input to the sealed cavity. a gas, such as argon, forms a working area;

Step 3: Turn on the laser with a wavelength of 808 nm, and then supply a wire-shaped material having a cross-sectional diameter of 10 μm to 5 mm to the processing region through a feeding mechanism, or a strip-shaped material having a cross-sectional width of 10 μm to 10 mm and a thickness of 10 μm to 5 mm, using a laser Melting the supplied raw materials;

Step 4: judging whether the processing is completed, otherwise, the laser beam focus of the laser source in the laser transmitting system rises one level, and proceeds to step three to perform the next layer scanning operation, and then proceeds to step three;

Step 5: Clean up and recycle excess raw materials;

Step 6: Take out the product.

Embodiment 2: As shown in FIG. 1 , a laser forming method for aluminum material, characterized in that: the specific steps are:

Step 1: Using a computer to establish a geometric model of the formed aluminum structural device, and layering the geometric model of the design, planning the formed scanning path, and selecting a reasonable forming parameter;

Step 2: blowing a protective gas, such as argon, to the open processing area;

Step 3: Turn on the laser with a wavelength of 808 nm, and then supply a wire-shaped material having a cross-sectional diameter of 10 μm to 5 mm to the processing region, or a strip-shaped material having a cross-sectional width of 10 μm to 10 mm and a thickness of 10 μm to 5 mm, and supply the raw material by using a laser. melt;

Step 4: Determine whether the processing is completed, otherwise, lower the forming plate by one layer, proceed to step 3 to continue processing, scan the next layer, and then proceed to step 5;

Step 5: Clean up and recycle excess raw materials;

Step 6: Take out the product.

Embodiment 3: As shown in FIG. 2, a laser forming method of aluminum material, the specific steps are:

Step 1: According to the machined parts, use the computer to build a three-dimensional model of the parts;

Step 2: cutting the processed part into a two-dimensional plane to generate a scan path, and transmitting the scan path to the manufacturing system;

Step 3: Vacuum is taken from the closed processing cavity in the manufacturing system, and when the air pressure reaches 1×10 ^-5 Pa, the vacuuming operation is stopped;

Step 4: injecting argon into the sealed processing chamber by using a shielding gas delivery device;

Step 5: spraying the aluminum alloy powder raw material having a particle size ranging from 2 nm to 0.5 mm directly to the processing region by using a nozzle to the sealed processing chamber;

Step 6: Turn on the continuous laser melting aluminum alloy powder raw material with a wavelength of 808 nm;

Step 7: The control system determines whether the part is formed according to the scan path, if not, proceeds to step eight, and then proceeds to step IX;

Step 8: Adjust the height of the material deposition component in the closed processing chamber, and proceed to step 5;

Step 9: Clean the surface powder of the part;

Step 10: Take out the formed part.

According to a large number of experiments on the laser absorption rate of aluminum alloy powder, as shown in Fig. 5, when the laser wavelength range is from 800 nm to 850 nm, the absorption rate of the aluminum alloy powder has a peak value, and the absorption rate exceeds 70%, in this embodiment. The laser with a wavelength of 808 nm is used as the processing light source, and the absorption peak of the aluminum alloy powder is fully utilized, thereby maximizing energy conservation and improving forming efficiency. As shown in FIG. 7, the forming process of the additive manufacturing system and method is fast. The surface gloss is good and flatter. As shown in Fig. 8, when the laser wavelength ranges from 800nm to 850nm, the surface of the aluminum alloy molded part is smooth and compact, and has high molding quality. When the laser wavelength ranges from 800nm to 850nm, the aluminum alloy is used. The surface of the molded part has the highest precision R _a of 0.62 μm and a high surface quality. As shown in Fig. 9, the workpiece has a very fine grain and a dense structure, and the average grain size is less than 1 μm. The gray cell structure is an Al matrix, and the white fiber is a Si phase. According to the test structure, the product formed by the method and system of the invention can be obtained, and has high quality, beautiful appearance and high application value; as shown in FIG. 10, the laser selective melting method and system of the invention are adopted. The hardness test results of the prepared AlSi10Mg aluminum alloy molded parts under different process conditions can be seen that the Vickers hardness value is basically stable between HV110 and HV130, and the average value is HV120±3, which is larger than the HV95～HV105 of the traditional AlSi10Mg cast material. , indicating that the molded part has excellent mechanical properties.

Embodiment 4: As shown in FIG. 3, a laser forming method of aluminum material adopts the following steps:

Step 1: use a computer to establish a geometric model to generate a laser scanning path;

Step 2: preheating the forming substrate;

Step 3: vacuuming the forming chamber, the pressure of the vacuum is in the range of 1 × 10 ^-5 Pa;

Step 4: injecting a shielding gas into the forming chamber, in this embodiment, argon gas is used;

Step 5: feeding a powder raw material to the forming chamber, the powder raw material being an AlSi10Mg aluminum alloy powder having a powder material size ranging from 10 nm to 500 μm;

Step 6: using a powder laying device to carry out the powdering operation of the powder raw material, and laying the powder raw material on the forming substrate, and the thickness of the coating is 30 μm-100 μm;

Step 7: Turn on a continuous laser beam with a wavelength of 808 nm to melt the powder raw material;

Step 8: According to the laser scanning path, determine whether the product processing is completed, if not, proceed to step IX, and then proceed to step ten;

Step 9: The forming cylinder in the forming chamber is lowered by one layer, and the process proceeds to step 5, and the next layer of the forming part is paved;

Step 10: Remove excess powder material;

Step 11: Take out the formed part.

As shown in Figure 5: After a large number of experimental tests, the reflectance of AlSi10Mg aluminum alloy powder to laser is as low as 32.506% when the laser wavelength ranges from 700nm to 900nm. In the laser forming process, AlSi10Mg aluminum alloy powder can be fully absorbed. The energy utilization efficiency is high, the forming speed is fast, and the forming precision is high, and the formation of the AlSi10Mg aluminum alloy powder is accelerated. As shown in Fig. 7, when the laser wavelength range is from 800 nm to 850 nm, the surface of the aluminum alloy molded part is smooth and compact, and has high molding quality, as shown in Fig. 8, when the laser wavelength ranges from 800 nm to 850 nm, the optimized process is performed. Under the condition of parameters, the highest precision R _a surface of aluminum alloy molded parts can reach 0.62μm, which has high surface quality. The Vickers hardness value of the aluminum alloy molded parts is basically stable between HV110 and HV130 (shown in Figure 10), and the average value is HV120±3, which is larger than the HV95～HV105 of the conventional AlSi10Mg cast material. It shows that the molded part has excellent mechanical properties.

As a deformation, a pure aluminum powder material or an aluminum-based composite material (AlSi10Mg/CNT) powder may be used. As shown in FIG. 4, when the laser wavelength ranges from 700 nm to 900 nm, the reflectance of the pure aluminum powder to the laser is the lowest. 75.464%, when the laser wavelength range shown in Figure 6 is 700nm ~ 900nm, the AlSi10Mg/CNT composite powder material with different carbon nanotubes added has the lowest reflectivity of the laser, and the lowest reflectivity is 18%-25. %. It can be noted that when the wavelength is from 700 nm to 900 nm, the AlSi10Mg/CNT composite powder material has a strong peak in the absorption rate of the laser, and the absorption rate exceeds 75%.

The finished product is tested. As shown in Fig. 7, when the laser wavelength ranges from 800 nm to 850 nm, the surface of the aluminum alloy molded part is smooth and compact, and has high molding quality. Figure 8 shows that the laser wavelength range is from 800 nm to 850 nm. The surface of the aluminum alloy molded part has the highest precision R _a of 0.62 μm and a high surface quality. Figure 9 shows that the grain is very fine and the structure is dense, and the average grain size is less than 1 μm. The gray cell structure is an Al matrix, and the white fiber is a Si phase. According to the test structure, the product formed by the method and system of the invention can be obtained, has high quality, beautiful appearance and high application value, as shown in FIG. 10, which is prepared by the laser selective melting method and system of the invention. The hardness test results of AlSi10Mg aluminum alloy molded parts under different process conditions can be seen that the Vickers hardness value is basically stable between HV110 and HV130, and the average value is HV120±3, which is larger than the HV95～HV105 of the traditional AlSi10Mg casting material. It shows that the molded part has excellent mechanical properties.

Claims

A laser forming method for aluminum material, characterized in that: the specific step is

Step 1: use a computer to establish a geometric model to generate a forming path;

Step 2: manufacturing a vacuum or protective gas processing environment;

Step 3: supplying raw materials to the processing area, and melting and supplying the raw materials by using a laser having a wavelength of 700 to 900 nm;

Step 4: Determine whether the processing is completed, or not, proceed to step three, scan the next layer, if yes, proceed to step 5;

Step 5: Clean up and recycle excess raw materials;

Step 6: Take out the product.
The laser forming method for aluminum according to claim 1, wherein in the third step, the raw material is a powder material having a particle diameter ranging from 1 nm to 1 mm, and the powder material is supplied by directly spraying the nozzle into the processing region. give away.
The laser forming method of the aluminum material according to claim 1, wherein step 1.1 is provided between the first step and the second step, specifically preheating the forming substrate;

The specific method for manufacturing the protective gas processing environment in the second step is

2.1 The vacuum is extracted from the closed processing chamber, and the gas pressure ranges from 1×10 -5 Pa to 1×10 4 Pa;

2.2 adding a protective gas to the closed processing chamber;

The specific steps in the third step are:

3.1 feeding a powder raw material having a particle size ranging from 10 nm to 500 μm into the forming chamber;

3.2 using the powder laying device to carry out the powdering operation of the powder raw materials;

3.3 Turn on the laser with a wavelength of 700-900 nm to melt the powder material.
A laser forming method for an aluminum material according to claim 2 or 3, characterized in that said powder The final raw material is aluminum, or aluminum alloy, or aluminum-based composite material.
A laser forming method for an aluminum material according to claim 1, wherein said step three is specifically

3.1 supply of raw materials to the processing area;

3.2 Turn on the laser with a wavelength of 700 to 900 nm.
A laser forming method for an aluminum material according to claim 1, wherein said step three is specifically

3.1 Turn on the laser with a wavelength of 700-900 nm;

3.2 Supply raw materials to the processing area.
The laser forming method for aluminum according to claim 1, wherein the protective gas processing environment in the second step is a method of blowing a protective gas to the open processing region.
A laser forming method for an aluminum material according to claim 1, wherein said supply raw material is a wire-shaped material having a cross-sectional diameter of 10 μm to 5 mm; or a strip-shaped material having a cross-sectional width of 10 μm to 10 mm and a thickness of 10 μm to 5 mm. .
The laser forming method of aluminum according to claim 1, wherein the laser having a wavelength of from 700 nm to 900 nm is a continuous laser, or a pulsed laser, or a quasi-continuous laser.
The laser forming method for aluminum according to claim 1, wherein in the fourth step, the specific mode of scanning the next layer is: after scanning a layer, the focus of the laser beam is raised by one layer, or Lower the processing area by one layer.