A high-efficiency and high-precision quality control method for laser selective melting

Abstract

The present invention belongs to the field of advanced manufacturing technology, and discloses a quality control method for high-efficiency and high-precision laser selective melting forming, which uses a high-power laser beam to form a high-efficiency forming area with a larger layer thickness, scanning speed and scanning spacing; uses a low-power laser beam to form a high-precision forming area with a smaller layer thickness, scanning speed and scanning spacing; when the transition area is located above the high-efficiency forming area and below the high-precision forming area, the laser power, layer thickness, scanning speed and scanning spacing are all or partially reduced layer by layer to form; when the transition area is located above the high-precision forming area and below the high-efficiency forming area, the laser power, layer thickness, scanning speed and scanning spacing are all or partially increased layer by layer to form, and the corresponding parameters of the transition area are between the values ​​of the corresponding parameters of the other two areas. The present invention can achieve high-efficiency and high-precision SLM forming of metal parts under the premise of ensuring the transition quality of different areas.

Description

Technical Field

[0001] The present invention belongs to the field of advanced manufacturing technology, and more specifically, relates to a quality control method for high-efficiency and high-precision laser selective melting forming. Background Art

[0002] Selective Laser Melting (SLM) is one of the fastest growing and most widely used metal 3D printing technologies. It uses a scanning galvanometer to drive a high-energy laser beam to selectively melt the pre-laid metal powder bed according to the model slicing data of the metal parts. Through layer-by-layer melting and accumulation, it can achieve high-density, high-precision, and structurally functional integrated forming of complex metal parts.

[0003] However, most commercial SLM equipment currently uses low-power lasers (power P < 1000W). In order to meet the high demand for laser energy density for complete melting of metal powder, only a small scanning speed (V), scanning spacing (S) and layer thickness (T) can be used, so the forming efficiency is generally low (≤ 5mm). 3 / s), which seriously restricts the large-scale application of SLM technology in the industrial field.

[0004] In view of the low forming efficiency of conventional SLM technology, domestic and foreign research institutions have turned their attention to high-power SLM technology based on kilowatt-class lasers (P≥1000W). They have successively used high-power SLM to carry out experiments on various material systems and studied the forming quality and forming efficiency. The results show that the use of high-power SLM technology can achieve several times or even dozens of times the forming efficiency, and the key indicators such as density, strength, and elongation of the formed parts can reach or even exceed those of conventional SLM. The core of high-power SLM to improve the forming efficiency is to increase the laser power, thereby increasing the available scanning speed, scanning spacing, and layer thickness. Since the formed component is formed by stacking the laser cladding channels layer by layer, the increase in scanning spacing and layer thickness will inevitably lead to a decrease in forming accuracy. In addition, the interaction between high-power laser and powder is intense, and the resulting "melt migration" and "melt droplet splashing" will make the surface of SLM formed parts rough. These problems have greatly hindered the promotion and application of high-power SLM technology.

[0005] In order to solve the problem of decreased forming accuracy and rough surface of formed parts in high-power SLM technology, the inventor's unit recently proposed a dual-beam SLM forming method (patent CN112091213A) that takes into account both forming efficiency and forming quality. This method divides the digital model of metal parts into two areas: one is the area with high forming accuracy requirements, using conventional low-power lasers to achieve high-precision forming; the other is the area with high forming efficiency requirements, using kilowatt-level high-power lasers to achieve high-efficiency forming; when this method is used to form metal parts, high and low-power lasers are alternately used for forming according to the partitioning of the digital model of the parts, thereby taking into account both forming efficiency and forming accuracy. In order to improve the quality of the high-power laser forming area, the inventor's unit also proposed a dual-beam SLM forming method and system (patent CN112276081A) that takes into account both forming efficiency and forming quality, and optimizes the energy distribution mode of the kilowatt-level high-power laser used in the high-efficiency forming area to a ring or flat-top mode, so that the internal metallurgical defects and residual stress of the high-power laser forming area are reduced.

[0006] However, due to the principle of laser processing, even if an optimized laser energy distribution mode is used, the surface roughness of the high-power laser forming area (i.e., the high-efficiency forming area of ​​the component) will still be significantly higher than that of the low-power laser forming area (i.e., the high-precision forming area of ​​the component). In this case, during the SLM forming of metal parts, if a high-precision forming area is to be further formed on the surface of the high-efficiency forming area, the high-efficiency forming area will have a larger surface roughness and the surface fluctuations will even be greater than the powder layer thickness set for the subsequent high-precision forming area, which will undoubtedly affect the powder laying quality during the subsequent high-precision forming area. At the least, it will reduce the forming accuracy of the subsequent high-precision forming area and cause a large number of metallurgical defects to form at the interface of different areas. At the worst, it will directly cause the damage of the powder laying device and force the processing to be interrupted. On the other hand, during the SLM forming process of metal parts, if it is necessary to continue to form a high-efficiency forming area on the surface of the high-precision forming area, the action depth of the high-power laser used in the subsequent high-efficiency forming area may penetrate the powder layer, which will have a negative impact on the quality of the formed high-precision forming area.

[0007] In summary, corresponding solutions are proposed to address the existing problems in the transition between the high-power laser forming area (i.e., the high-efficiency forming area of ​​the component) and the low-power laser forming area (i.e., the high-precision forming area of ​​the component), thereby achieving high-efficiency and high-precision SLM forming of the component while ensuring the transition quality of different areas, which is of great significance for the large-scale promotion and application of SLM technology. Summary of the invention

[0008] In view of the above defects or improvement needs of the prior art, the present invention provides a quality control method for high-efficiency and high-precision laser selective melting forming, which aims to solve the transition quality problem between the high-precision forming area and the high-efficiency forming area in the existing high-power laser and low-power laser collaborative SLM forming process, thereby achieving high-efficiency and high-precision SLM forming of parts while ensuring the forming quality.

[0009] To achieve the above-mentioned purpose, the present invention proposes a quality control method for high-efficiency and high-precision laser selective melting forming, which is characterized in that a high-power laser beam is used to form a high-efficiency forming area of ​​a metal part with a larger layer thickness, scanning speed and scanning spacing; a low-power laser beam is used to form a high-precision forming area of ​​a metal part with a smaller layer thickness, scanning speed and scanning spacing; for a transition area between the high-efficiency forming area and the high-precision forming area, the values ​​of the laser power, layer thickness, scanning speed and scanning spacing used are between the values ​​of the laser power, layer thickness, scanning speed and scanning spacing corresponding to the high-precision forming area and the high-efficiency forming area, and when the transition area is located above the high-efficiency forming area and below the high-precision forming area, the laser power, layer thickness, scanning speed and scanning spacing are all or partially reduced layer by layer to form; when the transition area is located above the high-precision forming area and below the high-efficiency forming area, the laser power, layer thickness, scanning speed and scanning spacing are all or partially increased layer by layer to form, thereby achieving high-efficiency and high-precision SLM forming of metal parts while ensuring the transition quality of different areas.

[0010] As a further preferred embodiment, the laser beam energy distribution mode adopted in the high-efficiency forming area is a high-order multi-mode, a flat-top mode or a ring mode, and the laser power P e ≥1000W; the laser beam energy distribution mode used in the high-precision forming area is Gaussian mode, and the laser power P a <1000W.

[0011] As a further preferred embodiment, if the transition region is located above the high-efficiency forming region and below the high-precision forming region, the transition region is formed by low-power laser, the energy distribution mode of the low-power laser is Gaussian mode, and the laser power P e-a Reduce layer by layer and satisfy P a ≤P e-a ≤P e If the transition area is located above the high-precision forming area and below the high-efficiency forming area, the transition area is formed by high-power laser, and the energy distribution mode of the high-power laser is high-order multi-mode, flat-top mode or ring mode. The laser power P e-a Improve step by step and meet P a ≤P e-a ≤P e .

[0012] As a further preferred embodiment, the layer thickness T of the high-efficiency forming region is e >0.05mm, scanning speed V e >1500mm / s, scanning distance S e >0.10mm; layer thickness T used in high-precision forming areas a , Scanning speed V a , scanning spacing S a Satisfy: 0.01mm≤T a ≤0.05mm, 300mm / s≤V a ≤1500mm / s, 0.06mm≤S a ≤0.10mm.

[0013] As a further preferred embodiment, if the transition region is located above the high-efficiency forming region and below the high-precision forming region, the layer thickness T of the transition region is e-a Reduce layer by layer and satisfy T a ≤T e-a ≤T e If the transition region is located above the high-precision forming region and below the high-efficiency forming region, the layer thickness T e-a Increase layer by layer and satisfy T a ≤T e-a ≤T e .

[0014] As a further preferred embodiment, if the transition region is located above the high-efficiency forming region and below the high-precision forming region, the scanning speed V of the transition region is e-a Reduce layer by layer and satisfy V a ≤V e-a ≤V e If the transition area is located above the high-precision forming area and below the high-efficiency forming area, the scanning speed V e-a Increase layer by layer and satisfy V a ≤V e-a ≤V e .

[0015] As a further preferred embodiment, if the transition region is located above the high-efficiency forming region and below the high-precision forming region, the scanning spacing S of the transition region is e-a Reduce layer by layer and satisfy S a ≤S e-a ≤S e If the transition area is located above the high-precision forming area and below the high-efficiency forming area, the scanning spacing S of the transition area e-a Increase layer by layer and satisfy S a ≤S e-a ≤Se .

[0016] As a further preferred embodiment, the transition region satisfies the following conditions when implementing all or part of the layer-by-layer gradual laser processing parameters:

[0017] If the transition area is located above the high-efficiency forming area and below the high-precision forming area, then:

[0018]

[0019] If the transition area is located above the high-precision forming area and below the high-efficiency forming area, then:

[0020]

[0021] In the formula, are the laser power, layer thickness, scanning speed and scanning spacing corresponding to the i-th layer in the transition region, respectively; are respectively the laser power, layer thickness, scanning speed and scanning spacing corresponding to the i+1th layer in the transition region; i≥1; K1 and K2 are dimensionless constants, and their values ​​satisfy: 0.5≤K1≤1, 1≤K2≤2.

[0022] As a further preferred embodiment, when the transition region is located above the high-efficiency forming region and below the high-precision forming region, laser remelting is performed layer by layer on each layer of the transition region or laser remelting is performed on the last layer of the transition region; laser remelting uses a low-power laser, and the laser energy distribution mode is a Gaussian mode; the laser power, scanning speed and scanning spacing used in laser remelting meet the following requirements:

[0023]

[0024] Where P ri 、V ri , S ri are the laser power, scanning speed and scanning spacing used for laser remelting corresponding to the i-th layer in the transition region, respectively; are the laser power, scanning speed and scanning spacing used for forming the i-th layer in the transition region, respectively;

[0025] As further preferred, the number of layers N in the transition region satisfies: 2≤N≤20.

[0026] In general, the above technical solution conceived by the present invention has the following technical advantages compared with the prior art:

[0027] 1. The quality control method for high-efficiency and high-precision SLM forming proposed in the present invention divides the metal parts to be formed into a high-efficiency forming area, a high-precision forming area and a transition area therebetween, and implements all or part of the laser processing parameters gradually changing layer by layer in the transition area. This can achieve high-efficiency and high-precision SLM forming of parts while ensuring the forming quality of the transition area.

[0028] 2. The present invention adopts low-power laser beam forming for the transition area from the high-efficiency forming area to the high-precision forming area, and proposes a method for reducing all or part of the processing parameters such as laser power, layer thickness, scanning speed, and scanning spacing layer by layer. When necessary, laser remelting is also performed on the forming layer, thereby eliminating the negative impact of the higher surface roughness of the high-efficiency forming area on the subsequent high-precision forming area.

[0029] 3. The present invention adopts high-power laser beam forming for the transition area from the high-precision forming area to the high-efficiency forming area, and proposes a method of increasing all or part of the processing parameters such as laser power, layer thickness, scanning speed, and scanning spacing layer by layer, which can avoid the influence of subsequent forming on the quality of the already formed high-precision forming area.

[0030] 4. The present invention optimizes the selection range of laser processing parameters (laser power, layer thickness, scanning speed, scanning spacing) and laser beam energy distribution pattern in the high-efficiency forming area, high-precision forming area and transition area, and establishes the laser processing parameter matching criteria of adjacent forming layers within the transition area, thereby further optimizing the forming quality of the transition area and ensuring high-efficiency and high-precision SLM forming of metal parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a flow chart of a high-efficiency and high-precision quality control method for selective laser melting provided by an embodiment of the present invention;

[0032] Figure 2 This is a forming area division diagram of a high-temperature alloy blade of an aircraft engine provided by an embodiment of the present invention;

[0033] Figure 3 It is a forming area division diagram of a copper alloy combustion chamber of a rocket engine provided by an embodiment of the present invention;

[0034] Figure 4 This is a forming area division diagram of a lightweight titanium alloy wheel hub for an automobile provided by an embodiment of the present invention;

[0035] Figure 5 This is a forming area division diagram of a high-strength steel cabin door of a passenger aircraft provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0037] The embodiment of the present invention provides a high-efficiency and high-precision laser selective melting quality control method, the basic idea of ​​which is: using a high-power laser beam (power P e ) with a larger layer thickness T e , Scanning speed V e and scanning spacing S e High efficiency forming area for forming metal parts; using low power laser beam (power P a ) with a smaller layer thickness T a , Scanning speed V a and scanning spacing S a High-precision forming area for forming metal parts; for the transition area between the high-efficiency forming area and the high-precision forming area, when the high-precision forming area is formed on the surface of the high-efficiency forming area (that is, the transition area is located above the high-efficiency forming area and below the high-precision forming area), the laser power P e-a , layer thickness T e-a , Scanning speed V e-a and scanning spacing S e-a The whole or part of the material is formed by reducing the size layer by layer, and P a ≤P e-a ≤P e , T a ≤T e-a ≤T e , V a ≤V e-a ≤V e , S a ≤S e-a ≤S e , thereby eliminating the negative impact of the high surface roughness of the high-efficiency forming area on the subsequent forming; when the high-efficiency forming area is formed on the surface of the high-precision forming area (that is, the transition area is located above the high-precision forming area and below the high-efficiency forming area), the laser power P e-a , layer thickness T e-a , Scanning speed V e-a and scanning spacing S e-a The whole or part of the layer is formed by increasing the size layer by layer, and P a ≤P e-a ≤P e , T a ≤T e-a ≤Te , V a ≤V e-a ≤V e , S a ≤S e-a ≤S e , thereby avoiding the subsequent forming from affecting the quality of the already formed high-precision forming area. The above method is used to achieve high-efficiency and high-precision SLM forming of metal parts while ensuring the transition quality of different areas.

[0038] Specifically, Figure 1 As shown, the quality control method of the present invention is divided into the following steps:

[0039] (1) The digital model of the metal part to be formed is divided into a high-efficiency forming area, a high-precision forming area, and a transition area between the two. Specifically, according to the structural characteristics of the digital model of the metal part and the processing accuracy requirements, it is divided into three types of areas and sliced ​​differently: the first is a high-efficiency forming area with a simple structure or convenient for subsequent fine processing, and the slice layer thickness is T e ; The second is the high-precision forming area with complex structure or inability or difficulty to carry out subsequent fine processing. The slice layer thickness is T a ; The third is the transition area from the high-precision forming area to the high-efficiency forming area along the layer-by-layer printing direction, and the transition area from the high-efficiency forming area to the high-precision forming area along the layer-by-layer printing direction. The slice layer thickness is T e-a ;

[0040] (2) Setting the corresponding processing parameters for different forming areas: A high-power laser beam of the kilowatt class is used in the high-efficiency forming area to implement a larger layer thickness, scanning speed and scanning spacing; a low-power laser beam is used in the high-precision forming area to implement a smaller layer thickness, scanning speed and scanning spacing; for the transition area between the high-efficiency forming area and the high-precision forming area, if the transition area is located above the high-efficiency forming area and below the high-precision forming area (i.e., the transition area is formed on the high-efficiency forming area), a low-power laser is used to form the area under the condition that the laser power, layer thickness, scanning speed and scanning spacing are all or partially reduced layer by layer; if the transition area is located above the high-precision forming area and below the high-efficiency forming area (i.e., the transition area is formed on the high-precision forming area), a high-power laser is used to form the area under the condition that the laser power, layer thickness, scanning speed and scanning spacing are all or partially increased layer by layer;

[0041] (3) Carry out high-power and low-power dual-laser collaborative SLM forming of metal parts: Based on the above processing parameters, high-efficiency and high-precision SLM forming of metal parts can be achieved while ensuring the forming quality.

[0042] Specifically, the high-efficiency forming area and the high-precision forming area can be divided according to actual forming requirements and needs, and the present invention does not make any special restrictions. Specifically, the laser beam energy distribution mode used in the high-efficiency forming area is a high-order multi-mode, a flat-top mode or a ring mode, and the laser power P e ≥1000W; the laser beam energy distribution mode used in the high-precision forming area is Gaussian mode, and the laser power P a <1000 W. Using the above-mentioned laser modes and powers can further improve the density and mechanical properties of high-efficiency forming areas and high-precision forming areas.

[0043] More specifically, if the transition region is located above the high-efficiency forming region and below the high-precision forming region, the transition region is formed by a low-power laser whose energy distribution mode is a Gaussian mode and whose laser power P e-a Reduce layer by layer and satisfy P a ≤P e-a ≤P e , using a laser power that decreases layer by layer, and the size is between the laser power of the high-efficiency forming area and the laser power of the high-precision forming area, which can eliminate the melt pile caused by the intense laser-powder interaction in the high-efficiency forming area and avoid affecting the processing quality of the subsequent high-precision forming area. If the transition area is located above the high-precision forming area and below the high-efficiency forming area, the transition area is formed by a high-power laser. The energy distribution mode of the high-power laser is a high-order multi-mode, a flat-top mode or a ring mode. The laser power P e-a Improve step by step and meet P a ≤P e-a ≤P e By increasing the laser power layer by layer and the size between the laser powers of the high-efficiency forming area and the high-precision forming area, the adverse effect of the violent melt flow behavior in the subsequent high-efficiency forming area on the surface quality of the already formed high-precision forming area can be reduced.

[0044] Furthermore, the layer thickness T used in the high-efficiency forming area e >0.05mm, scanning speed V e >1500mm / s, scanning distance S e >0.10mm, using the above process with laser power P e , while ensuring complete melting of the metal powder, further improve the processing efficiency of the high-efficiency forming area. The layer thickness T a , Scanning speed V a , scanning spacing S a Satisfy: 0.01mm≤T a ≤0.05mm, 300mm / s≤V a≤1500mm / s, 0.06mm≤S a ≤0.10mm, using the above process with laser power P a , further improving the processing accuracy of high-precision forming areas.

[0045] Furthermore, if the transition region is located above the high-efficiency forming region and below the high-precision forming region, the layer thickness T of the transition region is e-a Reduce layer by layer and satisfy T a ≤T e-a ≤T e , using a layer thickness that decreases layer by layer, and the size is between the layer thickness of the high-efficiency forming area and the layer thickness of the high-precision forming area, combined with a layer-by-layer decreasing laser power P e-a , eliminating the melt pile in the high-efficiency forming area to avoid affecting the processing quality of the subsequent high-precision forming area. If the transition area is located above the high-precision forming area and below the high-efficiency forming area, the layer thickness T e-a Increase layer by layer and satisfy T a ≤T e-a ≤T e , using a layer thickness that increases layer by layer, and the size is between the layer thickness of the high-efficiency forming area and the layer thickness of the high-precision forming area, combined with a gradually increasing laser power P e-a , reducing the impact of subsequent high-efficiency forming areas on the surface quality of the already formed high-precision areas.

[0046] Furthermore, if the transition region is located above the high-efficiency forming region and below the high-precision forming region, the scanning speed V of the transition region is e-a Reduce layer by layer and satisfy V a ≤V e-a ≤V e , using a scanning speed that decreases layer by layer, and the size is between the scanning speeds of the high-efficiency forming area and the high-precision forming area, combined with a laser power P that decreases layer by layer e-a , T e-a , eliminate the melt pile in the high-efficiency forming area to avoid affecting the processing quality of the subsequent high-precision forming area. If the transition area is located above the high-precision forming area and below the high-efficiency forming area, the scanning speed V e-a Increase layer by layer and satisfy V a ≤V e-a ≤V e , using a scanning speed that increases layer by layer, and the size is between the scanning speeds of the high-efficiency forming area and the high-precision forming area, combined with the laser power P that increases layer by layer e-a , T e-a , reducing the impact of subsequent high-efficiency forming areas on the surface quality of the already formed high-precision areas.

[0047] Furthermore, if the transition region is located above the high-efficiency forming region and below the high-precision forming region, the scanning spacing S of the transition region is e-a Reduce layer by layer and satisfy S a ≤S e-a ≤S e , using a scanning pitch that decreases layer by layer, and the size is between the scanning pitch of the high-efficiency forming area and the scanning pitch of the high-precision forming area, combined with a laser power P that decreases layer by layer e-a , T e-a 、V e-a , eliminate the melt pile in the high-efficiency forming area to avoid affecting the processing quality of the subsequent high-precision forming area. If the transition area is located above the high-precision forming area and below the high-efficiency forming area, the scanning spacing S of the transition area e-a Increase layer by layer and satisfy S a ≤S e-a ≤S e , using a scanning pitch that increases layer by layer, and the size is between the scanning pitch of the high-efficiency forming area and the scanning pitch of the high-precision forming area, combined with the laser power P that increases layer by layer e-a , T e-a 、V e-a , reducing the impact of subsequent high-efficiency forming areas on the surface quality of the already formed high-precision areas.

[0048] Preferably, the transition region satisfies the following conditions when implementing all or part of the layer-by-layer gradual laser processing parameters:

[0049] If the transition area is located above the high-efficiency forming area and below the high-precision forming area, then:

[0050]

[0051] If the transition area is located above the high-precision forming area and below the high-efficiency forming area, then:

[0052]

[0053] In the formula, are the laser power, layer thickness, scanning speed and scanning spacing corresponding to the i-th layer in the transition region, respectively; They are respectively the laser power, layer thickness, scanning speed and scanning spacing corresponding to the i+1th layer in the transition region; i≥1; K1 and K2 are dimensionless coefficients with values ​​of 0.5≤K1≤1, 1≤K2≤2.

[0054] Furthermore, the number of layers N of a single transition region satisfies: 2≤N≤20.

[0055] Preferably, when the transition region is located above the high-efficiency forming region and below the high-precision forming region, laser remelting can be performed layer by layer on each layer of the transition region, or laser remelting can be performed on the last layer of the transition region. Specifically, the laser remelting uses a low-power laser, and the laser energy distribution mode is a Gaussian mode. Furthermore, the laser power P used for laser remelting is r , Scanning speed V r and scanning spacing S r satisfy:

[0056]

[0057] Where P ri 、V ri , S ri are the laser power, scanning speed and scanning spacing used for laser remelting corresponding to the i-th layer in the transition region, respectively; are respectively the laser power, scanning speed and scanning spacing used for forming the i-th layer in the transition region;

[0058] Preferably, when laser remelting is performed on a layer in the transition region, the layer is laser remelted 1-5 times.

[0059] The following are embodiments of the present invention:

[0060] Example 1

[0061] This embodiment provides a quality control method for high-efficiency and high-precision SLM forming of complex high-temperature alloy parts, and the selected metal parts to be processed are high-temperature alloy blades of aircraft engines. Figure 2 The forming area division diagram of the aircraft engine high temperature alloy blade in the embodiment of the present invention, the high efficiency and high precision quality control strategy of the SLM forming process is as follows:

[0062] (1) According to the structural characteristics and machining accuracy requirements of different positions of aircraft engine high-temperature alloy blades, the model can be divided into five parts from bottom to top: high-precision forming area A, transition area B (located above the high-precision forming area and below the high-efficiency forming area), high-efficiency forming area C, transition area D (located above the high-efficiency forming area and below the high-precision forming area), and high-precision forming area E;

[0063] (2) A fixed set of processing parameters is implemented for the high-precision forming area and the high-efficiency forming area: The low-power laser beam energy distribution mode used in the high-precision forming areas A and E of the aircraft engine high-temperature alloy blade is the Gaussian mode, and the SLM forming process implements a smaller laser power, layer thickness, scanning speed and scanning spacing, specifically P a =300W, T a =0.05mm, V a=1000mm / s, S a =0.10mm; The kilowatt-class high-power laser beam energy distribution used in the high-efficiency forming area C of the aircraft engine high-temperature alloy blade is a high-order multi-mode, flat-top mode or annular mode. The SLM forming process implements a larger laser power, layer thickness and other processing parameters, specifically P e =2000W, T e =0.20mm, V e =2000mm / s, S e =0.14mm;

[0064] (3) The transition area B of the aircraft engine high-temperature alloy blade (located above the high-precision forming area and below the high-efficiency forming area) is formed by using a high-power laser with an energy distribution mode of high-order multi-mode, flat-top mode or annular mode. The laser power, layer thickness, scanning speed and scanning spacing are all increased layer by layer to reduce the influence of the violent melt flow behavior of the high-efficiency forming area C on the surface quality of the formed high-precision forming area A. Specifically, the transition area B contains 4 forming layers, P (e-a)1 =500W,T (e-a)1 =0.09mm, V (e-a)1 =1000mm / s, S (e-a)1 =0.10mm; P (e-a)2 =1000W,T (e-a)2 =0.13mm; P (e-a)3 =1500W,T (e-a)3 =0.17mm; P (e-a)4 =2000W,T (e-a)4 =0.20mm; other processing parameters that are automatically calculated and implemented by the SLM forming software and increase layer by layer specifically meet the following requirements: Where K2 = 1.2;

[0065] (4) The transition area D of the aircraft engine high-temperature alloy blade (located above the high-efficiency forming area and below the high-precision forming area) is formed by using a low-power laser with a Gaussian energy distribution mode, and the laser power, layer thickness, scanning speed and scanning spacing are all reduced layer by layer, and laser remelting is performed layer by layer until the melt pile generated by the intense laser-powder interaction in the middle high-efficiency forming area is eliminated to avoid affecting the processing quality of the high-precision forming area E; specifically, the transition area D includes 5 forming layers, P (e-a)1 =1000W,T (e-a)1 =0.16mm, V (e-a)1 =1600mm / s, S (e-a)1 =0.14mm; P (e-a)2 =800W,T (e-a)2 =0.12mm; P (e-a)3=600W,T (e-a)3 =0.08mm; P (e-a)4 =400W,T (e-a)4 =0.06mm; P (e-a)5 =300W,T (e-a)5 =0.05mm, other layer-by-layer processing parameters automatically calculated and implemented by the SLM forming software specifically meet the following requirements: K1 = 0.8; in addition, the last layer of the transition region was laser remelted five times with a laser power of P r , Scanning speed V r and scanning spacing S r They are: 300W, 1600mm / s, 0.14mm;

[0066] (5) Based on the above processing strategies, SLM forming of aircraft engine high-temperature alloy blades is carried out while ensuring the transition quality of different regions, so as to achieve high-efficiency and high-precision manufacturing of aircraft engine high-temperature alloy blades.

[0067] Example 2

[0068] This embodiment provides a quality control method for high-efficiency and high-precision SLM forming of complex copper alloy parts, and the metal parts to be processed are copper alloy combustion chambers of rocket engines. Figure 3 The forming area division diagram of the copper alloy combustion chamber of the rocket engine in the embodiment of the present invention, the high efficiency and high precision quality control strategy of the SLM forming process is as follows:

[0069] (1) According to the structural characteristics and machining accuracy requirements of different positions of the copper alloy combustion chamber of the rocket engine, the model can be divided into seven parts from bottom to top: high-efficiency forming area A, transition area B (located above the high-efficiency forming area and below the high-precision forming area), high-precision forming area C, transition area D (located above the high-precision forming area and below the high-efficiency forming area), high-efficiency forming area E, transition area F (located above the high-efficiency forming area and below the high-precision forming area), and high-precision forming area G;

[0070] (2) A fixed set of processing parameters is implemented for the high-precision forming area and the high-efficiency forming area. The low-power laser beam energy distribution mode used in the high-precision forming areas C and G of the rocket engine copper alloy combustion chamber is the Gaussian mode. The SLM forming process implements a smaller laser power, layer thickness, scanning speed and scanning spacing, specifically P a =250W, T a =0.02mm, V a =1000mm / s, S a=0.10mm; the kilowatt-class high-power laser beam energy distribution used in the high-efficiency forming areas A and E of the rocket engine copper alloy combustion chamber is a high-order multi-mode, flat-top mode or annular mode. The SLM forming process implements a larger laser power, layer thickness, scanning speed and scanning spacing, specifically P e =2000W, T e =0.10mm, V e =1600mm / s, S e =0.14mm.

[0071] (3) The transition areas B and F of the rocket engine copper alloy combustion chamber, where high efficiency is transformed into high precision, are formed by using low-power laser with Gaussian energy distribution, and the laser power, layer thickness, scanning speed and scanning spacing are gradually reduced. Laser remelting is then performed layer by layer until the melt pile-up caused by the intense laser-powder interaction in the middle high-efficiency forming area is eliminated, thereby avoiding affecting the processing quality of the subsequent high-precision forming area. Specifically, the transition area B contains 5 forming layers, P (e-a)1 =1000W,T (e-a)1 =0.08mm, V (e-a)1 =1500mm / s, S (e-a)1 =0.12mm; P (e-a)2 =800W,T (e-a)2 =0.06mm; P (e-a)3 =600W,T (e-a)3 =0.04μm; P (e-a)4 =400W,T (e-a)4 =0.02mm; P (e-a)5 =250W,T (e-a)5 =0.02mm, other processing parameters that are automatically calculated and implemented by the SLM forming software to reduce layer by layer specifically meet the following requirements: Where K1 = 1.0; In addition, the last layer of the transition region was laser remelted three times, with a laser power of P r , Scanning speed V r and scanning spacing S r They are: 250W, 1500mm / s, 0.12mm;

[0072] (4) The transition area D of the rocket engine copper alloy combustion chamber from high precision to high efficiency is formed by using a high-power laser with an energy distribution mode of high-order multi-mode, flat-top mode or annular mode. The laser power, layer thickness, scanning speed and scanning spacing are all increased layer by layer to reduce the influence of the violent melt flow behavior in the high-efficiency forming area on the surface quality of the formed middle high-precision area. Specifically, the transition area D includes 4 forming layers, P (e-a)1 =750W,T (e-a)1=0.04mm, V (e-a)1 =1000mm / s, S (e-a)1 =0.10mm; P (e-a)2 =1250W,T (e-a)2 =0.06mm; P (e-a)3 =1750W,T (e-a)3 =0.08mm; P (e-a)4 =2000W,T (e-a)4 =0.10mm, other processing parameters that are automatically calculated and implemented by the SLM forming software to increase layer by layer specifically meet the following requirements: Where K2 = 1.1;

[0073] (5) Based on the above processing strategies, SLM forming of the copper alloy combustion chamber of the rocket engine is carried out while ensuring the transition quality of different areas, so as to achieve high-efficiency and high-precision manufacturing of the copper alloy combustion chamber of the rocket engine.

[0074] Example 3

[0075] This embodiment provides a quality control method for high-efficiency and high-precision SLM forming of complex titanium alloy parts, and the metal parts to be processed are lightweight titanium alloy wheels for automobiles. Figure 4 The forming area division diagram of the lightweight titanium alloy wheel hub for automobiles in the embodiment of the present invention is shown in FIG. The high-efficiency and high-precision quality control strategy of the SLM forming process is as follows:

[0076] (1) According to the structural characteristics and processing accuracy requirements of different positions of lightweight titanium alloy wheels for automobiles, the model can be roughly divided into three parts from bottom to top: high-efficiency forming area A, transition area B (located above the high-efficiency forming area and below the high-precision forming area), and high-precision forming area C;

[0077] (2) A fixed set of processing parameters is implemented for the high-precision forming area and the high-efficiency forming area. The low-power laser beam energy distribution mode used in the high-precision forming area C on the top of the lightweight titanium alloy wheel hub of the automobile is the Gaussian mode. The SLM forming process implements a smaller laser power, layer thickness, scanning speed and scanning spacing, specifically P a =270W, T a =0.03mm, V a =1200mm / s, S a =0.10mm; the kilowatt-class high-power laser beam energy distribution used in the high-efficiency forming area A in the middle and lower part of the lightweight titanium alloy wheel hub of the automobile is high-order multi-mode, flat-top mode or annular mode. The SLM forming process implements larger laser power, layer thickness and other processing parameters, specifically P e =2000W, T e =0.15mm, Ve =1600mm / s, S e =0.14mm;

[0078] (3) The transition area B where the lightweight titanium alloy wheel hub of an automobile changes from high efficiency to high precision is formed by using a low-power laser with a Gaussian energy distribution. The laser power, layer thickness, scanning speed, and scanning spacing are all reduced layer by layer, and laser remelting is performed layer by layer until the melt pile generated by the intense laser-powder interaction in the middle and lower high-efficiency forming areas is eliminated to avoid affecting the processing quality of the top high-precision forming area. Specifically, the transition area B includes 4 forming layers, P (e-a)1 =1000W,T (e-a)1 =0.12mm, V (e-a)1 =1600mm / s, S (e-a)1 =0.12mm; P (e-a)2 =800W,T (e-a)2 =0.09mm; P (e-a)3 =600W,T (e-a)3 =0.06μm; P (e-a)4 =400W,T (e-a)4 =0.03mm; fixed scanning spacing, other layer-by-layer processing parameters automatically calculated and implemented by the SLM forming software, specifically satisfying: K1 = 0.9; In addition, the last layer of the transition region was laser remelted four times layer by layer, with a laser power of P r , Scanning speed V r and scanning spacing S r They are: 270W, 1600mm / s, 0.14mm;

[0079] (4) Based on the above processing strategies, SLM forming of lightweight titanium alloy wheels for automobiles is carried out while ensuring the transition quality of different areas, so as to achieve high-efficiency and high-precision manufacturing of lightweight titanium alloy wheels for automobiles.

[0080] Example 4

[0081] This embodiment provides a quality control method for high-efficiency and high-precision SLM forming of complex high-strength steel parts, and the metal parts to be processed are high-strength steel cabin doors of passenger aircraft. Figure 5 The forming area division diagram of the high-strength steel cabin door of the passenger aircraft in the embodiment of the present invention, the high-efficiency and high-precision quality control strategy of the SLM forming process is as follows:

[0082] (1) According to the structural characteristics and processing accuracy requirements of different positions of the high-strength steel cabin door of the passenger aircraft, the model can be roughly divided into five parts from bottom to top: high-precision forming area A, transition area B (located above the high-precision forming area and below the high-efficiency forming area), high-efficiency forming area C, transition area D (located above the high-efficiency forming area and below the high-precision forming area) and high-precision forming area E;

[0083] (2) A fixed set of processing parameters is implemented for the high-precision forming area and the high-efficiency forming area. The low-power laser beam energy distribution mode used in the high-precision forming areas A and E of the high-strength steel cabin door of the passenger aircraft is the Gaussian mode. The SLM forming process implements a smaller laser power, layer thickness, scanning speed and scanning spacing, specifically P a =300W, T a =0.05mm, V a =1000mm / s, S a =0.10mm; The energy distribution of the kilowatt-class high-power laser beam used in the high-efficiency forming area C of the high-strength steel cabin door of the passenger aircraft is high-order multi-mode, flat-top mode or ring mode. The SLM forming process implements larger laser power, layer thickness and other processing parameters, specifically P e =2000W, T e =0.30mm, V e =1600mm / s, S e =0.14mm;

[0084] (3) The transition area B where the high-strength steel cabin door of the passenger aircraft changes from high precision to high efficiency uses a high-power laser with an energy distribution mode of high-order multi-mode, flat-top mode or annular mode. The laser power, layer thickness, scanning speed and scanning spacing are gradually increased to reduce the influence of the violent melt flow behavior of the high-efficiency forming area C on the surface quality of the formed high-precision area A. Specifically, the transition area B contains 5 forming layers, P (e-a)1 =600W,T (e-a)1 =0.10mm, V (e-a)1 =1000mm / s, S (e-a)1 =0.10mm; P (e-a)2 =900W,T (e-a)2 =0.15mm, V (e-a)2 =1200mm / s, S (e-a)2 =0.11mm; P (e-a)3 =1200W,T (e-a)3 =0.20mm, V (e-a)3 =1400mm / s, S (e-a)3 =0.12mm; P (e-a)4 =1600W,T (e-a)4 =0.25mm, V(e-a)4 =1600mm / s, S (e-a)4 =0.13mm; P (e-a)5 =2000W,T (e-a)5 =0.30mm, V (e-a)5 =1600mm / s, S (e-a)5 =0.14mm;

[0085] (4) The transition area D where the high-strength steel cabin door of the passenger aircraft changes from high efficiency to high precision is formed by using a low-power laser with a Gaussian energy distribution mode. The laser power, layer thickness, scanning speed and scanning spacing are reduced layer by layer, and laser remelting is performed layer by layer until the melt pile generated by the intense laser-powder interaction in the high-efficiency forming area C is eliminated to avoid affecting the processing quality of the top high-precision forming area. Specifically, the transition area D contains 5 forming layers, P (e-a)1 =1000W,T (e-a)1 =0.25mm, V (e-a)1 =1600mm / s, S (e-a)1 =0.12mm; P (e-a)2 =800W,T (e-a)2 =0.20mm, V (e-a)2 =1400mm / s, S (e-a)2 =0.12mm; P (e-a)3 =600W,T (e-a)3 =0.15mm, V (e-a)3 =1300mm / s, S (e-a)3 =0.11mm; P (e-a)4 =400W,T (e-a)4 =0.10mm, V (e-a)4 =1100mm / s, S (e-a)4 =0.11mm; P (e-a)5 =300W,T (e-a)5 =0.05mm, V (e-a)5 =1000mm / s, S (e-a)5 =0.10mm; In addition, laser remelting was performed once for each forming layer in the transition area, and the laser power P r , Scanning speed V r and scanning spacing S r They are: r1 =600W, V r1 =1600mm / s, S r1 =0.12mm; P r2 =500W, V r2 =1400mm / s, S r2 =0.12mm; P r3 =400W, Vr3 =1300mm / s, S r3 =0.11mm; P r4 =300W, V r4 =1100mm / s, S r4 =0.11mm; P r5 =300W, V r5 =1000mm / s, S r5 =0.10mm;

[0086] (5) Based on the above processing strategies, SLM forming of high-strength steel cabin doors of passenger aircraft is carried out under the premise of ensuring the transition quality of different areas, so as to achieve high-efficiency and high-precision manufacturing of high-strength steel cabin doors of passenger aircraft.

[0087] In summary, the present invention divides the digital model of the metal parts to be formed into a high-efficiency forming area, a high-precision forming area and a transition area between the first two, and differentially implements layer-by-layer laser processing parameters in the transition area from high-efficiency forming to high-precision forming and in the transition area from high-precision forming to high-efficiency forming. It can achieve high-efficiency and high-precision SLM forming of complex metal parts while ensuring the forming quality.

[0088] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A high-efficiency and high-precision quality control method for laser selective melting, characterized in that: High-efficiency forming area for forming metal parts using high-power laser beam with large layer thickness, scanning speed and scanning spacing, where the layer thickness T e >0.05mm, scanning speed V e >1500mm / s, scanning distance S e >0.10mm; low-power laser beam is used to form high-precision forming areas of metal parts with smaller layer thickness, scanning speed and scanning spacing, where the layer thickness T a , Scanning speed V a , scanning spacing S a Satisfy: 0.01mm≤T a ≤0.05mm, 300mm / s≤V a ≤1500mm / s, 0.06mm≤S a ≤0.10mm; for the transition area between the high-efficiency forming area and the high-precision forming area, the values ​​of the laser power, layer thickness, scanning speed and scanning spacing used are between the values ​​of the laser power, layer thickness, scanning speed and scanning spacing corresponding to the high-precision forming area and the high-efficiency forming area, and when the transition area is located above the high-efficiency forming area and below the high-precision forming area, the laser power, layer thickness, scanning speed and scanning spacing are fully or partially reduced layer by layer for forming; when the transition area is located above the high-precision forming area and below the high-efficiency forming area, the laser power, layer thickness, scanning speed and scanning spacing are fully or partially increased layer by layer for forming, so as to achieve high-efficiency and high-precision SLM forming of metal parts under the premise of ensuring the transition quality of different areas.

2. The high-efficiency and high-precision laser selective melting quality control method according to claim 1, characterized in that: The laser beam energy distribution mode used in the high-efficiency forming area is high-order multi-mode, flat-top mode or ring mode, and the laser power P e ≥1000W; the laser beam energy distribution mode used in the high-precision forming area is Gaussian mode, and the laser power P a <1000W.

3. The high-efficiency and high-precision laser selective melting quality control method according to claim 2, characterized in that: If the transition area is located above the high-efficiency forming area and below the high-precision forming area, the transition area is formed by low-power laser, and the energy distribution mode of the low-power laser is Gaussian mode. The laser power P e-a Reduce layer by layer and satisfy P a ≤P e-a ≤P e If the transition area is located above the high-precision forming area and below the high-efficiency forming area, the transition area is formed by high-power laser, and the energy distribution mode of the high-power laser is high-order multi-mode, flat-top mode or ring mode. The laser power P e-a Improve step by step and meet P a ≤P e-a ≤P e .

4. The high-efficiency and high-precision laser selective melting quality control method according to claim 1, characterized in that: If the transition region is located above the high-efficiency forming region and below the high-precision forming region, the layer thickness T e-a Reduce layer by layer and satisfy T a ≤T e-a ≤T e If the transition region is located above the high-precision forming region and below the high-efficiency forming region, the layer thickness T e-a Increase layer by layer and satisfy T a ≤T e-a ≤T e .

5. The high-efficiency and high-precision laser selective melting quality control method according to claim 1, characterized in that: If the transition area is located above the high-efficiency forming area and below the high-precision forming area, the scanning speed V of the transition area e-a Reduce layer by layer and satisfy V a ≤V e-a ≤V e If the transition area is located above the high-precision forming area and below the high-efficiency forming area, the scanning speed V e-a Increase layer by layer and satisfy V a ≤V e-a ≤V e .

6. The high-efficiency and high-precision laser selective melting quality control method according to claim 1, characterized in that: If the transition area is located above the high-efficiency forming area and below the high-precision forming area, the scanning spacing S of the transition area is e-a Reduce layer by layer and satisfy S a ≤S e-a ≤S e If the transition area is located above the high-precision forming area and below the high-efficiency forming area, the scanning spacing S of the transition area e-a Increase layer by layer and satisfy S a ≤S e-a ≤S e .

7. The high-efficiency and high-precision laser selective melting quality control method according to claim 1, characterized in that: The transition area meets the following conditions when implementing all or part of the laser processing parameters that are gradually changed layer by layer: If the transition area is located above the high-efficiency forming area and below the high-precision forming area, then: If the transition area is located above the high-precision forming area and below the high-efficiency forming area, then: In the formula, are the laser power, layer thickness, scanning speed and scanning spacing corresponding to the i-th layer in the transition region, respectively; are respectively the laser power, layer thickness, scanning speed and scanning spacing corresponding to the i+1th layer in the transition region; i≥1; K1 and K2 are dimensionless constants, and their values ​​satisfy: 0.5≤K1≤1, 1≤K2≤2.

8. The high-efficiency and high-precision laser selective melting quality control method according to claim 1, characterized in that: When the transition area is located above the high-efficiency forming area and below the high-precision forming area, laser remelting is performed layer by layer on each layer of the transition area or on the last layer of the transition area; laser remelting uses a low-power laser, and the laser energy distribution mode is a Gaussian mode; the laser power, scanning speed and scanning spacing used in laser remelting meet the following requirements: Where P ri 、V ri , S ri are the laser power, scanning speed and scanning spacing used for laser remelting corresponding to the i-th layer in the transition region, respectively; are the laser power, scanning speed and scanning spacing used for forming the i-th layer in the transition region, respectively.

9. The high-efficiency and high-precision laser selective melting quality control method according to any one of claims 1 to 8, characterized in that: The number of layers N in the transition region satisfies: 2≤N≤20.

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