Forming method and forming device for breathable die steel with different pore diameters

Abstract

The present application provides a forming method for a breathable die steel with different pore diameters, including: constructing three-dimensional model data of the breathable die steel, and discretely dividing the three-dimensional model data into a plurality of printing layer models stacked layer by layer; laying metal powder; planning process parameters for printing the current printing layer model, and laser-melting the metal powder according to the process parameters along the path of the printing layer model, so as to print a corresponding printing layer, the process parameters including a defocus value, and the printing layer including first holes with a first pore diameter; adjusting the defocus value in the process parameters of the next printing layer model, and thus obtaining a laser spot with corresponding dimensions; printing the next printing layer on the current printing layer, the next printing layer including second holes with a second pore diameter, the first holes being communicated with the second holes and the first pore diameter being different from the second pore diameter, so as to obtain a breathable die steel with different pore diameters. The present application also provides a forming device for a breathable die steel with different pore diameters.

Description

Technical Field

[0001] The present application relates to the technical field of additive manufacturing, and particularly relates to a forming method and a forming device for a breathable die steel with different pore diameters. Background Art

[0002] Additive manufacturing technology directly manufactures solid parts by the way of layer-by-layer material accumulation, and can directly print and form a solid three-dimensional model designed in a computer-aided design (CAD) three-dimensional software. Selective laser melting (SLM) technology is one of the important technologies in the field of metal AM. It uses a high-energy density laser as a heat source and selectively melts metal powder by laser to obtain complex metal components with high degrees of freedom and generate parts with a high relative density of nearly 100%.

[0003] Preparing a breathable die steel by selective laser melting is more convenient and faster compared with traditional processing techniques. Breathable die steels are widely used in the field of injection molds to effectively exhaust air during the injection process, so that the plastic melt to be injected can be better formed, and phenomena such as air entrapment and ablation of the plastic melt caused by poor air permeability can be avoided. However, in practical applications, if the pores are small, the breathable die steel cannot achieve a high air permeability; if the pores are large, it is easy for the plastic melt to flow into the pores, resulting in defective injection molded products. Summary of the Invention

[0004] In view of this, the present application provides a forming method for a breathable die steel with different pore diameters to solve the above problems.

[0005] In addition, it is also necessary to provide a forming device applying the forming method for a breathable die steel with different pore diameters.

[0006] The present application provides a forming method for a breathable die steel with different pore diameters, including the following steps: constructing three-dimensional model data of the breathable die steel, and discretely dividing the three-dimensional model data into a plurality of printing layer models stacked layer by layer;

[0007] Laying metal powder;

[0008] Planning process parameters for printing the current printing layer model, and laser melting the metal powder according to the process parameters along the path of the printing layer model to print a corresponding printing layer. The process parameters include a defocus value, and the printing layer includes first holes with a first pore diameter;

[0009] Laying the metal powder on the current printing layer;

[0010] Adjusting the defocus value in the process parameters of the next printing layer model to obtain a laser spot with a corresponding size;

[0011] The metal powder is laser melted according to the adjusted process parameters along the path of the printing layer model, so as to print the next printing layer on the current printing layer. The next printing layer includes a second hole with a second hole diameter. The first hole communicates with the second hole and the first hole diameter is different from the second hole diameter, so as to obtain the breathable die steel with different hole diameters.

[0012] The present application also provides a forming device for executing the breathable die steel with different hole diameters, which is used to execute the forming method of the breathable die steel. The forming device includes a feeding unit, a laser, a forming chamber and a dynamic focusing module;

[0013] The feeding unit is used to lay the metal powder in the forming chamber;

[0014] The laser is used to emit a laser beam towards the metal powder according to the process parameters, so that the metal powder melts and solidifies to form a corresponding printing layer. The process parameters include the defocus value of the laser. The printing layer includes a first hole with a first hole diameter;

[0015] The dynamic focusing module is used to adjust the defocus value in the process parameters to obtain a laser spot with a corresponding size;

[0016] The feeding unit is also used to re-lay the metal powder on the current printing layer;

[0017] The laser is also used to emit a laser beam towards the metal powder according to the adjusted process parameters, so that the metal powder melts and solidifies to form the next printing layer on the current printing layer. The printing layer includes a first hole with a first hole diameter laid in the forming chamber. The next printing layer includes a second hole with a second hole diameter. The first hole communicates with the second hole and the first hole diameter is different from the second hole diameter.

[0018] In the present application, during the process of printing the breathable die steel, after the first printing layer with the first hole is formed, the size of the laser spot during the printing process is adjusted by the dynamic focusing module, so as to form the next printing layer with the second hole. The first hole and the second hole communicate with each other and have different hole diameters, so that a gradient hole is formed between the first hole and the second hole. When the first hole with a smaller hole diameter contacts the cavity, it can prevent the injected plastic melt from flowing into the pores, ensuring that the breathable die steel has a certain strength and air permeability; when the second hole with a larger hole diameter communicates with the outside, it is convenient for the plastic melt to exhaust quickly during the injection process. Description of the Drawings

[0019] Figure 1 It is a schematic diagram of a forming device for the breathable die steel provided by the present application.

[0020] Figure 2 It is a schematic structural diagram of the dynamic focusing module in this application.

[0021] Figure 3 It is a partial cross-sectional schematic diagram of the breathable die steel in the first embodiment of this application.

[0022] Figure 4 It is a top view of the breathable die steel in the second embodiment of this application.

[0023] Description of main component symbols

[0024] Forming device 100

[0025] Feeding unit 10

[0026] Laser 20

[0027] Forming chamber 30

[0028] Perforation 31

[0029] Control unit 40

[0030] Galvo unit 51

[0031] X-direction galvo 511

[0032] Y-direction galvo 512

[0033] Dynamic focusing module 52

[0034] Motor 521

[0035] Lens group 522

[0036] Focusing lens 523

[0037] Forming platform 61

[0038] Forming cylinder 62

[0039] Piston lifting mechanism 63

[0040] Breathable die steel 70

[0041] First printing layer 71

[0042] Second printing layer 72

[0043] Third printing layer 73

[0044] First hole 711

[0045] Second hole 721

[0046] Third hole 731

[0047] First area 74

[0048] Second Region 75

[0049] Third Region 76

[0050] Fourth Region 77

[0051] First Stomata 741

[0052] Second Stomata 751

[0053] Third Stomata 761

[0054] Fourth Stomata 771

[0055] Focus f

[0056] The following specific embodiments will further illustrate the present application in combination with the above-mentioned appendices Figures 1-4 The present application will be further described below Specific Embodiments

[0057] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments

[0058] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly on the other element or there may also be an intermediate element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time. When an element is considered to be "disposed on" another element, it can be directly disposed on the other element or there may be an intermediate element at the same time

[0059] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs. The terms used in the description of this application in this specification are only for the purpose of describing specific embodiments and are not intended to limit this application

[0060] In order to further illustrate the technical means and effects adopted by the present application to achieve the predetermined purpose, the following detailed description of the present application is made with reference to the accompanying drawings and embodiments

[0061] Please refer to Figure 1, this application provides a forming device 100 for breathable die steel with different apertures, which is used to execute the forming method of breathable die steel 70. The forming device 100 includes a feeding unit 10, a laser 20, a forming chamber 30 and a control unit 40. The forming chamber 30 is also provided with a forming cylinder 62, and the control unit 40 is electrically connected to the feeding unit 10, the laser 20 and the forming cylinder 62 respectively. The control unit 40 controls the feeding unit 10, the laser 20 and the forming cylinder 62 to work together, so as to print the breathable die steel 70. Among them, the feeding unit 10 is used to lay metal powder onto the forming platform 61 in the forming chamber 30. The laser 20 is used to emit laser to melt the metal powder until the breathable die steel 70 is formed.

[0062] Refer to Figure 1 , the forming platform 61 is movably connected in the forming cylinder 62. A perforation 31 is also opened at the top of the forming chamber 30, and the laser emitted by the laser 20 passes through the perforation 31 and enters the forming chamber 30, and acts on the metal powder.

[0063] Refer to Figure 1 and Figure 2 , in some embodiments, a galvanometer unit 51 is further provided outside the forming chamber 30, and the galvanometer unit 51 is directly opposite to the perforation 31. The galvanometer unit 51 swings regularly according to a preset program in the control unit 40, and the laser is reflected by the galvanometer unit 51 and focused on the forming platform 61 to melt the metal powder to form a printing layer. The control unit 40 also controls the galvanometer unit 51 to move the laser according to a predetermined scanning strategy. In some embodiments, the galvanometer unit 51 includes an X-direction galvanometer 511 and a Y-direction galvanometer 512. The X-direction galvanometer 511 and the Y-direction galvanometer 512 are used to adjust the path of the laser, so that the laser is aligned with the metal powder on the forming platform 61 to facilitate the laser to melt the metal powder to form a printing layer.

[0064] Refer to Figure 1 and Figure 2, a dynamic focusing module 52 is further provided between the laser 20 and the galvanometer unit 51. The laser emitted by the laser 20 is focused on the forming platform 61 after passing through the dynamic focusing module 52 and the galvanometer unit 51. The dynamic focusing module 52 includes a motor 521, a movable lens group 522, and a focusing lens 523. In some embodiments, the lens group 522 is composed of a combination of multiple lenses. The motor 521 drives the lens group 522 to move, thereby changing the angle of the laser passing through the lens group 522, further changing the incident angle of the laser towards the focusing lens 523. The laser passing through the focusing lens 523 is reflected by two galvanometers in the galvanometer unit 51 onto the current printing layer of the breathable die steel 70 in the forming chamber 30. The size of the laser spot converging on the printing layer changes with the change of the incident angle of the laser passing through the focusing lens 523, so that the focus f of the laser converges on the printing layer, or above the printing layer, or below the printing layer. When the focus f of the laser converges on the printing layer, the size of the corresponding laser spot is the smallest; when the focus f of the laser converges above or below the printing layer, defocusing occurs, and at this time, the size of the corresponding laser spot increases. Among them, the defocus value is the distance between the laser focus f and the current printing layer. When the laser focus f is above the printing layer, it is positive defocus, and when the laser focus f is below the printing layer, it is negative defocus. Therefore, by changing the defocus value of the printing process parameters, laser spots of corresponding different sizes can be obtained.

[0065] Refer to Figure 1 , in some embodiments, a piston lifting mechanism 63 is provided in the forming cylinder 62, and the forming platform 61 is located above the piston lifting mechanism 63. The piston lifting mechanism 63 is used to drive the forming platform 61 to move up and down in the forming cylinder 62. The forming platform 61 is flush with the bottom surface of the forming chamber 30. When each printing layer completes the forming process, the piston lifting mechanism 63 drives the forming platform 61 to descend a preset distance to ensure that the horizontal position of the next printing layer corresponds to the bottom surface position of the forming chamber 30.

[0066] Refer to Figure 1 、 Figure 2 and Figure 3 , an embodiment of the present application provides a method for forming a breathable die steel with different apertures, including the following steps:

[0067] Step 1: Construct three-dimensional model data of the breathable die steel 70 to be printed, and discretely divide the three-dimensional model data into multiple printing layer models stacked layer by layer.

[0068] Step 2: Plan the process parameters for printing the current printing layer model, select the process parameters of laser 3D printing by using the forming device 100 and print the corresponding printing layer, so as to form a first printing layer 71 on the breathable die steel 70, and form a first hole 711 with a first aperture on the first printing layer 71.

[0069] Step 3: Through the dynamic focusing module 52, adjust the defocus value in the process parameters of the downward printing layer model, so as to obtain a laser spot with a corresponding size.

[0070] Step 4: Print the second printing layer 72 on the current printing layer according to the adjusted process parameters, and form a second hole 721 with a second aperture on the second printing layer 72. The first hole 711 communicates with the second hole 721 and the first aperture is different from the second aperture, that is, a breathable die steel 70 with a gradient setting of aperture sizes is obtained.

[0071] By adjusting the size of the laser spot, the width of the molten metal powder melting track in the selective laser melting process is changed, and then the melting track gap formed between the widths of adjacent melting tracks is changed, that is, the aperture size of the breathable die pores is changed.

[0072] In some embodiments, the preparation method further includes the following steps:

[0073] Step 5: Adjust the defocus value in the process parameters of the next printing layer model again, so as to obtain a laser spot with a corresponding size. Print the third printing layer on the current printing layer according to the adjusted process parameters, and form a third hole 731 with a third aperture on the third printing layer 73. The third hole 731 communicates with the first hole 711 and the second hole 721, and the first aperture, the second aperture and the third aperture are all different. In this embodiment, the breathable die steel 70 includes three printing layers as an example, but is not limited thereto. For example, in some other embodiments, the breathable die steel 70 may have four, five, six printing layers and multiple printing layers. In some other embodiments, some of the multi-layer aperture sizes may also be the same.

[0074] In some embodiments, the central axes of the first hole 711, the second hole 721 and the third hole 731 coincide.

[0075] The solution of the present invention will be explained below in conjunction with embodiments. Those skilled in the art will understand that the following examples are only for explaining the present invention and should not be construed as a limitation of the present invention.

[0076] Embodiment 1

[0077] Please refer to Figure 1 、 Figure 2 and Figure 3, the breathable die steel 70 specifically includes a first printing layer 71, a second printing layer 72, and a third printing layer 73 that are sequentially stacked. The first printing layer 71 forms a first hole 711 with a first pore diameter, the second printing layer 72 forms a second hole 721 with a second pore diameter, and the third printing layer 73 forms a third hole 731 with a third pore diameter. Among them, the first hole 711, the second hole 721, and the third hole 731 are connected, and the pore diameters among the three are different. In this embodiment, the pore diameters of the first hole 711, the second hole 721, and the third hole 731 gradually increase.

[0078] The forming method of the above-mentioned breathable die steel 70 includes the following steps:

[0079] Step S11: Construct three-dimensional model data of the breathable die steel 70, and discretely divide the three-dimensional model data into several layers of models stacked layer by layer to obtain the printing layer information of the breathable die steel 70.

[0080] Step S12: Plan the process parameters of the printing layer model of the first printing layer 71, select appropriate printing process parameters by using the forming device 100, and print the first printing layer 71 so that the first printing layer 71 has the first hole 711.

[0081] Specifically, take metal powder. The feeding unit 10 evenly lays the metal powder on the forming platform 61 of the forming chamber 30 according to the obtained forming information for printing the first printing layer 71. The laser 20 emits laser to melt the metal powder in the first forming area according to the information of printing the first printing layer 71, forming the first printing layer 71 including the first hole 711. During the laser printing process, the scanning pitch is 150 μm, the laser power is 300 W, the laser speed is 1200 mm / s, and the defocus value is set to 4 mm. At this time, the laser spot size is 110 μm, the width of the melting track is 110 μm, and melting track pores are formed between adjacent melting tracks. The melting track pores are about 40 μm, and the pore diameter of the first hole 711 of the formed breathable die steel 70 can be obtained as 40 μm.

[0082] Step S13: Through the dynamic focusing module 52, adjust the defocus value of the process parameters for printing the second printing layer 72 to obtain a laser spot with a corresponding size. The laser 20 prints the second printing layer 72 according to the process parameters for printing the second printing layer 72, and forms the second hole 721 on the second printing layer 72.

[0083] Specifically, by adjusting the motor 521 in the dynamic focusing module 52 to drive the lens group 522, the angle of the laser passing through the lens group 522 is changed, and the incident angle of the laser hitting the focusing lens 523 is changed, so that the laser passes through the focusing lens 523 either at the focal point or defocused, the defocus value is changed, and a laser spot of a corresponding size is obtained. The laser 20 emits laser according to the information of printing the second printing layer 72 and melts the metal powder in the second forming area of the second printing layer 72 by using an alternating vertical scanning strategy to form the second printing layer 72 with the second holes 721. The scanning pitch is 150 μm, the laser power is 300 W, the laser speed is 1200 mm / s, and the defocus value is set to 3 mm. At this time, the laser spot size is 101 μm, the width of the melting track is 101 μm, and the porosity of the melting track is about 50 μm. The aperture of the second hole 721 of the formed breathable die steel 70 can be 50 μm.

[0084] Step S14: Through the dynamic focusing module 52, adjust the defocus value of the process parameters for printing the third printing layer 73 to obtain a laser spot of a corresponding size. The laser 20 prints the third printing layer 73 according to the process parameters of printing the third printing layer 73, and forms the third holes 731 on the third printing layer 73.

[0085] Specifically, in the same principle as in step S13, by changing the defocus value through the dynamic focusing module 52, the laser 20 emits laser according to the information of printing the third printing layer 73 and melts the metal powder in the third forming area on the third printing layer 73 by using an alternating vertical scanning strategy to form the third printing layer 73 with the third holes 731. The scanning pitch is 150 μm, the laser power is 300 W, the laser speed is 1200 mm / s, and the defocus value is set to 2 mm. At this time, the laser spot size is 92 μm, the width of the melting track is 92 μm, and the porosity of the melting track is about 60 μm. The aperture of the third hole 731 of the formed breathable die steel 70 can be 60 μm.

[0086] By forming breathable holes with different gradients on the breathable die steel 70, the first holes 711 are in contact with the cavity, which can prevent the plastic melt during injection from flowing into the pores and ensure that the breathable die steel 70 has a certain strength. The third holes 731 are communicated with the outside to facilitate the rapid exhaust during the injection of the plastic melt, thereby meeting the requirements of a certain air permeability.

[0087] In other embodiments, if the breathable die steel 70 has multiple layers, the above step S14 can be sequentially performed, and the corresponding defocus value can be changed through the dynamic focusing module 52 to form holes with different apertures and connected to each other on each layer.

[0088] According to multiple implementation tests, the defocus value can be changed through the dynamic focusing module 52 as shown in Table 1, so as to adjust the laser spot size in real time.

[0089] Table 1 Size data of laser spot corresponding to defocus value

[0090]

[0091] Example Two

[0092] Refer to Figure 4 In Example Two, the difference from Example One is that a number of holes with different apertures can also be formed on the same printing layer. In this example, taking the same printing layer as an example, it is exemplified to form four first air holes 741, second air holes 751, third air holes 761 and fourth air holes 771 with different apertures, and the distances between these four air holes are set. Four printing forming areas are formed on the printing layer of the permeable die steel 70, namely the corresponding first area 74, second area 75, third area 76 and fourth area 77. The permeable die steel 70 in this example is prepared according to the following steps:

[0093] Step S21: Construct a data import and forming system for the printing layer of the permeable die steel 70 to be printed, and obtain the forming data of the printing layer of the permeable die steel 70.

[0094] Step S22: Plan the process parameters of the four printing forming areas in the printing layer, and use the forming device 100 to print the corresponding printing layer.

[0095] Step S23: The feeding unit 10 evenly lays the material on the forming platform 61 according to the obtained forming information of the printing layer, and the laser 20 emits laser to melt the metal powder in the first area 74.

[0096] Specifically, the laser 20 emits laser according to the obtained forming information of the first area 74, and melts the metal powder in the first area 74 on the printing layer to form the first air hole 741. During the process of melting the metal powder in the first area 74, the scanning pitch of the laser is 150 μm, the laser power is 300 W, the laser speed is 1200 mm / s, the defocus value is selected as 1 mm, its laser spot is 80 μm, the width of the melting track is 80 μm, the porosity of the formed melting track is about 70 μm, and the porosity of the formed permeable steel is about 70 μm, that is, the aperture of the first air hole 741 is 70 μm.

[0097] Step S24: The laser 20 emits laser to melt the metal powder in the second area 75.

[0098] Specifically, the laser 20 obtains a laser spot of corresponding size by adjusting the dynamic focusing module 52 to change the defocus value at the same laser scanning pitch, laser power, and scanning speed as in step S23, and melts the metal powder in the second zone 75 to form the second air hole 751. Among them, the defocus value is 2 mm, the corresponding laser spot is 92 μm, the width of the melting track is 92 μm, the porosity of the formed melting track is about 60 μm, and the porosity of the formed breathable steel is about 60 μm, that is, the aperture of the second air hole 751 is 60 μm.

[0099] Step S25: The laser 20 emits laser to melt the metal powder in the third zone 76.

[0100] Specifically, the laser 20 obtains a laser spot of corresponding size by adjusting the dynamic focusing module 52 to change the defocus value at the same laser scanning pitch, laser power, and scanning speed as in step S23, and melts the metal powder in the third zone 76 to form the third air hole 761. Among them, the defocus value is 3 mm, the corresponding laser spot is 101 μm, the width of the melting track is 101 μm, the porosity of the formed melting track is about 50 μm, and the porosity of the formed breathable steel is about 50 μm, that is, the aperture of the third air hole 761 is 50 μm.

[0101] Step S26: The laser 20 emits laser to melt the metal powder in the fourth zone 77.

[0102] Specifically, the laser 20 obtains a laser spot of corresponding size by adjusting the dynamic focusing module 52 to change the defocus value at the same laser scanning pitch, laser power, and scanning speed as in step S23, and melts the metal powder in the fourth zone 77 to form the fourth air hole 771. Among them, the defocus value is 4 mm, the corresponding laser spot is 110 μm, the width of the melting track is 110 μm, the porosity of the formed melting track is about 40 μm, and the porosity of the formed breathable steel is about 40 μm, that is, the aperture of the fourth air hole 771 is 40 μm.

[0103] On the same printing layer, the defocus value can be changed in real time through the dynamic focusing module 52, and laser spots of corresponding sizes can be obtained through the corresponding defocus values, so that air holes of different aperture sizes can be obtained on the same printing layer, so as to meet the requirements of the breathable die steel 70 for the air hole sizes required by different injection melts.

[0104] In this application, during the printing process of the breathable die steel 70, after the first printed layer 71 with the first hole 711 is formed, the defocus value during the printing process is adjusted through the dynamic focusing module 52 to obtain a laser spot with a corresponding size, thereby forming the next printed layer with the second hole 721. The first hole 711 and the second hole 721 are connected and have different pore diameters, so that a gradient hole is formed between the first hole 711 and the second hole 721. When the first hole 711 with a smaller pore diameter contacts the cavity, it can prevent the injected plastic melt from flowing into the pores, ensuring that the breathable die steel 70 has a certain strength and air permeability; when the second hole 721 with a larger pore diameter communicates with the outside, it is convenient for rapid exhaust during the injection process of the plastic melt.

[0105] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application and not to limit them. Although the present application has been described in detail with reference to the embodiments, those of ordinary skill in the art should understand that the technical solutions of the present application can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present application.

Claims

1. A forming method of breathable die steel with different pore diameters, characterized in that It includes the following steps: Construct three-dimensional model data of the breathable die steel, and discretely divide the three-dimensional model data into multiple printed layer models stacked layer by layer; Lay metal powder; Plan process parameters for printing the current printed layer model, and laser-melt the metal powder along the path of the printed layer model according to the process parameters, thereby printing a corresponding printed layer. The process parameters include a defocus value, and the printed layer includes a first hole having a first aperture; Lay the metal powder on the current printed layer; Adjust the defocus value in the process parameters of the next printed layer model, thereby obtaining a laser spot of a corresponding size. The process parameters further include a scanning strategy, and the scanning strategy includes an alternately vertical scanning strategy; Laser-melt the metal powder along the path of the printed layer model according to the adjusted process parameters, thereby printing the next printed layer on the current printed layer. The next printed layer includes a second hole having a second aperture. The first hole communicates with the second hole and the first aperture is smaller than the second aperture, thereby obtaining the breathable die steel with different apertures.

2. The forming method of the breathable die steel with different pore diameters according to claim 1, characterized in that The central axes of the first hole and the second hole coincide.

3. The forming method of the breathable die steel with different pore diameters according to claim 1, characterized in that, The process parameters further include a scanning pitch, a laser power, and a laser speed.

4. The forming method of the breathable die steel with different pore diameters as described in claim 1, characterized in that, Each printed layer is formed with a plurality of first holes or second holes having different aperture sizes, and the plurality of first holes or second holes are arranged at intervals.

5. A forming device for breathable die steel with different pore diameters, which is used to perform the forming method of breathable die steel with different pore diameters according to any one of claims 1 to 4, and is characterized in that, The forming device includes a feeding unit, a laser, a forming chamber, and a dynamic focusing module; The feeding unit is used for laying metal powder in the forming chamber; The laser is used for emitting laser light towards the metal powder according to process parameters, so that the metal powder melts and solidifies to form a corresponding printed layer. The process parameters include the defocus value of the laser, and the printed layer includes a first hole having a first aperture; The dynamic focusing module is used for adjusting the defocus value in the process parameters to obtain a laser spot of a corresponding size; The feeding unit is further used for re-laying the metal powder on the current printed layer; The laser is further used for emitting a laser beam towards the metal powder according to the adjusted process parameters, so that the metal powder melts and solidifies to form the next printed layer on the current printed layer. The printed layer includes a first hole having a first aperture, and the next printed layer includes a second hole having a second aperture. The first hole communicates with the second hole and the first aperture is smaller than the second aperture.

6. The forming device of the breathable die steel with different aperture diameters as described in claim 5, characterized in that, The central axes of the first hole and the second hole coincide.

7. The forming device for the breathable die steel with different apertures as described in claim 5, characterized in that, The forming device further includes a control unit. The control unit is used for constructing three-dimensional model data of the breathable die steel, and discretely dividing the three-dimensional model data into multiple printed layer models stacked layer by layer; the control unit is further used for planning process parameters for printing each printed layer model, and controlling the laser to print out the printed layer according to the corresponding process parameters.

8. The forming device of the breathable die steel with different pore diameters according to claim 5, characterized in that, The dynamic focusing module includes a lens group, a motor for driving the lens group to move, and a focusing lens. The lens group is used to change the incident angle of the laser beam on the focusing lens so as to change the defocus value of the printing layer.

9. The forming device for breathable die steel with different pore diameters according to claim 5, characterized in that, Each of the printing layers is formed with a plurality of first holes or second holes having different aperture sizes, and the plurality of first holes or the second holes are arranged at intervals.

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