Three-dimensional printing method and three-dimensional printing device

Abstract

The present application provides a three-dimensional printing method, comprising the steps of: providing a three-dimensional printing model, the three-dimensional printing model comprising a plurality of scanning layers, each scanning layer comprising a printing area and a non-printing area other than the printing area. Laying powder within a scanning layer, the powder covering the printing area and the non-printing area. Calculating the area difference between the printing area of ​​the current scanning layer and the next scanning layer. When the area difference is greater than a preset value, emitting a first energy beam to scan the printing area of ​​the current scanning layer and emitting a second energy beam to scan the non-printing area of ​​the current scanning layer, the energy of the first energy beam being higher than the energy of the second energy beam, the first energy beam being used to melt the powder, and the second energy beam being unable to melt the powder. The three-dimensional printing method provided by the present application can ensure the steady-state operation of the galvanometer, while providing an optimized scanning path process method, which can effectively reduce the risk of deformation of three-dimensional printed parts. In addition, the present application also provides a three-dimensional printing device.

Description

Technical Field

[0001] The present application relates to a three-dimensional printing method and a three-dimensional printing device. Background Art

[0002] Selective laser melting (SLM) is a major technical approach in additive manufacturing of metal materials. This technology uses laser as the energy source and scans the metal powder bed layer by layer according to the path planned in the three-dimensional slice model. The scanned metal powder is melted and solidified to achieve the effect of metallurgical bonding, and finally the metal parts designed by the model are obtained.

[0003] Generally, when the cross-sectional areas of two adjacent layers being scanned change suddenly, there is a difference in the melting or solidification process of the metal powders of the two adjacent layers, which causes thermal stress inside the metal part and causes unpredictable deformation. Summary of the invention

[0004] The present application provides a three-dimensional printing method to solve the problems in the background technology.

[0005] In addition, the present application also provides a three-dimensional printing device.

[0006] A three-dimensional printing method comprises the following steps: providing a three-dimensional printing model, the three-dimensional printing model comprising a plurality of scanning layers, each of the scanning layers comprising a printing area and a non-printing area other than the printing area. Laying powder within the range of one of the scanning layers, the powder covering the printing area and the non-printing area. Calculating the area difference between the printing areas of the current scanning layer and the next scanning layer. When the area difference is greater than a preset value, emitting a first energy beam to scan the printing area of ​​the current scanning layer and emitting a second energy beam to scan the non-printing area of ​​the current scanning layer, the energy of the first energy beam being higher than the energy of the second energy beam, the first energy beam being used to melt the powder, and the second energy beam being unable to melt the powder.

[0007] Furthermore, the method further comprises the step of: when the area difference is less than or equal to the preset value, emitting the first energy beam to scan the printing area and the non-printing area of ​​the current scanning layer.

[0008] Further, the scanning layer includes a first scanning layer and a second scanning layer adjacent to the first scanning layer, the first scanning layer includes a first printing area, the second scanning layer includes a second printing area, the first printing area is projected onto the second scanning layer to form a first projection area, and the non-printing area includes a partial area where the first projection area does not overlap with the second printing area.

[0009] Further, the scanning layer includes a third scanning layer, the third scanning layer includes a third printing area, the area of ​​the third printing area is larger than the area of ​​other printing areas, the third printing area is projected onto each other scanning layer to form a third projection area, and the non-printing area includes a partial area where each printing area does not overlap with the third projection area.

[0010] Furthermore, the area of ​​the non-printing area is proportional to the area of ​​a partial region of each of the printing areas that does not overlap with the third projection area.

[0011] Furthermore, the first energy beam traverses the printing area along a first path, and the second energy beam traverses the non-printing area along a second path, and the first path is connected to the second path in an alternating manner.

[0012] Furthermore, a plurality of the first paths are arranged in parallel, and the second path includes a plurality of connecting segments and a plurality of extending ends, the extending ends are respectively connected to opposite ends of each of the first paths, and the connecting segment connects every two adjacent extending ends.

[0013] Further, a moving speed of the first energy beam along the first path is the same as a moving speed of the second energy beam along the second path.

[0014] Furthermore, the energy beam includes any one of a laser beam, an electron beam and a plasma beam.

[0015] A three-dimensional printing device includes a control unit, a powder spreading unit, an energy unit, and a driving unit. The control unit is used to provide a three-dimensional printing model, and the control unit is also used to slice the three-dimensional printing model to obtain multiple scanning layers, each of which includes a printing area and a non-printing area other than the printing area. The powder spreading unit is used to spread powder within the range of a scanning layer, and the powder covers the printing area and the non-printing area. The control unit is also used to calculate the area difference between the printing areas of the current scanning layer and the next scanning layer, and the control unit is also used to control the energy unit to emit a first energy beam and a second energy beam when the area difference is greater than a preset value, and the energy of the first energy beam is higher than the energy of the second energy beam. The driving unit is used to drive the first energy beam to scan the printing area of ​​the current scanning layer, and is also used to drive the second energy beam to scan the non-printing area of ​​the current scanning layer, the first energy beam is used to melt the powder, and the second energy beam cannot melt the powder.

[0016] The three-dimensional printing method provided by the present application sets a printing area and a non-printing area in each scanning layer. The printing area is scanned by a first energy beam to melt and form, and the non-printing area is scanned by a second energy beam with lower energy. The second energy beam does not melt the powder, thereby increasing the cooling and heat dissipation time of the printing area, reducing the accumulated thermal stress due to insufficient cooling time, and reducing the risk of deformation of three-dimensional printed parts. That is, the present application can effectively reduce the risk of deformation of three-dimensional printed parts through an optimized scanning path process. In addition, the drive unit is kept working continuously during the entire scanning process, so that the steady-state operation of the drive unit can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A schematic diagram of a metal melting 3D printer provided in accordance with an embodiment of the present application.

[0018] Figure 2 A schematic diagram of a first scanning layer and a second scanning layer provided in an embodiment of the present application.

[0019] Figure 3 for Figure 1 A top view of the first scanning layer and the second scanning layer is shown.

[0020] Figure 4 A schematic diagram of a third scanning layer and other scanning layers provided in another embodiment of the present application.

[0021] Figure 5 Schematic diagram of the first path and the second path provided in this application.

[0022] Main component symbols

[0023] First scanning layer 10

[0024] First printing area 11

[0025] The first projection area 111

[0026] First non-printing area 12

[0027] Second scanning layer 20

[0028] Second printing area 21

[0029] The second non-printing area 22

[0030] The third scanning layer 40

[0031] The third printing area 41

[0032] The third projection area 411

[0033] First Path 50

[0034] Second Path 60

[0035] Connection section 61

[0036] Extension end 62

[0037] Metal Melting 3D Printer 100

[0038] Energy Unit 101

[0039] Drive unit 102

[0040] Powder spreading unit 103

[0041] Control unit 104. DETAILED DESCRIPTION

[0042] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments.

[0043] Some embodiments of the present application are described in detail. In the absence of conflict, the following embodiments and features of the embodiments can be combined with each other.

[0044] The present application provides a three-dimensional printing method, which can be applied to a three-dimensional molding system, wherein the three-dimensional molding system is used to use a high-energy beam to melt powder layer by layer to form a three-dimensional printed body.

[0045] See also Figure 1 , the three-dimensional molding system can be a metal melting 3D printer 100, and the metal melting 3D printer 100 includes an energy unit 101, a drive unit 102, a powder spreading unit 103 and a control unit 104. The energy unit 101 is used to emit an energy beam (for example, a laser beam, an electron beam, a plasma beam), and the powder spreading unit 103 is used to lay metal powder layer by layer (not shown). The drive unit 102 is used to reflect the energy beam to each layer of the metal powder, thereby melting the metal powder layer by layer. The control unit 104 is used to control the start and stop of the energy unit 101 and the drive unit 102. In other embodiments of the present application, the three-dimensional molding system can also be any one of a ceramic 3D printer and a powder sintering 3D printer.

[0046] The energy unit 101 may be any one of a gas laser, a solid laser, a semiconductor laser and a dye laser.

[0047] The driving unit 102 may be a central processing unit (CPU), or other general-purpose processors, a digital signal processor (DSP), an application specific integrated circuit (ASIC), etc.

[0048] The powder spreading unit 103 includes a powder spreading substrate (not shown), a powder storage mechanism (not shown) and a powder scraping mechanism (not shown). The powder storage mechanism is used to release a certain amount of metal powder onto the powder spreading substrate one by one, and the powder scraping mechanism is used to scrape the metal powder on the powder spreading substrate flat.

[0049] The three-dimensional printing method comprises the steps of:

[0050] S1: Importing a three-dimensional printing model of a pre-printed body into the control unit 104, the control unit 104 slices the three-dimensional printing model to obtain a plurality of scanning layers, each of which includes a printing area and a non-printing area other than the printing area.

[0051] S2: The powder spreading unit 103 spreads metal powder within a scanning layer range, and the metal powder covers the printing area and the non-printing area.

[0052] S3: The control unit 104 calculates the area difference △S between the current scanning layer and the next scanning layer in the printing area. When the area difference △S is greater than a preset value, the control unit 104 controls the energy unit 101 to emit a first energy beam and a second energy beam, wherein the energy of the second energy beam is lower than the energy of the first energy beam. For example, the energy of the first energy beam is higher than the melting point of the metal powder, while the energy of the second energy beam is lower than the melting point of the metal powder. The control unit 104 also controls the drive unit 102 to start, thereby reflecting the first energy beam to the metal powder in the current printing area, so that the metal powder in the printing area is melted and formed. Then, the drive unit 102 also reflects the second energy beam to the current non-printing area. Since the energy of the second energy beam is relatively low, the metal powder in the non-printing area cannot be melted. Thus, the scanning of the printing area in one of the scanning layers is completed. In some embodiments, the preset value is 0.5~1.2cm 2 The driving unit 102 is a galvanometer.

[0053] When the area difference ΔS is less than or equal to a preset value, the driving unit 102 reflects the first energy beam scanning beam to scan the printing area and the non-printing area of ​​the current scanning layer.

[0054] In this embodiment, in step S3, the control unit 104 can control the energy unit 101 to emit the first energy beam and the second energy beam at the same time. In other embodiments of the present application, the control unit 104 controls the first energy beam to be emitted first and then the second energy beam.

[0055] S4: Repeat steps S2 to S3 multiple times to complete the scanning of the printing areas in the multiple scanning layers, and each time a scanning of the printing area in the scanning layer is completed, a layer of molten metal powder will be added, and finally a three-dimensional printed body is obtained.

[0056] In this embodiment, the first energy beam is an infrared laser beam, and the second energy beam is a visible light beam, that is, when scanning the non-printing area, the energy unit 101 only emits a visible light beam without emitting an infrared laser beam, and the drive unit 102 reflects the visible light beam to the non-printing area (i.e., empty scanning), so that the molten metal powder in the printing area has enough time to cool, thereby reducing the thermal stress caused by the excessive area difference ΔS between two adjacent layers and reducing the risk of deformation. On the other hand, since the drive unit 102 maintains steady-state operation without shutting down during the scanning process of the non-printing area (i.e., the cooling process of the printing area), the drive unit 102 can ensure steady-state operation of the drive unit 102.

[0057] In this example, see Figure 2 and Figure 3 The scanning layer includes a first scanning layer 10 and a second scanning layer 20 adjacent to the first scanning layer 10. The first scanning layer 10 includes a first printing area 11 and a first non-printing area 12 except the first printing area 11. The first printing area 11 may be located in the center area of ​​the first scanning layer 10. The first non-printing area 12 surrounds the first printing area 11. Similarly, the second scanning layer 20 includes a second printing area 21 and a second non-printing area 22 except the second printing area 21. The second printing area 21 is opposite to the first printing area 11, and the second non-printing area 22 is opposite to the first non-printing area 12.

[0058] The first printing area 11 is forwardly projected onto the second scanning layer 20 to form a first projection area 111, and the first projection area 111 covers the second printing area 21, that is, the area of ​​the first printing area 11 is larger than the area of ​​the second printing area 21. The second non-printing area 22 is a partial area that does not overlap the first projection area 111 and the second printing area 21. If the area difference between the first printing area 11 and the second printing area 21 is greater than the preset value, the driving unit 102 performs an empty scan in the first non-printing area 12, thereby reserving more cooling time for the second printing area 21.

[0059] In another embodiment of the present application, see Figure 4 , the scanning layer may further include a third scanning layer 40, the third scanning layer 40 includes a third printing area 41, the area of ​​the third printing area 41 is larger than the area of ​​other printing areas, and the third printing area 41 is projected on each other scanning layer to form a third projection area 411. The non-printing area includes a portion that does not overlap with each other printing area and the third projection area 411. The driving unit 102 performs an empty scan in the non-printing area, thereby reserving more cooling time for the next printing area. The area of ​​the non-printing area is proportional to the area of ​​the partial area that does not overlap with each printing area and the third projection area 411, and the proportional coefficient may be 0.5, 1, 1.5, etc. In some embodiments, when the scanning layer includes only two scanning layers, the third scanning layer 40 may be the first scanning layer 10.

[0060] In this example, see Figure 5 , the driving unit 102 reflects the first energy beam to traverse the printing area along the first path 50, and reflects the second energy beam to traverse the non-printing area along the second path 60, and the first path 50 and the second path 60 are alternately connected. Therefore, after the first energy beam completes scanning along the first path 50, the second energy beam is switched to scan along the second path 60, so that the effect of alternating cooling can be achieved.

[0061] In this embodiment, the first path 50 is substantially a straight line segment, and a plurality of the first paths 50 are arranged in parallel. The second path 60 includes a plurality of connecting segments 61 and a plurality of extending ends 62. The extending ends 62 are respectively connected to opposite ends of each of the first paths 50 along the extending direction of the first path 50. The connecting segment 61 connects every two adjacent extending ends 62, thereby realizing alternating connection between the first path 50 and the second path 60.

[0062] In this embodiment, a moving speed of the first energy beam along the first path 50 is the same as a moving speed of the second energy beam along the second path 60 .

[0063] The three-dimensional printing method provided by the present application sets a printing area and a non-printing area in each scanning layer. The printing area is scanned by a first energy beam to melt and form, and the non-printing area is scanned by a second energy beam with lower energy. The second energy beam does not melt the powder, thereby increasing the cooling and heat dissipation time of the printing area, reducing the accumulation of thermal stress due to insufficient cooling time, and reducing the risk of deformation. That is, the present application can effectively reduce the risk of deformation of three-dimensional printed parts through an optimized scanning path process. In addition, the drive unit 102 is kept working continuously during the entire scanning process, so that the drive unit 102 can operate in a steady state.

Claims

1. A three-dimensional printing method, characterized in that: Includes steps: Providing a three-dimensional printing model, the three-dimensional printing model comprising a plurality of scanning layers, each of the scanning layers comprising a printing area and a non-printing area other than the printing area; Laying powder within the scanning layer, wherein the powder covers the printing area and the non-printing area; Calculating the area difference between the printing area of ​​the current scanning layer and the next scanning layer; When the area difference is less than or equal to a preset value, a first energy beam is emitted to scan the printing area and the non-printing area of ​​the current scanning layer, wherein the preset value is 0.5-1.2 cm 2 ; When the area difference is greater than the preset value, the first energy beam is emitted to scan the printing area of ​​the current scanning layer and the second energy beam is emitted to scan the non-printing area of ​​the current scanning layer, the energy of the first energy beam is higher than the energy of the second energy beam, the first energy beam is used to melt the powder, and the second energy beam cannot melt the powder.

2. The three-dimensional printing method according to claim 1, characterized in that: The scanning layer includes a first scanning layer and a second scanning layer adjacent to the first scanning layer, the first scanning layer includes a first printing area, the second scanning layer includes a second printing area, the first printing area is projected onto the second scanning layer to form a first projection area, and the non-printing area includes a partial area where the first projection area does not overlap with the second printing area.

3. The three-dimensional printing method according to claim 1, characterized in that: The scanning layer includes a third scanning layer, the third scanning layer includes a third printing area, the area of ​​the third printing area is larger than the area of ​​other printing areas, the third printing area is projected onto each other scanning layer to form a third projection area, and the non-printing area includes a partial area where each printing area does not overlap with the third projection area.

4. The three-dimensional printing method according to claim 3, characterized in that: The area of ​​the non-printing area is proportional to the area of ​​the partial region where each of the printing areas does not overlap with the third projection area.

5. The three-dimensional printing method according to claim 1, characterized in that: The first energy beam traverses the printing area along a first path, and the second energy beam traverses the non-printing area along a second path, and the first path is connected to the second path in an alternating manner.

6. The three-dimensional printing method according to claim 5, characterized in that: A plurality of the first paths are arranged in parallel, and the second path includes a plurality of connecting segments and a plurality of extending ends, the extending ends are respectively connected to two opposite ends of each of the first paths, and the connecting segment connects every two adjacent extending ends.

7. The three-dimensional printing method according to claim 5, characterized in that: The moving speed of the first energy beam along the first path is the same as the moving speed of the second energy beam along the second path.

8. The three-dimensional printing method according to claim 1, characterized in that: The energy beam includes any one of a laser beam, an electron beam and a plasma beam.

9. A three-dimensional printing device, characterized in that: Includes steps: A control unit, used for providing a three-dimensional printing model, and further used for slicing the three-dimensional printing model to obtain a plurality of scanning layers, each of the scanning layers comprising a printing area and a non-printing area other than the printing area; A powder spreading unit, used for spreading powder within a scanning layer, wherein the powder covers the printing area and the non-printing area; Energy unit; as well as Drive unit; The control unit is further configured to calculate the area difference between the printing area of ​​the current scanning layer and the next scanning layer, and when the area difference is less than or equal to a preset value, emit a first energy beam to scan the printing area and the non-printing area of ​​the current scanning layer, wherein the preset value is 0.5-1.2 cm 2 ; When the area difference is greater than the preset value, the energy unit is controlled to emit the first energy beam and the second energy beam, and the energy of the first energy beam is higher than the energy of the second energy beam; The driving unit is used to drive the first energy beam to scan the printing area of ​​the current scanning layer, and is also used to drive the second energy beam to scan the non-printing area of ​​the current scanning layer. The first energy beam is used to melt the powder, and the second energy beam cannot melt the powder.

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