Support-free 3D printing method

Abstract

The invention provides a support-free 3D printing method which comprises the following steps that a three-dimensional model of a to-be-printed piece is divided into a plurality of printing units in the first direction, the first direction is parallel to the height direction of the three-dimensional model of the to-be-printed piece, and each printing unit is divided into a first area part and a second area part in the first direction; the printing units are sequentially printed from bottom to top in the first direction, when the printing units are printed, the first area part is firstly printed, and after the first area part is printed, the second area part is divided into at most two printing layers in the first direction; the lowermost printing layer in the at most two printing layers is subjected to scanning forming at first scanning power, first scanning speed and first scanning interval; wherein the energy density of the lowermost printing layer in each printing unit is set as E1, the energy density of the second area part in each printing unit is set as E2, and 0.25 * E1 < = E2.

Description

Technical Field

[0001] This application relates to the field of optoelectronic composite cables, and more particularly to a supportless 3D printing method. Background Technology

[0002] When printing large-format suspended parts at 0°, it is often necessary to set a support structure at the bottom of the suspended part for printing. However, setting up the support structure increases printing time and material costs, and removing the support structure is also time-consuming and laborious. Summary of the Invention

[0003] This application provides a supportless 3D printing method to solve the problem that a suspended part needs to be set up when printing a large-format suspended part at 0° in the known technology.

[0004] This application provides a supportless 3D printing method, comprising the following steps: dividing a three-dimensional model of a workpiece to be printed into multiple printing units along a first direction, the first direction being parallel to the height direction of the three-dimensional model of the workpiece to be printed; further dividing each printing unit into a first section and a second section along the first direction; printing each printing unit sequentially from bottom to top along the first direction; when printing each printing unit, printing the first section first; after printing the first section, dividing the second section into at most two printing layers along the first direction; the lowermost printing layer of the at most two printing layers being scanned and formed with a first scanning power, a first scanning speed, and a first scanning interval; wherein, the volume energy density of the lowermost printing layer in each printing unit is set to E1, the volume energy density of the second section in each printing unit is set to E2, and 0.25*E1≤E2.

[0005] In one possible implementation, the lowermost printed layer of each of the second regions is printed using a linear scanning method, and the number of scans is one. The first scanning power is not less than 180W, the first scanning speed is not greater than 850mm / s, and the first scanning spacing is not greater than 60μm-95μm.

[0006] In one possible implementation, the volume energy density E1 of the lowest printing layer in each of the printing units is not less than 10⁸ J / mm². 3 .

[0007] In one possible implementation, if the number of printing units does not exceed 5, the volume energy density E2 of the second region in each printing unit and the volume energy density E1 of the lowest printing layer in that printing unit satisfy the relationship 0.25*E1≤E2.

[0008] In one possible implementation, if the number of printing units exceeds 5, the first to the fifth printing units satisfy the relationship 0.25*E1≤E2;

[0009] The volume energy density of the bottommost printed layer in the fifth printing unit is set to E. 51 The volume energy density of the second region in each of the printing units after the fifth printing unit is set to E. 52 0.25*E 51 ≤E 52 ;

[0010] The volume energy density of the lowest printed layer in each of the printing units following the fifth printing unit is set to E3, and the volume energy density of the second region in each of the printing units following the fifth printing unit is set to E4, 0.55*E 51 ≤E3≤0.9*E 51 ; 0.55*E 52 ≤E4≤0.9*E 52 .

[0011] In one possible implementation, if each of the second regions is divided into two printing layers, the uppermost printing layer in each of the second regions is scanned and formed with a second scanning power, a second scanning speed, and a second scanning spacing.

[0012] The second scanning speed is 1000-1250 mm / s, and the second scanning interval is 0.1-0.12 mm.

[0013] In one possible implementation, after printing one of the printing units, the next printing unit is printed after a wait of at least 30 minutes.

[0014] In one possible implementation, when printing the lowermost printed layer in each of the printing units or other areas of the workpiece to be printed, the volume energy density is changed by adjusting the layer thickness of the current printed area.

[0015] In one possible implementation, after printing the second region in each of the printing units, the volume energy density is changed by maintaining the scanning power constant and adjusting the spot diameter.

[0016] In one possible implementation, after each set of ten printing units is printed, the temperature difference between the second section of the first printing unit and the second section of the last printing unit is detected. If the temperature difference exceeds 40°C, printing is stopped until the temperature difference does not exceed 40°C, at which point printing resumes.

[0017] The supportless 3D printing method of this application divides the second region, which is a suspended structure, into at most two printing layers for printing. This ensures that the bottommost printing layer of the second region will not warp due to excessive stress after printing. Simultaneously, by controlling various printing parameters such as volume energy density during the printing of the second region, this application ensures a good bonding effect between the formed second region and other structures, avoiding delamination or detachment, thereby enabling the printing of large-format, 0° supportless workpieces. Attached Figure Description

[0018] Figure 1 This is a schematic flowchart of the supportless 3D printing method of this application in one embodiment.

[0019] Figure 2 This is a schematic diagram of the structure of the part to be printed in one embodiment of the supportless 3D printing method of this application.

[0020] Figure 3 This is a schematic diagram of the printing unit structure in one embodiment of the supportless 3D printing method of this application.

[0021] Figure 4 This is a photograph of a workpiece formed using a printing method.

[0022] Figure 5 This is a photograph of a workpiece formed using another printing method.

[0023] Figure 6 This is a photograph of a workpiece formed using another printing method.

[0024] Figure 7 This is a photograph of the workpiece formed using the supportless 3D printing method described in this application.

[0025] Figure 8 This is a photograph of a workpiece formed using the supportless 3D printing method described in this application, taken from another perspective.

[0026] Explanation of key component symbols:

[0027] 100 Supportless 3D Printing Methods

[0028] First direction Z

[0029] Item to be printed 1

[0030] Printing Unit 10

[0031] First District 11

[0032] Second District 12

[0033] The following detailed description, in conjunction with the accompanying drawings, will further illustrate this application. Detailed Implementation

[0034] The following description will refer to the accompanying drawings to provide a more complete picture of the present application. The drawings illustrate exemplary embodiments of the present application. However, the present application may be implemented in many different forms and should not be construed as limited to the exemplary embodiments set forth herein. These exemplary embodiments are provided to make the present application thorough and complete, and to fully convey the scope of the present application to those skilled in the art. Similar reference numerals denote the same or similar components.

[0035] The terminology used herein is for the purpose of describing particular exemplary embodiments only and is not intended to limit the application. As used herein, unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “the” are intended to also include the plural forms. Furthermore, when used herein, “comprising” and / or “including” and / or “having,” integers, steps, operations, components, and / or components, but does not exclude the presence or addition of one or more other features, regions, integers, steps, operations, components, and / or groups thereof.

[0036] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. Furthermore, unless expressly defined herein, terms such as those defined in a general dictionary should be interpreted as having the same meaning as they have in the relevant art and in the content of this application, and will not be interpreted as having an idealized or overly formal meaning.

[0037] The specific embodiments of this application will be further described in detail below with reference to the accompanying drawings.

[0038] like Figures 1 to 3 As shown, this embodiment provides a supportless 3D printing method 100, applied in the field of metal 3D printing, to print metal parts in a supportless manner. It is understood that in other embodiments, the supportless 3D printing method 100 of this application can also be applied to the field of non-metal printing, and its specific application field is not specifically limited in this application. The supportless 3D printing method 100 includes the following steps:

[0039] S1. Along the first direction Z, the three-dimensional model of the part to be printed 1 is divided into multiple printing units 10. The first direction Z is parallel to the height direction of the three-dimensional model of the part to be printed 1. Along the first direction Z, each printing unit 10 is further divided into a first section 11 and a second section 12.

[0040] In this step, the multiple printing units 10 have roughly the same structure, and each printing unit 10 has both a suspended structure and a non-suspended structure. Specifically, the first section 11 is the non-suspended structure of the printing unit 10, and the second section 12 is the suspended structure of the printing unit 10.

[0041] In this embodiment, the part to be printed 1 is cylindrical in shape, and is divided into multiple printing units 10 along its height direction, each of which is also cylindrical. The first section 11 is a cylindrical structure with open ends and a hollow interior. The second section 12 covers the top surface of the first section 11 and closes the opening at the top of the first section 11. The second section 12 is disc-shaped, and its top and bottom surfaces are parallel to each other along the first direction Z. The normals of the top and bottom surfaces of the second section 12 are parallel to the first direction Z, thus the second section 12 serves as a suspended structure with a 0° large format.

[0042] It is understood that in other embodiments, the printable part 1 may also have only a 0° large-format suspended structure or other structures. The specific structure of the printable part 1 provided in this application is only used as an example to illustrate the printing principle of the 0° large-format suspended structure. Based on the printing principle of the 0° large-format suspended structure provided in this application, those skilled in the art can realize the printing of printable parts 1 with other shapes or structures having a 0° large-format suspended structure.

[0043] S2. Print each printing unit 10 sequentially from bottom to top along the first direction Z. When printing each printing unit 10, first print the first region 11. After printing the first region 11, divide the second region 12 into at most two printing layers along the first direction Z. The lowermost printing layer of the at most two printing layers is scanned and formed with the first scanning power, the first scanning speed, and the first scanning spacing. The volume energy density of the lowermost printing layer in each printing unit 10 is set to E1, and the volume energy density of the second region 12 in each printing unit 10 is set to E2, where 0.25*E1≤E2.

[0044] In this embodiment, the first section 11 serves as a non-suspended structure of the printing unit 10. It is a conventional printed part, and the first section 11 can be printed and formed using existing printing methods. The specific printing methods and related parameters are not specifically limited in this application.

[0045] After printing the first section 11, powder is spread on the top surface of the first section 11 and the second section 12 is printed on the basis of the first section 11. That is, the second section 12, which is a suspended structure with a large 0° format, is printed on the basis of the printed first section 11.

[0046] In this embodiment, the second section 12 is divided into two printing layers, which are stacked along the first direction Z. After printing the first section 11, the bottommost printing layer is printed first, and after printing the bottommost printing layer, the other printing layer above it is printed, thereby completing the printing of the entire second section 12.

[0047] The bottommost printed layer serves as the forming layer for the suspended surface. It needs to be printed on the open end of the first section 11, which is open at both ends and hollow inside. Therefore, when printing the bottommost printed layer, it is necessary to reasonably control various parameters during printing to ensure that the bottommost printed layer will not warp or delaminate from the first section 11 after forming.

[0048] In this embodiment, when printing the bottommost printing layer of each second section 12, a linear scanning method is used to fill the suspended surface, and the number of scans is one. The first scanning power is not less than 180W, the first scanning speed is not greater than 850mm / s, and the first scanning spacing is not greater than 60μm-95μm. The first scanning spacing does not exceed the diameter of a single light spot.

[0049] Furthermore, the volume energy density E1 of the lowest printed layer in the second region 12 of each printing unit 10 is not less than 108 J / mm². 3 .

[0050] Thus, when printing the bottommost printing layer of each second region 12, this application uses a high laser power while ensuring a high volume energy density input, and combines it with a slow scanning speed and a relatively small scanning gap to ensure that each region of the bottommost printing layer can be tightly connected during the forming process and that there will be no warping or other problems, thereby ensuring that the suspended surface is formed smoothly.

[0051] In this embodiment, if the number of printing units 10 does not exceed 5, the volume energy density E2 of the second region 12 in each printing unit 10 and the volume energy density E1 of the lowest printing layer in the printing unit 10 satisfy the relationship 0.25*E1≤E2.

[0052] That is, when planning the printing parameters of the second section 12, by controlling the relationship between the total volume energy density E2 input to the second section 12 and the volume energy density E1 of the bottommost printing layer in the second section 12 during printing, it is ensured that the bottommost printing layer has a good metallurgical bonding effect with the other printing layers of the second section 12, and avoids phenomena such as delamination or peeling during the printing process.

[0053] Specifically, the value of E1 only needs to be not less than 108 J / mm. 3The specific value can be selected and entered according to the actual printing requirements to determine the appropriate volume energy density. Correspondingly, the value of E2 only needs to satisfy 0.25*E1≤E2, and its specific value can be selected and entered according to the actual printing requirements to determine the appropriate volume energy density.

[0054] In other embodiments, if the number of printing units 10 exceeds 5, that is, when the number of printing units 10 is 6 or 7, the first to fifth printing units 10 satisfy the relationship 0.25*E1≤E2.

[0055] Furthermore, for ease of subsequent reading, the volume energy density of the bottommost printing layer in the fifth printing unit 10 is set to E. 51 Let the volume energy density of the second region 12 in each printing unit 10 after the fifth printing unit 10 be E. 52 0.25*E 51 ≤E 52 .

[0056] The volume energy density of the lowest printed layer in each printed unit 10 after the fifth printed unit 10 is set to E3, and the volume energy density of the second region 12 in each printed unit 10 after the fifth printed unit 10 is set to E4, 0.55*E 51 ≤E3≤0.9*E 51 0.55*E 52 ≤E4≤0.9*E 52 .

[0057] Thus, by controlling the relationship between the total volume energy density input to the second section 12 in the first five printing units 10 and the volume energy density of the bottommost printing layer in the second section 12 during printing, the structural stability of the solid formed by the bottom five printing units 10 is ensured to be better. When the subsequent printing units 10 continue printing based on the solid formed by the five printing units 10, the input of their volume energy density is controlled based on the volume energy density of the second section 12 in the fifth printing unit 10 and the bottommost printing layer in the second section 12, ensuring that the forming of the sixth and subsequent printing units 10 is more stable.

[0058] It is worth noting that, when planning printing parameters, in addition to directly controlling the volume energy density input according to the formula mentioned above, the volume energy density can also be indirectly changed by controlling other parameters. Specific implementation methods are described below:

[0059] In some embodiments, when printing the lowermost printing layer in each printing unit 10 or other areas of the workpiece 1 to be printed, the volume energy density is changed by adjusting the layer thickness of the current printing area. For example, the thickness of the current layer can be increased or decreased by 30 μm to 100 μm.

[0060] In some embodiments, after printing the second region 12 in each printing unit 10, the volume energy density is changed by maintaining a constant scanning power and adjusting the spot diameter. For example, the spot diameter is increased to a range exceeding 60μm-95μm corresponding to the first scanning interval. In this way, with the input scanning power remaining constant, the area of ​​a single spot increases, thereby reducing the input volume energy density and achieving adjustment of the volume energy density.

[0061] Both of the above control methods should be considered as implementation methods of volume energy density regulation in this application.

[0062] In this embodiment, as described above, each second section 12 is divided into two printing layers. After printing the bottommost printing layer of each second section 12 according to the above method, the upper printing layer continues to be printed on the extrusion of the bottommost printing layer. The upper printing layer is also printed using a linear scanning method and scanned once. Furthermore, the upper printing layer is formed by scanning with a second scanning power, a second scanning speed, and a second scanning spacing.

[0063] The second scanning speed is 1000-1250 mm / s, and the second scanning spacing is 0.1-0.12 mm. Both the second scanning speed and the second scanning spacing are greater than the first scanning speed and the first scanning spacing. This is because the lowermost printing layer in the second section 12 has already been printed as the main suspended layer. The subsequent upper printing layers are printed on the basis of the printed suspended layer, which can be printed using a faster scanning speed and a larger scanning spacing, thereby increasing the printing speed while ensuring the forming quality.

[0064] It is understood that in other embodiments, if the thickness of the second region 12 is small, the second region 12 can be directly used as a printing layer, that is, the second region 12 is not divided into two printing layers. In this case, when printing the second region 12, the second region 12 can be printed in the same way as the lowermost printing layer of the second region 12 described above, which will not be repeated here.

[0065] In this embodiment, after printing one printing unit 10, at least 30 minutes are waited before printing the next printing unit 10. After printing one printing unit 10, the newly printed printing unit 10 is hot, and it needs to be cooled for a certain period of time before printing the next printing unit 10. This avoids the second region 12 of the next printing unit 10 from coming into contact with the hotter previous printing unit 10 and deforming due to heat, resulting in warping or other problems.

[0066] Furthermore, after printing ten printing units 10 each time, the temperature difference between the second section 12 of the first printing unit 10 and the second section 12 of the last printing unit 10 is detected. If the temperature difference exceeds 40°C, printing is stopped until the temperature difference does not exceed 40°C, and then printing is resumed to ensure that the upper and lower parts of the formed workpiece will not deform due to excessive temperature difference.

[0067] In summary, the supportless 3D printing method 100 of this application, by printing the second region 12, which is a suspended structure, in at most two printing layers, ensures that the lowest printing layer of the second region 12 will not warp due to excessive stress after printing. Simultaneously, by controlling various printing parameters such as the volume energy density during the printing of the second region 12, this application ensures a good bonding effect between the formed second region 12 and other structures, avoiding delamination or detachment, thereby enabling the printing of large-format 0° supportless workpieces. Furthermore, when printing structures with a minimum forming angle of 0° using the supportless 3D printing method 100 of this application, it is not necessary to set up a support structure or control the angle between the laser beam and the formed part. This allows for the rapid formation of parts with a suspended surface diameter ≥100mm without adding supports. This application is well-suited for situations where removing supports is inconvenient for low-angle parts within complex structures, and it also improves printing efficiency, reduces material costs, and shortens post-processing time.

[0068] Furthermore, in order to better illustrate the printing quality of the workpiece formed by the supportless 3D printing method 100 of this application, we will now take a printing method different from the printing method of this application as an example to illustrate the process and obtain an image of the corresponding printed entity.

[0069] like Figure 4 As shown, Figure 4 When the molded part is printed, the volume energy density E1 of the lowest layer of the second region 12 in the printing unit 10 is less than 108 J / mm². 3 This caused the printed parts to crack.

[0070] like Figure 5 As shown, Figure 5 When the molded part is printed, the volume energy density E1 of the lowest layer of the second region 12 in the printing unit 10 is less than 108 J / mm². 3 This results in the powder being melted during printing, but the resulting structure lacks sufficient tension, leading to problems such as warping.

[0071] like Figure 6 As shown, Figure 6 When the molded part is printed, the volume energy density E1 of the lowest layer of the second region 12 in the printing unit 10 is greater than 108 J / mm². 3 However, the volume energy density E2 of the second region 12 in the printing unit 10 does not satisfy the relationship 0.25*E1≤E2 with the volume energy density E1 of the lowest printing layer in the printing unit 10, resulting in the problem that although the lower surface of the printed part is intact, its solid part is cracked.

[0072] like Figure 7 and Figure 8 As shown, Figure 7 and Figure 8 The printed part was formed using the supportless 3D printing method of this application 100, and it had no cracking problems and no warping on the surface.

[0073] It is worth noting that the above Figure 4 , Figure 5 ,and Figure 6 The printing method used in the printed parts adopts the single comparison principle and Figure 7 and Figure 8 The supportless 3D printing method 100 of this application is compared with the method in this application, that is, except for the parameters disclosed above, the other printing steps and printing parameters are the same as those of the supportless 3D printing method 100 of this application.

[0074] The specific embodiments of this application have been described above with reference to the accompanying drawings. However, those skilled in the art will understand that various changes and substitutions can be made to the specific embodiments of this application without departing from the ratio range defined in this application. All such changes and substitutions fall within the ratio range defined in this application.

Claims

1. A free support 3D printing method, characterized in that, The method comprises the following steps: dividing a three-dimensional model of a to-be-printed object into a plurality of printing units along a first direction parallel to a height direction of the three-dimensional model of the to-be-printed object, and further dividing each printing unit into a first zone and a second zone along the first direction; printing each printing unit in turn from bottom to top along the first direction, and printing the first zone first, and after the first zone is printed, dividing the second zone into at most two printing layers along the first direction, and the lowermost printing layer of the at most two printing layers is formed by scanning at a first scanning power, a first scanning speed and a first scanning pitch; wherein the volume energy density of the lowermost printing layer in each printing unit is set as E1, the volume energy density of the second zone in each printing unit is set as E2, and 0.25*E1≤E2.

2. The free-standing 3D printing method of claim 1, wherein, The lowermost printing layer in each second zone is printed in a linear scanning manner, and the scanning is performed once, the first scanning power is not less than 180 W, the first scanning speed is not greater than 850 mm / s, and the first scanning pitch is not greater than 60 μm-95 μm.

3. The free-standing 3D printing method of claim 1, wherein, The volume energy density E1 of the lowermost printing layer in each of the printing units is not less than 108 J / mm 3 .

4. The free-standing 3D printing method of claim 1, wherein, If the number of printing units is not more than 5, the volume energy density E2 of the second zone in each printing unit and the volume energy density E1 of the lowermost printing layer in the printing unit satisfy the relationship 0.25*E1≤E2.

5. The free support 3D printing method of claim 1, wherein, If the number of printing units is more than 5, the first printing unit to the fifth printing unit satisfy the relationship 0.25*E1≤E2. The volume energy density of the bottommost printed layer in the fifth printing unit is set to E. 51 The volume energy density of the second region in each of the printing units after the fifth printing unit is set to E. 52 0.25*E 51 ≤E 52 ; the volumetric energy density of the lowermost printing layer in each of the printing units after the fifth printing unit is set to E3, the volumetric energy density of the second section in each of the printing units after the fifth printing unit is set to E4, 0.55*E 51 ≤ E3 ≤ 0.9*E 51 ; 0.55*E 52 ≤ E4 ≤ 0.9*E 52 .

6. The free support 3D printing method of claim 1, wherein, If each second zone is divided into two printing layers, the uppermost printing layer in each second zone is formed by scanning at a second scanning power, a second scanning speed and a second scanning pitch. Wherein, the second scanning speed is 1000-1250 mm / s, and the second scanning pitch is 0.1-0.12 mm.

7. The free support 3D printing method of claim 1, wherein, After printing one printing unit, at least 30 min is waited before printing the next printing unit.

8. The free support 3D printing method of claim 1, wherein, When printing the lowermost printing layer in each printing unit or other zones of the to-be-printed object, the volume energy density is changed by adjusting the layer thickness of the current printing zone.

9. The free-standing 3D printing method of claim 1, wherein, After printing the second zone in each printing unit, the volume energy density is changed by maintaining the scanning power unchanged and adjusting the spot diameter.

10. The free-standing 3D printing method of claim 1, wherein, After printing ten printing units each time, the temperature difference between the second zone of the first printing unit and the second zone of the last printing unit in the ten printing units is detected, if the temperature difference exceeds 40℃, the printing is stopped until the temperature difference does not exceed 40℃, and then the printing is resumed.

Images