SLM additive manufacturing suspension surface support design method

Abstract

The invention relates to the technical field of supporting design methods, in particular to an SLM additive manufacturing overhanging surface supporting design method, the bottom end of a second auxiliary supporting plate starts from the rightmost end of the bottom of a printed piece, the top end of the second auxiliary supporting plate ends at the rightmost end of the overhanging surface of the printed piece, and the middle point of the second auxiliary supporting plate is located in the middle of the printed piece. The first auxiliary supporting plate is fixedly connected with the second auxiliary supporting plate; the main supporting plate is located above the first auxiliary supporting plate and the second auxiliary supporting plate, the length of the main supporting plate is reduced, materials are saved, and cost is reduced. One part of heat generated during printing is dissipated from the heat conduction grooves, the other part of heat is dissipated from the heat dissipation holes, the two heat dissipation structures work at the same time, heat dissipation is accelerated, the situation that mechanical strength of the supporting part at the bottom end is reduced due to heat accumulation, and the supporting effect on a printed piece is lost is prevented, and the distance of the top provides space for cutting off the main supporting plate. The distance of the bottom provides a space for mounting and dismounting the bottom end supporting part.

Description

Technical Field

[0001] The present invention relates to the technical field of support design methods, and in particular to a method for designing supports for overhanging surfaces in SLM additive manufacturing. Background Art

[0002] SLM additive manufacturing is the abbreviation of Selective Laser Melting (SLM), which is an additive manufacturing process, commonly known as 3D printing technology. It uses a high-power density laser beam to melt and solidify metal powder layer by layer to build solid parts with complex geometric shapes. SLM technology is an important method in the field of metal additive manufacturing, and is particularly suitable for producing complex structures and customized products that are difficult to achieve with traditional processing methods.

[0003] Selective laser melting (SLM) is a technology that uses a 30-100μm fine laser spot to scan the selected area on the newly laid powder layer point by point, and after forming the surface contour, the layers are stacked and formed to directly obtain functional parts of almost any shape with complete metallurgical bonding, with a density of nearly 100%. SLM can form parts of any complex structure, improve design freedom, break through traditional processing constraints, and create more added value for products based on the functionality of the parts. At present, SLM technology has been widely used in aerospace, molds, medical, automotive and other industrial fields.

[0004] In the laser selective melting SLM technology, the role of support is to strengthen and support the stability of the part and the building platform; second, to take away the excess heat during the part building process; third, to prevent part warping and reduce the probability of failure during the part building process. In this process, the cost of removing the support structure may account for 70% of the total cost in post-processing. If you want to improve the efficiency of additive manufacturing and reduce costs, you must consider how to minimize the use of support structures when designing parts.

[0005] Although supports can be designed to be minimized, it is not always possible to eliminate them completely. This is because supports have three main functions: Isolation of material: Supports can be used to fix material that is not connected to the previous layer (i.e., overhangs that form an angle of less than 45° with the substrate, or local minimum features). It is best to integrate support structures into the component design. Residual stress: In principle, residual stress during processing is reduced by design, avoiding sharp edges and avoiding large areas of processing directly attached to the build plate. If this is not possible, supports can be applied to relieve stress in the part and prevent material from falling off the build plate. This method is not recommended for mass production of parts. Heat dissipation channel: Unmelted powder is an insulator. Supports will transfer some heat away from the lower surface area, which helps to avoid powder burning, excessive melting, deformation and discoloration, especially for the lower surface facing the scraper direction.

[0006] Support features: Keep the parts in position during printing to avoid being pulled by the scraper. Heat conduction and heat dissipation. Support cantilever beam protrusion structure. Removable. Maintain support interval. Control infiltrated powder. Easy to handle later.

[0007] The existing technology requires adding supports for overhang structures less than 45°, otherwise the parts cannot be successfully printed. In particular, for parts that overhang too high from the substrate, more supports need to be added. If the supports are too high, they may not be strong enough to hold the parts, resulting in deformation or failure of printing.

[0008] Because the overhanging surface of the printed part needs to be supported to ensure the successful printing of the part, if no support is added, the printing here will collapse and warp, resulting in the failure of the part to print. The current technology requires too much support for the overhanging surface, which wastes too much material and increases the cost of support removal and grinding, and increases the printing time. If the part is high and the overhanging surface is high, more support is required, and the strength of the support is weakened, which may not be able to hold the part, resulting in deformation of the printed part or failure of printing due to warping and deformation. Summary of the invention

[0009] The main purpose of the present invention is to provide a method for designing overhanging surface supports in SLM additive manufacturing, so as to solve the problems of too much added supports and weak support strength proposed in the related art.

[0010] In order to achieve the above-mentioned object, according to one aspect of the present invention, a method for designing overhanging surface supports for SLM additive manufacturing is provided, comprising the following steps: S1: selecting a placement angle of a printed part, identifying an overhanging surface (the angle formed with a substrate is less than 45°), fixing a first auxiliary support plate, a second auxiliary support plate, a main support plate and a bottom support portion, determining the required additional support surface, fixing and connecting the middle parts of the first auxiliary support plate and the second auxiliary support plate, and placing them in a forming area of ​​the printed part, so that the tops of the first auxiliary support plate and the second auxiliary support plate are located below the overhanging surface of the printed part, and the bottoms are located above the bottom of the printed part;

[0011] S2: Perform SLM manufacturing and printing on the printed part;

[0012] S3: After printing is completed, the first auxiliary support plate, the second auxiliary support plate, the main support plate and the bottom support portion are removed from the printed part.

[0013] Further, when the height of the overhanging surface of the printed part is less than 50 mm, the middle parts of the first auxiliary support plate and the second auxiliary support plate are tangent to each other, and S1 includes:

[0014] S1.1: A plurality of bottom support parts are fixedly arranged on the bottom of the first auxiliary support plate and the second auxiliary support plate, wherein the top of the bottom support part on the left side is fixedly connected to the bottom surface of the first auxiliary support plate, and the top of the bottom support part on the right side is fixedly connected to the bottom surface of the second auxiliary support plate;

[0015] S1.2: Fix the bottom of all the bottom support parts to the bottom surface of the printed part;

[0016] S1.3: Fix a plurality of main support plates above the first auxiliary support plate and the second auxiliary support plate, so that the bottoms of the main support plates are flush with the bottoms of the overhanging surfaces of the printed parts;

[0017] When the height of the overhanging surface of the printed part is not less than 50 mm, the first auxiliary support plate and the second auxiliary support plate intersect in the middle, and S1 includes:

[0018] S1.4: Cross and fix the middle parts of the first auxiliary support plate and the second auxiliary support plate, and place them in the forming area of ​​the printed part, so that the top of the first auxiliary support plate and the second auxiliary support plate are 0.6 mm to 2.0 mm away from the overhanging surface of the printed part, and the bottom is 1.0 mm to 5.0 mm away from the bottom of the printed part;

[0019] S1.5: Fix a plurality of bottom support parts to the bottom of the first auxiliary support plate and the second auxiliary support plate, the top of the bottom support part on the left side is fixedly connected to the bottom surface of the first auxiliary support plate, the top of the bottom support part on the right side is fixedly connected to the bottom surface of the second auxiliary support plate, and the bottoms of all the bottom support parts are fixedly connected to the bottom surface of the printed part;

[0020] S1.6: A portion of the support branch plate is fixed on the left side of the first auxiliary support plate, and the top of the support branch plate is closely attached to the inner side of the left wall of the printed part; another portion of the support branch plate is fixed on the right side of the second auxiliary support plate, and the top of the support branch plate is closely attached to the inner side of the right wall of the printed part;

[0021] S1.7: A plurality of main support plates are fixedly arranged above the first auxiliary support plate and the second auxiliary support plate, and the bottoms of the main support plates are flush with the bottoms of the overhanging surfaces of the printed parts;

[0022] S3 includes:

[0023] S3.1: Use a wire cutting machine to cut off the connection between the bottom support and the printed part, and use a grinder to grind the bottom surface of the printed part flat;

[0024] S3.2: Use a wire cutting machine to cut off the connection between the main support plate and the printed part, and use a grinder to grind the bottom surface of the overhanging surface of the printed part to make it smooth, and finally remove the printed part from the support structure;

[0025] S3.3: Use a wire cutter to cut off the connection between the support branch and the printed part, and use a grinder to smooth the side walls of the printed part, and finally remove the printed part from the support structure.

[0026] Furthermore, the bottom end of the first auxiliary support plate starts from the leftmost end of the bottom of the printed part, and the top end ends at the leftmost end of the overhanging surface of the printed part. The midpoint of the first auxiliary support plate is located in the middle of the printed part. The thickness of the first auxiliary support plate is 0.3mm~1.0mm. The bottom end of the second auxiliary support plate starts from the rightmost end of the bottom of the printed part, and the top end ends at the rightmost end of the overhanging surface of the printed part. The midpoint of the second auxiliary support plate is located in the middle of the printed part. The thickness of the second auxiliary support plate is 0.3mm~1.0mm. The first auxiliary support plate is fixedly connected to the second auxiliary support plate.

[0027] Furthermore, the main support plate is located above the first auxiliary support plate and the second auxiliary support plate, the bottom of the main support plate above the first auxiliary support plate is fixedly connected to the first auxiliary support plate, and the top is fixedly connected to the printed part, the bottom of the main support plate above the second auxiliary support plate is fixedly connected to the second auxiliary support plate, and the top is fixedly connected to the printed part, and the main support plate is used to support the overhanging surface of the printed part.

[0028] Furthermore, the support branch plates are distributed on the left and right sides of the first auxiliary support plate and the second auxiliary support plate, one end of the support branch plates on the left are fixedly connected to the inner side of the left side wall of the printed part, and the other end are fixedly connected to the outer wall of the second auxiliary support plate, and one end of the support branch plates on the right are fixedly connected to the inner side of the right side wall of the printed part, and the other end are fixedly connected to the outer wall of the first auxiliary support plate.

[0029] Furthermore, the bottom support portion includes a support column, a conical support portion, a plurality of oblique support portions and a bottom plate portion, and the conical support portion is conical and is located between the support column and the bottom plate portion.

[0030] Furthermore, the top of the conical support part is fixedly connected to the bottom of the support column, and the bottom is fixedly connected to the top of the bottom plate part. The oblique support part is located at the outer circle of the bottom of the conical support part, and the top of the oblique support part is fixedly connected to the conical support part, and the bottom is fixedly connected to the bottom plate part.

[0031] Furthermore, the conical support portion includes a conical column, a plurality of heat dissipation holes and a heat conduction hole. The conical column is fixedly connected to the support column. The heat conduction hole is arranged at the bottom of the conical column. The heat dissipation holes are all located on the side wall of the conical column and are all connected to the heat conduction holes. The heat dissipation holes are all inclined upward with an inclination angle of 35° to 50°.

[0032] Furthermore, the bottom plate portion includes a bottom plate, a plurality of heat-conducting grooves and a through hole. The bottom plate is fixedly arranged at the bottom of the conical column. The through hole is located in the middle of the bottom plate and is connected to the heat-conducting hole. The heat-conducting grooves are all located on the bottom surface of the bottom plate. The cross-sectional size of the top end of the heat-conducting groove is larger than the cross-sectional size of the bottom end, and the cross-sectional size of the middle part of the heat-conducting groove is larger than the cross-sectional size of the top end.

[0033] Furthermore, the diagonal support part includes a diagonal support column, a diagonal support plate and a plurality of convex strips, the bottom end of the diagonal support column is fixedly connected to the bottom plate, and the top end is fixedly connected to the diagonal support plate, the diagonal support column is inclined, the inclination angle of the diagonal support column is 55°~70°, the angle between the diagonal support column and the diagonal support plate is 40°~55°, and the convex strips are fixedly arranged on the upper surface of the diagonal support plate and fixedly connected to the conical column.

[0034] Compared with the prior art, the present invention has the following beneficial effects: the main support plate is located above the first auxiliary support plate and the second auxiliary support plate, which reduces the length of the main support plate, saves materials and reduces costs; part of the heat generated during printing is dissipated from the heat conduction groove, and the other part is dissipated from the heat dissipation holes. The two heat dissipation structures work simultaneously to accelerate heat dissipation and prevent the mechanical stress of the bottom support part from being reduced due to heat accumulation, causing it to lose its supporting effect on the printed part; the top of the first auxiliary support plate and the second auxiliary support plate are 1.0 mm away from the overhanging surface of the printed part, and the bottom is 3.0 mm away from the bottom of the printed part. The distance at the top provides space for cutting off the main support plate, and the distance at the bottom provides space for installing and removing the bottom support part. If the distance is too small, it is not conducive to removing the support, and if the distance is too large, the supporting component is too long, its slenderness ratio is large, and the supporting strength is reduced accordingly. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is an overall schematic diagram of the high overhang surface support of the present invention;

[0036] Figure 2It is a schematic diagram of the low overhang surface support structure of the present invention;

[0037] Figure 3 This is a schematic diagram of the top structure of the first auxiliary support plate of the present invention;

[0038] Figure 4 This is a schematic diagram of the top structure of the second auxiliary support plate of the present invention;

[0039] Figure 5 This is a schematic diagram of the bottom support structure of the present invention;

[0040] Figure 6 It is a schematic diagram of the structure of the conical support portion of the present invention;

[0041] Figure 7 It is a schematic diagram of the bottom plate structure of the present invention;

[0042] Figure 8 It is a schematic diagram of the structure of the diagonal bracing part of the present invention.

[0043] Illustration Description:

[0044] 1. Printed part; 2. First auxiliary support plate; 3. Second auxiliary support plate; 4. Main support plate; 5. Bottom support part; 6. Support branch plate; 51. Support column; 52. Conical support part; 53. Diagonal support part; 54. Bottom plate; 521. Conical column; 522. Heat dissipation hole; 523. Heat conduction hole; 531. Diagonal support column; 532. Diagonal support plate; 533. Raised strip; 541. Bottom plate; 542. Heat conduction groove; 543. Through hole. DETAILED DESCRIPTION

[0045] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation mode, structure, characteristics and effects of the present invention are described in detail below in combination with the accompanying drawings and preferred embodiments.

[0046] See also Figures 1 to 8 , this embodiment provides a method for designing overhanging surface support of SLM additive manufacturing, comprising the following steps: if the overhanging surface height of the printed part 1 is less than 50 mm, the middle parts of the first auxiliary support plate 2 and the second auxiliary support plate 3 are tangent:

[0047] S1: Select the placement angle of the printed part 1, identify the overhanging surface (the angle formed with the substrate is less than 45°), fix the first auxiliary support plate 2, the second auxiliary support plate 3, the main support plate 4 and the bottom support portion 5, determine the required additional support surface, fix the middle of the first auxiliary support plate 2 and the second auxiliary support plate 3, and place them in the forming area of ​​the printed part 1, so that the top of the first auxiliary support plate 2 and the second auxiliary support plate 3 are located below the overhanging surface of the printed part 1, and the bottom is located above the bottom of the printed part 1;

[0048] S2: Perform SLM manufacturing and printing on the printed part 1;

[0049] S3: After printing is completed, the first auxiliary support plate 2, the second auxiliary support plate 3, the main support plate 4 and the bottom support portion 5 are removed from the printed part 1.

[0050] When the height of the overhanging surface of the printed part 1 is less than 50 mm, the first auxiliary support plate 2 and the second auxiliary support plate 3 are tangent in the middle, and S1 includes:

[0051] S1.1: A plurality of bottom support parts 5 are fixedly arranged at the bottom of the first auxiliary support plate 2 and the second auxiliary support plate 3, wherein the top of the bottom support part 5 on the left side is fixedly connected to the bottom surface of the first auxiliary support plate 2, and the top of the bottom support part 5 on the right side is fixedly connected to the bottom surface of the second auxiliary support plate 3;

[0052] S1.2: Fix the bottom of all the bottom support parts 5 to the bottom surface of the printed part 1;

[0053] S1.3: A plurality of main support plates 4 are fixedly arranged above the first auxiliary support plate 2 and the second auxiliary support plate 3, and the bottoms of the main support plates 4 are flush with the bottoms of the overhanging surfaces of the printed part 1;

[0054] When the height of the overhanging surface of the printed part 1 is not less than 50 mm, the first auxiliary support plate 2 and the second auxiliary support plate 3 intersect in the middle, and S1 includes:

[0055] S1.4: Cross and fix the middle parts of the first auxiliary support plate 2 and the second auxiliary support plate 3, and place them in the forming area of ​​the printed part 1, so that the top of the first auxiliary support plate 2 and the second auxiliary support plate 3 are 0.6mm to 2.0mm away from the overhanging surface of the printed part 1, and the bottom is 1.0mm to 5.0mm away from the bottom of the printed part 1;

[0056] S1.5: Fix a plurality of bottom support parts 5 to the bottom of the first auxiliary support plate 2 and the second auxiliary support plate 3, the top of the bottom support part 5 on the left side is fixedly connected to the bottom surface of the first auxiliary support plate 2, the top of the bottom support part 5 on the right side is fixedly connected to the bottom surface of the second auxiliary support plate 3, and the bottoms of all the bottom support parts 5 are fixedly connected to the bottom surface of the printed part 1;

[0057] S1.6: A portion of the support branch plate 6 is fixedly arranged on the left side of the first auxiliary support plate 2, and the top of the support branch plate 6 is closely attached to the inner side of the left side wall of the printed part 1; another portion of the support branch plate 6 is fixedly arranged on the right side of the second auxiliary support plate 3, and the top of the support branch plate 6 is closely attached to the inner side of the right side wall of the printed part 1;

[0058] S1.7: A plurality of main support plates 4 are fixedly arranged above the first auxiliary support plate 2 and the second auxiliary support plate 3, and the bottoms of the main support plates 4 are flush with the bottoms of the overhanging surfaces of the printed part 1;

[0059] S3 includes:

[0060] S3.1: Use a wire cutting machine to cut off the connection between the bottom support portion 5 and the printed part 1, and use a grinder to grind the bottom surface of the printed part 1 flat;

[0061] S3.2: Use a wire cutting machine to cut off the connection between the main support plate 4 and the printed part 1, and use a grinder to grind the bottom surface of the overhanging surface of the printed part 1 flat, and finally remove the printed part 1 from the support structure;

[0062] S3.3: Use a wire cutting machine to cut off the connection between the support branch plate 6 and the printed part 1, and use a grinder to grind the side wall of the printed part 1 to make it smooth, and finally remove the printed part 1 from the supporting structure.

[0063] During installation, the tops of the first auxiliary support plate 2 and the second auxiliary support plate 3 are 0.6 mm to 2.0 mm away from the overhanging surface of the printed part 1 , and the bottoms are 1.0 mm to 5.0 mm away from the bottom of the printed part 1 .

[0064] The bottom end of the first auxiliary support plate 2 starts from the leftmost end of the bottom of the print 1, and the top ends at the leftmost end of the overhanging surface of the print 1. The midpoint of the first auxiliary support plate 2 is located in the middle of the print 1. The thickness of the first auxiliary support plate 2 is 0.3mm~1.0mm, and 0.8mm is preferably used in this embodiment. If it is too thick, it will waste support materials, and if it is too thin, the support strength will not be enough. The bottom end of the second auxiliary support plate 3 starts from the rightmost end of the bottom of the print 1, and the top ends at the rightmost end of the overhanging surface of the print 1. The midpoint of the second auxiliary support plate 3 is located in the middle of the print 1. The thickness of the second auxiliary support plate 3 is 0.3mm~1.0mm, and 0.8mm is preferably used in this embodiment. If it is too thick, it will waste support materials, and if it is too thin, the support strength will not be enough. The first auxiliary support plate 2 is fixedly connected to the second auxiliary support plate 3.

[0065] The main support plate 4 is located above the first auxiliary support plate 2 and the second auxiliary support plate 3. The bottom of the main support plate 4 above the first auxiliary support plate 2 is fixedly connected to the first auxiliary support plate 2, and the top is fixedly connected to the printed part 1. The bottom of the main support plate 4 above the second auxiliary support plate 3 is fixedly connected to the second auxiliary support plate 3, and the top is fixedly connected to the printed part 1. The main support plate 4 is used to support the overhanging surface of the printed part 1.

[0066] The supporting branch plates 6 are distributed on the left and right sides of the first auxiliary supporting plate 2 and the second auxiliary supporting plate 3. One end of the left supporting branch plates 6 are fixedly connected to the inner side of the left side wall of the printed part 1, and the other end are fixedly connected to the outer wall of the second auxiliary supporting plate 3. One end of the right supporting branch plates 6 are fixedly connected to the inner side of the right side wall of the printed part 1, and the other end are fixedly connected to the outer wall of the first auxiliary supporting plate 2. The number of supporting branch plates 6 can be increased or decreased according to the deformation degree of the printed part 1. In this embodiment, six supporting branch plates 6 are preferably used, three on each side, to increase the connection points between the supporting structure and the printed part 1 and enhance the connection strength.

[0067] The bottom support portion 5 includes a support column 51 , a conical support portion 52 , a plurality of oblique support portions 53 and a bottom plate portion 54 . The conical support portion 52 is conical and is located between the support column 51 and the bottom plate portion 54 .

[0068] The top of the conical support portion 52 is fixedly connected to the bottom of the support column 51, and the bottom is fixedly connected to the top of the bottom plate portion 54. The oblique support portion 53 is located at the outer circle of the bottom of the conical support portion 52, and the top of the oblique support portion 53 is fixedly connected to the conical support portion 52, and the bottom is fixedly connected to the bottom plate portion 54.

[0069] The conical support portion 52 includes a conical column 521, a plurality of heat dissipation holes 522 and a heat conduction hole 523. The conical column 521 is fixedly connected to the support column 51. The heat conduction hole 523 is arranged at the bottom of the conical column 521. The heat dissipation holes 522 are all located on the side wall of the conical column 521 and are all connected to the heat conduction holes 523. The heat dissipation holes 522 are all inclined upward with an inclination angle of 35° to 50°. The preferred inclination angle in this embodiment is 40°, which is conducive to the diffusion of heat generated during printing.

[0070] The bottom plate portion 54 includes a bottom plate 541, a plurality of heat-conducting grooves 542 and a through hole 543. The bottom plate 541 is fixedly arranged at the bottom of the conical column 521. The bottom plate 541 increases the contact area between the conical column 521 and the printed part 1, reduces the pressure on the printed part 1, and prevents the conical column 521 from crushing the printed part 1. The through hole 543 is located in the middle of the bottom plate 541 and is connected to the heat-conducting hole 523. The heat-conducting grooves 542 are all located on the bottom surface of the bottom plate 541. The cross-sectional size of the top end of the heat-conducting groove 542 is larger than the cross-sectional size of the bottom end, and the cross-sectional size of the middle part of the heat-conducting groove 542 is larger than the cross-sectional size of the top end. The heat generated during printing easily enters the heat-conducting groove 542 from the top with a larger cross-sectional size and gathers in the middle thereof. A portion of the heat is compressed when it flows out of the heat-conducting groove 542 from the bottom with a smaller cross-sectional size, and the flow rate is accelerated, taking away more heat. Another portion of the heat enters the heat dissipation hole 522 through the through hole 543 and the heat-conducting hole 523 and is discharged. The inclined heat dissipation hole 522 conforms to the trend of rising heat, accelerates its flow rate, and improves the cooling rate, thereby avoiding reducing the mechanical stress of the bottom support part 5 due to heat accumulation, causing it to lose its supporting function for the printed part 1.

[0071] The diagonal support portion 53 includes a diagonal support column 531, a diagonal support plate 532 and a plurality of convex strips 533. The bottom end of the diagonal support column 531 is fixedly connected to the bottom plate 541, and the top end is fixedly connected to the diagonal support plate 532. The diagonal support column 531 is inclined, and the inclination angle of the diagonal support column 531 is 55° to 70°. In this embodiment, 65° is preferred. The inwardly inclined diagonal support column 531 increases the stability of the conical support portion 52 to prevent it from being deformed under the tensile stress of the printed part 1. The included angle between the diagonal support column 531 and the diagonal support plate 532 is 40° to 55°, and 50° is preferred in this embodiment. The inclined diagonal support plate 532 increases the connection area with the conical column 521, reduces the pressure exerted on it by the diagonal support column 531, and prevents the diagonal support column 531 from crushing the conical column 521. The convex strips 533 are fixedly arranged on the upper surface of the diagonal support plate 532 and fixedly connected to the conical column 521. Grooves are formed between the convex strips 533, which is conducive to heat dissipation.

[0072] In this embodiment, the top of the first auxiliary support plate 2 and the second auxiliary support plate 3 are preferably 1.0 mm away from the overhanging surface of the printed part 1, and the bottom is 3.0 mm away from the bottom of the printed part 1. The top distance provides space for cutting off the main support plate 4, and the bottom distance provides space for installing and removing the bottom support part 5. If the distance is too small, it will be inconvenient to remove the support, and if the distance is too large, the supporting component will be too long, its aspect ratio will be large, and the supporting strength will be reduced accordingly.

[0073] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A method for designing overhanging surface supports for SLM additive manufacturing, characterized in that: The steps include: S1: Selecting a placement angle of the printed part (1), identifying the overhanging surface, fixing the first auxiliary support plate (2), the second auxiliary support plate (3), the main support plate (4) and the bottom support portion (5), determining the required additional support surface, fixing and connecting the middle parts of the first auxiliary support plate (2) and the second auxiliary support plate (3), and placing them in the forming area of ​​the printed part (1), so that the tops of the first auxiliary support plate (2) and the second auxiliary support plate (3) are located below the overhanging surface of the printed part (1), and the bottoms are located above the bottom of the printed part (1); S2: Perform SLM manufacturing and printing on the print part (1); S3: After printing is completed, the first auxiliary support plate (2), the second auxiliary support plate (3), the main support plate (4) and the bottom support portion (5) are removed from the printed piece (1).

2. The method for designing overhanging surface supports for SLM additive manufacturing according to claim 1, characterized in that: When the height of the overhanging surface of the printed piece (1) is less than 50 mm, the middle parts of the first auxiliary support plate (2) and the second auxiliary support plate (3) are tangent to each other, and S1 includes: S1.1: A plurality of bottom support parts (5) are fixedly arranged on the bottom of the first auxiliary support plate (2) and the second auxiliary support plate (3), wherein the top of the bottom support part (5) on the left side is fixedly connected to the bottom surface of the first auxiliary support plate (2), and the top of the bottom support part (5) on the right side is fixedly connected to the bottom surface of the second auxiliary support plate (3); S1.2: Fix the bottoms of all the bottom support parts (5) to the bottom surface of the printed part (1); S1.3: A plurality of main support plates (4) are fixedly arranged above the first auxiliary support plate (2) and the second auxiliary support plate (3), wherein the bottoms of the main support plates (4) are flush with the bottoms of the overhanging surfaces of the printed part (1); When the height of the overhanging surface of the printed piece (1) is not less than 50 mm, the first auxiliary support plate (2) and the second auxiliary support plate (3) intersect in the middle, and S1 includes: S1.4: The first auxiliary support plate (2) and the second auxiliary support plate (3) are cross-fixed and connected in the middle, and are placed in the forming area of ​​the printed part (1), so that the top of the first auxiliary support plate (2) and the second auxiliary support plate (3) are 0.6 mm to 2.0 mm away from the overhanging surface of the printed part (1), and the bottom is 1.0 mm to 5.0 mm away from the bottom of the printed part (1); S1.5: A plurality of bottom support parts (5) are fixedly arranged on the bottom of the first auxiliary support plate (2) and the second auxiliary support plate (3), the top of the bottom support part (5) on the left side is fixedly connected to the bottom surface of the first auxiliary support plate (2), the top of the bottom support part (5) on the right side is fixedly connected to the bottom surface of the second auxiliary support plate (3), and the bottoms of all the bottom support parts (5) are fixedly connected to the bottom surface of the printed workpiece (1); S1.6: A portion of the support branch plate (6) is fixedly arranged on the left side of the first auxiliary support plate (2), and the top end of the support branch plate (6) is closely attached to the inner side of the left side wall of the printed part (1); another portion of the support branch plate (6) is fixedly arranged on the right side of the second auxiliary support plate (3), and the top end of the support branch plate (6) is closely attached to the inner side of the right side wall of the printed part (1); S1.7: A plurality of main support plates (4) are fixedly arranged above the first auxiliary support plate (2) and the second auxiliary support plate (3), wherein the bottoms of the main support plates (4) are flush with the bottoms of the overhanging surfaces of the printed part (1); S3 includes: S3.1: Use a wire cutting machine to cut off the connection between the bottom support portion (5) and the printed part (1), and use a grinding machine to grind the bottom surface of the printed part (1) to make it smooth; S3.2: Use a wire cutting machine to cut off the connection between the main support plate (4) and the printed part (1), and use a grinder to grind the bottom surface of the overhanging surface of the printed part (1) to make it smooth, and finally remove the printed part (1) from the support structure; S3.3: Use a wire cutting machine to cut off the connection between the support branch plate (6) and the printed part (1), and use a grinder to grind the side wall of the printed part (1) to make it smooth, and finally remove the printed part (1) from the support structure.

3. The method for designing overhanging surface supports for SLM additive manufacturing according to claim 1, characterized in that: The bottom end of the first auxiliary support plate (2) starts from the leftmost end of the bottom of the printed part (1), and the top end ends at the leftmost end of the overhanging surface of the printed part (1); the midpoint of the first auxiliary support plate (2) is located in the middle of the printed part (1); the thickness of the first auxiliary support plate (2) is 0.3 mm to 1.0 mm; the bottom end of the second auxiliary support plate (3) starts from the rightmost end of the bottom of the printed part (1), and the top end ends at the rightmost end of the overhanging surface of the printed part (1); the midpoint of the second auxiliary support plate (3) is located in the middle of the printed part (1); the thickness of the second auxiliary support plate (3) is 0.3 mm to 1.0 mm; the first auxiliary support plate (2) is fixedly connected to the second auxiliary support plate (3).

4. The method for designing overhanging surface supports for SLM additive manufacturing according to claim 1, characterized in that: The main support plate (4) is located above the first auxiliary support plate (2) and the second auxiliary support plate (3); the bottom of the main support plate (4) above the first auxiliary support plate (2) is fixedly connected to the first auxiliary support plate (2), and the top is fixedly connected to the printed part (1); the bottom of the main support plate (4) above the second auxiliary support plate (3) is fixedly connected to the second auxiliary support plate (3), and the top is fixedly connected to the printed part (1); the main support plate (4) is used to support the overhanging surface of the printed part (1).

5. The method for designing overhanging surface supports for SLM additive manufacturing according to claim 1, characterized in that: The support branch plates (6) are distributed on the left and right sides of the first auxiliary support plate (2) and the second auxiliary support plate (3); one end of the left support branch plate (6) is fixedly connected to the inner side of the left side wall of the printed part (1), and the other end is fixedly connected to the outer wall of the second auxiliary support plate (3); one end of the right support branch plate (6) is fixedly connected to the inner side of the right side wall of the printed part (1), and the other end is fixedly connected to the outer wall of the first auxiliary support plate (2).

6. The method for designing overhanging surface supports for SLM additive manufacturing according to claim 1, characterized in that: The bottom support portion (5) comprises a support column (51), a conical support portion (52), a plurality of oblique support portions (53) and a bottom plate portion (54); the conical support portion (52) is conical and is located between the support column (51) and the bottom plate portion (54).

7. The method for designing overhanging surface supports for SLM additive manufacturing according to claim 6, characterized in that: The top of the conical support portion (52) is fixedly connected to the bottom of the support column (51), and the bottom is fixedly connected to the top of the bottom plate portion (54). The oblique support portion (53) is located at the outer circle of the bottom of the conical support portion (52). The top of the oblique support portion (53) is fixedly connected to the conical support portion (52), and the bottom is fixedly connected to the bottom plate portion (54).

8. The method for designing overhanging surface supports for SLM additive manufacturing according to claim 6, characterized in that: The conical support portion (52) comprises a conical column (521), a plurality of heat dissipation holes (522) and a heat conduction hole (523); the conical column (521) is fixedly connected to the support column (51); the heat conduction hole (523) is arranged at the bottom of the conical column (521); the heat dissipation holes (522) are all located on the side wall of the conical column (521) and are all connected to the heat conduction hole (523); the heat dissipation holes (522) are all inclined upwards, and the inclination angle is 35° to 50°.

9. The method for designing overhanging surface supports for SLM additive manufacturing according to claim 8, characterized in that: The bottom plate portion (54) comprises a bottom plate (541), a plurality of heat-conducting grooves (542) and a through hole (543); the bottom plate (541) is fixedly arranged at the bottom of the conical column (521); the through hole (543) is located in the middle of the bottom plate (541) and is connected to the heat-conducting hole (523); the heat-conducting grooves (542) are all located on the bottom surface of the bottom plate (541); the cross-sectional size of the top end of the heat-conducting groove (542) is larger than the cross-sectional size of the bottom end; and the cross-sectional size of the middle part of the heat-conducting groove (542) is larger than the cross-sectional size of the top end.

10. The method for designing overhanging surface supports for SLM additive manufacturing according to claim 9, characterized in that: The diagonal support portion (53) comprises a diagonal support column (531), a diagonal support plate (532) and a plurality of convex strips (533); the bottom end of the diagonal support column (531) is fixedly connected to the bottom plate (541), and the top end is fixedly connected to the diagonal support plate (532); the diagonal support column (531) is inclined, the inclination angle of the diagonal support column (531) is 55° to 70°, the angle between the diagonal support column (531) and the diagonal support plate (532) is 40° to 55°, and the convex strips (533) are fixedly arranged on the upper surface of the diagonal support plate (532) and fixedly connected to the conical column (521).

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