3D printing small round hole part forming method
By adjusting the laser path planning of the small circular hole, the problems of forming accuracy and channel blockage in the SLM process were solved, and high-precision micro-hole forming was achieved.
Patent Information
- Application Number
- CN202511782634.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-30
- Publication Date
- 2026-02-24
AI Technical Summary
Existing SLM processes suffer from energy buildup due to frequent laser switching when forming minute features, such as small circular holes with a diameter of less than 0.5 mm. This can affect the forming accuracy of the parts and potentially cause hole blockage.
A novel laser path planning strategy is adopted to generate a polygonal approximate contour by adjusting the number of laser vectors, vector length, and start-end offset of the small circular hole contour. This avoids the laser energy from concentrating at the edge of the hole, ensures that the vector length is greater than the width of the molten pool, and prioritizes contour scanning to form a stable molten pool.
It improves the forming accuracy and consistency of small round hole parts, avoids channel blockage, and achieves high-precision forming of small round holes with a diameter of less than 0.5mm.
Smart Images
Figure CN121551632A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of additive manufacturing technology, and in particular relates to a method for forming small circular hole parts by 3D printing. Background Technology
[0002] Selective Laser Melting (SLM) is a digital model-based metal additive manufacturing technology that achieves integrated forming of complex three-dimensional structures by melting metal powder layer by layer. This technology eliminates the need for traditional molds, enabling the efficient manufacture of parts with internal irregular structures (such as spiral channels and lattice crystals) and complex external geometries (such as multi-level steps and asymmetric surfaces). It overcomes the limitations of traditional manufacturing in terms of tool accessibility for machining small-sized structures, as well as the bottlenecks in casting and forging processes that hinder lightweight lattice designs. It has already achieved large-scale applications in aerospace, medical implants, and consumer electronics, significantly shortening product development cycles, improving material utilization, and reducing overall manufacturing costs.
[0003] However, existing SLM processes still face significant challenges when forming minute features, especially fine structures such as small circular holes with diameters less than 0.5 mm. Current mainstream slicing and path planning methods do not provide special treatment for the small hole region; their contour slicing method is consistent with that of conventional structures, such as... Figure 1 As shown, this results in an excessively short laser scanning vector. This short vector causes frequent laser switching during actual printing, which, in extremely small parts, not only fails to improve forming accuracy but also causes energy accumulation in a small area, leading to excessive local energy concentration, affecting dimensional accuracy, and causing problems such as blocked holes after printing. To alleviate this phenomenon, some processes correct it by adjusting the spot compensation parameters; however, this adjustment causes inaccuracies in the dimensions of other parts, often requiring adjustments to the hole size based on experience before printing, a complex process with low dimensional accuracy. Therefore, there is an urgent need to develop a new laser path planning strategy for fine structures such as small holes. Summary of the Invention
[0004] To overcome the problems existing in the prior art, this invention proposes a method for forming small circular hole parts in 3D printing. This invention effectively suppresses energy accumulation, avoids hole blockage, and improves the accuracy of 3D printed parts with fine structures such as small holes, resulting in parts with high dimensional accuracy, good surface roughness, and high microstructure properties.
[0005] This invention is implemented as follows: a method for forming small circular hole parts by 3D printing, comprising the following steps: a) Construct a 3D digital model of the part and repair the part model; b) Based on the material and structural characteristics of the small circular hole of the part: including the molten pool width of the metal powder material used, the theoretical aperture of the small circular hole, the laser power, the scanning speed, and the forming process parameters such as layer thickness; The number of laser vectors for the small circular hole contour, the length of a single laser vector segment, and the distance between the entity vector and the contour vector are set to obtain the laser vector planning path at the small circular hole. The contour vector distribution is a vector distribution with staggered start and end points. Based on the above parameters, the theoretical contour of the small circular hole is vector-adjusted to generate a polygonal approximate contour composed of segmented straight line vectors. At least one of the starting and ending points of each segmented vector is offset from the theoretical hole boundary to the interior of the part entity, so that the laser start point and / or stop point are located inside the hole edge, avoiding the accumulation of heat energy at the hole edge. c) Import the slices into the device and print them.
[0006] In the above technical solution, preferably, the width of the molten pool of the metal powder material is obtained through experimental calibration. Specifically, under the same forming process parameters, a single molten pool is scanned, its actual molten width is measured, and the average value of multiple repeated experiments is taken as the molten pool width.
[0007] In the above technical solution, preferably, during the forming process, contour scanning is performed before internal solid filling scanning to ensure that a stable molten pool contour has been formed at the hole boundary before filling.
[0008] In the above technical solution, preferably, the vectors at the contour of the small circular hole are arranged in a clockwise or counterclockwise order.
[0009] In the above technical solution, preferably, the small circular hole includes a through hole, as well as a blind hole, a stepped hole, and a portion of an irregularly shaped microhole with a circular cross-section.
[0010] In the above technical solution, preferably, the part is manufactured by selective laser melting.
[0011] In the above technical solution, preferably, after 3D printing is completed, the surface and internal metal powder of the formed part are cleaned, and the part is separated from the substrate by wire cutting to obtain a small round hole part.
[0012] The advantages and positive effects of this invention are: 1) This invention designs a novel path planning method, which is suitable for forming small-sized, fine-structured parts such as small circular holes. By staggering the starting points of each scanning vector segment, the energy accumulation caused by frequent laser switching is avoided from affecting the forming of fine structures, thereby improving the dimensional accuracy of the formed parts.
[0013] 2) This invention ensures that the length of each vector segment is not less than the width of the molten pool, eliminating frequent laser start-stop caused by excessively short vectors; by shifting the starting point and / or ending point of each vector towards the interior of the part, the position of the laser switching beam is made as far away as possible from the theoretical hole boundary, avoiding the accumulation of heat energy at the hole edge; and by coordinating and controlling parameters such as the number of vectors N, vector length L, and contour-filling spacing, a multi-parameter coupled shape control mechanism is constructed, which prevents the small round hole from being blocked during the forming process, achieving high-precision and high-consistency forming of small round holes with a diameter of less than 0.5mm. Attached Figure Description
[0014] Figure 1 This is a schematic diagram of the slicing path of the small circular hole provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the digital model of the part to be printed provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the laser vector at the small circular hole provided in an embodiment of the present invention. Detailed Implementation
[0015] To further understand the content, features, and effects of this invention, the following embodiments are provided, and detailed descriptions are given below in conjunction with the accompanying drawings: To facilitate a clear description of the technical solutions in the embodiments of the present invention, it should be noted that in the embodiments of the present invention, the terms "first" and "second" are used to distinguish identical or similar items with essentially the same function and effect. For example, the first threshold and the second threshold are merely used to distinguish different thresholds and do not limit their order. Those skilled in the art will understand that the terms "first" and "second" do not limit the quantity or execution order, and the terms "first" and "second" are not necessarily different.
[0016] It should be noted that in this invention, the terms "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in this invention should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.
[0017] In this invention, "at least one" refers to one or more, and "more than one" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c can represent: a, b, c, a combination of a and b, a combination of a and c, a combination of b and c, or a, b, and c, where a, b, and c can be single or multiple.
[0018] Please see Figure 2 and Figure 3 This invention provides a method for forming small circular hole parts using 3D printing, comprising the following steps: a) Construct a 3D digital model of the part. Open the model of the part to be formed using Magics software, and use the repair wizard function to repair the part model, such as... Figure 2 As shown.
[0019] b) Based on the material and structural characteristics of the small circular hole of the part: including the molten pool width of the metal powder material used, the theoretical aperture of the small circular hole, the laser power, the scanning speed, and the forming process parameters such as layer thickness; By setting appropriate laser vector counts for the small circular hole contour, laser vector length per segment, and distance between the entity vector and the contour vector, a suitable laser vector planning path for the small circular hole can be obtained, such as... Figure 3 As shown; and the contour vector distribution is a vector distribution with staggered start and end points, this arrangement can be applied to most commonly used materials.
[0020] Based on the above parameters, the theoretical contour of the small circular hole is vector-adjusted to generate a polygonal approximate contour composed of N straight line vectors. At least one point of the start and end of each vector segment is offset from the theoretical hole boundary towards the interior of the part body, so that the laser on / off point is located inside the hole edge, avoiding the accumulation of heat energy at the hole edge. This offset setting ensures that the offset vector can still effectively define the geometric boundary of the hole, while the distance setting between the solid vector and the contour vector avoids overlapping sintering of the contour scan and the internal filling scan near the hole edge.
[0021] c) Import the slices into the device and print them.
[0022] As a preferred embodiment, the molten pool width of the metal powder material used is obtained through experimental calibration. Specifically, under the same forming process parameters, a single molten channel is scanned, its actual molten width is measured, and the average value of multiple repeated experiments is taken as the result to ensure calculation accuracy.
[0023] In a preferred embodiment, during the forming process, contour scanning is performed before internal solid filling scanning to ensure that a stable molten pool contour is formed at the hole boundary before filling.
[0024] In a preferred embodiment, the vectors at the outline of the small circular hole are arranged in a clockwise or counterclockwise order.
[0025] In a preferred embodiment, the small circular hole includes a through hole, as well as blind holes, stepped holes, and portions of irregularly shaped micro-holes with circular cross-sections. For micro-grooves or arc-shaped notches that are not perfectly circular, if their radius of curvature is ≤0.25mm, this method is also applicable, treating them as local arc segments and performing path planning according to the same principle.
[0026] As a preferred embodiment, the part is manufactured by selective laser melting.
[0027] In a preferred embodiment, after 3D printing is completed, the surface and internal metal powder of the formed part are cleaned, and the part is separated from the substrate by wire cutting to obtain a small circular hole part.
[0028] This invention achieves more precise forming of small-sized (less than 0.5mm in diameter) circular holes and similar fine-structured parts using laser selective melting forming. The method involves planning a laser path for the circular hole area of the part, differing from the conventional part contour. The scanning method adjusts the vector at the small hole according to the specific size of the part and the material used for printing. An appropriate number of contour vectors is selected, and parameters such as the number of contour laser vectors, laser vector length, and the distance between the solid vector and the contour vector are adjusted according to different materials and structural dimensions to achieve the desired forming effect. The vector length is controlled to be greater than the width of the molten pool. The scanning method extends a portion of the contour vectors into the interior of the part, misaligning the laser switch endpoint with the small hole structure. During actual printing, the number of vectors, vector length, and laser sintering parameters at the small hole are adjusted according to the specific digital model to achieve the desired printing effect.
[0029] The forming method of the present invention is applicable to commonly used SLM metal materials such as titanium alloys, nickel-based high-temperature alloys, stainless steel, and aluminum alloys. It can effectively suppress overheating of hole edges and hole closure under different material systems.
[0030] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall fall within the scope of the technical solution of the present invention.
Claims
1. A method for forming small circular hole parts using 3D printing, characterized in that, Includes the following steps: a) Construct a 3D digital model of the part and repair the part model; b) Based on the material and structural characteristics of the small circular hole of the part: including the molten pool width of the metal powder material used, the theoretical aperture of the small circular hole, the laser power, the scanning speed, and the forming process parameters such as layer thickness; The number of laser vectors for the small circular hole contour, the length of a single laser vector segment, and the distance between the entity vector and the contour vector are set to obtain the laser vector planning path at the small circular hole. The contour vector distribution is a vector distribution with staggered start and end points. Based on the above parameters, the theoretical contour of the small circular hole is vector-adjusted to generate a polygonal approximate contour composed of N straight line vectors. At least one of the starting and ending points of each vector is offset from the theoretical hole boundary to the interior of the part entity, so that the laser start point and / or stop point are located inside the hole edge, avoiding the accumulation of heat energy at the hole edge. c) Import the slices into the device and print them.
2. The method for forming small circular hole parts by 3D printing according to claim 1, characterized in that, The width of the molten pool of the metal powder material used was obtained through experimental calibration. Specifically, under the same forming process parameters, a single molten pool was scanned, its actual molten width was measured, and the average value of multiple repeated experiments was taken as the molten pool width.
3. The method for forming small circular hole parts by 3D printing according to claim 1, characterized in that, During the forming process, contour scanning is performed before internal solid filling scanning to ensure that a stable molten pool contour is formed at the hole boundary before filling.
4. The method for forming small circular hole parts by 3D printing according to claim 1, characterized in that, The vectors at the outline of the small circular hole are arranged in clockwise or counterclockwise order.
5. The method for forming small circular hole parts by 3D printing according to claim 1, characterized in that, The small circular holes include through holes, as well as blind holes, stepped holes, and portions of irregularly shaped micro-holes with circular cross-sections.
6. The method for forming small circular hole parts by 3D printing according to claim 1, characterized in that, The part is manufactured by selective laser melting.
7. The method for forming small circular hole parts by 3D printing according to claim 1, characterized in that, After 3D printing is completed, the surface and internal metal powder of the formed part are cleaned, and the part is separated from the substrate by wire cutting to obtain the small round hole part.