Method for carrying out laser cladding on inclined support-free structure
By tilting the component at an angle θ, the optimal parameters for laser cladding were determined, solving the problems of interference between the laser head and the part and lack of support, thus enabling the successful laser cladding manufacturing of complex parts.
Patent Information
- Application Number
- CN202511320335.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-16
- Publication Date
- 2025-12-09
AI Technical Summary
Conventional laser cladding methods are prone to interference between the laser head and the part and lack of support when manufacturing closed centrifugal wheels or complex parts, making effective printing impossible.
By calculating the required tilt angle θ of the component, keeping the laser head vertical, and tilting the component at the angle θ, multiple sets of single-channel single-layer and multi-channel single-layer laser cladding experiments were conducted to determine the optimal laser power, scanning speed, and powder feeding parameters, thereby avoiding interference between the laser head and the part and solving the problem of lack of support.
This technology enables successful laser cladding on tilted, unsupported structures, ensuring the smooth operation of the cladding process and providing a new method for laser additive manufacturing of closed centrifugal wheels and other enclosed structures.
Smart Images
Figure CN121087481A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of additive manufacturing technology, and in particular to a method for laser cladding on an inclined, unsupported structure. Background Technology
[0002] With the development of additive manufacturing, laser cladding, due to its high degree of freedom in forming, has been increasingly widely used in the manufacturing of complex parts. Laser cladding technology allows for free forming, unconstrained by spatial dimensions and materials, enabling both forming and partial repair, and resulting in higher density parts. In particular, laser cladding allows for the convenient and appropriate intervention of subtractive processing and heat treatment processes in the intermediate stages of the additive manufacturing process to achieve the high precision and performance requirements of the formed parts. Therefore, using laser cladding to manufacture closed impellers or similar complex parts has unique advantages.
[0003] However, closed structures are difficult to form, a typical example being the forming of closed centrifugal wheels. These unsupported structures with constraints can cause interference between the laser cladding nozzle and the already formed impeller blades. In traditional normal processing methods, the substrate is placed horizontally, and the laser head is perpendicular to the substrate. Suitable laser cladding parameters are obtained through experiments or calculations, and the overlap rate for multi-pass single-layer laser cladding is derived from the morphology of single-pass single-layer laser cladding. These parameters and overlap rates are then used for multi-pass single-layer or multi-pass multi-layer laser cladding. However, for the manufacturing of closed centrifugal wheels or complex parts, conventional laser cladding suffers from interference between the laser head and the component, as well as the unsupported structure with constraints, making the cladding process impossible. Summary of the Invention
[0004] To overcome the shortcomings of existing technologies, this invention provides a method for laser cladding on tilted, unsupported structures. This method solves the problems of interference between the laser head and the component, and the inability to print due to lack of support, that occur with conventional laser cladding, especially for closed centrifugal wheels or complex-shaped parts. Therefore, tilted components are required for laser cladding manufacturing. This method first calculates the required tilt angle θ of the component and obtains the optimal parameter through multiple sets of experiments with different parameter combinations. Then, while keeping the laser head vertical, the component is tilted at the angle θ. Using this parameter, laser cladding is performed on the component, resolving the interference and lack of support problems and ensuring a smooth cladding process. This provides a new laser additive manufacturing method for closed centrifugal wheels and other enclosed structures.
[0005] The technical solution adopted in this invention is a method for laser cladding on an inclined, unsupported structure. The method is characterized by first calculating the required tilt angle θ of the component, and then obtaining the optimal parameters through multiple sets of experiments with different parameter combinations. Next, while keeping the laser head vertical, the component is tilted at an angle θ. Different laser powers, scanning speeds, and powder feed rates are selected, and multiple sets of single-pass single-layer and multi-pass single-layer laser cladding experiments are conducted on a substrate with an tilt angle of θ to determine the optimal laser cladding parameters. These parameters are then used to perform laser cladding on the component. The specific steps of the method are as follows:
[0006] Step 1: Calculate the angle θ that the component needs to tilt.
[0007] Keep the laser head perpendicular to the horizontal plane. Let point O be the intersection of the laser head centerline and the component. Rotate the component around point O. Point A is the point on the component that makes straight contact with the left side of the laser head. Point B is the intersection of the laser head centerline and the bottom surface of the laser head. Draw a perpendicular line downwards along BO, with intersection points C and D. Adjust the vertical position of the laser head so that the distance between point B and point O is 40mm. According to geometric relationships:
[0008] ∠AOB=∠DCE=θ(1)
[0009]
[0010] The required angle of inclination for the component is:
[0011]
[0012] Step 2: Determine the height h of the single-pass, single-layer laser cladding on the inclined substrate, and the total number of cladding layers n, based on the required cladding layer thickness h' of the component, so that...
[0013] h'≤n×h (4)
[0015] The height w of a single-pass, single-layer laser cladding on the inclined substrate, and the total number of cladding passes n, are determined based on the required cladding layer thickness w' of the component, so that...
[0016] w'≤n×w (5)
[0018] Step 3: Conduct multiple sets of single-pass single-layer laser cladding experiments on inclined ordinary round bars. Select different combinations of laser power, scanning speed and powder feed. On ordinary round bars with an inclination angle of θ, conduct multiple sets of single-pass single-layer laser cladding experiments. Measure the width W and height h of each single-pass single-layer cladding layer, as well as the actual morphology of the single-pass single-layer laser cladding. Finally, determine the optimal single-pass single-layer laser cladding parameters.
[0019] Step 4: Conduct multiple single-layer laser cladding experiments on tilted ordinary round bars.
[0020] Based on the required number of laser cladding passes for the component, starting from the initial point (0, 0) on the inclined ordinary round bar, perform the first single-layer laser cladding pass clockwise along the positive X-axis in the Cartesian coordinate system. Then, shift the starting point a certain distance towards the positive Y-axis and perform the second single-layer laser cladding pass clockwise along the positive X-axis. Repeat the above steps until the required number of passes is reached. Calculate the overlap rate n of each single-layer laser cladding pass to ensure the surface quality of the multi-layer cladding layer. The calculation formula is as follows:
[0021]
[0022]
[0023] W = A1C1(9)
[0024] in, Area of the first cladding layer, C is the horizontal connection area of the highest points of the first and second cladding layers, and W is the horizontal distance between the highest points of the two cladding layers.
[0025] Step 5: Conduct a single-pass, multi-layer laser cladding experiment on an inclined ordinary round bar.
[0026] Depending on the required number of laser cladding layers for the component, single-pass multi-layer additive manufacturing on inclined circular bars exhibits a characteristic where the weld width gradually increases until it stabilizes, while the peak offset increases with the number of layers, which is detrimental to additive manufacturing. Therefore, manufacturing single-pass multi-layer additive structures on inclined substrates requires parameter control and determination of the offset of each layer relative to the next, ensuring that the laser aligns with the weld center of the next layer during further deposition. This guarantees the quality of the cladding layer, and the lateral offset Y and longitudinal offset Z are calculated.
[0027] Y = h·sinθ (10)
[0029] Z = h·cosθ (11)
[0031] Step Six: Conduct multi-layer, multi-pass cladding tests on inclined, unsupported components.
[0032] Starting from the component's starting point, perform the first cladding process clockwise along the positive X-axis. Then, shift the starting point a certain distance towards the positive Y-axis and perform the second cladding process clockwise along the positive X-axis. Repeat these steps until the required number of cladding passes are reached. Then, return to the starting point and calculate the lateral offset Y and longitudinal offset Z. Move the laser head to begin the second layer of laser cladding. Repeat these steps until the laser cladding manufacturing of the unsupported structure is complete.
[0033] The beneficial effect of this invention is that it provides a solution to the problem of interference between the laser head and the part that occurs when using conventional laser cladding methods for complex parts. By tilting the component at a certain angle, the interference problem between the laser head and the part is avoided, and the problem of unsupported components is solved, allowing the cladding process to proceed normally. This provides a new laser additive manufacturing method for closed centrifugal wheels and other closed structures. Attached Figure Description
[0034] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0035] Figure 1 This is a schematic diagram of the manufacturing method according to an embodiment of the present invention;
[0036] Figure 2 This is a schematic diagram of an unsupported component according to an embodiment of the present invention;
[0037] Figure 3 This is a schematic diagram of the cladding of an inclined circular cylindrical material according to an embodiment of the present invention; wherein 1 is a circular cylindrical material, 2 is a laser head, 3 is the five-axis of a five-axis CNC machine tool, which can rotate clockwise and counterclockwise, and 4 is the four-axis of a five-axis CNC machine tool, which can adjust the tilt angle;
[0038] Figure 4 This is a schematic diagram of a component after cladding is completed according to an embodiment of the present invention;
[0039] Figure 5 This is a schematic diagram of laser cladding of an inclined component according to an embodiment of the present invention; where 1 is the component and 2 is the laser head.
[0040] Figure 6 This is a schematic diagram of a tilted single-track multi-layer offset according to an embodiment of the present invention;
[0041] Figure 7 This is a schematic diagram of two laser cladding overlaps in an embodiment of the present invention. Detailed Implementation
[0042] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0043] The purpose of this invention is to provide a method for laser cladding on an inclined, unsupported structure.
[0044] This invention provides a novel laser additive manufacturing method for closed centrifugal wheels and other enclosed structures. To make the above-mentioned objects, features, and advantages of this invention more apparent and understandable, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.
[0045] The implementation of the present invention will now be described in detail with reference to the technical solution and accompanying drawings.
[0046] Figure 2 This is a schematic diagram of the unsupported structure of the present invention. Due to the presence of constrained unsupported structures, the components need to be tilted at a certain angle and then sealed by laser cladding. The laser cladding powder material is 316L, with a particle size of 53μm-150μm. The required width for laser cladding is 8mm, and the required height is 49mm. The specific steps of the method are as follows:
[0047] The first step is to calculate the required tilt angle θ of the surface to be repaired.
[0048] The measured AB = 35mm. Since the distance between the laser head tip and the cladding surface needs to be maintained at 40mm, BO = 40mm. have to Therefore, the component needs to be tilted at an angle of 41.2°.
[0049] The second step involves keeping the laser head perpendicular to the horizontal plane and tilting the circular cylindrical material at a 41.2° angle, with the laser head tip 40mm from the cladding surface. Cladding is then performed clockwise from the starting point of the tilted cylindrical material along the positive X-axis. The effects of laser power, scanning speed, and powder feed rate on the morphology and dimensions of the tilted cylindrical material's single-layer, single-pass stack were investigated. Laser power ranges from 1500W to 2300W, scanning speeds from 5mm / s to 9mm / s, and powder feed rates from 13.22g / min to 14.7g / min were selected. Twenty-four orthogonal experiments were conducted to obtain the forming rules and optimal forming process window for tilted laser powder feeding additive manufacturing. Experimental data show that with increasing laser power, layer width, layer height, and peak offset all increase; powder feed rate has the greatest impact on layer width. With increasing scanning speed, layer height, layer width, and peak offset all decrease. With increasing powder feed rate, layer height, layer width, and peak offset all increase, but layer height changes relatively little, while layer width increases significantly. To ensure proper forming, using a coupling parameter of lower laser power, higher scanning speed, and lower powder feed rate can mitigate flow phenomena during additive manufacturing on inclined cylindrical materials. The optimal process parameters were: laser power 1700W, powder feed rate 14.33g / min, and scanning speed 7mm / s. The actual dimensions of the single-pass, single-layer laser cladding on the inclined circular cylindrical material were: single-layer cladding height 1.2mm, single-pass, single-layer cladding width w 3.2mm, and peak offset 0.488mm.
[0050] The third step begins with the inclined circular column material. Starting from the initial point along the positive X-axis, the first cladding is performed by rotating clockwise. Then, the initial point is shifted 2.4mm towards the positive Y-axis, and the second cladding is performed along the positive X-axis. This process is repeated until the required number of cladding layers is reached. In this embodiment, a total of three single-layer laser cladding layers were performed. The calculated overlap rate is 0.25. The lateral distance between the two cladding layers is 2.4mm.
[0051] The fourth step involves conducting a single-pass, multi-layer experiment on an inclined circular cylindrical material. Based on the previous single-pass, single-layer experiment, the single-layer cladding height is 1.2 mm, and the single-pass, single-layer cladding width (w) is 3.2 mm. Since the required cladding height in the single-pass, multi-layer model is the height at the center of the weld bead, not the offset height, measurements using a laser profilometer show that the height at the center of the weld bead is approximately 20% lower than the offset height. Therefore, the center height (h) of the first layer is 0.96 mm. Substituting these values into the formula, the laser head offset (Y) = h·sinθ = 0.6 mm, and the lifting height (Z) = h·cosθ = 0.72 mm. The laser head is then moved 0.6 mm in the negative Y-axis direction and 0.72 mm in the positive Z-axis direction. Experiments show that the layer height increases with the number of layers, with the average single-layer height increasing by 1.4 mm for the first three layers. Calculations indicate that the laser head offset (Y) is approximately 0.7 mm, and the dimensions stabilize after the fourth layer, with the average single-layer height increasing by 1.2 mm. The laser head offset Y is about 0.6mm. The above steps are repeated until the required number of layers is reached. In this embodiment, a total of 17 single-layer laser cladding processes were performed.
[0052] Step 5: Keep the laser head perpendicular to the horizontal plane and tilt the component at 41.2°, with the laser head tip 40mm from the cladding surface. Define the tangent direction of the component's clockwise rotation as the positive X-axis, and the direction perpendicular to it to the right as the positive Y-axis. According to the above process parameters, this embodiment requires multiple single-layer laser cladding passes along the positive Y-axis, followed by multi-layer cladding along the Z-axis. Starting from the starting point on the component surface, rotate clockwise along the positive X-axis for the first cladding pass. Then, shift the starting point 2.4mm towards the positive Y-axis and rotate clockwise along the positive X-axis for the second cladding pass. Repeat these steps until the required number of passes is reached. In this embodiment, a total of 3 single-layer laser cladding passes were performed, and the overlap rate calculated using the formula is 0.25. The lateral distance between the two cladding layers is 3.2mm. Return to the starting point and move it 0.6mm in the negative Y-axis direction and 0.72mm in the positive Z-axis direction. Repeat the above steps until the required cladding width and height are achieved, completing the closure of the unsupported component. The resulting cladding layer meets the production process requirements.
[0053] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A method for laser cladding on an inclined, unsupported structure, characterized in that, Includes the following steps: Step 1: Calculate the angle θ that the component needs to tilt. Keep the laser head perpendicular to the horizontal plane. Let point O be the intersection of the laser head's centerline and the component. Rotate the component around point O. Let point A be the point on the component that makes straight-line contact with the left side of the laser head. Let point B be the intersection of the laser head's centerline and the bottom surface of the laser head. Adjust the laser head's vertical position so that point B is 40mm away from point O. Based on geometric relationships... Calculate the tilt angle θ, where AB is the horizontal distance between points A and B, and BO = 40 mm; Step 2: Determine the size and total quantity of each cladding layer. The height h and the total number of laser cladding layers n on the inclined substrate are determined according to the required cladding layer thickness h' of the component, so that h'≤n×h; the width w and the total number of laser cladding layers m on the inclined substrate are determined according to the required cladding layer width w' of the component, so that w'≤m×w; Step 3: Single-pass single-layer laser cladding experiment By selecting different combinations of laser power, scanning speed and powder feed, multiple sets of single-pass single-layer laser cladding experiments were carried out on a substrate with an inclination angle of θ. The width w and height h of each cladding layer and the actual morphology were measured to determine the optimal single-pass single-layer laser cladding parameters. Step 4: Multi-channel single-layer laser cladding experiment After performing the first single-layer cladding in a clockwise direction along the positive X-axis of the Cartesian coordinate system, shift the starting point a certain distance in the positive Y-axis direction. Repeat the above operation until the total number of passes (m) is reached. Calculate the overlap rate to ensure the surface quality of the cladding layer. Where C is the lateral distance between the highest points of the two cladding layers, and W is the width of a single cladding layer; Step 5: Single-pass multilayer laser cladding experiment Based on the total number of layers n, when performing single-pass multi-layer cladding on an inclined substrate, calculate the lateral offset Y and longitudinal offset Z of each layer relative to the next layer, Y = h·sinθ, Z = h·cosθ, and adjust the laser head position to align the laser with the center of the next layer weld. Step Six: Multi-layer, multi-pass cladding of inclined, unsupported components After completing multiple single-layer cladding passes clockwise along the positive X-axis from the starting point of the component, the laser head position is adjusted according to Y and Z, and multiple layers of cladding are repeated until the laser cladding of the unsupported structure is completed.
2. The method for laser cladding on an inclined, unsupported structure according to claim 1, characterized in that: In step one, AB is the horizontal distance from point A, the straight contact point between the component and the left side of the laser head, to the center line of the laser head.
3. The method for laser cladding on an inclined, unsupported structure according to claim 1, characterized in that: In step three, the combination of laser power, scanning speed and powder feeding amount needs to be screened through experiments, and the forming quality (including density and surface flatness) of a single-pass single-layer cladding layer is used as the criterion for judging the optimal parameters.
4. The method for laser cladding on an inclined, unsupported structure according to claim 1, characterized in that: In step four, the offset distance of the starting point in the positive Y-axis direction matches the C value to meet the overlap rate requirement.
5. The method for laser cladding on an inclined, unsupported structure according to claim 1, characterized in that: In step five, the lateral offset Y is the distance moved along the negative Y-axis, and the longitudinal offset Z is the distance moved along the positive Z-axis.
6. The method for laser cladding on an inclined, unsupported structure according to claim 1, characterized in that: The unsupported structure includes a closed centrifugal wheel or other complex parts with a closed structure.
7. The method for laser cladding on an inclined, unsupported structure according to claim 1, characterized in that: In step six, during the multi-layer, multi-pass cladding process, the laser head remains perpendicular to the horizontal plane, and the component maintains a constant tilt angle θ.