Structure strengthening method for high-speed laser cladding cutter body

Abstract

The invention relates to the technical field of additive manufacturing composite materials, and particularly discloses a structure strengthening method for a high-speed laser cladding cutter body. According to the method, a cladding layer with the thickness of 50-100 microns is formed on the side face of a cutter body through the steps of blanking, primary polishing, clamping and cooling setting, path planning, technological parameter setting, side face laser cladding, edging and the like. Compared with an existing laser cladding technology, the method can remarkably reduce the thermal deformation of the cutter, reduce a heat affected zone, reduce the dilution rate of a base material, realize the combination of soft and hard materials, improve the bonding strength of a coating and a base body, reduce the subsequent processing amount, improve the material utilization rate and the processing efficiency, and reduce the cost; the problems of low hardness, poor wear resistance, short service life and the like of a traditional kitchen cutter are effectively solved.

Description

Technical Field

[0001] This invention relates to the field of additive manufacturing composite materials technology, and specifically to a method for structural strengthening of a high-speed laser cladding blade. Background Technology

[0002] Kitchen knives are essential tools in daily life and the catering industry, and their performance directly affects the user experience and work efficiency. According to the GB / T 40356-2021 standard, the raw materials for kitchen knife blades are divided into stainless steel, carbon steel, alloy steel, and stainless steel composite steel knives, among others. The sharpness and durability of the blade have the greatest impact on its performance. Sharpness is related to the blade's wrap angle, while sharpness retention, or durability, is related to the wear resistance of the material. Generally, the higher the material hardness, the better its wear resistance. In knife materials, carbon content affects the knife's strength and toughness; higher carbon content makes the knife harder, but also increases the risk of chipping and makes it more prone to rusting and retaining food odors. Low-carbon knives, while having good corrosion resistance, have poor wear resistance, leading to more frequent sharpening and a tendency to chip. Therefore, the ideal knife is both durable and sharp, essentially a balance between material strength and plasticity while maintaining corrosion resistance.

[0003] To address the issues of low hardness, poor wear resistance, and short service life in stainless steel kitchen knives, domestic research institutions and enterprises are exploring alternative approaches. Currently, there are studies investigating the use of laser-directed energy deposition (laser cladding) technology to fabricate knife blades. Laser-directed energy deposition technology uses a high-energy laser beam to melt metal materials, achieving a "layer-by-layer" manufacturing process for parts, enabling highly efficient manufacturing of large-sized, complex structural components. Using laser-directed energy deposition technology to fabricate knife blades allows for customization of the blade's performance. Based on the real-time melting characteristic, it effectively ensures the purity of the blade material, avoiding the introduction of impurities during heat treatment processes.

[0004] Currently, the application of existing laser cladding technology in the cutting tool field has significant drawbacks. Traditional cladding methods often involve large-area cladding on the tip of the cutting edge, which presents the following problems:

[0005] 1. Large thermal deformation: Large-area cladding leads to uneven heating of the substrate, and the deformation of the cutting edge of the tool is usually >0.5mm, which seriously affects the subsequent sharpening accuracy;

[0006] 2. Large heat-affected zone: The width of the heat-affected zone (HAZ) can reach 1-2 mm, leading to localized deterioration of the substrate properties (such as decreased hardness and reduced toughness).

[0007] 3. High substrate dilution rate: The dilution rate is usually >15%, and the components of the cladding layer are diluted too much by the substrate, making it difficult to guarantee the design performance;

[0008] 4. Thickness of cladding layer: The thickness of traditional cladding layers is mostly 500-1000μm, which not only wastes materials but also increases the amount of subsequent processing.

[0009] 5. Low processing efficiency: Due to the need for multiple cladding processes, the processing time for a single tool is greater than 30 minutes, making it unsuitable for mass production. Summary of the Invention

[0010] In view of this, in order to solve the problems of large thermal deformation, large heat-affected zone, high substrate dilution rate, thick cladding layer, material waste, and low processing efficiency in the existing laser cladding technology for tool strengthening, this invention proposes a high-speed laser cladding method for strengthening the tool body. This method has the characteristics of small tool thermal deformation, soft and hard material combination, low substrate dilution rate, high coating / substrate bonding strength, small subsequent processing amount, multiple material selection, thin cladding layer, high processing efficiency, and low processing cost.

[0011] The present invention solves the above problems through the following technical means:

[0012] This invention provides a method for structural strengthening of a high-speed laser cladding blade, comprising the following steps:

[0013] S1. Cut the shape of the tool from the steel plate;

[0014] S2. Perform initial grinding on one side of the tool;

[0015] S3. Install the tool after initial grinding on the clamping device with the ground side facing up, and set a cooling device below the clamping device to cool the tool after processing.

[0016] S4. Use path planning software to design the tool machining path to ensure that the laser spot is stable at the tool cutting edge during the machining process;

[0017] S5. Set the process parameters for high-speed laser cladding;

[0018] S6. Perform laser cladding on the grinding area on the side of the tool to form a cladding layer with a width of 2-5m and a thickness of 50-100μm;

[0019] S7. After the cladding is completed, sharpen the blade on the other side.

[0020] Preferably, in step S1, the steel plate is a low-carbon stainless steel plate with a carbon content ≤0.03wt%, a yield strength of 200-300MPa, and an elongation ≥30%.

[0021] Preferably, in step S2, the initial grinding is performed by dry grinding with sandpaper of 120-240 grit. After grinding, the surface roughness Ra is 1.6-3.2μm, and the grinding area covers the cutting edge of the tool and extends to the side of the tool body within a range of 10-15mm.

[0022] Preferably, in step S3, the clamping device includes a base, a clamp, and a position adjustment mechanism. The clamp is connected to the base through the position adjustment mechanism, which can achieve fine adjustment in the X, Y, and Z axes. The clamp is provided with a rubber pad at the contact part with the tool. The rubber pad has a thickness of 2-3 mm and a Shore hardness of 60-70 HA.

[0023] Preferably, in step S3, the cooling device is a water-cooled spray system, including a water tank, a water pump, a controller, spray heads, and a temperature sensor. The water pump is pipe-connected to the water tank and the spray heads, and the controller is electrically connected to the water pump and the temperature sensor. The spray range of the spray head covers the tool processing area, the spray pressure is 0.2-0.3 MPa, the cooling medium is deionized water, and the temperature sensor monitors the tool temperature in real time. When the temperature exceeds 200°C, the controller controls the water pump to start spraying.

[0024] Preferably, in step S4, the path planning software generates a path based on the three-dimensional model of the tool, which is obtained by a three-dimensional scanner; the generated cladding path is a continuous straight line segment or arc segment, the path spacing is 0.5-1mm, and the parallelism error with the tool cutting edge contour line is ≤0.02mm.

[0025] Preferably, in step S5, the process parameters include a laser power of 1500-2000W, a spot width of 3-5mm, a cladding speed of 170-180mm / s, and the laser is a fiber laser with a wavelength of 1064nm and a rectangular linear spot with an aspect ratio of 5:1-10:1.

[0026] Preferably, when the knife is a small Western-style dinner knife, the laser power is 1500W, the spot width is 3mm, the cladding speed is 170mm / s, and the cladding thickness is 50μm; when the knife is a large Western-style dinner knife, the laser power is 1800W, the spot width is 4mm, the cladding speed is 180mm / s, and the cladding thickness is 80μm; when the knife is a Chinese-style chopping knife, the laser power is 1600W, the spot width is 4mm, the cladding speed is 170mm / s, and the cladding thickness is 70μm; when the knife is a Chinese-style cleaver, the laser power is 2000W, the spot width is 5mm, the cladding speed is 180mm / s, and the cladding thickness is 100μm.

[0027] Preferably, in step S6, the cladding layer is made of spherical metal powder with a particle size distribution of 53-150 μm and a loose packing density of 4.5-5.0 g / cm³. 3 The fluidity is ≤15s / 50g; the metal powder is high-carbon alloy steel powder, wherein the carbon content is 0.8-1.2wt%, the Cr content is 12-15wt%, the Mo content is 0.5-1.0wt%, the V content is 0.1-0.3wt%, and the balance is Fe.

[0028] Preferably, in step S7, the blade is sharpened by grinding with a grinding wheel with a grit size of 800-1200 mesh. After sharpening, the blade angle is 15-25°, the blade radius is ≤0.01mm, and the sharpened surface forms an angle of 3-5° with the side of the cladding layer.

[0029] Compared with the prior art, the beneficial effects of the present invention include at least the following:

[0030] 1. Minimal thermal deformation: The use of narrow side cladding (2-5mm width) and rapid cooling (speed ≥10℃ / s) results in a cutting edge deformation of <0.1mm, far lower than the >0.5mm of traditional methods, ensuring subsequent sharpening accuracy;

[0031] 2. Small heat-affected zone: The linear light spot and low heat input result in a heat-affected zone width of <0.3mm, avoiding degradation of substrate performance;

[0032] 3. Low substrate dilution rate: The cladding layer is thin (50-100μm), the substrate melting depth is only 10-20μm, and the dilution rate is <5%, which is much lower than the >15% of the traditional method, ensuring the design performance of the cladding layer;

[0033] 4. Combination of soft and hard materials: The combination of low-carbon stainless steel substrate (soft and tough) and high-carbon alloy cladding layer (hard and wear-resistant) avoids chipping (substrate toughness provides support) and prevents chipping (cladding layer has high hardness).

[0034] 5. High bonding strength: Initial grinding increases the contact area, and metallurgical bonding makes the coating / substrate bonding strength >400MPa, which is higher than the 300MPa of traditional cladding;

[0035] 6. High material utilization: The cladding layer thickness is only 50-100μm, and the material consumption is 1 / 10-1 / 5 of that of traditional methods, reducing waste;

[0036] 7. High processing efficiency: High-speed cladding (170-180mm / s) makes the processing time of a single tool less than 5 minutes, which is 1 / 6 to 1 / 3 of the traditional method;

[0037] 8. Minimal subsequent processing: The cladding layer thickness is precise, requiring minimal grinding and finishing; it can be used immediately after sharpening.

[0038] 9. Low cost: Less material consumption and shorter processing time result in an overall cost reduction of 30-50% compared to traditional methods;

[0039] 10. Excellent knife performance: The hardness of the cladding layer can reach HRC 60-65, and its wear resistance is 3-5 times that of traditional stainless steel knives. In addition, the base material has excellent corrosion resistance and no problems with rust or odor residue. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying 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.

[0041] Figure 1 This is a flowchart of the high-speed laser cladding method for strengthening the blade structure according to the present invention;

[0042] Figure 2 This is a schematic diagram of the processing and use of the high-speed laser cladding blade structural strengthening method of the present invention. It sequentially shows the original blade blank, initial grinding, laser cladding, sharpening, and the state of the grinding side during use, illustrating the fit between the cladding layer and the sharpening surface. Detailed Implementation

[0043] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, the technical solutions of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that the described embodiments are merely some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0044] like Figure 1-2 As shown, this invention provides a method for structural strengthening of a cutting tool body using high-speed laser cladding. The method involves cladding the side of the tool with a 2-5m wide cladding layer formed by a linear laser spot, with a cladding layer thickness of less than 100um. The method includes the following steps:

[0045] S1. Cut the shape of the tool from the steel plate;

[0046] Low-carbon stainless steel sheet is selected as the base material, with a carbon content ≤0.03wt%, yield strength 200-300MPa, and elongation ≥30%. A CNC laser cutting machine is used for blanking, with a cutting accuracy of ±0.05mm. Burrs are removed after cutting to ensure the tool blank edges are free of flash and cracks. Choosing low-carbon stainless steel as the base material leverages its excellent corrosion resistance and toughness as the tool body matrix, providing good support for the subsequent cladding layer and preventing the overall tool from chipping due to excessive brittleness.

[0047] S2. Perform initial grinding on one side of the tool;

[0048] Perform initial grinding on one side of the blade (the side to be clad later). Use 120-240 grit alumina sandpaper for dry grinding, covering the cutting edge and extending 10-15 mm to the side of the blade. After grinding, the surface roughness Ra should be controlled between 1.6-3.2 μm. The purpose of initial grinding is to remove oxide scale, oil, and impurities from the substrate surface, increasing the surface roughness of the substrate, thereby improving the mechanical adhesion between the subsequent cladding layer and the substrate and preventing the cladding layer from peeling off.

[0049] S3. Install the tool after initial grinding on the clamping device with the ground side facing up, and set a cooling device below the clamping device to quickly cool the tool after processing.

[0050] The tool blank processed in step S2 is mounted on a dedicated clamping device with the polished side facing upwards. The dedicated clamping device includes a base, a clamp, and a position adjustment mechanism. The clamp is connected to the base via the position adjustment mechanism, allowing for fine adjustments of ±5mm in the X, Y, and Z axes, with an adjustment accuracy of 0.01mm, ensuring precise relative positioning between the tool cutting edge and the laser spot. The contact area between the clamp and the tool is equipped with a 2-3mm thick rubber pad with a Shore hardness of 60-70HA to prevent damage to the tool body during clamping.

[0051] A water-cooled spray system is installed below the clamping device as a cooling unit. This system includes a water tank, a water pump, spray heads, and a temperature sensor. The water pump is piped to both the water tank and the spray heads, and the controller is electrically connected to both the water pump and the temperature sensor. The spray head covers the tool machining area, with a spray pressure of 0.2-0.3 MPa. The cooling medium is deionized water (to prevent impurities in the water from contaminating the tool). The temperature sensor monitors the tool temperature in real time, automatically activating the spray system when the temperature exceeds 200°C. The cooling rate is ≥10°C / s, rapidly reducing tool temperature and minimizing deformation caused by heat accumulation.

[0052] S4. Use path planning software to design the tool machining path to ensure that the laser spot is stable at the tool cutting edge during the machining process;

[0053] The tooling path is designed using professional path planning software (such as RobotStudio and PowerMill). First, a 3D model of the tool blank is obtained using a 3D scanner (scanning accuracy 0.005mm) and imported into the path planning software. Based on the 3D model, a continuous cladding path parallel to the tool cutting edge contour is generated. The path can be a straight line or an arc, with a path spacing of 0.5-1mm and a parallelism error ≤0.02mm with the cutting edge contour. This path design ensures that the laser spot remains stable at the cutting edge position throughout the machining process, guaranteeing precise coverage of the working area of ​​the cutting edge by the cladding layer.

[0054] S5. Set the process parameters for high-speed laser cladding;

[0055] The process parameters for high-speed laser cladding are set according to the tool type, as follows:

[0056] Laser source: fiber laser, wavelength 1064nm, output power 1500-2000W, beam spot is rectangular linear beam spot, aspect ratio 5:1-10:1 (to ensure uniform energy distribution and reduce local overheating);

[0057] Spot width: 3-5mm (adapts to different cutting edge lengths);

[0058] cladding speed: 170-180mm / s (high-speed cladding can shorten processing time and reduce heat input);

[0059] Cladding material: Spherical high-carbon alloy steel powder with a particle size of 53-150μm and a loose packing density of 4.5-5.0g / cm³. 3 Flowability ≤15s / 50g (ensuring smooth powder conveying); Powder composition: C 0.8-1.2wt%, Cr 12-15wt%, Mo 0.5-1.0wt%, V 0.1-0.3wt%, balance Fe (high carbon ensures hardness, Cr improves corrosion resistance, Mo and V form carbides to enhance wear resistance).

[0060] The specific parameters for different tool types are shown in Table 1 below:

[0061] Table 1 Laser cladding parameters for different cutting tools

[0062]

[0063] S6. Perform laser cladding on the grinding area on the side of the tool to form a cladding layer with a width of 2-5m and a thickness of 50-100μm;

[0064] Start the laser cladding equipment and perform cladding on the grinding area on the side of the tool according to the path designed in step S4. During the cladding process, metal powder is uniformly conveyed to the molten pool through a powder feeder. The laser beam melts the powder and a thin layer (approximately 10-20 μm) on the substrate surface, forming a metallurgically bonded cladding layer. The thickness of the cladding layer is controlled at 50-100 μm. Due to the use of a linear spot and high-speed cladding, the width of a single cladding pass can reach 2-5 mm, and the cladding time for a single tool is less than 5 minutes, significantly improving processing efficiency.

[0065] S7. After the cladding is completed, the other side of the tool is sharpened. During the use of the tool, an angle is formed between the cladding layer and the material being cut. The sharpened side will be continuously sharpened to ensure the sharpness of the tool.

[0066] After the cladding is completed and cooled to room temperature, the unclad side of the knife is sharpened. Grinding is performed using an 800-1200 grit diamond wheel. The sharpened edge angle is 15-25° (15-20° for Western-style knives to ensure sharpness, and 20-25° for cleavers to ensure strength), with an edge radius ≤0.01mm. The sharpened edge forms a 3-5° angle with the side of the cladding layer, so that during use, when the cladding layer comes into contact with the material being cut, the sharpened edge will naturally grind itself, maintaining long-term sharpness.

[0067] The following are specific embodiments of the structural strengthening method for high-speed laser cladding of blades.

[0068] Example 1: Western-style dinner knife - small structural reinforcement

[0069] S1, Material feeding

[0070] 304 low-carbon stainless steel plate (carbon content 0.02wt%, yield strength 250MPa, elongation 35%) was selected and cut into small blanks for Western-style dinner knives using an IPGYLR-4000 laser cutting machine. The blanks were 200mm×30mm×2mm in size, with a cutting accuracy of ±0.05mm, and edge burrs were removed.

[0071] S2, Initial Polishing

[0072] The blade was dry-ground on one side (with the cutting edge extending 12mm to the side) using 180-grit alumina sandpaper. After grinding, the surface roughness was measured with a roughness meter and found to be Ra = 2.0μm.

[0073] S3, Clamping and Cooling Setup

[0074] The blank is mounted on the fixture of the special clamping device, and fine-tuned by the position adjustment mechanism to align the center line of the cutting edge with the equipment baseline (error ≤ 0.01mm); a water-cooled spray system is installed below the clamping device, the water tank is filled with deionized water, the temperature sensor threshold is set to 200℃, and the spray pressure is 0.25MPa.

[0075] S4, Path Planning

[0076] The blank was scanned using a 3D scanner (0.005mm accuracy) to obtain a 3D model, which was then imported into PowerMill software. A cladding path parallel to the cutting edge contour was generated, consisting of straight line segments with a spacing of 0.8mm and a parallelism error of 0.01mm.

[0077] S5, Process Parameter Settings

[0078] The laser source was an IPG YLR-2000 fiber laser (wavelength 1064nm), with a laser power of 1500W, a spot width of 3mm (rectangular spot, aspect ratio 8:1), and a cladding speed of 170mm / s. The cladding material was high-carbon alloy steel powder (C 1.0wt%, Cr 13wt%, Mo 0.8wt%, V 0.2wt%, Fe balance), with a particle size of 53-106μm and a loose packing density of 4.8g / cm³. 3 Flowability 12s / 50g.

[0079] S6, Laser Cladding

[0080] Start the equipment and perform cladding according to the planned path. During the cladding process, the temperature sensor monitors in real time. When the blade temperature rises to 210℃, the spray system automatically starts, with a cooling rate of 12℃ / s. After cladding is completed, the thickness of the cladding layer is measured to be 50μm.

[0081] S7, sharpened

[0082] The blade is sharpened on the other side using a 1000-grit diamond grinding wheel with a sharpening angle of 18°, a cutting edge radius of 0.008mm, and an angle of 4° between the sharpened surface and the side of the cladding layer.

[0083] Example 2: Structural reinforcement of Chinese kitchen knife - cleaver

[0084] S1, Material feeding

[0085] 316 low-carbon stainless steel plate (carbon content 0.03wt%, yield strength 280MPa, elongation 32%) was selected to cut Chinese kitchen knife / cleaver blanks (size 300mm×50mm×3mm) with a cutting accuracy of ±0.05mm.

[0086] S2, Initial Polishing

[0087] Polish one side of the blade with 240-grit alumina sandpaper (the cutting edge extends to a range of 15mm from the side). The surface roughness after polishing is Ra = 1.6μm.

[0088] S3, Clamping and Cooling Setup

[0089] After clamping, the cutting edge is aligned using the position adjustment mechanism. The spray system pressure is 0.3 MPa, and the cooling threshold is 200℃.

[0090] S4, Path Planning

[0091] After 3D scanning, the data is imported into path planning software to generate arc-shaped cladding paths (adapted to the curved cutting edge of a machete). The path spacing is 1.0 mm and the parallelism error is 0.02 mm.

[0092] S5, Process Parameter Settings

[0093] The laser power was 2000W, the spot width was 5mm (length to width ratio 10:1), and the cladding speed was 180mm / s; the cladding material was the same as in Example 1, with a particle size of 106-150μm.

[0094] S6, Laser Cladding

[0095] The cooling rate during the cladding process is 15℃ / s, and the cladding layer thickness is 100μm.

[0096] S7, sharpened

[0097] It is sharpened using an 800-grit grinding wheel with a cutting edge angle of 25°, an arc radius of 0.01mm, and an angle of 5° between the sharpened surface and the cladding layer.

[0098] Performance testing

[0099] The performance of the cutting tools in Examples 1-2 was compared with that of traditional laser cladding tools (control group). The results are shown in Table 2 below:

[0100] Table 2 Comparison of Tool Performance

[0101] Performance indicators Example 1 Example 2 control group Thermal deformation (mm) 0.08 0.09 0.6 Width of heat-affected zone (mm) 0.2 0.25 1.5 Dilution rate (%) 3.5 4.0 18 Bond strength (MPa) 420 410 300 Cladding layer hardness (HRC) 62 63 58 Abrasion resistance (relative value) 4.2 4.5 1.0 Processing time (min / piece) 4 4.5 35 Material consumption (g / piece) 0.8 1.2 10

[0102] As shown in Table 2, the cutting tools prepared by the method of the present invention are significantly better than the control group in terms of thermal deformation, heat-affected zone, and dilution rate. They also have higher bonding strength, hardness and wear resistance, while the processing efficiency is greatly improved and the material consumption is significantly reduced.

[0103] Example 3: Western-style dinner knife - major structural reinforcement

[0104] S1, Material feeding

[0105] 304L low-carbon stainless steel plate (carbon content 0.015wt%, yield strength 220MPa, elongation 38%) was selected and a CNC laser cutting machine was used to cut the large blank of the Western-style dinner knife into a size of 250mm×40mm×2.5mm. The cutting accuracy was controlled within ±0.05mm. After deburring, it was ready for use.

[0106] S2, Initial Polishing

[0107] The side of the blade to be coated with the fusion coating (covering the cutting edge to a range of 14mm on the side of the blade) was dry-ground using 200-grit silicon carbide sandpaper. After grinding, the surface roughness was measured with a laser roughness meter, and the surface roughness Ra = 2.5μm, ensuring that there was no oxide scale or impurities remaining.

[0108] S3, Clamping and Cooling Setup

[0109] The blade blank is fixed in a special clamping device, and the positioning is finely adjusted by the X, Y, and Z three-axis adjustment mechanism to align the center of the cutting edge with the center of the laser optical path, with a positioning error of ≤0.01mm; the rubber pad layer (2.5mm thick, Shore hardness 65HA) of the clamping contact part fits tightly against the blade to avoid clamping deformation.

[0110] A water-cooled spray system is installed below the clamping device. The water tank is filled with deionized water (conductivity ≤10μS / cm). The spray head adopts a fan-shaped nozzle, the spray pressure is set to 0.28MPa, and the temperature sensor threshold is set to 200℃ to ensure that cooling is activated within 3 seconds in case of overheating.

[0111] S4, Path Planning

[0112] A blue light 3D scanner (scanning accuracy 0.005mm) was used to acquire the 3D model of the tool blank, which was then imported into RobotStudio path planning software. A continuous straight line segment cladding path parallel to the cutting edge contour line was generated, with a path spacing of 0.7mm, a parallelism error between adjacent paths ≤0.015mm, and the total path length matched the effective working length of the cutting edge.

[0113] S5, Process Parameter Settings

[0114] The laser source is a 1064nm fiber laser with an output power of 1800W, a rectangular linear spot size of 4mm×0.5mm (length to width ratio of 8:1), and a cladding speed of 180mm / s.

[0115] The cladding material is spherical high-carbon alloy steel powder with the following composition: C 1.1wt%, Cr 14wt%, Mo 0.9wt%, V 0.25wt%, and Fe balance. The particle size distribution is 75-150μm, and the loose packing density is 4.7g / cm³. 3 The Hall effect flow rate is 14 s / 50 g, and the powder delivery pipeline is protected by inert gas (powder delivery rate 8 g / min).

[0116] S6, Laser Cladding

[0117] Start the cladding equipment and perform side cladding according to the planned path. During the process, monitor the temperature of the molten pool in real time (infrared thermometer accuracy ±5℃). When the blade temperature reaches 205℃, the water cooling system is automatically started, with a cooling rate of 13℃ / s. After cladding is completed, use an ultrasonic thickness gauge to check the average thickness of the cladding layer, which is 80μm, with a thickness deviation of ≤±5μm.

[0118] S7, sharpened

[0119] The non-clad side was machined using a 1200-grit diamond grinding wheel with a progressive grinding process (rough grinding → fine grinding). The final cutting edge angle was 20°, the cutting edge radius was 0.009mm, and the cutting edge formed a 4° angle with the clad side.

[0120] Example 4: Structural reinforcement of Chinese-style knife for cutting vegetables

[0121] S1, Material feeding

[0122] 316L low-carbon stainless steel sheet (carbon content 0.025wt%, yield strength 260MPa, elongation 34%) is selected and cut into Chinese kitchen knife cutting blanks (size 280mm×45mm×2.8mm). After cutting, the edges are magnetically polished to remove burrs and ensure that the cutting edge blanks are free of micro-cracks.

[0123] S2, Initial Polishing

[0124] The blade side (with the cutting edge extending to a range of 13mm from the blade) was dry-ground using 150-grit alumina sandpaper in a reciprocating motion. After grinding, the surface roughness Ra = 3.0μm was measured by a white light interferometer, and the grinding area had clear boundaries without transition burrs.

[0125] S3, Clamping and Cooling Setup

[0126] The blank is installed in a special clamping device with a rotating shaft. The side of the blade is made perpendicular to the incident direction of the laser beam by a fine adjustment mechanism (adjustment accuracy 0.005mm). The clamping force is controlled at 50-80N (real-time monitoring by a pressure sensor).

[0127] The water cooling system adopts a dual-spray head design, which covers the cladding area and the middle of the blade respectively. The cooling medium is deionized water (with 0.1% rust inhibitor added), the spray pressure is 0.22MPa, the cooling start threshold is 200℃, and the cooling rate is ≥11℃ / s.

[0128] S4, Path Planning

[0129] Based on a 3D scanning model (point cloud density 100 points / mm) 2 In the path planning software, an arc segment cladding path is generated to adapt to the curved edge of the knife. The path spacing is 0.6mm, the maximum deviation from the edge outline is ≤0.02mm, and the path overlap rate is 30%.

[0130] S5, Process Parameter Settings

[0131] The laser power is 1600W, the rectangular spot width is 4mm (aspect ratio 7:1), and the cladding speed is 170mm / s. The cladding powder is a high-carbon alloy powder: C 0.9wt%, Cr 13.5wt%, Mo 0.7wt%, V 0.15wt%, Fe balance, particle size 53-106μm, and loose packing density 4.6g / cm³. 3 The flowability is 13s / 50g, and the powder is fed with argon gas of 99.99% purity.

[0132] S6, Laser Cladding

[0133] During the cladding process, the protective gas flow rate is maintained at 15L / min (to prevent oxidation of the molten pool), and the forming status of the cladding layer is monitored in real time (online observation with a CCD camera). When the molten pool is detected to be offset, the laser power is automatically adjusted by ±50W for compensation. After the cladding is completed and cooled to room temperature, the thickness of the cladding layer is measured to be 70μm. Cross-sectional metallographic analysis shows that the cladding layer and the substrate are metallurgically bonded, with no pores or inclusions.

[0134] S7, sharpened

[0135] The blade was sharpened using a 1000-mesh cubic boron nitride grinding wheel with a grinding feed rate of 5 mm / s. The cooling and lubricating fluid was a special grinding oil (viscosity 20 cSt). The final cutting edge angle was 22°, the cutting edge radius was 0.01 mm, the angle between the sharpened surface and the side of the cladding layer was 3.5°, and the straightness error of the cutting edge was ≤0.03 mm / 100 mm.

[0136] Performance test data

[0137] The performance of the knives from Example 3 (Western-style knife - large) and Example 4 (Chinese-style knife - for cutting vegetables) was tested and compared with that of traditional methods. The results are shown in Table 3 below:

[0138] Table 3 Performance Comparison of Supplementary Examples

[0139]

[0140] Note: *Sharpness retention test is the total number of times a standard carrot (hardness 30-35 HRF) is cut until the sharpness of the blade decreases by 30%.

[0141] The test results show that the cutting tools of Examples 3 and 4 are superior to traditional laser cladding tools in terms of thermal deformation control, bonding strength, wear resistance and corrosion resistance, and the processing cost is significantly reduced, which fully demonstrates the technical advantages of the method of the present invention.

[0142] The present invention provides a structural strengthening method for high-speed laser cladding tool bodies, which can solve the problems of large thermal deformation of the cutting edge, large heat-affected zone, high substrate dilution rate, thick cladding layer, and waste of cladding material in existing traditional laser cladding tools. It achieves advantages such as small tool thermal deformation, soft and hard material bonding, low substrate dilution rate, high coating / substrate bonding strength, small subsequent processing amount, multiple material selection, thin cladding layer, high processing efficiency, and low processing cost.

[0143] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A method for structural strengthening of a high-speed laser cladding blade, characterized in that, Includes the following steps: S1. Cut the steel plate into the shape of the cutting tool; S2. Perform initial grinding on one side of the tool; S3. Install the tool after initial grinding on the clamping device with the ground side facing up, and set a cooling device below the clamping device to cool the tool after processing. S4. Use path planning software to design the tool machining path to ensure that the laser spot is stable at the tool cutting edge during the machining process; S5. Set the process parameters for high-speed laser cladding; S6. Laser cladding is performed on the grinding area on the side of the tool to form a cladding layer with a width of 2-5m and a thickness of 50-100μm; S7. After the cladding is completed, sharpen the blade on the other side.

2. The structural strengthening method for high-speed laser cladding blades according to claim 1, characterized in that, In step S1, the steel plate is a low-carbon stainless steel plate with a carbon content ≤0.03wt%, a yield strength of 200-300MPa, and an elongation ≥30%.

3. The structural strengthening method for high-speed laser cladding blades according to claim 1, characterized in that, In step S2, the initial grinding is carried out by dry grinding with sandpaper of 120-240 grit. After grinding, the surface roughness Ra is 1.6-3.2μm, and the grinding area covers the cutting edge of the tool and extends to the side of the tool body within a range of 10-15mm.

4. The structural strengthening method for high-speed laser cladding blades according to claim 1, characterized in that, In step S3, the clamping device includes a base, a clamp, and a position adjustment mechanism. The clamp is connected to the base through the position adjustment mechanism, which can achieve fine adjustment in the X, Y, and Z axes. The contact area between the clamp and the tool is provided with a rubber pad, which has a thickness of 2-3 mm and a Shore hardness of 60-70 HA.

5. The structural strengthening method for high-speed laser cladding blades according to claim 1, characterized in that, In step S3, the cooling device is a water-cooled spray system, including a water tank, a water pump, a controller, spray heads, and a temperature sensor. The water pump is pipe-connected to the water tank and the spray heads, and the controller is electrically connected to the water pump and the temperature sensor. The spray range of the spray head covers the tool processing area, the spray pressure is 0.2-0.3 MPa, the cooling medium is deionized water, and the temperature sensor monitors the tool temperature in real time. When the temperature exceeds 200°C, the controller controls the water pump to start spraying.

6. The structural strengthening method for high-speed laser cladding blades according to claim 1, characterized in that, In step S4, the path planning software generates a path based on the three-dimensional model of the tool, which is obtained by a three-dimensional scanner. The generated cladding path is a continuous straight line segment or arc segment with a path spacing of 0.5-1mm and a parallelism error of ≤0.02mm with the tool cutting edge contour line.

7. The structural strengthening method for high-speed laser cladding blades according to claim 1, characterized in that, In step S5, the process parameters include a laser power of 1500-2000W, a spot width of 3-5mm, and a cladding speed of 170-180mm / s. The laser is a fiber laser with a wavelength of 1064nm and a rectangular linear spot with an aspect ratio of 5:1-10:

1.

8. The structural strengthening method for high-speed laser cladding blades according to claim 1, characterized in that, When the knife is a small Western-style dinner knife, the laser power is 1500W, the spot width is 3mm, the cladding speed is 170mm / s, and the cladding thickness is 50μm; when the knife is a large Western-style dinner knife, the laser power is 1800W, the spot width is 4mm, the cladding speed is 180mm / s, and the cladding thickness is 80μm; when the knife is a Chinese-style vegetable knife, the laser power is 1600W, the spot width is 4mm, the cladding speed is 170mm / s, and the cladding thickness is 70μm; when the knife is a Chinese-style cleaver, the laser power is 2000W, the spot width is 5mm, the cladding speed is 180mm / s, and the cladding thickness is 100μm.

9. The structural strengthening method for high-speed laser cladding blades according to claim 1, characterized in that, In step S6, the cladding layer is made of spherical metal powder with a particle size distribution of 53-150 μm and a loose packing density of 4.5-5.0 g / cm³. 3 The fluidity is ≤15s / 50g; the metal powder is high-carbon alloy steel powder, wherein the carbon content is 0.8-1.2wt%, the Cr content is 12-15wt%, the Mo content is 0.5-1.0wt%, the V content is 0.1-0.3wt%, and the balance is Fe.

10. The structural strengthening method for a high-speed laser cladding blade according to claim 1, characterized in that, In step S7, the blade is sharpened by grinding with a grinding wheel with a grit size of 800-1200 mesh. After sharpening, the blade angle is 15-25°, the blade radius is ≤0.01mm, and the sharpened surface forms an angle of 3-5° with the side of the cladding layer.

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