Preparation method of ultrasonic vibration assisted laser cladding structured grinding wheel

Abstract

The invention relates to a method for preparing a structured grinding wheel through ultrasonic vibration assisted laser cladding. An ultrasonic vibration process and a laser cladding process are combined. The grinding wheel base body is connected with ultrasonic vibration equipment, and normal vibration is transmitted; metal binding agent powder and abrasive particles are mixed according to the proportion; and depositing a binding agent layer and an abrasive particle layer on the end face of the vibrating grinding wheel base body according to the determined process parameters by adopting laser cladding equipment according to the designed'impact-free track 'path. The method has the advantages of being short in period, simple in process, prominent in abrasive particle, high in abrasive particle holding force, low in grinding temperature, good in workpiece surface quality and the like, and by means of the cavitation effect of ultrasonic vibration and the acoustic streaming stirring effect, the defects that the number of defects in a laser cladding grinding wheel coating is large, and the mechanical performance is poor are avoided to the maximum extent; and meanwhile, the characteristic of high design freedom degree of the abrasive particle layer deposited through the laser cladding technology is exerted, different material binders and abrasive particles can be selected according to different scenes, the pattern of the abrasive particle layer is customized, and the method is suitable for machining difficult-to-machine materials with different requirements.

Description

Technical Field

[0001] The invention relates to the technical field of laser additive manufacturing of structured grinding wheels, and in particular to a method for preparing an ultrasonic vibration-assisted laser cladding structured grinding wheel. Background Art

[0002] With the rapid development of modern manufacturing industry, the requirements for the surface quality and processing accuracy of mechanical parts in the field of mechanical processing are constantly increasing, and the requirements for the grinding performance of grinding wheels are also increasing. Compared with the traditional grinding wheel manufacturing process, additive manufacturing technology can customize the shape structure and surface abrasive arrangement of grinding wheels according to the requirements of grinding tasks. Therefore, exploring the additive manufacturing method of structured grinding wheels has important research significance and application value. Summary of the invention

[0003] In view of the above problems, the purpose of the present invention is to provide a method for preparing a structured grinding wheel by ultrasonic vibration assisted laser cladding, taking the structured CBN grinding wheel as the research object and the secondary laser cladding technology as the process basis, giving full play to the role of ultrasonic assistance in the grinding wheel preparation process, and improving the overall grinding performance of the grinding wheel by optimizing the process parameters and the grinding wheel structure.

[0004] The technical solution adopted by the present invention is as follows:

[0005] The present invention proposes a method for preparing an ultrasonic vibration-assisted laser cladding structured grinding wheel, which prepares an end surface structured grinding wheel by combining normal ultrasonic vibration technology with laser cladding technology, and includes the following steps:

[0006] S1. According to the actual size of the grinding wheel matrix, the abrasive layer structure without impact texture is designed on the surface of the grinding wheel matrix using 3D software;

[0007] S2, saving the model of the grinding wheel substrate and the abrasive layer without impact texture in STEP format, inputting the three-dimensional model into PQart software, taking the center of the circular end face of the grinding wheel as the tool setting point, setting it as the initial point of the laser cladding trajectory, and generating the laser cladding trajectory;

[0008] S3, dividing the metal binder into two parts, one part of which is uniformly mixed with abrasive grains in a determined ratio to form a powder for abrasive grain layer deposition;

[0009] S4, determining the process parameters of laser cladding of the metal binder layer and the abrasive layer;

[0010] S5, fixing the substrate, turning on the ultrasonic vibration equipment, and depositing a metal binder layer on the surface of the grinding wheel substrate according to the laser cladding trajectory generated in step S2 and the process parameters determined in step S4;

[0011] S6: Depositing an abrasive layer on the surface of the metal bond layer of the grinding wheel according to the laser cladding trajectory generated in step S2 and the process parameters determined in step S4 to complete the preparation of the structured grinding wheel

[0012] Furthermore, in step S3, a portion of the metal binder and the abrasive particles are uniformly mixed in a mass ratio of 6:1.

[0013] Furthermore, in step S5, the ultrasonic amplitude is 3-8 μm, the frequency is 15-25 kHz, and the vibration direction is perpendicular to the end face of the grinding wheel.

[0014] Furthermore, in the step S1, the inlet angle β1 of the grinding fluid channel without the impact texture track pattern and the terminal angle β2 of the grinding fluid channel are both 30°.

[0015] Furthermore, in step S4, the process parameters of laser cladding of the metal binder layer are: powder feeding gas flow rate is 6-10L / min argon, shielding gas flow rate is 10-20L / min argon, laser power is 380-450W, scanning speed is 5-6mm / s, and powder feeding rate is 1.2-1.4r / min; the process parameters of laser cladding of the abrasive layer are: powder feeding gas flow rate is 6-10L / min argon, shielding gas flow rate is 10-20L / min argon, laser power is 350-400W, scanning speed is 5-6mm / s, and powder feeding rate is 1.4-1.6r / min.

[0016] Furthermore, in step S4, the diameter of the laser spot of laser cladding is 1-1.2 mm.

[0017] Furthermore, in step S3, the metal binder is Cu-Sn-Ti powder.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. The structured CBN grinding wheel prepared by the ultrasonic-assisted laser cladding technology of the present invention can be customized in shape, structure and surface abrasive arrangement of the grinding wheel according to the requirements of the grinding task.

[0020] 2. The present invention can realize rapid additive manufacturing of structured CBN grinding wheels under special working environments, with high flexibility and short production cycle.

[0021] 3. The present invention prepares structured CBN grinding wheels through ultrasonic-assisted laser cladding technology, which can effectively improve production efficiency, reduce resource consumption, and is conducive to sustainable development.

[0022] 4. The present invention uses the cavitation effect of ultrasonic vibration and the acoustic flow stirring effect to avoid the drawbacks of many defects and poor mechanical properties in the laser cladding grinding wheel coating to the greatest extent. At the same time, it takes advantage of the high degree of freedom in the design of the deposited abrasive layer of laser cladding technology. It can select binders and abrasives of different materials according to different usage scenarios, customize the abrasive layer pattern, and is suitable for processing difficult-to-process materials with different requirements. The present invention provides an effective method for the rapid preparation of high-performance grinding wheels for use in the fields of aerospace, bioengineering, electronic components, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic diagram of the equipment principle of ultrasonic assisted laser cladding technology;

[0024] Figure 2 The schematic diagram of the principle of preparing the structured grinding wheel of the present invention;

[0025] Figure 3 It is a schematic diagram of the quality evaluation standard of the cladding layer;

[0026] Figure 4 Schematic diagram of substrate design and scanning path. DETAILED DESCRIPTION

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] See attached Figure 1-4 The present invention proposes a method for preparing an ultrasonic vibration-assisted laser cladding structured grinding wheel, which prepares an end surface structured grinding wheel by combining normal ultrasonic vibration technology with laser cladding technology. The specific implementation process is as follows:

[0029] In this embodiment, according to the characteristics of additive manufacturing technology and the requirements of grinding wheel grinding tasks, titanium-plated CBN-980T abrasive grains are selected as the grinding wheel abrasive material; Cu-Sn-Ti metal binder is selected as the binder material; and 45 steel is selected as the grinding wheel matrix material.

[0030] S1. According to the actual size of the grinding wheel matrix, the abrasive layer structure with no impact texture is designed on the surface of the grinding wheel matrix using 3D software.

[0031] S2. Generate a three-dimensional model of the grinding wheel surface cladding trajectory of the grinding wheel substrate and the impact-free texture abrasive layer in SolidWorks and save it in STEP format. Input the three-dimensional model into the PQart software and pick up the edge of the cladding trajectory in the three-dimensional model. Take the center of the circular end face of the grinding wheel as the tool point and set it as the initial point of the laser cladding trajectory to generate the laser cladding trajectory. Export the programming code of the trajectory through the post-program and import it into the KUKA robot control system after optimization. The curved motion of the KUKA robot is composed of a combination of multiple arc instructions or straight line instructions to form a curved path. To ensure the accuracy of the curve, set the straight line point step to 1mm.

[0032] Among them, the laser cladding structured trajectory is designed as an "impact-free trajectory", and the inflow angle and outflow angle of the grinding fluid are both 30°; the initial point of the laser cladding trajectory is the center of the circle, and each cladding trajectory diverges from the center of the end face to the circumference, with a total of fifteen cladding trajectories.

[0033] S3, the Cu-Sn-Ti metal binder is divided into two parts, one part of which is directly used as the metal binder deposition powder, and the other part is mixed with the titanium-plated CBN-980T abrasive in a LHK ball mill at a mass ratio of 6:1 for one hour; then put it into a dryer and dry it at 100°C for one hour to use as the abrasive layer deposition powder;

[0034] S4, determining the process parameters of laser cladding of the metal binder layer and the abrasive layer; wherein

[0035] The process parameters of laser cladding of metal binder layer are as follows: powder feeding gas flow rate is 6-10L / min argon, shielding gas flow rate is 10-20L / min argon, laser power is 380-450W, scanning speed is 5-6mm / s, powder feeding rate is 1.2-1.4r / min;

[0036] The process parameters of laser cladding of abrasive layer are as follows: powder feeding gas flow rate is 6-10L / min argon, shielding gas flow rate is 10-20L / min argon, laser power is 350-400W, scanning speed is 5-6mm / s, and powder feeding rate is 1.4-1.6r / min.

[0037] Among them, the laser spot diameter of laser cladding is 1-1.2mm.

[0038] S5, fix the substrate, turn on the ultrasonic vibration equipment, set the ultrasonic amplitude to 3-8 μm, the frequency to 15-25 kHz, and the vibration direction to be perpendicular to the end face of the grinding wheel; deposit a metal binder layer on the surface of the grinding wheel substrate according to the laser cladding trajectory generated in step S2 and the process parameters determined in step S4;

[0039] The shape coefficient of the cladding layer and the depth of the mixed melt zone were selected as the evaluation indicators of the cladding quality of the metal binder layer, and the ultrasonic-assisted laser cladding process of the metal binder layer was completed by using reciprocating scanning as the laser scanning method.

[0040] Before processing the substrate, its surface is cleaned to remove impurities such as oil, oxides, etc., and the end face of the substrate is appropriately roughened to improve the bonding strength between the cladding layer and the substrate. If necessary, the substrate is laser heated to achieve preheating to reduce thermal stress during the cladding process.

[0041] In this embodiment, the end face diameter of the grinding wheel base is 50 mm. The ultrasonic application method is to directly connect the grinding wheel base with the ultrasonic horn through threads, so a fine thread matching the ultrasonic horn is designed on the grinding wheel handle, the thread part is 20 mm long, and the corresponding grinding wheel handle diameter is φ12.7 mm.

[0042] S6. Depositing an abrasive layer on the surface of the metal binder layer of the grinding wheel according to the laser cladding trajectory generated in step S2 and the process parameters determined in step S4 to complete the preparation of the structured grinding wheel.

[0043] The width-height product of the cladding layer and the number of effective abrasive particles were selected as the evaluation criteria for the cladding quality of the abrasive layer, and reciprocating scanning was used as the laser scanning method to complete the ultrasonic-assisted laser cladding process of the abrasive layer.

[0044] According to the above steps, the preparation process of ultrasonic-assisted laser cladding structured grinding wheels of all designed trajectories is completed.

[0045] Compared with the traditional grinding wheel manufacturing process, additive manufacturing technology can customize the shape structure and surface abrasive arrangement of the grinding wheel according to the requirements of the grinding task. The additive manufacturing of structured grinding wheels has important research significance and application value. This paper takes structured CBN grinding wheels as the research object and ultrasonic-assisted laser cladding technology as the process basis. By optimizing the process parameters and the grinding wheel structure, the overall grinding performance of the grinding wheel is improved.

[0046] The method for preparing the structured CBN grinding wheel adopted by the present invention is a secondary cladding method based on ultrasonic-assisted laser cladding technology, which is completed by feeding the metal binder powder and the abrasive layer powder in a sequential order. That is, the metal binder is first clad on the substrate to form a metal binder layer with a structured track, and then a layer of mixed powder of binder and abrasive is clad on the metal binder layer with a lower laser power according to the same scanning path. This secondary cladding method enables a strong metallurgical bond to be formed between the metal binder and the substrate, and between the metal binder and the CBN abrasive.

[0047] Matters not described in detail in the present invention are all known technologies.

[0048] The embodiments described above are merely descriptions of preferred implementation modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for preparing an ultrasonic vibration-assisted laser cladding structured grinding wheel, characterized in that: The method prepares an end surface structured grinding wheel by combining normal ultrasonic vibration technology with laser cladding technology, and comprises the following steps: S1. According to the actual size of the grinding wheel matrix, the abrasive layer structure without impact texture is designed on the surface of the grinding wheel matrix using 3D software; S2, saving the model of the grinding wheel substrate and the abrasive layer without impact texture in STEP format, inputting the three-dimensional model into PQart software, taking the center of the circular end face of the grinding wheel as the tool setting point, setting it as the initial point of the laser cladding trajectory, and generating the laser cladding trajectory; S3, dividing the metal binder into two parts, one part of which is uniformly mixed with abrasive grains in a determined ratio to form a powder for abrasive grain layer deposition; S4, determining the process parameters of laser cladding of the metal binder layer and the abrasive layer; S5, fixing the substrate, turning on the ultrasonic vibration equipment, and depositing a metal binder layer on the surface of the grinding wheel substrate according to the laser cladding trajectory generated in step S2 and the process parameters determined in step S4; S6. Depositing an abrasive layer on the surface of the metal binder layer of the grinding wheel according to the laser cladding trajectory generated in step S2 and the process parameters determined in step S4 to complete the preparation of the structured grinding wheel.

2. The method for preparing a structured grinding wheel by ultrasonic vibration-assisted laser cladding according to claim 1, characterized in that: In the step S3, a portion of the metal binder and the abrasive grains are uniformly mixed in a mass ratio of 6:

1.

3. The method for preparing a structured grinding wheel by ultrasonic vibration-assisted laser cladding according to claim 1, characterized in that: In step S5, the ultrasonic amplitude is 3-8 μm, the frequency is 15-25 kHz, and the vibration direction is perpendicular to the end face of the grinding wheel.

4. The method for preparing a structured grinding wheel by ultrasonic vibration-assisted laser cladding according to claim 1, characterized in that: In the step S1, the inlet angle β1 of the grinding fluid channel without the impact texture track pattern and the terminal angle β2 of the grinding fluid channel are both 30°.

5. The method for preparing a structured grinding wheel by ultrasonic vibration-assisted laser cladding according to claim 1, characterized in that: In the step S4, the process parameters of the laser cladding of the metal binder layer are: the powder feeding gas flow rate is 6-10L / min argon, the shielding gas flow rate is 10-20L / min argon, the laser power is 380-450W, the scanning speed is 5-6mm / s, and the powder feeding rate is 1.2-1.4r / min; the process parameters of the laser cladding of the abrasive layer are: the powder feeding gas flow rate is 6-10L / min argon, the shielding gas flow rate is 10-20L / min argon, the laser power is 350-400W, the scanning speed is 5-6mm / s, and the powder feeding rate is 1.4-1.6r / min.

6. The method for preparing a structured grinding wheel by ultrasonic vibration-assisted laser cladding according to claim 5, characterized in that: In step S4, the diameter of the laser spot of laser cladding is 1-1.2 mm.

7. The method for preparing a structured grinding wheel by ultrasonic vibration-assisted laser cladding according to claim 6, characterized in that: In the step S3, the metal binder is Cu-Sn-Ti powder.

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