High-precision electroplating grinding rod and preparation method thereof

Abstract

The invention discloses a high-precision electroplating grinding rod and a preparation method thereof, and belongs to the technical field of precision grinding tools. The electroplated grinding rod comprises a metal matrix and a composite coating, the composite coating comprises uniformly dispersed abrasive particles, the abrasive particle size distribution D90 / D10 is less than or equal to 1.5, the volume ratio is 15-45%, and the surface roughness Ra of the coating is less than or equal to 0.8 mu m. The preparation method comprises the steps of matrix pretreatment, grinding material ultrasonic-mechanical stirring synergistic dispersion, pulse electroplating and precise polishing. By optimizing the grinding material dispersion process and pulse electroplating parameters, the grinding material distribution uniformity is improved by more than 50%, the coating binding force is improved by 60%, the service life of a grinding rod is prolonged by two times, and the surface roughness Ra of a workpiece is reduced to be less than or equal to 0.1 mu m. The method is suitable for ultra-precision machining of high-hardness materials and has remarkable economic benefits and industrial application value.

Description

Technical Field

[0001] The present invention relates to the technical field of precision grinding tools, and particularly relates to a high-precision electroplated grinding rod and a preparation method thereof. Background Art

[0002] Due to the uneven distribution of abrasives and insufficient bonding force in the coating of traditional electroplated grinding rods, the grinding accuracy and service life are relatively low. In the prior art, it is difficult to achieve high-uniform dispersion of abrasives by ordinary electroplating processes, and the surface roughness of the coating is relatively high, affecting the machining accuracy.

[0003] The present invention prepares a high-precision and long-service-life electroplated grinding rod by optimizing the abrasive dispersion process, adopting pulse electroplating technology and combining with precision polishing.

[0004] Therefore, how to provide a high-precision electroplated grinding rod and a preparation method thereof to solve the problems existing in the prior art is of great significance for its application. Summary of the Invention

[0005] In view of this, the purpose of this application is to provide a high-precision electroplated grinding rod and a preparation method thereof to solve the problems in the prior art that it is difficult to achieve high-uniform dispersion of abrasives by ordinary electroplating processes, and the surface roughness of the coating is relatively high, affecting the machining accuracy.

[0006] To achieve the above purpose, the present invention provides the following technical solutions:

[0007] A high-precision electroplated grinding rod, comprising:

[0008] A metal substrate;

[0009] A composite coating, which is coated on the surface of the metal substrate by an electroplating process and contains a metal matrix phase and uniformly dispersed abrasive particles;

[0010] The particle size distribution of the abrasive particles D90 / D10 ≤ 1.5, and the volume ratio is 15 - 45%;

[0011] The surface roughness Ra of the composite coating ≤ 0.8 μm.

[0012] Preferably, the metal substrate is a cemented carbide or stainless steel that has been mirror-finished, and its surface roughness Ra ≤ 0.2 μm.

[0013] Preferably, the abrasive particles are selected from at least one of diamond, cubic boron nitride, silicon carbide or alumina, and the particle size range is 1 - 50 μm.

[0014] Preferably, the metal matrix phase is nickel, nickel-cobalt alloy or nickel-phosphorus alloy, the coating thickness is 10 - 200 μm, and the Vickers hardness ≥ 600 HV.

[0015] Preparation method of high-precision electroplated grinding rod, comprising the following steps:

[0016] S1: Substrate pretreatment: degreasing, pickling and activation treatment of the metal substrate;

[0017] S2: Abrasive dispersion: adding abrasive particles into the electroplating solution, and adopting the synergistic treatment of ultrasonic dispersion and mechanical stirring to keep the abrasive in a suspended state;

[0018] S2: Pulse electroplating: carrying out pulse electroplating under the conditions of current density 1-10 A / dm 2 , duty cycle 10-50%, and frequency 50-1000 Hz;

[0019] S4: Post-treatment: carrying out polishing treatment after plating to make the surface roughness reach Ra≤0.8 μm.

[0020] Preferably, the electroplating solution in S2 is a nickel sulfamate system, containing 50-120 g / L of nickel ions, with a pH value of 3.5-4.5 and a temperature of 45-65 °C.

[0021] Preferably, a periodic reverse pulse current is adopted in S3, and the ratio of the forward energization time to the reverse energization time is 5:1 to 10:1.

[0022] Preferably, the polishing treatment in S4 adopts a chemical mechanical polishing process, uses a polishing solution containing nano-silica, and the polishing pressure is 0.1-0.5 MPa.

[0023] Compared with the prior art, the beneficial effects of the present invention are:

[0024] 1. High-precision grinding: By strictly controlling the abrasive particle size distribution (D90 / D10≤1.5) and the surface polishing process (Ra≤0.8 μm), the surface roughness of the machined workpiece reaches Ra≤0.1 μm, meeting the requirements of ultra-precision machining.

[0025] 2. Significantly improved abrasive distribution uniformity: Adopting the synergistic process of ultrasonic dispersion and mechanical stirring, the coefficient of variation (CV) of the abrasive spacing is reduced from 28-35% in the traditional process to 12-15%, avoiding the problem of uneven local wear caused by abrasive agglomeration.

[0026] 3. Enhanced coating adhesion: Pulse electroplating combined with substrate activation treatment enables the critical coating adhesion (Lc) to reach 38-45 N, which is more than 60% higher than that of traditional direct current electroplating (20-26 N), effectively preventing abrasive shedding.

[0027] 4. Greatly extended service life: The service life of the grinding rod reaches 1000-1500 meters (400-600 meters in the traditional process), mainly due to the uniform distribution of abrasives and the high-temperature stability of the coating (hardness retention rate >90% at 400 °C).

[0028] 5. Process economy optimization: The pulse electroplating time is shortened by 40% (2 hours vs. 3.5 hours in the traditional process), the abrasive utilization rate reaches 95% (70% in the traditional process), and the comprehensive cost is reduced by 20%.

[0029] 6. Wide application range: It can be adapted to various abrasives such as diamond, CBN, and SiC, and is suitable for precision machining of high-hardness materials such as cemented carbide, ceramics, and bearing steel.

[0030] The above description is only an overview of the technical solution of this application. In order to understand the technical means of this application more clearly, so as to be implemented in accordance with the content of the specification, and in order to make the above and other purposes, features, and advantages of this application more obvious and understandable, the following describes in detail with reference to the preferred embodiments of this application and the accompanying drawings.

[0031] Those skilled in the art will understand the above and other purposes, advantages, and features of this application more clearly according to the following detailed description of the specific embodiments of this application in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the following will briefly introduce the drawings required to be used in the description of the embodiments or the prior art. Obviously, the following drawings are some embodiments of this application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings. In all the drawings, similar elements or parts are generally denoted by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to actual scale.

[0033] Figure 1 It is a flowchart of the preparation method of the present invention;

[0034] Figure 2 It is a structural schematic diagram of the present invention;

[0035] Figure 3 It is a test result diagram of the abrasive distribution uniformity of the present invention;

[0036] Figure 4 It is a test result diagram of the coating adhesion of the present invention;

[0037] Figure 5 It is a comparison result diagram of the grinding performance of the present invention;

[0038] Figure 6 It is a test result diagram of the high-temperature resistance performance of Example 2.

[0039] In the figure: 1. Metal matrix; 2. Composite coating. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0040] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the following will clearly and completely describe the technical solutions in the embodiments of this application with reference to the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are some, but not all, of the embodiments of this application. In the following description, specific details such as specific configurations and components are provided only to assist in a comprehensive understanding of the embodiments of this application. Therefore, those skilled in the art should clearly understand that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of this application. Additionally, descriptions of known functions and configurations are omitted for clarity and conciseness in the embodiments.

[0041] In addition, this application may repeat reference numerals and / or letters in different instances. This repetition is for the purpose of simplicity and clarity and does not in itself indicate the relationship between the various embodiments and / or arrangements discussed.

[0042] The term "and / or" in this document is merely a description of the associated relationship of the associated objects, indicating that three relationships may exist. For example, A and / or B may represent: A exists alone, B exists alone, and both A and B exist simultaneously. The term " / and" in this document describes another associated object relationship, indicating that two relationships may exist. For example, A / and B may represent: A exists alone, and both A and B exist. Additionally, the character " / " in this document generally indicates that the associated objects before and after are in an "or" relationship.

[0043] It should also be noted that in this document, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprising," "including," or any other variant thereof are intended to cover non-exclusive inclusion.

[0044] Please refer to Figure 1-2 , this invention provides a technical solution for a high-precision electroplated grinding rod and its preparation method:

[0045] Example 1: Diamond High-Precision Electroplated Grinding Rod

[0046] 1. Raw Materials and Equipment

[0047] Metal matrix: Cemented carbide rod (diameter 5 mm, length 100 mm, Ra = 0.15 μm)

[0048] Abrasive: Diamond micropowder (average particle size 10 μm, D90 / D10 = 1.3)

[0049] Electroplating solution: Nickel sulfamate system (Ni 2+80 g / L, pH = 4.0, temperature 50 °C)

[0050] Equipment: ultrasonic disperser, pulse electroplating power supply, chemical mechanical polishing machine

[0051] 2. Preparation method

[0052] (1) Substrate pretreatment:

[0053] Successively carry out ultrasonic degreasing with acetone → pickling with 10% hydrochloric acid → activation with 5% sulfuric acid, wash with water and then dry.

[0054] (2) Abrasive dispersion:

[0055] Add diamond micropowder (volume ratio 30%) to the electroplating solution, ultrasonically disperse for 30 min (power 300 W), and mechanically stir simultaneously (rotation speed 200 rpm).

[0056] (3) Pulse electroplating:

[0057] Adopt the forward pulse mode (current density 3 A / dm 2 , duty cycle 30%, frequency 500 Hz), electroplating time 120 min, coating thickness about 50 μm.

[0058] (4) Post-treatment:

[0059] Adopt chemical mechanical polishing (nano-SiO2 polishing solution, pressure 0.3 MPa, rotation speed 100 rpm, time 20 min), and finally the surface roughness Ra = 0.6 μm.

[0060] 3. Performance test

[0061] Uniformity of abrasive distribution: SEM observation shows that there is no agglomeration of abrasives and the distribution is uniform.

[0062] Coating hardness: Vickers hardness measurement is 650 HV.

[0063] Grinding test: Processing stainless steel workpieces, the surface roughness Ra ≤ 0.1 μm, and the service life is increased by 2 times compared with traditional grinding rods.

[0064] Example 2: Cubic boron nitride (CBN) high-precision electroplated grinding rod

[0065] 1. Raw materials and equipment

[0066] Metal substrate: 304 stainless steel rod (diameter 8 mm, length 150 mm, Ra = 0.18 μm)

[0067] Abrasive: CBN micropowder (average particle size 20 μm, D90 / D10 = 1.4)

[0068] Electroplating solution: nickel-cobalt alloy plating solution (Ni2+ 100 g / L, Co 2+ 20 g / L, pH = 4.2, temperature 55 °C)

[0069] 2. Preparation method

[0070] (1) Substrate pretreatment: same as Example 1.

[0071] (2) Abrasive dispersion:

[0072] CBN micropowder (volume ratio 25%) is added to the plating solution, with ultrasonic + mechanical stirring (power 350 W, rotation speed 250 rpm).

[0073] (3) Pulse electroplating:

[0074] Periodic reverse pulse (forward current density 5 A / dm 2 , reverse current density 0.5 A / dm 2 , duty cycle 40%, frequency 200 Hz), electroplating for 150 min, coating thickness 80 μm.

[0075] (4) Post-treatment:

[0076] Chemical mechanical polishing (nano-Al2O3 polishing solution, pressure 0.2 MPa), Ra = 0.7 μm.

[0077] 3. Performance testing

[0078] Coating adhesion: no peeling in the scratch test, excellent adhesion.

[0079] Heat resistance: hardness retention rate > 90% after heat treatment at 400 °C.

[0080] Example 3: Composite abrasive (diamond + SiC) high-precision electroplated grinding rod

[0081] 1. Raw materials and equipment

[0082] Metal substrate: cemented carbide (Ra = 0.1 μm)

[0083] Abrasive: diamond (5 μm) + silicon carbide (15 μm) (mixing ratio 1:1, total volume ratio 35%)

[0084] Plating solution: nickel-phosphorus alloy plating solution (Ni 2+ 60 g / L, sodium hypophosphite 20 g / L, pH = 3.8, temperature 60 °C)

[0085] 2. Preparation method

[0086] (1) Substrate pretreatment: same as Example 1.

[0087] (2) Abrasive dispersion:

[0088] Ultrasonically disperse the mixed abrasive for 40 min (power 400 W), and mechanically stir (300 rpm).

[0089] (3) Pulse electroplating:

[0090] High-frequency pulse (frequency 1000 Hz, duty cycle 20%, current density 2 A / dm 2 ), coating thickness 100 μm.

[0091] (4) Post-treatment:

[0092] Precision polishing (nano-diamond polishing fluid), Ra = 0.5 μm.

[0093] 3. Performance testing

[0094] Grinding efficiency: 30% higher than that of single abrasive.

[0095] Life test: The coating does not peel off after continuous processing for 100 hours.

[0096] Conclusion

[0097] By optimizing the abrasive dispersion, pulse electroplating parameters and post-treatment process, the present invention prepares an electroplated grinding rod with high precision and high wear resistance, which is suitable for the field of ultra-precision machining. The examples show that the product is significantly superior to the traditional process in terms of abrasive distribution uniformity, surface roughness and service life.

[0098] Comprehensive testing:

[0099] 1. Abrasive distribution uniformity test

[0100] Test method: Observe the cross-section of the coating by SEM scanning electron microscope, and statistically analyze the abrasive distribution uniformity (represented by the coefficient of variation CV% of the abrasive spacing. The smaller the CV, the more uniform the distribution)

[0101] The test results are as Figure 3 shown:

[0102] Conclusion: The ultrasonic + mechanical stirring synergistic dispersion technology of the present invention makes the abrasive distribution more uniform (CV reduced by more than 50%).

[0103] 2. Coating adhesion test

[0104] Test method: Adopt a scratch test (load 0 - 50 N, scratch speed 10 mm / min), and record the critical load (Lc) when the coating peels off

[0105] The test results are as Figure 4 shown:

[0106] Conclusion: Pulse electroplating combined with optimized pretreatment process improves the coating adhesion by more than 60%.

[0107] 3. Comparison of grinding performance

[0108] Test conditions:

[0109] Workpiece material: GCr15 bearing steel (hardness 62HRC)

[0110] Grinding parameters: rotational speed 3000 rpm, feed rate 0.1 mm / s, coolant lubrication

[0111] Evaluation indicators: surface roughness (Ra) of the workpiece after grinding, life of the grinding rod (measured by grinding length)

[0112] Test results are as Figure 5 shown:

[0113] Conclusion:

[0114] The grinding rod of the present invention reduces the surface roughness of the workpiece by 30% - 50%.

[0115] The life is extended by more than 2 times, mainly due to the uniform distribution of abrasives and the high bonding strength of the coating.

[0116] 4. High temperature resistance performance (special test for Example 2)

[0117] Test method: Heat treat the CBN grinding rod at 400 °C for 2 hours, and test the hardness retention rate and grinding performance after cooling.

[0118] Test results are as Figure 6 shown:

[0119] Conclusion: The nickel-cobalt alloy coating has excellent high temperature stability, and the hardness retention rate > 90%, far higher than the traditional process.

[0120] Comprehensive conclusion:

[0121] The high-precision electroplated grinding rod of the present invention is significantly superior to the traditional process in terms of uniform distribution of abrasives, coating bonding strength, grinding accuracy, service life and high temperature stability, and is especially suitable for ultra-precision machining of high-hardness materials (such as cemented carbide, ceramics). The test data can provide a reliable basis for industrial application.

[0122] The above are only the preferred embodiments of the present invention, and it does not limit the protection scope of the present invention accordingly. For those skilled in the art, the present invention can have various changes and modifications. Any changes, modifications, substitutions, integrations and parameter changes to these embodiments within the spirit and principle of the present invention by means of conventional substitutions or capable of achieving the same functions without departing from the principle and spirit of the present invention fall within the protection scope of the present invention.

Claims

1. A high-precision electroplated grinding rod, characterized in that, Comprising: A metal substrate (1); A composite coating (2), which is coated on the surface of the metal substrate (1) by an electroplating process and contains a metal matrix phase and uniformly dispersed abrasive particles; The particle size distribution D90 / D10 of the abrasive particles is ≤1.5, and the volume proportion is 15-45%; The surface roughness Ra of the composite coating (2) is ≤0.8 μm.

2. The high-precision electroplated grinding rod according to claim 1, wherein, The metal substrate (1) is cemented carbide or stainless steel that has been mirror-finished, and its surface roughness Ra is ≤0.2 μm.

3. The high-precision electroplated grinding rod according to claim 1, characterized in that, The abrasive particles are selected from at least one of diamond, cubic boron nitride, silicon carbide or alumina, and the particle size range is 1-50 μm.

4. The high-precision electroplated grinding rod according to claim 1, wherein The metal matrix phase is nickel, nickel-cobalt alloy or nickel-phosphorus alloy, the coating thickness is 10-200 μm, and the Vickers hardness is ≥600 HV.

5. The preparation method of the high-precision electroplated grinding rod according to any one of claims 1-4, characterized in that, Including the following steps: S1: Substrate pretreatment: Degreasing, pickling and activation treatment are carried out on the metal substrate; S2: Abrasive dispersion: The abrasive particles are added to the electroplating solution, and ultrasonic dispersion and mechanical stirring are used in combination to keep the abrasive in a suspended state; S2: Pulse electroplating: Conduct pulse electroplating under the conditions of a current density of 1-10 A / dm 2 , a duty cycle of 10-50%, and a frequency of 50-1000 Hz; S4: Post-treatment: Polishing treatment is carried out after plating to make the surface roughness reach Ra ≤0.8 μm.

6. The preparation method according to claim 5, wherein In the S2, the electroplating solution is a nickel sulfamate system, containing 50-120 g / L of nickel ions, with a pH value of 3.5-4.5 and a temperature of 45-65 °C.

7. The preparation method according to claim 5, characterized in that, In the S3, a periodic reverse pulse current is used, and the ratio of the forward conduction time to the reverse conduction time is 5:1 to 10:

1.

8. The preparation method according to claim 5, characterized in that, The polishing treatment in the S4 uses a chemical mechanical polishing process, uses a polishing solution containing nano-silica, and the polishing pressure is 0.1-0.5 MPa.

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