Multi-coating diamond dental bur and manufacturing process

Abstract

The invention discloses a multi-coating diamond dental bur and a manufacturing process thereof. The process comprises the following steps: carrying out electroplating pretreatment on a bur base body; the bur base body is electroplated in electroplating liquid containing first diamond, a first nickel layer embedded with a first diamond layer is formed, and the outer end of the first diamond layer is exposed out of the first nickel layer; the bur base body is electroplated in electroplating liquid containing second diamond, a second nickel layer embedded with a second diamond layer is formed on the first nickel layer, and the inner end of the second diamond layer is supported on the first diamond layer or clamped between the first diamond layers; and if other diamond layers exist, electroplating of the other diamond layers continues to be completed according to the operation in the step (3). The dental bur has a strong diamond structure and a hard coating, the holding force and the adhesive force are greatly improved, the rate of exposure can be improved, meanwhile, the yield is improved, the coating and the diamond can be prevented from falling off, and the product performance index is greatly improved.

Description

Technical Field

[0001] The invention relates to a dental turning needle, in particular to a multi-layer diamond dental turning needle and a manufacturing process. Background Art

[0002] During clinical use, the important technical indicators of dental needles are mainly durability, sharpness and concentricity. In clinical treatment, the rotation speed of dental needles reaches 300,000-400,000 / minute and the treatment targets are the teeth with the highest hardness. Dental needles are a product with very high requirements for use.

[0003] At present, dental diamond needles mainly use single-layer sand electroplating technology. The main components of diamond electroplating technology are nickel layer and diamond. The hardness of the electroplated nickel layer is generally 150-300HV, and the diamond particle size is generally 80-120 microns. The diamond particle size is irregular in shape. After the single-layer diamond is combined with the nickel layer, there is a large amount of pure nickel layer area in the intersection of diamond and the bottom layer and diamond and diamond. The nickel layer is relatively soft and the nickel layer thickness of the dental needle product is only tens of microns. However, dental needles are used in clinical high-speed rotation (30-4 00,000 rpm). During the use of dental burs, due to the soft nickel layer and high-speed rotation, shear force and other forces, the nickel layer at the intersection of the plating and the dental bur base will be affected by the force and the plating will fall off. The soft plating will also lead to insufficient diamond holding force and diamond falling off. Due to the soft hardness and insufficient thickness of the nickel layer, the diamond edge rate generally does not exceed 25%, resulting in insufficient sharpness of the product during use. The single-layer dental diamond bur electroplating will also cause sparse diamonds on the surface, resulting in a low product qualification rate.

[0004] For this purpose, we gradually began to develop multi-layer diamond dental needles. However, multi-layer diamond dental needles have to go through a lot of tests and verifications to be effective. For example, when the first layer of sand is attached to the dental needle base, various nickel nodules, stacking, uneven distribution and other process difficulties will appear. In particular, the third layer of sanding process is more likely to damage the first two layers of sand, such as causing the first two layers of sand to fall off, and the plating is too thick and reduces the cutting edge rate. The electroplating process of multi-layer dental diamond needles is not only the application of different electroplating basic knowledge and electroplating processes in the diamond electroplating discipline to combine into a multi-layer diamond electroplating process, but also an innovation in the electroplating coating structure. The combination of different levels of distribution and different particle sizes of diamond and coating produces better coating bonding strength and toughness. It is also one of the main reasons why our peers gave up this innovation due to the complexity and difficulty of the process and the high feasibility requirements. Summary of the invention

[0005] The purpose of the present invention is to overcome the above-mentioned problems and provide a multi-layer diamond dental bur, which has a strong diamond structural force and a harder coating, greatly improving the holding force and adhesion, not only improving the cutting edge rate, but also preventing the coating and diamond from falling off, and at the same time improving the uniform distribution of diamonds and appropriate gaps on the diamond surface of the dental diamond bur electroplated product, thereby increasing the product qualification rate to at least 95%.

[0006] The purpose of the present invention is to overcome the above-mentioned problems and provide a manufacturing process for a multi-layer diamond dental bur.

[0007] The purpose of the present invention is achieved through the following technical solutions:

[0008] A multi-layer diamond dental bur, comprising a bur base and an electroplating structure arranged on the bur base;

[0009] The electroplating structure includes a nickel layer and a diamond layer, and the nickel layer is wrapped on the needle substrate; the electroplating structure includes a nickel layer and a diamond layer, and the nickel layer is wrapped on the needle substrate; the diamond layer is embedded in the nickel layer, and the diamond layer is provided with at least two layers, and along the direction away from the needle substrate, the other diamond layer is supported on the previous diamond layer or sandwiched between the previous diamond layers.

[0010] A preferred embodiment of the present invention is that the diamond layer is provided with three layers, namely a first diamond layer, a second diamond layer and a third diamond layer, wherein the first diamond layer is arranged on the needle substrate and buried in the nickel layer, and the thickness of the first diamond layer is less than the thickness of the nickel layer; the inner end of the second diamond layer is arranged on the first diamond layer, and the outer end of the second diamond layer extends outside the nickel layer (exposing about 40% of the total diamond height); the inner end of the diamonds in the third diamond layer is embedded in the nickel layer, and the diamonds in the third diamond layer are sandwiched between the diamonds in the second diamond layer, and also about 40% of the total diamond height is exposed.

[0011] In a preferred embodiment of the present invention, the diamond grain size of the third diamond layer is larger than the diamond grain size of the first diamond layer but smaller than the diamond grain size of the third diamond layer.

[0012] A manufacturing process for a multi-layer diamond dental bur, comprising the following steps:

[0013] (1) Pre-plating treatment of the needle substrate;

[0014] (2) electroplating the needle substrate in an electroplating solution containing a first diamond to form a first nickel layer embedded with a first diamond layer, wherein an outer end of the first diamond layer is exposed outside the first nickel layer;

[0015] (3) electroplating the needle substrate in an electroplating solution containing a second diamond to form a second nickel layer embedded with a second diamond layer on the first nickel layer, wherein the inner end of the second diamond layer is supported on the first diamond layer or sandwiched between the first diamond layers;

[0016] (4) If there are other diamond layers, continue to electroplate the other diamond layers according to the operation of step (3) until all diamond electroplating work is completed;

[0017] If there are no other diamond layers, the multi-layer diamond electroplating work is completed.

[0018] In a preferred embodiment of the present invention, in step (1), the electroplating pretreatment includes the following: chemical degreasing, alkaline degreasing, ultrasonic degreasing, hot water cleaning, water cleaning, chemical etching, water cleaning, chemical activation, water cleaning, and pre-nickel plating.

[0019] Furthermore, the chemical degreasing uses an acetone solution and ultrasonic cleaning for 15 minutes;

[0020] Alkaline washing and degreasing use 35~45g·L -1 NaOH, 25-35 g·L -1 Na 2 CO 3 , 25~30g·L -1 of alkali solution, keep warm at 80℃ for 20min, and clean under ultrasonic conditions for 10min;

[0021] The chemical etching uses HF and HNO 3 The mixed solution was etched until red smoke appeared, and the volume ratio of the mixed solution was 40wt.% HF: 65wt.% HNO 3 =1∶3.

[0022] In a preferred embodiment of the present invention, the electroplating operation in step (2) is:

[0023] Evenly spread the first diamond in the first electroplating tank of the electroplating device; install the needle substrate on the fixture, and place the installed needle substrate at the designated position of the first electroplating tank;

[0024] The electroplating device is started, the electroplating liquid is input into the first electroplating tank through the liquid supply mechanism, and the air flow used to blow up the first diamond is delivered to the bottom of the first electroplating tank through the air supply mechanism, so that the first diamond floats in the electroplating liquid in the first electroplating tank; under the action of the electric current, the electroplating liquid carries the first diamond and is adsorbed on the needle substrate to form a first nickel layer and a first diamond layer.

[0025] Furthermore, the electroplating time of the electroplating operation in step (2) is 10-30 min, and the current density is 1-2 A / dm 2The pH of the plating solution is 2-6, the temperature of the plating solution is 50-80°C, the flow rate of the plating solution is 5-7L / min, and the gas flow rate of the gas supply mechanism is 1-1.2m 3 / min.

[0026] Furthermore, the particle size of the first diamond in step (2) is 10-40 μm.

[0027] In a preferred embodiment of the present invention, the electroplating operation in step (3) is:

[0028] The electroplating solution is transported to a second electroplating tank, wherein the bottom and side surfaces of the second electroplating tank are both provided with liquid transporting through holes;

[0029] placing the air-permeable package containing the second diamond in a second electroplating tank;

[0030] The needle substrate after the electroplating in step (2) is obliquely inserted into the second diamond in the second electroplating tank, and the second diamond near the needle substrate is in direct contact with the outer end of the first diamond layer;

[0031] The electroplating device is started. Under the action of electric current, the electroplating liquid is adsorbed on the first nickel layer of the needle substrate to form a second nickel layer. At the same time, the second nickel layer fixes the second diamond in contact with the outer end of the first diamond layer on the first nickel layer to form a second diamond layer.

[0032] Furthermore, the electroplating time of the electroplating operation in step (3) is 40-70 min, and the current density is 1.5-3 A / dm 2 , the pH of the plating solution is 2-6, the temperature of the plating solution is 50-80°C, and the flow rate of the plating solution is 5-7L / min.

[0033] Furthermore, the particle size of the second diamond in step (3) is 80-120 μm.

[0034] In a preferred embodiment of the present invention, in step (4), the electroplating operation of the third diamond layer is:

[0035] The electroplating solution is transported to a third electroplating tank, wherein the bottom and side surfaces of the third electroplating tank are both provided with liquid transporting through holes;

[0036] placing the air-permeable package containing the third diamond in the third electroplating tank;

[0037] Two air supply pipes are provided on both sides of the bottom of the third electroplating tank, and the angle between the outlet direction of the air supply pipe and the horizontal plane is 45°. The air supply pipes are used to deliver airflow to the third diamond, and the airflow is used to loosen the third diamond.

[0038] The needle substrate after the electroplating in step (3) is obliquely inserted into the third diamond in the third electroplating tank, and the third diamond part close to the needle substrate is inserted into the gap of the second diamond layer;

[0039] The electroplating device is started. Under the action of electric current, the electroplating liquid is adsorbed on the second nickel layer of the needle substrate to form a third nickel layer. At the same time, the third nickel layer fixes the third diamond in the gap of the second diamond layer to form a third diamond layer. The outer ends of the third diamond layer and the second diamond layer are exposed outside the third nickel layer.

[0040] Furthermore, the electroplating time of step (4) is 20-40 min, and the current density is 1-3 A / dm 2 , the pH of the plating solution is 3-7, the temperature of the plating solution is 50-80℃, and the gas flow rate is 0.8-1.0m 3 / min.

[0041] Furthermore, the particle size of the third diamond in step (4) is 40-60 μm.

[0042] In a preferred embodiment of the present invention, after completing step (4), the nickel layer is further thickened.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] 1. The first diamond layer of the present invention first forms a hardened diamond thin nickel layer on the surface of the needle substrate, and then the second diamond layer is embedded in the coating of the first diamond layer instead of the softer pure nickel layer, thereby improving the hardness and adhesion of the first nickel layer and reducing the internal stress between the pure nickel layers, thereby reducing the probability of the coating and diamond falling off due to shear force and other forces and internal stress problems during the use of the diamond needle.

[0045] 2. Attach the third diamond layer between the second diamond layer. By combining the third diamond layer with the nickel layer and embedding it in the gaps between other diamonds, the second diamond layer can be stabilized and the internal stress between the pure nickel layers can be reduced. At the same time, the third diamond layer is exposed, so that the diamond particles on the surface of the dental needle are exposed and the surface diamond distribution is more even, which increases the wear-resistant force area. Therefore, the problem of diamond falling off during use due to the thin nickel layer and the soft hardness of the single nickel layer will not occur, thereby improving the cutting edge rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1-3 The present invention is a process diagram of the manufacturing process of the multi-layer diamond dental bur.

[0047] Figure 4 The figure is a comparison chart of the cutting performances of the multi-layered diamond dental bur and the single-layered diamond dental bur of the present invention. DETAILED DESCRIPTION

[0048] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described below in conjunction with embodiments and drawings, but the embodiments of the present invention are not limited thereto.

[0049] Combination Figure 3 The multi-layered diamond dental bur of this embodiment comprises a bur base 1 and an electroplating structure arranged on the bur base 1; the electroplating structure comprises a nickel layer 2 and a diamond layer, the nickel layer 2 is wrapped on the bur base 1; the diamond layer is provided with three layers (of course, it can also be two or four layers) and are respectively a first diamond layer 3, a second diamond layer 4 and a third diamond layer 5, the first diamond layer 3 is arranged on the bur base 1 and buried in the nickel layer 2, and the thickness of the first diamond layer 3 is less than the thickness of the nickel layer 2; the inner end of the second diamond layer 4 is arranged on the first diamond layer 3, and the outer end of the second diamond layer 4 extends outside the nickel layer 2; the inner end of the diamond of the third diamond layer 5 is embedded in the nickel layer 2, and the diamond of the third diamond layer 5 is sandwiched between the diamonds of the second diamond layer 4.

[0050] Furthermore, the diamond grain size of the third diamond layer 5 is larger than the diamond grain size of the first diamond layer 3 but smaller than the diamond grain size of the third diamond layer 5 .

[0051] Combination Figure 1-3 The manufacturing process of the multi-layer diamond dental bur needle of this embodiment comprises the following steps:

[0052] (1) The needle substrate 1 is subjected to the following pre-plating treatments: chemical degreasing, alkaline degreasing, ultrasonic degreasing, hot water cleaning, water cleaning, chemical etching, water cleaning, chemical activation, water cleaning, and pre-nickel plating.

[0053] Furthermore, the chemical degreasing uses an acetone solution and ultrasonic cleaning for 15 minutes.

[0054] Alkaline washing and degreasing use 35~45g·L -1 NaOH, 25-35 g·L -1 Na 2 CO 3 , 25~30g·L -1 of alkali solution, keep it warm at 80℃ for 20min, and clean it under ultrasonic conditions for 10min.

[0055] The chemical etching uses HF and HNO 3 The mixed solution was etched until red smoke appeared, and the volume ratio of the mixed solution was 40wt.% HF: 65wt.% HNO 3 =1∶3.

[0056] (2) Spreading the first diamond evenly in the first electroplating tank of the electroplating device, the particle size of the first diamond is 10-40 μm; installing the needle substrate 1 on the fixture, and placing the installed needle substrate 1 at the specified position of the first electroplating tank; using the floating sand method, starting the electroplating device, inputting the electroplating solution into the first electroplating tank through the liquid supply mechanism, and delivering the air flow used to blow the first diamond and the plating solution to the bottom of the first electroplating tank through the air supply mechanism, so that the first diamond floats in the electroplating solution of the first electroplating tank; under the action of the electric current, the electroplating solution carries the first diamond and is adsorbed on the needle substrate 1 to form a first nickel layer 2 and a first diamond layer 3, and the outer end of the first diamond layer 3 is exposed outside the first nickel layer 2, such as Figure 1 .

[0057] Furthermore, the electroplating time of the electroplating operation in step (2) is 10-30 min, and the current density is 1-2 A / dm 2 The pH of the plating solution is 2-6, the temperature of the plating solution is 50-80°C, the flow rate of the plating solution is 5-7L / min, and the gas flow rate of the gas supply mechanism is 1-1.2m 3 / min.

[0058] (3) delivering the electroplating solution to a second electroplating tank, wherein the bottom and side surfaces of the second electroplating tank are provided with liquid delivery holes; wrapping a nylon cloth containing a second diamond and placing it in the second electroplating tank, wherein the particle size of the second diamond in step (3) is 80-120 μm; obliquely inserting the needle substrate 1 electroplated in step (2) into the second diamond in the second electroplating tank, wherein the sand embedding method is used, wherein the second diamond part close to the needle substrate 1 is in direct contact with the outer end of the first diamond layer 3; starting the electroplating device, wherein under the action of the electric current, the electroplating solution is adsorbed on the first nickel layer 2 of the needle substrate 1 to form a second nickel layer 2, and at the same time, the second nickel layer 2 fixes the second diamond in contact with the outer end of the first diamond layer 3 on the first nickel layer 2 to form a second diamond layer 4, wherein the inner end of the second diamond layer 4 is supported on the first diamond layer 3, such as Figure 2 .

[0059] Furthermore, the electroplating time of the electroplating operation in step (3) is 40-70 min, and the current density is 1.5-3 A / dm 2 , the pH of the plating solution is 2-6, the temperature of the plating solution is 50-80°C, and the flow rate of the plating solution is 5-7L / min.

[0060] (4) delivering the electroplating solution to a third electroplating tank, wherein the bottom and side surfaces of the third electroplating tank are provided with liquid delivery holes; wrapping the third diamond with nylon cloth and placing it in the third electroplating tank; further, the particle size of the third diamond is 40-60 μm; two air supply pipes are provided on both sides of the bottom of the third electroplating tank, and the angle between the outlet direction of the air supply pipe and the horizontal plane is 45°, and the air flow is delivered to the third diamond through the air supply pipe, and the third diamond is loosened by the air flow, so that the third diamond is fully in contact with the plating solution; further, the air pressure is controlled at a gas flow rate of 0.8-1.0 m 3 / min, the gas should not be too large, so that the third diamond in the third electroplating tank has a slight loose feeling, to ensure that the third diamond in the third electroplating tank is not densely packed due to gravity, so that the plating solution, current and other media are fully in contact with the third diamond in the third electroplating tank, and at the same time, it can also ensure that the needle substrate 1 is inserted into the third electroplating tank at an angle of 45 degrees without damaging the attached second diamond layer 4.

[0061] The needle substrate 1 after the electroplating in step (3) is obliquely inserted into the third diamond in the third electroplating tank. At this time, the third diamond part close to the needle substrate 1 is inserted into the gap of the second diamond layer 4; the electroplating device is started. Under the action of the current, the electroplating liquid is adsorbed on the second nickel layer 2 of the needle substrate 1 to form a third nickel layer 2. At the same time, the third nickel layer 2 fixes the third diamond in the gap of the second diamond layer 4 to form a third diamond layer 5. The outer ends of the third diamond layer 5 and the second diamond layer 4 are both exposed outside the third nickel layer 2. Figure 3 .

[0062] Furthermore, the electroplating time of step (4) is 20-40 min, and the current density is 1-3 A / dm 2 , the pH of the plating solution is 3-7, the temperature of the plating solution is 50-80℃, and the gas flow rate is 0.8-1.0m 3 / min.

[0063] (5) Thicken the nickel layer 2 to complete the multi-layer diamond plating work.

[0064] Specifically, in order to verify the performance of the multi-layer diamond process turning needle, a machinable glass-ceramic rod was used as the cutting substrate for cutting tests. The performance parameters of the glass-ceramic rod are similar to those of human tooth enamel.

[0065] The test conditions are: the rotation speed of the dental handpiece is 340,000 rpm, deionized water is used as the coolant, the coolant flow rate is 22 ml / min, the load applied to the tip of the needle is about 100 g, and the use length of the needle is 4 mm.

[0066] During the cutting test, ten passes of 13 mm in length were cut and the cutting time was recorded. The cutting efficiency was expressed as the time taken to cut a unit distance of the glass-ceramic rod (mm / s).

[0067] For comparison, a single-layer diamond turning needle is used for comparison. Figure 4 .

[0068] The above is a preferred embodiment of the present invention, but the embodiment of the present invention is not limited to the above content. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A multi-layer diamond dental bur, comprising a bur base and an electroplating structure arranged on the bur base; characterized in that: The electroplating structure includes a nickel layer and a diamond layer, and the nickel layer is wrapped on the needle substrate; the electroplating structure includes a nickel layer and a diamond layer, and the nickel layer is wrapped on the needle substrate; the diamond layer is embedded in the nickel layer, and the diamond layer is provided with at least two layers, and along the direction away from the needle substrate, the other diamond layer is supported on the previous diamond layer or sandwiched between the previous diamond layers.

2. The multi-layer diamond dental bur according to claim 1, characterized in that: The diamond layer is provided with three layers, namely, a first diamond layer, a second diamond layer and a third diamond layer. The first diamond layer is provided on the needle substrate and buried in the nickel layer. The thickness of the first diamond layer is less than that of the nickel layer. The inner end of the second diamond layer is provided on the first diamond layer, and the outer end of the second diamond layer extends outside the nickel layer. The inner ends of the diamonds of the third diamond layer are embedded in the nickel layer, and the diamonds of the third diamond layer are sandwiched between the diamonds of the second diamond layer.

3. A manufacturing process for the multi-layer diamond dental bur according to any one of claims 1 to 2, characterized in that: The following steps are involved: (1) Pre-plating treatment of the needle substrate; (2) electroplating the needle substrate in an electroplating solution containing a first diamond to form a first nickel layer embedded with a first diamond layer, wherein an outer end of the first diamond layer is exposed outside the first nickel layer; (3) electroplating the needle substrate in an electroplating solution containing a second diamond to form a second nickel layer embedded with a second diamond layer on the first nickel layer, wherein the inner end of the second diamond layer is supported on the first diamond layer or sandwiched between the first diamond layers; (4) If there are other diamond layers, continue to electroplate the other diamond layers according to the operation of step (3) until all diamond electroplating work is completed; If there are no other diamond layers, the multi-layer diamond electroplating work is completed.

4. The manufacturing process of the multi-layer diamond dental bur according to claim 3, characterized in that: In step (1), the electroplating pre-treatment includes The following: chemical degreasing, alkaline degreasing, ultrasonic degreasing, hot water cleaning, water cleaning, chemical etching, water cleaning, chemical activation, water cleaning, pre-nickel plating; The chemical degreasing adopts acetone solution and ultrasonic cleaning for 15 minutes; Alkaline washing and degreasing use 35~45g·L -1 NaOH, 25-35 g·L -1 Na2CO3, 25~30g·L -1 of alkali solution, keep warm at 80℃ for 20min, and clean under ultrasonic conditions for 10min; The chemical etching uses a mixed solution of HF and HNO3 to etch until red smoke is emitted, and the volume ratio of the mixed solution is 40wt.% HF:65wt.% HNO3=1:

3.

5. The manufacturing process of the multi-layered diamond dental bur according to claim 3, characterized in that: The electroplating operation of step (2) is: Evenly spread the first diamond in the first electroplating tank of the electroplating device, wherein the particle size of the first diamond is 10-40 μm; install the needle substrate on the fixture, and place the installed needle substrate at the designated position of the first electroplating tank; The electroplating device is started, the electroplating liquid is input into the first electroplating tank through the liquid supply mechanism, and the air flow used to blow up the first diamond is delivered to the bottom of the first electroplating tank through the air supply mechanism, so that the first diamond floats in the electroplating liquid in the first electroplating tank; under the action of the electric current, the electroplating liquid carries the first diamond and is adsorbed on the needle substrate as the electroplating liquid flows continuously, forming a first nickel layer and a first diamond layer.

6. The manufacturing process of the multi-layered diamond dental bur according to claim 5, characterized in that: The electroplating time of step (2) is 10-30 min, and the current density is 1-2 A / dm 2 , the pH of the plating solution is 2-6, the temperature of the plating solution is 50-80°C, the flow rate of the plating solution is 5-7L / min, and the gas flow rate of the gas supply mechanism is 1-1.2m3 / min.

7. The manufacturing process of the multi-layered diamond dental bur according to claim 3, characterized in that: The electroplating operation of step (3) is: The electroplating solution is transported to a second electroplating tank, wherein the bottom and side surfaces of the second electroplating tank are both provided with liquid transporting through holes; placing a permeable package containing a second diamond in a second electroplating tank, wherein the particle size of the second diamond is 80-120 μm; The needle substrate after the electroplating in step (2) is obliquely inserted into the second diamond in the second electroplating tank, and the second diamond near the needle substrate is in direct contact with the outer end of the first diamond layer; The electroplating device is started. Under the action of electric current, the electroplating liquid is adsorbed on the first nickel layer of the needle substrate to form a second nickel layer. At the same time, the second nickel layer fixes the second diamond in contact with the outer end of the first diamond layer on the first nickel layer to form a second diamond layer.

8. The manufacturing process of the multi-layered diamond dental bur according to claim 7, characterized in that: The electroplating time of step (3) is 40-70 min, and the current density is 1.5-3 A / dm 2 , the pH of the plating solution is 2-6, the temperature of the plating solution is 50-80°C, and the flow rate of the plating solution is 5-7L / min.

9. The manufacturing process of the multi-layered diamond dental bur according to claim 3, characterized in that: In step (4), the electroplating operation of the third diamond layer is: The electroplating solution is transported to a third electroplating tank, wherein the bottom and side surfaces of the third electroplating tank are both provided with liquid transporting through holes; placing a gas permeable package containing a third diamond in a third electroplating tank, wherein the particle size of the third diamond is 40-60 μm; Two air supply pipes are provided on both sides of the bottom of the third electroplating tank. The outlet direction of the air supply pipe forms an angle of 45° with the horizontal plane. The air supply pipes are used to deliver airflow to the third diamond, and the airflow is used to loosen the third diamond, so that the third diamond is in full contact with the electroplating solution and is convenient for inserting the needle substrate. The needle substrate after the electroplating in step (3) is obliquely inserted into the third diamond in the third electroplating tank, and the third diamond part close to the needle substrate is inserted into the gap of the second diamond layer; The electroplating device is started. Under the action of electric current, the electroplating liquid is adsorbed on the second nickel layer of the needle substrate to form a third nickel layer. At the same time, the third nickel layer fixes the third diamond in the gap of the second diamond layer to form a third diamond layer. The outer ends of the third diamond layer and the second diamond layer are exposed outside the third nickel layer.

10. The manufacturing process of the multi-layered diamond dental bur according to claim 9, characterized in that: The electroplating time of step (4) is 20-40 min, and the current density is 1-3 A / dm 2 , the pH of the plating solution is 3-7, the temperature of the plating solution is 50-80℃, and the gas flow rate is 0.8-1.0m3 / min.

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