Jacking drill bit for sapphire processing and preparation method thereof

Abstract

The trepanning drill bit comprises a steel base body and a diamond tooth dividing tool bit, a welding table is arranged on the steel base body, the diamond tooth dividing tool bit is welded to the welding table, a first chip groove is formed in the bottom of the diamond tooth dividing tool bit, and a second chip groove is formed in the top of the diamond tooth dividing tool bit. The invention further discloses a preparation method of the trepanning drill bit, and the preparation method comprises the steps that the diamond tool bit is prepared from a composite material of diamond and metal powder (iron, cobalt, tungsten, copper and tin) through a powder metallurgy technology, and then the tool bit and the steel base body are combined together in a laser welding mode to form the trepanning drill bit. According to the trepanning drill bit, the danger that the diamond tooth dividing tool bit falls off in the drilling process is avoided, the water drainage and chip removal capacity of the trepanning drill bit is greatly improved, the concentricity of the prepared trepanning drill bit is smaller than 0.05 mm, and the trepanning drill bit has the advantages that the toughness and brittleness are good, the diamond exposure is good, the bar drawing efficiency is high, the service life of the drill bit reaches 20 m, and the bar drawing yield is high.

Description

Technical Field

[0001] The invention relates to the field of diamond drill bits, and in particular to a diamond drill bit for sapphire processing and a preparation method thereof. Background Art

[0002] In recent years, with the development of electronic information technology, especially the rapid development of semiconductor lighting industry, the market demand for sapphire substrates has become increasingly strong. Single crystal sapphire has been widely used due to its excellent optical properties, mechanical properties, high strength, high hardness, strong corrosion resistance, abrasion resistance, excellent insulation performance and other characteristics. Sapphire materials have been in short supply in the field of LED applications. Sapphire substrates are the preferred substrates for the current blue, purple, white light diodes (LED) and blue laser (LD) industries, and are the key materials for manufacturing semiconductor blue light-emitting diodes. They are also the preferred materials for nitride semiconductor substrates and integrated circuit substrates. Under special requirements, there are no alternative products. The cost-effectiveness of sapphire continues to improve and will become the best choice for LED upstream substrate materials.

[0003] Sapphire is increasingly used, but due to its high brittleness, high hardness, and stable chemical properties, the mass production technology is still immature, inefficient, and has serious cracks, scratches, and edge collapse, which brings great difficulties to processing. After the sapphire grows into a crystal column, the first step is to use a trepanning drill to trepan the sapphire from the crystal column to form a sapphire column, and then cut, grind, and slice it. At present, the trepanning drill used in sapphire processing has the following problems:

[0004] (1) The drill bit is not sharp enough, resulting in slippage and failure to advance, low drilling efficiency, and even serious cracks on the crystal surface;

[0005] (2) The chip removal ability of the trepanning drill bit is poor, resulting in the inability to remove the drilled cuttings in time, making it difficult to feed the drill and resulting in poor surface quality of the excavated crystal rod;

[0006] (3) The life of the trepanning drill bit is short, which increases the processing cost. Summary of the invention

[0007] The purpose of the present invention is to provide a trepanning drill bit for sapphire processing and a preparation method thereof, so as to solve the problems existing in the prior art that the trepanning drill bit is not sharp enough, has poor chip removal ability, leads to poor surface quality of sapphire crystal rod, and has a short service life of the drill bit.

[0008] In order to solve the above technical problems, the present invention is implemented by the following technical solutions:

[0009] A drill bit for sapphire processing comprises a steel substrate and a diamond segmented tooth bit, wherein a welding platform is arranged on the steel substrate, the diamond segmented tooth bit is welded on the welding platform, a first chip removal groove is arranged at the bottom of the diamond segmented tooth bit, and a second chip removal groove is arranged at the top of the diamond segmented tooth bit, and the raw materials of the diamond segmented tooth bit comprise a metal powder mixture and zinc diamond, wherein the volume fraction of zinc diamond accounts for 20%-40%, and the particle size is 200-350 μm, and the metal powder mixture comprises the following raw materials in weight percentage: 30%-50% of nano copper powder, 2%-5% of tin powder, 25%-35% of nano iron powder, 10%-20% of ultrafine cobalt powder, and 5%-10% of nano nickel powder.

[0010] Preferably, the thickness L of the welding platform is 0.2 mm≦L≦0.8 mm, and the depth D is 3 mm≦D≦6 mm.

[0011] Preferably, at least one first chip removal groove is provided, and a groove width W of the first chip removal groove is 3 mm≦W≦8 mm, and a groove depth H is 0.2 mm≦H≦0.8 mm.

[0012] Preferably, at least two of the second chip removal grooves are provided, and the groove width T of the second chip removal groove is 1mm≦W≦6mm, and the groove depth X is 5mm≦X≦12mm.

[0013] Preferably, the groove depth H of the first chip removal groove is less than or equal to the thickness L of the welding platform.

[0014] Preferably, the cross-sectional shapes of the first chip removal groove and the second chip removal groove are rectangular, trapezoidal, arc-shaped or triangular.

[0015] A method for preparing a trepanning drill bit for sapphire processing specifically comprises the following steps:

[0016] (1) Ingredients: Weigh the following raw materials in the following weight proportions: 30-50 parts of nano copper powder, 2-5 parts of tin powder, 25-35 parts of nano iron powder, 10-20 parts of ultrafine cobalt powder, 5-10 parts of nano nickel powder, 20%-40% (based on 400%) concentration of zinc diamond, and a particle size of 200-350 um, and mix the above raw materials to obtain alloy matrix powder;

[0017] (2) Mixing: The alloy matrix powder obtained in step (1) above is put into a mixer, firstly steel balls are added and dry mixed for 1 hour, then alcohol is added and mixed for 1 hour;

[0018] (3) Granulation: Add 30 g / kg of granulating agent to the powder mixed in step (2) above, and add 800 ml / kg of isopropanol at the same time, stirring continuously during the addition process, and after stirring evenly, pass through a 20# sieve, and then put it into an oven for baking at a temperature of 100°C for a baking time of 1 hour. Finally, pour the dried powder into a 30# sieve and sieve to disperse the lumps;

[0019] (4) Cold pressing: cold pressing the powder granulated in step (3) into a cold pressed blank according to the weight required by the cutter head;

[0020] (5) Hot pressing and sintering: the cutter head after cold pressing in the above step (4) is placed in a graphite mold for hot pressing and sintering, the sintering temperature is 800-900°C, the pressure is 25Mpa, and the holding time is 180S;

[0021] (6) Subsequent processing: Deburring the cutter head sintered in step (5) above, and grinding the curvature of the welding surface, to finally obtain a diamond tooth cutter head with the required curvature;

[0022] (7) Laser welding: The diamond cutter head obtained in step (6) is welded on a welding table of a steel substrate, wherein the welding power is 3.0 kW and the welding speed is 10-18 mm / s. Finally, subsequent sharpening, polishing and testing are performed to obtain a qualified drill bit, which is then put into storage.

[0023] Preferably, in the above step (7), a laser welding machine is used for welding, and the welding speed is 15 mm / s. The present invention has the following beneficial effects:

[0024] (1) The drill bit of the present invention increases the laser welding area by adding a welding table, improves the strength of laser welding, avoids the risk of the diamond tooth cutter head falling off during the drilling process, ensures the stability and safety of drilling, extends the service life of the drill bit, and reduces the processing cost;

[0025] (2) By providing chip removal grooves at the top and bottom of the diamond tooth cutter head, the drainage and chip removal capabilities of the trepanning drill bit are greatly improved, ensuring the stability and safety of drilling, while greatly improving the drilling efficiency of the drill bit and the surface quality of the sapphire crystal rod removed;

[0026] (3) Diamond toothed cutter heads are made of a composite material of zinc diamond and metal powder using powder metallurgy technology, and then the diamond toothed cutter heads are combined with a steel matrix by laser welding. Adding zinc to the diamond cutter heads can enhance the hardness of the cutter heads, because zinc can react chemically with metal powder to form a coating, and then form a high-hardness metal matrix. Combined with the selection of metal mixed powder raw materials, the concentricity of the drill head can be less than 0.05mm, and it has the advantages of excellent toughness and brittleness, good diamond blade output, high rod extraction efficiency, a drill life of 20m, and a high rod extraction yield rate. In addition, the surface finish of the sapphire crystal rod and the comprehensive performance of the drill head have reached the international advanced level. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a structural schematic diagram of the present invention.

[0028] In the figure: 1-steel substrate; 2-diamond toothed cutter head; 3-first chip groove; 4-second chip groove. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] like Figure 1 As shown, a core drill bit for sapphire processing comprises a steel substrate 1 and a diamond toothed cutter head 2, a welding platform is arranged on the steel substrate 1, the diamond toothed cutter head 2 is welded on the welding platform, a first chip removal groove 3 is arranged at the bottom of the diamond toothed cutter head 2, a second chip removal groove 4 is arranged at the top of the diamond toothed cutter head 2, and the raw materials of the diamond toothed cutter head 2 comprise a metal powder mixture and zinc diamond, wherein the volume fraction of zinc diamond accounts for 20%-40%, and the particle size is 200-350μm, and the metal powder mixture comprises the following raw materials in weight percentage: 30%-50% of nano copper powder, 2%-5% of tin powder, 25%-35% of nano iron powder, 10%-20% of ultrafine cobalt powder, and 5%-10% of nano nickel powder.

[0031] The core drill bit of the present invention increases the laser welding area and improves the strength of laser welding by adding a welding table, thereby avoiding the risk of the diamond toothed cutter head 2 falling off during the drilling process and ensuring the stability and safety of drilling; by providing chip removal grooves on the top and bottom of the diamond toothed cutter head 2, the water and chip removal capabilities of the core drill bit are greatly improved, ensuring the stability and safety of drilling, and at the same time greatly improving the drilling efficiency of the drill bit and the surface quality of the sapphire crystal rod taken out.

[0032] Specifically, the thickness L of the welding platform is 0.2 mm≦L≦0.8 mm, and the depth D is 3 mm≦D≦6 mm. The size design of the welding platform can improve the welding strength between the diamond segmented cutter head 2 and the steel substrate 1, thereby improving the stability and safety of the core drill.

[0033] Specifically, at least one first chip groove 3 is provided, and the groove width W of the first chip groove 3 is 3mm≦W≦8mm, and the groove depth H is 0.2mm≦H≦0.8mm. At least two second chip grooves 4 are provided, and the groove width T of the second chip groove 4 is 1mm≦W≦6mm, and the groove depth X is 5mm≦X≦12mm. The size design of the above chip grooves ensures the strength of the diamond toothed cutter head 2, and has better water and chip removal capabilities, ensuring the stability and safety of drilling, while greatly improving the drilling efficiency of the drill bit and the surface quality of the sapphire crystal rod taken out.

[0034] Specifically, the groove depth H of the first chip removal groove 3 is less than or equal to the thickness L of the welding platform. The above design will not affect the welding strength between the diamond segmented tooth bit 2 and the steel substrate 1, and can ensure a certain water and chip removal capacity.

[0035] Specifically, the cross-sectional shape of the first chip groove 3 and the second chip groove 4 is rectangular, trapezoidal, arc-shaped or triangular. The above design can be used to set chip grooves of different cross-sectional shapes according to the use requirements, so as to ensure the strength and chip removal capacity of the diamond tooth bit 2, improve the use stability of the drill bit, extend the service life, and reduce the use cost.

[0036] The following is a further detailed description using a method for preparing a trepanning drill bit for sapphire processing as an example.

[0037] Example 1

[0038] A trepanning drill bit for sapphire processing comprises a steel substrate 1 and a diamond segmented tooth bit 2, wherein a welding platform is arranged on the steel substrate 1, the diamond segmented tooth bit 2 is welded on the welding platform, a first chip removal groove 3 is arranged at the bottom of the diamond segmented tooth bit 2, a second chip removal groove 4 is arranged at the top of the diamond segmented tooth bit 2, and the raw materials of the diamond segmented tooth bit 2 comprise a metal powder mixture and zinc diamond, wherein the volume fraction of zinc diamond accounts for 20%-40%, and the particle size is 200-350 μm, and the metal powder mixture comprises the following raw materials in weight percentage: 30%-50% of nano copper powder, 2%-5% of tin powder, 25%-35% of nano iron powder, 10%-20% of ultrafine cobalt powder, and 5%-10% of nano nickel powder, and specifically comprises the following steps:

[0039] (1) Ingredients: Weigh the following raw materials in the following weight ratios: 50 parts of nano copper powder, 5 parts of tin powder, 25 parts of nano iron powder, 10 parts of ultrafine cobalt powder, 10 parts of nano nickel powder, and 20% (400%) concentration of zinc diamond with a particle size of 350 μm. Mix the above raw materials to obtain alloy matrix powder;

[0040] (2) Mixing: The alloy matrix powder obtained in step (1) above is put into a mixer, firstly steel balls are added and dry mixed for 1 hour, then alcohol is added and mixed for 1 hour;

[0041] (3) Granulation: Add 30 g / kg of granulating agent to the powder mixed in step (2) above, and add 800 ml / kg of isopropanol at the same time, stirring continuously during the addition process, and after stirring evenly, pass through a 20# sieve, and then put it into an oven for baking at a temperature of 100°C for a baking time of 1 hour. Finally, pour the dried powder into a 30# sieve and sieve to disperse the lumps;

[0042] (4) Cold pressing: cold pressing the powder granulated in step (3) into a cold pressed blank according to the weight required by the cutter head;

[0043] (5) Hot pressing and sintering: the cutter head after cold pressing in the above step (4) is placed in a graphite mold for hot pressing and sintering, the sintering temperature is 800-900°C, the pressure is 25Mpa, and the holding time is 180S;

[0044] (6) Subsequent processing: Deburring the cutter head sintered in step (5) above, and grinding the curvature of the welding surface, to finally obtain a diamond tooth cutter head with the required curvature;

[0045] (7) Laser welding: The diamond cutter head obtained in step (6) is welded on a welding table of a steel substrate, wherein the welding power is 3.0 kW and the welding speed is 10 mm / s. Finally, subsequent sharpening, polishing and testing are performed to obtain a qualified trepanning drill bit, which is then put into storage.

[0046] Example 2

[0047] This embodiment is the same as embodiment 1, except that 30 parts of nano copper powder, 5 parts of tin powder, 35 parts of nano iron powder, 20 parts of ultrafine cobalt powder, 10 parts of nano nickel powder are weighed, the concentration of zinc diamond is 30% (based on 400%), the particle size is 200um, and the welding speed is 14mm / s.

[0048] Example 3

[0049] This embodiment is the same as embodiment 1, except that 45 parts of nano copper powder, 2 parts of tin powder, 30 parts of nano iron powder, 18 parts of ultrafine cobalt powder, and 5 parts of nano nickel powder are weighed, the concentration of zinc diamond is 40% (based on 400%), the particle size is 280um, and the welding speed is 15mm / s.

[0050] Example 4

[0051] This embodiment is the same as embodiment 1, except that 40 parts of nano copper powder, 3 parts of tin powder, 34 parts of nano iron powder, 17 parts of ultrafine cobalt powder, 6 parts of nano nickel powder are weighed, the concentration of zinc diamond is 25% (based on 400%), the particle size is 320um, and the welding speed is 18mm / s.

[0052] In the drill bits prepared in Examples 1-4, the diamond toothed cutter head 2 is prepared from a composite material of zinc diamond and metal powder by powder metallurgy, and then the diamond toothed cutter head 2 is combined with the steel substrate 1 by laser welding. In each embodiment, only the raw material weight percentage and welding speed of the diamond toothed cutter head 2 are slightly different. By testing various performances of the drill bits formed therefrom, it is found that the performances are not much different, as shown in Table 1 below:

[0053] Table 1

[0054] Drill bit concentricity Drill bit service life Chip removal capacity Example 1 0.04mm 18m good Example 2 0.03mm 20m good Example 3 0.05mm 19m good Example 4 0.04mm 18m good

[0055] It can be seen from the above table that the present invention can enhance the hardness of the diamond bit by adding zinc to the bit through the design of the bit raw material and the ratio, because zinc can react chemically with the metal powder to form a coating, and then form a high-hardness metal matrix. Combined with the selection of the metal mixed powder raw material and the ratio, the concentricity of the trepanning drill bit can be less than 0.05mm, and it has the advantages of excellent toughness and brittleness, good diamond blade, high rod-pulling efficiency, a drill bit life of about 20m, a high rod-pulling yield rate, and the surface finish of the sapphire crystal rod. The comprehensive performance of the drill bit reaches the international advanced level.

[0056] The above are only preferred embodiments of the present invention, and are not intended to limit the implementation methods and protection scope of the present invention. Those skilled in the art should be aware that all solutions obtained by equivalent substitutions and obvious changes made using the description and illustrations of the present invention should be included in the protection scope of the present invention.

Claims

1. A trepanning drill bit for sapphire processing, comprising a steel matrix and a diamond toothed cutter head, characterized in that: A welding platform is arranged on the steel substrate, the diamond toothed cutter head is welded on the welding platform, a first chip removal groove is arranged at the bottom of the diamond toothed cutter head, a second chip removal groove is arranged at the top of the diamond toothed cutter head, and the raw materials of the diamond toothed cutter head include a metal powder mixture and zinc diamond, wherein the volume fraction of zinc diamond accounts for 20%-40%, and the particle size is 200-350μm, and the metal powder mixture includes the following raw materials in weight percentage: 30%-50% nano copper powder, 2%-5% tin powder, 25%-35% nano iron powder, 10%-20% ultrafine cobalt powder, and 5%-10% nano nickel powder.

2. A trepanning drill bit for sapphire processing according to claim 1, characterized in that: The thickness L of the welding platform is 0.2 mm≦L≦0.8 mm, and the depth D is 3 mm≦D≦6 mm.

3. A trepanning drill bit for sapphire processing according to claim 2, characterized in that: At least one first chip removal groove is provided, and the groove width W of the first chip removal groove is 3mm≦W≦8mm, and the groove depth H is 0.2mm≦H≦0.8mm.

4. A trepanning drill bit for sapphire processing according to claim 3, characterized in that: At least two second chip removal grooves are provided, and the groove width T of the second chip removal groove is 1mm≦W≦6mm, and the groove depth X is 5mm≦X≦12mm.

5. A trepanning drill bit for sapphire processing according to claim 3, characterized in that: The groove depth H of the first chip removal groove is less than or equal to the thickness L of the welding platform.

6. A trepanning drill bit for sapphire processing according to claim 1, characterized in that: The cross-sectional shapes of the first chip removal groove and the second chip removal groove are rectangular, trapezoidal, arc-shaped or triangular.

7. A method for preparing a trepanning drill bit for sapphire processing according to any one of claims 1 to 6, characterized in that: The specific steps include: (1) Ingredients: Weigh the following raw materials in the following weight proportions: 30-50 parts of nano copper powder, 2-5 parts of tin powder, 25-35 parts of nano iron powder, 10-20 parts of ultrafine cobalt powder, 5-10 parts of nano nickel powder, 20%-40% (based on 400%) concentration of zinc diamond, and a particle size of 200-350 um, and mix the above raw materials to obtain alloy matrix powder; (2) Mixing: The alloy matrix powder obtained in step (1) above is put into a mixer, firstly steel balls are added and dry mixed for 1 hour, then alcohol is added and mixed for 1 hour; (3) Granulation: Add 30 g / kg of granulating agent to the powder mixed in step (2) above, and add 800 ml / kg of isopropanol at the same time, stirring continuously during the addition process, and after stirring evenly, pass through a 20# sieve, and then put it into an oven for baking at a temperature of 100°C for a baking time of 1 hour. Finally, pour the dried powder into a 30# sieve and sieve to disperse the lumps; (4) Cold pressing: cold pressing the powder granulated in step (3) into a cold pressed blank according to the weight required by the cutter head; (5) Hot pressing and sintering: the cutter head after cold pressing in the above step (4) is placed in a graphite mold for hot pressing and sintering, the sintering temperature is 800-900°C, the pressure is 25Mpa, and the holding time is 180S; (6) Subsequent processing: Deburring the cutter head sintered in step (5) above, and grinding the curvature of the welding surface, to finally obtain a diamond tooth cutter head with the required curvature; (7) Laser welding: The diamond cutter head obtained in step (6) is welded on a welding table of a steel substrate, wherein the welding power is 3.0 kW and the welding speed is 10-18 mm / s. Finally, subsequent sharpening, polishing and testing are performed to obtain a qualified drill bit, which is then put into storage.

8. The method for preparing a trepanning drill bit for sapphire processing according to claim 7, characterized in that: In step (7), welding is performed using a fiber laser welding machine at a welding speed of 15 mm / s.

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