Diamond coating diversion mechanism and HFCVD furnace

Abstract

The utility model provides a diversion mechanism for a diamond coating and an HFCVD (High Frequency Chemical Vapor Deposition) furnace. The flow guide mechanism comprises a mechanism body, large flow guide holes and middle flow guide holes, the large flow guide holes and the middle flow guide holes are evenly distributed in the mechanism body, and each middle flow guide hole is formed between every two adjacent large flow guide holes. Furthermore, the flow guide mechanism further comprises a plurality of small flow guide holes formed between the large flow guide holes and the middle flow guide holes adjacent to the large flow guide holes. Therefore, on the basis of the principle that the cross sectional area of gas passing through the same gas flow is smaller and the flow speed is higher and the principle that the gas hole is smaller and the gas flow speed is higher and the gas can reach a farther position more quickly, the flow guide mechanism and the HFCVD furnace provided by the utility model have the advantages that the flow guide middle hole and the flow guide small hole are formed in the flow guide mechanism body; the carbon source gas in the raw material gas can be decomposed and then deposited on the upper portion, the middle portion and the lower portion of the tool to be machined, and therefore the uniformity of the thickness of the diamond coating in the longitudinal direction is achieved.

Description

Technical Field

[0001] This utility model relates to the field of coating technology, specifically to a flow guiding mechanism and an HFCVD furnace for improving the uniformity of HFCVD diamond coatings. Background Technology

[0002] HFCVD (Hot Filament Chemical Vapor Deposition) is a widely used technique for preparing diamond coatings. This technique uses an electric current to heat a tungsten or tantalum wire to approximately 2000°C, activating carbon source gas and hydrogen into active groups, which then diffuse onto the sample and deposit as a diamond coating. In typical HFCVD diamond coating equipment, the coating gas usually enters the furnace chamber from the top and then disperses to various parts of the chamber. However, in actual use, because the gas arrives at different locations within the furnace chamber at varying times, the number of active gas groups received at different locations varies, resulting in significant differences in coating thickness.

[0003] Current HFCVD diamond coating equipment typically employs a method such as Figure 1 The flow equalization device shown distributes gas relatively evenly to various positions within the HFCVD furnace cavity along the planar direction through the flow equalization orifice 1, resulting in a more uniform film thickness across the entire planar area. This type of HFCVD diamond coating equipment is primarily suitable for rod-shaped cutting tools, such as solid end mills. For these products, the focus is on the uniformity of film thickness at different positions on the same plane and the consistency of the entire batch. However, coatings produced by this type of equipment often exhibit longitudinal film thickness attenuation, with the film thickness at the upper end of the product being significantly higher than at the lower end. Since solid end mills primarily utilize the upper cutting edge position and undergo tool setting operations during use, this does not affect the accuracy of the solid end mill. However, for products such as drill bits and drawing dies, longitudinal dimensional consistency is required, and the film thickness attenuation characteristic significantly impacts the product's accuracy. Therefore, there is an urgent need for methods to improve the longitudinal film thickness consistency of coated products. Utility Model Content

[0004] In view of this, a primary objective of this invention is to provide a flow guiding mechanism for HFCVD diamond coatings to improve the longitudinal film thickness uniformity of diamond coatings deposited by HFCVD.

[0005] Specifically, a flow guiding mechanism for HFCVD diamond coating includes a mechanism body, large flow guiding holes, and medium flow guiding holes. The large flow guiding holes and medium flow guiding holes are evenly distributed on the mechanism body, and each medium flow guiding hole is disposed between two adjacent large flow guiding holes.

[0006] Based on the principle that the smaller the cross-sectional area through which gas passes for the same flow rate, the greater the flow velocity, the smaller the pore size, the faster the gas flow rate, and the faster it can reach a farther location. The diameter of the large guide orifice is 10-16 mm, which is the normal guide orifice used in existing HFCVD diamond coating production equipment. The diameter of the medium guide orifice is 1 / 3-2 / 3 of the diameter of the large guide orifice. Thus, the raw material gas flowing through the large guide orifice has a slower flow rate and mainly reaches the upper part of the HFCVD furnace cavity, where it is decomposed and deposited on the surface of the product to be coated. The raw material gas flowing through the medium guide orifice has a relatively faster flow rate and is injected more quickly to the lower part of the product to be coated. The gas decomposes and deposits directly near the lower part of the product to be coated, thereby improving the uniformity of the diamond coating thickness in the longitudinal direction.

[0007] Preferably, the flow guiding hole is a threaded hole structure, and the flow guiding mechanism further includes a hole plug nut that can be threadedly connected to the flow guiding hole.

[0008] Furthermore, the mechanism body also includes a plurality of uniformly distributed guide holes, which are disposed between adjacent guide holes and guide intermediate holes; in this way, the airflow distribution can reach the upper, middle and lower parts of the product to be coated, so as to further improve the uniformity of the diamond coating thickness in the longitudinal direction.

[0009] Preferably, the diameter of the middle guide hole is 1 / 3 to 2 / 3 of the diameter of the large guide hole, and the diameter of the small guide hole is 1 / 3 to 2 / 3 of the diameter of the middle guide hole.

[0010] Preferably, the guide hole has a threaded hole structure, and the guide mechanism further includes a small hole plugging nut that can be threadedly connected to the guide hole. Thus, the guide hole can be plugged or the small hole plugging nut can be removed from the guide hole according to actual needs.

[0011] Therefore, when machining mature products such as solid end mills, ordinary drills, and ordinary drawing dies, the guide holes and guide orifices can be plugged with center hole plugging nuts and small hole plugging nuts respectively. After sealing all threaded holes with nuts, the guide mechanism can be restored to its original guide hole distribution. This avoids deviations in coating performance and film thickness distribution caused by modifications to the guide mechanism when operating the original equipment process, thus preventing impacts on the performance of stable workpieces in mass production. Furthermore, when coating 30-80 mm thick products, the products can be elevated using tooling, concentrating them at the top of the furnace cavity for coating.

[0012] When coating products with a diameter of 80-180 mm, the large and medium guide holes can be opened, allowing the airflow to mainly reach the middle and upper parts of the furnace cavity; when coating products with a diameter of 180-300 mm, all guide holes should be opened to ensure that the gas reaches all positions in the furnace cavity from top to bottom.

[0013] The second objective of this invention is to provide an HFCVD furnace for diamond coating, comprising an HFCVD furnace body and the aforementioned flow guiding mechanism installed in the inner cavity formed by the HFCVD furnace body, wherein the product to be coated is placed below the flow guiding mechanism.

[0014] The products to be coated are solid carbide drill bits, reamers, drawing dies, or diamond saw blades, etc., which require high precision in all positions. The length of the products to be coated is 30-300 mm.

[0015] The HFCVD furnace also includes fixtures for placing products to be coated.

[0016] Therefore, the above-mentioned flow guiding mechanism and HFCVD furnace provided by this utility model, by setting flow guiding middle holes and flow guiding small holes on the body of the flow guiding mechanism, can decompose the carbon source gas in the raw material gas and deposit it on the upper, middle and lower parts of the tool to be processed, thereby achieving the uniformity of diamond coating thickness in the longitudinal direction. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of a flow equalization device in the prior art;

[0018] Figure 2 A top view of the flow guiding mechanism provided in Embodiment 1 of this utility model;

[0019] Figure 3 This is a schematic diagram of the HFCVD furnace provided in Embodiment 1 of this utility model;

[0020] Figure 4 A top view of the flow guiding mechanism provided in Embodiment 2 of this utility model;

[0021] Figure 5 A top view of the flow guiding mechanism provided in Embodiment 3 of this utility model;

[0022] Figure 6 This is a schematic diagram of the HFCVD furnace provided in Embodiment 3 of this utility model;

[0023] The component symbols in the above figures are as follows: 1. Flow equalization hole; 2. HFCVD furnace body; 3. Mechanism body; 31. Large flow guide hole; 32. Medium flow guide hole; 33. Medium hole plug nut; 34. Small flow guide hole; 4. Product to be coated; 5. Tooling.

[0024] In addition, the arrows in each diagram represent the direction of airflow. Detailed Implementation

[0025] All terms used in this utility model are common terms in the relevant field. Unless otherwise specified, the raw materials, equipment, preparation processes, testing methods, etc., used are all prior art in the relevant field.

[0026] like Figure 1 As shown, in existing HFCVD diamond coating deposition apparatuses, the raw gas passing through the flow equalization orifice 1 first decomposes and deposits as a coating on the upper end of the product 4 to be coated. Only the unused gas at the upper end reaches the lower end of the product 4 to be coated and deposits as a coating, resulting in a decrease in the thickness of the diamond coating in the longitudinal direction and uneven distribution. To solve this problem, this invention is based on the principle that the smaller the cross-sectional area through which the gas passes for the same flow rate, the greater the flow velocity; and the smaller the orifice, the faster the gas flow rate, and the faster it can reach a farther position. Therefore, a flow guiding mechanism and an HFCVD furnace for HFCVD diamond coating are designed.

[0027] The technical solution of this utility model will be further described in detail below through specific embodiments.

[0028] Example 1

[0029] Please see Figure 2 This embodiment provides a flow guiding mechanism for HFCVD diamond coating, comprising a mechanism body 3, multiple large flow guiding holes 31, and multiple medium flow guiding holes 32. The large flow guiding holes 31 and medium flow guiding holes 32 are uniformly distributed on the mechanism body. The large flow guiding holes 31 are normal flow guiding holes with a particle size of 12 mm, and the medium flow guiding holes 32 have a particle size of 6 mm. Each medium flow guiding hole 32 is located at the center between two adjacent large flow guiding holes 31.

[0030] Please refer to the following: Figure 3 This embodiment also provides an HFCVD furnace for diamond coating containing the aforementioned flow guiding mechanism, including an HFCVD furnace body 2 and the aforementioned flow guiding mechanism installed on the upper part of the inner cavity of the HFCVD furnace body 2. A product 4 to be coated is placed below the flow guiding mechanism, and the product 4 to be coated is inserted into a tooling 5. In this embodiment, the product 4 to be coated is a solid carbide drill bit.

[0031] When the raw material gas is introduced into the inner cavity of the HFCVD furnace body 2, the flow rate of the raw material gas through the large flow guide hole 31 in the flow guide mechanism is slow. It mainly reaches the upper part of the HFCVD furnace cavity and is decomposed and deposited on the surface of the product 4 to be coated in this area, so that a diamond coating is formed in the upper part of the product 4 to be coated. At the same time, the flow rate of the raw material gas through the middle flow guide hole 32 is relatively faster. Compared with the raw material gas through the large flow guide hole, it is sprayed to the lower part of the HFCVD furnace cavity more quickly and is decomposed and deposited on the surface of the product 4 to be coated in this area. That is, a diamond coating is formed in the lower part of the product 4 to be coated. Thus, the use of the flow guide mechanism and the HFCVD furnace provided in this embodiment to deposit a diamond coating on the product to be coated can effectively improve the uniformity of the diamond coating thickness in the longitudinal direction.

[0032] Example 2

[0033] Please refer to the following: Figure 4 This embodiment provides a flow guiding mechanism and an HFCVD furnace for diamond coating under HFCVD conditions. The structure is basically the same as that provided in Embodiment 1. The main difference is that the flow guiding mechanism also includes multiple hole plugging nuts 33 of the same specification, and the flow guiding hole 32 is designed as a threaded hole structure. The flow guiding hole 32 can correspond one-to-one with the hole plugging nut 33 and be threadedly connected.

[0034] Therefore, when machining mature products such as integral end mills, the guide holes 32 can be blocked by the center hole plugging nut 33. After sealing all the guide holes 32 with the center hole plugging nut 33, the guide mechanism can be restored to the original distribution of the large guide holes 31 (normal guide holes). This avoids deviations in coating performance and film thickness distribution caused by changes in the guide mechanism when the equipment is set up to the original process, which would affect the performance of the workpieces produced in batches. At the same time, when coating shorter products, the product can be raised by tooling, so that the product is concentrated on the upper side of the furnace cavity for coating. When coating medium-length products, the large guide holes 31 can be opened, and the airflow mainly reaches the upper part of the furnace cavity; when coating long products, all guide holes are opened, so that the raw material gas reaches all positions in the furnace cavity evenly.

[0035] Example 3

[0036] Please see Figure 5 and 6This embodiment provides a flow guiding mechanism and an HFCVD furnace for HFCVD diamond coating. The structure is basically the same as the corresponding structure provided in Embodiment 2, with the main difference being that the flow guiding mechanism also includes multiple flow guiding holes 34 evenly distributed on the mechanism body 3 and small hole plugging nuts of the same specification (not shown in the figure). The flow guiding holes 34 have a particle size of 3 mm and are designed as threaded holes, which can correspond one-to-one with the small hole plugging nuts and be threadedly connected. The flow guiding holes 34 are located in the middle position between adjacent large flow guiding holes and medium flow guiding holes, and the medium flow guiding holes have a particle size of 6 mm. Thus, during use, the raw material gas can simultaneously reach the upper, middle, and lower parts of the product to be coated through the large flow guiding hole 31, the medium flow guiding hole 32, and the small flow guiding hole 34, respectively, and be decomposed and deposited in the corresponding areas, thereby improving the uniformity of the diamond coating thickness in the longitudinal direction.

[0037] In addition, when processing ordinary products, the guide holes and guide orifices can be plugged with plug nuts for the middle and small holes respectively. After sealing all threaded holes with nuts, the guide mechanism can be restored to its original guide hole distribution. This avoids deviations in coating performance and film thickness distribution caused by modifications to the guide mechanism, which would otherwise affect the performance of stable workpieces in mass production. Furthermore, when coating shorter products, the product can be raised using tooling, concentrating the coating process on the upper side of the furnace cavity. When coating medium-length products, the guide holes and middle holes can be opened, allowing the mixed airflow to primarily reach the middle and upper parts of the furnace cavity. When coating longer products, all guide holes are opened, ensuring the gas evenly reaches all positions within the furnace cavity from top to bottom.

[0038] Therefore, when using the aforementioned flow guiding mechanism and HFCVD furnace provided in this embodiment of the invention to deposit a diamond coating, the raw material gas can simultaneously reach the upper, middle, and lower regions of the product to be coated. This significantly improves the longitudinal film thickness uniformity of the HFCVD diamond coating workpiece, reduces film thickness attenuation, and broadens the application range of HFCVD diamond coatings in applications requiring higher precision. Furthermore, this invention facilitates the development of HFCVD diamond coating processes for workpieces with higher uniformity requirements and allows for flexible switching of the original air inlet distribution, ensuring stable production operations.

[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of this utility model and not to limit it; although the utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of this utility model or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solution of this utility model, and all such modifications and substitutions should be covered within the scope of the technical solution claimed by this utility model.

Claims

1. A flow guiding mechanism for diamond coating, characterized in that: The device includes a main body, large flow guide holes, and medium flow guide holes. The large flow guide holes and medium flow guide holes are evenly distributed on the main body, and each medium flow guide hole is located between two adjacent large flow guide holes. The main body also includes a plurality of evenly distributed small flow guide holes, which are located between adjacent large flow guide holes and medium flow guide holes. The diameter of the medium flow guide hole is 1 / 3 to 2 / 3 of the diameter of the large flow guide hole, and the diameter of the small flow guide hole is 1 / 3 to 2 / 3 of the diameter of the medium flow guide hole.

2. The flow guiding mechanism according to claim 1, characterized in that: The flow guide hole is a threaded hole structure, and the flow guide mechanism also includes a hole plug nut that can be threadedly connected to the flow guide hole.

3. The flow guiding mechanism according to claim 1 or 2, characterized in that: The flow guiding orifice has a threaded hole structure, and the flow guiding mechanism also includes a small hole plug nut that can be threadedly connected to the flow guiding orifice.

4. An HFCVD furnace for diamond coating, characterized in that: The invention includes an HFCVD furnace body and a flow guiding mechanism as described in any one of claims 1-3, which is installed in the inner cavity formed by the HFCVD furnace body, wherein the lower part of the flow guiding mechanism is used to place the product to be coated.

5. The HFCVD furnace according to claim 4, characterized in that: The products to be coated are solid carbide drill bits, reamers, drawing dies, or diamond saw blades.

6. The HFCVD furnace according to claim 4, characterized in that: The length of the product to be coated is 30-300 mm.

7. The HFCVD furnace according to any one of claims 4-6, characterized in that: The HFCVD furnace also includes fixtures for placing the product to be coated.

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