Surface regeneration method for hard coating tools

Abstract

This invention provides a surface regeneration method for hard-coated tools that uses a simple and cost-effective process to reform a hard coating with excellent wear resistance and heat resistance while maintaining the original shape and dimensions of the hard-coated tool. [Solution] A method for regenerating a cemented carbide cutting tool having a hard coating on its surface, wherein the hard coating consists of a first hard coating containing TiAlN and a second hard coating containing AlCrN, laminated and coated in order from the cemented carbide tool, and the method comprises: a first step of removing only the second hard coating by immersing the cemented carbide cutting tool in a chemical solution; a second step of grinding the cutting edge of the cemented carbide cutting tool after the first step; a third step of performing shot blasting on the cutting edge of the cemented carbide cutting tool after the second step; and a fourth step of coating the cutting edge of the cemented carbide cutting tool with the second hard coating after the third step.

Description

Technical Field

[0006] ,

[0001] The present invention relates to a method for regenerating the surface of a tool such as a cutting tool coated with a hard film on the surface.

Background Art

[0002] Conventionally, in order to extend the life of a hard film-coated tool, a method for regenerating the tool surface after use has been disclosed. This method includes removing the worn portion from the tool surface and newly forming a hard film.

[0003] For example, Patent Document 1 discloses a technique for reforming a diamond-like carbon (DLC) film using the plasma CVD method, and regeneration of the tool surface is achieved. Also, Patent Document 2 discloses a regeneration method using the physical vapor deposition method (PVD) as a surface treatment method for a tool having a hard film.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, these regeneration methods have some problems. For example, when using the plasma CVD method or the PVD method, the uniformity of the hard film to be reformed may not be maintained, and as a result, the performance of the regenerated hard film-coated tool may decrease.

[0006] Furthermore, the regeneration process is complex, time-consuming, and costly, which is another problem. In addition, there is a risk that the original shape and dimensions of the hard coating tool may change during the regeneration process, making it difficult to apply to tools that require precise machining.

[0007] Therefore, the object of the present invention is to provide a method for regenerating a uniform and high-quality hard coating in order to solve these problems. Specifically, the present invention provides a surface regeneration method for hard coating tools that can reform a hard coating with excellent wear resistance and heat resistance while maintaining the original shape and dimensions of the hard coating tool, using a simple and cost-effective process. [Means for solving the problem]

[0008] The present invention relates to a method for regenerating a cemented carbide cutting tool having a hard coating on its surface, wherein the hard coating is applied in a manner in which a first hard coating containing TiAlN and a second hard coating containing AlCrN are laminated in order from the cemented carbide tool, and the method comprises a first step of removing only the second hard coating by immersing the cemented carbide cutting tool in a chemical solution, a second step of grinding the cutting edge of the cemented carbide cutting tool, a third step of performing shot blasting on the cutting edge of the cemented carbide cutting tool, and a fourth step of applying the second hard coating to the cutting edge of the cemented carbide cutting tool.

[0009] Furthermore, the cutting edge of the cutting blade can be coated with a first hard coating to a thickness of at least 2 μm, and the base of the cutting blade can be coated with a first hard coating to a thickness of at least 1 μm. It is desirable that the chemical solution used selectively removes only the chromium nitride film. [Effects of the Invention]

[0010] The present invention provides the following advantages for the regeneration method of cemented carbide cutting tools. The present invention allows for the selective removal of only the second hard coating (AlCrN) and subsequent re-coating. Therefore, tool life can be significantly extended through partial regeneration without replacing the entire tool.

[0011] Furthermore, by optimizing the cutting edge and surface condition of the tool through grinding and shot blasting, the cutting performance can be restored to like-new condition. This makes it possible to continue performing high-precision machining. In addition, tool refurbishment reduces the frequency of purchasing new tools, contributing to cost reduction. Moreover, the partial refurbishment process consumes fewer resources compared to new manufacturing, offering economic and environmental benefits.

[0012] Furthermore, since the regeneration process is completed in a relatively short time, tool downtime can be minimized. This improves the operating rate of the processing line and increases production efficiency. In addition, the regeneration method reduces the amount of waste tools. Moreover, selective coating removal and recoating enable the efficient use of resources and reduce the environmental impact. [Brief explanation of the drawing]

[0013] [Figure 1] This is a schematic cross-sectional view of a cemented carbide cutting tool before use. [Figure 2] This is a schematic cross-sectional view of a cemented carbide cutting tool after use. [Figure 3] This is a schematic cross-sectional view of a cemented carbide cutting tool after the second hard coating has been removed. [Figure 4] This is a schematic cross-sectional view of a cemented carbide cutting tool before grinding the cutting edge. [Figure 5] This is a schematic cross-sectional view of a cemented carbide cutting tool after the cutting edge has been ground. [Modes for carrying out the invention]

[0014] An embodiment of the present invention relating to a method for regenerating cemented carbide cutting tools will be described with reference to the drawings. Figure 1 shows a schematic cross-sectional view of a cemented carbide cutting tool before use, Figure 2 shows a schematic cross-sectional view of a cemented carbide cutting tool after use, Figure 3 shows a schematic cross-sectional view of a cemented carbide cutting tool after the second hard coating has been removed, Figure 4 shows a schematic cross-sectional view of a cemented carbide cutting tool before grinding the cutting edge, and Figure 5 shows a schematic cross-sectional view of a cemented carbide cutting tool after grinding the cutting edge.

[0015] <Step 1: Removal of the second hard coating> The cemented carbide cutting tool regeneration method according to the present invention is applicable to cemented carbide cutting tools whose cutting edge has been worn down by cutting processes, as shown in Figure 2, as shown in Figure 1, before use. In the first step of the regeneration method of the present invention, the cemented carbide cutting tool is immersed in a specific chemical solution. This chemical solution is one that selectively removes only the chromium nitride film. For example, Chitapier Chromium Solution (trade name) is chemically stable and has the property of selectively dissolving AlCrN, which is the second hard coating. Through this immersion, the outermost AlCrN layer is removed as shown in Figure 3, but the first hard coating, the TiAlN layer, remains. In this first step, it is necessary to appropriately adjust the temperature of the chemical solution and the immersion time, which enables selective removal of the hard coating.

[0016] <Step 2: Grinding the cutting edge> Following the first step described above, the second step involves grinding the cutting edge of the cemented carbide cutting tool. The purpose of grinding is to remove wear and damage to the cutting edge of the cutting tool, as shown in Figure 4, and to restore the original sharpness of the cutting edge. Grinding is performed using a high-precision grinding machine, performing fine grinding while maintaining the shape and angle of the cutting edge. This restores the sharpness of the cemented carbide cutting tool, as shown in Figure 5. During grinding, a water-based or oil-based coolant is used to suppress the temperature rise of the cemented carbide cutting tool and prevent thermal deformation. In addition, by checking the progress of grinding as needed and avoiding excessive grinding, the life of the cutting tool can be extended.

[0017] <Step 3: Shot blasting> After the aforementioned second step, shot blasting is performed on the cutting edge of the cemented carbide cutting tool. This treatment is carried out to form fine irregularities on the surface of the cemented carbide cutting tool and improve the adhesion of the new hard coating. Fine metal particles or ceramic particles are used for the shot blasting treatment. These particles are sprayed onto the surface of the cemented carbide cutting tool at high pressure to give a fine impact and thereby process the surface. By this step, a uniform roughness (surface roughness) can be imparted to the surface of the cemented carbide cutting tool, and the newly coated hard coating adheres firmly. The shot blasting treatment not only improves the durability of the cemented carbide cutting tool but also has the effect of increasing the surface strength of the cemented carbide cutting tool.

[0018] <Fourth step: Re - coating of the second hard coating> In the final fourth step, by re - coating the cutting edge of the cemented carbide cutting tool after the shot blasting treatment with AlCrN, which is the second hard coating, the state of the cemented carbide cutting tool before use as shown in Fig. 1 is restored. AlCrN has high wear resistance and heat resistance and greatly improves the performance of the cutting tool. In this coating step, coating methods such as physical vapor deposition (PVD) or chemical vapor deposition (CVD) are used. In the coating process, AlCrN is deposited on the surface of the cutting tool in a vacuum chamber. At this time, in order to ensure the uniformity of the coating, the cutting tool can be rotated or appropriate temperature and pressure can be maintained. After coating, the cemented carbide cutting tool is cooled to promote the hardening of the coating. Finally, due to the newly coated second hard coating, the wear resistance and cutting performance of the cemented carbide cutting tool are restored and it can be used again.

[0019] Also, since the method for regenerating the cemented carbide cutting tool in the present invention performs the treatment selectively for each step, the performance of the cemented carbide cutting tool can be maximally extracted. In particular, the shot blasting treatment in the third step forms fine irregularities on the surface, enhances the adhesion of the new hard coating, and greatly improves the cutting performance after re - coating. This step not only increases the surface strength but also improves the wear resistance of the cemented carbide cutting tool, so that the regenerated cemented carbide cutting tool exhibits performance similar to that of a new product.

[0020] Furthermore, by applying the method for recycling a cemented carbide cutting tool of the present invention, the frequency of purchasing new tools can be reduced, thereby contributing to cost reduction. In normal tool replacement, it is necessary to purchase an entirely new tool, but with the partial recycling method according to the present invention, it is possible to reuse the particularly expensive cemented carbide part as it is, thus significantly reducing the economic burden. This facilitates long-term cost management and enhances the competitiveness of enterprises.

[0021] Also, the method for recycling a cemented carbide cutting tool of the present invention has the feature of being environmentally friendly. When manufacturing new tools, consumption of resources and generation of waste are inevitable, but by adopting the recycling method of the present invention, the recycling rate of cemented carbide cutting tools can be increased, and waste reduction becomes possible. Thus, since the environmental load can be reduced by the recycling process, it is also very beneficial as part of a sustainable manufacturing process.

[0022] In the recycling process, selection of chemical solutions, immersion time, temperature control, etc. are important, and by appropriately adjusting these, the recycled cemented carbide cutting tool can maintain high-precision cutting performance. Furthermore, by combining shot blasting treatment and recoating, the finally obtained tool has extremely high wear resistance and can exhibit performance that can withstand long-term use. Thus, by making fine adjustments, the recycling accuracy of the cemented carbide cutting tool can be enhanced and it can be kept in a reusable state.

[0023] The method for recycling a cemented carbide cutting tool of the present invention can not only significantly extend the service life of the cemented carbide cutting tool, but also contribute to improving efficiency and cost-effectiveness in the manufacturing industry. The recycling process is completed in a relatively short time, and the downtime of the cemented carbide cutting tool can be minimized, so the operating rate of the processing line can be improved and productivity can be enhanced.

Claims

1. A method for regenerating a cemented carbide cutting tool having a hard coating on its surface, wherein the hard coating consists of a first hard coating containing TiAlN and a second hard coating containing AlCrN, laminated in order from the cemented carbide tool, and comprising: a first step of removing only the second hard coating by immersing the cemented carbide cutting tool in a chemical solution; a second step of grinding the cutting edge of the cemented carbide cutting tool after the first step; a third step of performing shot blasting on the cutting edge of the cemented carbide cutting tool after the second step; and a fourth step of coating the cutting edge of the cemented carbide cutting tool with the second hard coating after the third step.

2. The method for regenerating a cemented carbide cutting tool according to claim 1, characterized in that the cutting edge of the cutting blade before the first step is coated with the first hard coating to a thickness of at least 2 μm or more.

3. The method for regenerating a cemented carbide cutting tool according to claim 2, characterized in that the base of the cutting edge of the cutting edge before the first step is coated with the first hard coating to a thickness of at least 1 μm.

4. The method for regenerating a cemented carbide cutting tool according to any one of claims 1 to 3, characterized in that the chemical solution is a solution that selectively removes only the chromium nitride film.

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