A ball milling detection method for CNC blade coating

Abstract

The invention discloses a ball milling detection method for a CNC blade coating, which relates to the field of cemented carbide. The method first determines the basic information of the CNC blade, then adopts the corresponding CNC blade ball milling process according to the basic information, generates a ball milling pit on the surface of the CNC blade film layer after the ball milling is completed, measures the actual outer radius R2' and the actual inner radius R1' of the film layer at the ball milling pit, calculates the actual film layer (200) thickness T' according to the following formula (II), takes T' as the standard film layer thickness T, adopts formula (I) to establish the outer circle theoretical radius R2 of the film layer when the ball milling pit depth is twice the standard film layer thickness, compares the outer circle actual radius R2' with the outer circle theoretical radius R2, and verifies whether the ball milling process is appropriate. The invention classifies the types and thicknesses of existing coatings, accurately calculates, and develops a fast and effective ball milling process, which can quickly detect the film layer thickness and adhesion of the CNC blade, greatly improving the detection efficiency.

Description

Technical Field

[0001] The invention relates to the field of cemented carbide, in particular to a ball milling detection method for a CNC blade coating. Background Art

[0002] Carbide-coated cutting tools are one of the key elements in achieving efficient, high-quality, high-precision, and environmentally friendly machining, and their usage in the cutting field has exceeded 50%. Carbide inserts are commonly coated with a 1-20μm thick layer of refractory compounds using CVD, PVD, and PCVD coating processes. Coatings produced using different processes range from a single layer to dozens or even hundreds of layers. The strength of the coating's bond to the substrate, its microstructure, the thickness of each individual layer, its total thickness, and its composition all significantly impact the tool's cutting performance, lifespan, and ultimate machining speed. Ball milling, which can rapidly measure coating thickness and qualitatively analyze the coating's bonding strength, has been widely used internationally.

[0003] Ball milling involves grinding the coating surface with a steel ball of a specific diameter, wearing it through and leaving a circular (for flat surfaces) or elliptical (for cylindrical surfaces) indentation between the coating and the substrate. Grinding timing is crucial, ensuring the depth of the indentation exceeds the coating thickness. Furthermore, because the coating is very hard and it is difficult for a steel ball to directly wear through it, the grinding area on the steel ball should be coated with a small amount of diamond powder (particle size under 7μm) and sprayed with alcohol to dilute the diamond powder and provide lubrication during grinding.

[0004] The ball milling test is a mature method for measuring coating thickness. A rotating steel ball and abrasive fluid are used to grind the crown of the steel ball through the surface coating of the sample into the sample's base material. When examined under a microscope, the coating / base material appears as a circle, or in the case of multi-layer coatings, as a system of concentric circles. The thickness of the coating can be calculated by substituting the diameter of these circles and the diameter of the grinding ball into a formula. Currently, the ball milling thickness test method only provides a general test method (JBT 7707-1995 Ion Plating Hard Film Thickness Test Method Ball Milling Method), and does not propose corresponding ball milling parameter methods for various coatings, resulting in poor ball milling results. It also requires repeated trial and error, especially for enterprise operators who are not familiar with the principles of ball milling, making it even more difficult to implement.

[0005] The traditional grinding standard requires stopping grinding when the grinding depth reaches twice the thickness of the film layer. This is very difficult for operators to judge. Summary of the Invention

[0006] The purpose of the present invention is to solve at least one of the technical problems existing in the prior art and to provide a ball milling detection method for CNC blade coatings.

[0007] The technical solutions of the present invention are as follows:

[0008] A ball milling detection method for a CNC blade coating comprises the following steps:

[0009] A ball milling detection method for a CNC blade coating comprises the following steps:

[0010] First, the basic information of the CNC blade is determined, and then the corresponding CNC blade ball milling process is adopted according to the basic information. After the ball milling is completed, a ball milling pit is generated on the surface of the CNC blade film layer, and the actual outer radius R2' and the actual inner radius R1' of the film layer at the ball milling pit are measured. According to the following formula (II), the actual film thickness T' is calculated, and T' is taken as the standard film thickness T. The outer circle theoretical radius R2 of the film layer when the ball milling pit depth is twice the standard film thickness is established using formula (I). The outer circle actual radius R2' is compared with the outer circle theoretical radius R2 to check whether the ball milling process is appropriate. If R2'>R2, the ball milling process is adjusted; if R2'<R2, and the base (100) of the CNC blade is exposed, the ball milling process does not need to be adjusted.

[0011]

[0012] Where R is the radius of the grinding ball, T is the standard film thickness;

[0013] T'=(R2' 2 -R1' 2 ) / D (II);

[0014] Wherein T' is the actual film thickness; R2' is the actual radius of the outer circle; R1' is the actual radius of the inner circle; D is the diameter of the grinding ball, D = 2R.

[0015] As a preferred solution of the present invention, the ball milling process uses grinding balls to rotate and grind the surface of the CNC blade film layer, and at the same time, abrasives are applied to the surface of the grinding balls.

[0016] As a preferred embodiment of the present invention, the ball milling process includes ball milling time, rotation speed of the grinding balls and particle size of the grinding agent.

[0017] As a preferred embodiment of the present invention, the grinding balls have a density of 6-8 g / cm 3 steel balls or ceramic balls.

[0018] As a preferred embodiment of the present invention, the abrasive is diamond powder.

[0019] As a preferred solution of the present invention, the basic information includes film thickness, film type and film hardness.

[0020] As a preferred embodiment of the present invention, when the film type is PVD coating, the film hardness is 30-38GPa;

[0021] The film thickness range is 1-3μm, using the first grinding process; the film thickness range is 3-10μm, using the second grinding process;

[0022] When the film type is CVD coating, the film hardness is 20-30GPa;

[0023] The film thickness range is 6-10μm, and the third grinding process is adopted; the film thickness range is 10-20μm, and the fourth grinding process is adopted.

[0024] As a preferred embodiment of the present invention, the first grinding process is: grinding agent particle size 1-3 μm, rotation speed 800-1000 n / min, ball milling time 10-20 s;

[0025] The second grinding process is as follows: the grinding agent particle size is 1-3 μm, the rotation speed is 800-1000 n / min, and the ball milling time is 20-40 s;

[0026] The third grinding process is as follows: grinding agent particle size 3-5 μm, rotation speed 500-900 n / min, ball milling time 60-80 s;

[0027] The fourth grinding process is as follows: grinding agent particle size 3-5 μm, rotation speed 500-900 n / min, ball milling time 80-100 s.

[0028] As a preferred embodiment of the present invention, if R2'>R2, the ball milling time is shortened.

[0029] The beneficial effects of the present invention are: the method of the present invention classifies the basic information (category, thickness) of existing coatings, accurately calculates, and develops fast and effective ball milling parameters, thereby realizing rapid detection of the film thickness and adhesion of CNC blades, greatly improving detection efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a schematic diagram of the structure of the CNC blade after actual grinding;

[0031] Figure 2 This is a structural diagram of the standard film thickness after CNC blade grinding when it is twice the depth of the ball-milling pit;

[0032] Figure 3 The metallographic image of the CNC blade magnified 100 times Figure 1 ;

[0033] Figure 4 The metallographic image of the CNC blade magnified 100 times Figure 2 ;

[0034] In the figure, 100 is substrate, 200 is film layer, and 300 is grinding ball. DETAILED DESCRIPTION

[0035] This section will describe in detail the specific embodiments of the present invention. The preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the accompanying drawings is to supplement the description of the text part of the specification with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the present invention, but it should not be understood as a limitation on the scope of protection of the present invention.

[0036] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention.

[0037] In the description of the present invention, "several" means one or more, "many" means more than two, "greater than," "less than," and "exceed" are understood to exclude the number itself, while "above," "below," and "within" are understood to include the number itself. The use of "first" and "second" in the description is solely for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, implicitly specifying the number of the indicated technical features, or implicitly specifying the order of the indicated technical features.

[0038] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, and connecting should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0039] Reference Figures 1 to 2 , the preferred embodiment of the present invention:

[0040] A ball milling detection method for a CNC blade coating comprises the following steps:

[0041] A ball milling detection method for a CNC blade coating, characterized by comprising the following steps:

[0042] First, the basic information of the CNC blade is determined. Then, the corresponding CNC blade ball milling process is adopted according to the basic information. After the ball milling is completed, a ball milling pit is generated on the surface of the CNC blade film layer 200. The actual outer radius R2' and the actual inner radius R1' of the film layer at the ball milling pit are measured. According to the following formula (II), the actual film layer 200 thickness T' is calculated. T' is taken as the standard film layer thickness T. The theoretical outer radius R2 of the film layer 200 when the ball milling pit depth is twice the standard film layer thickness is established using formula (I). The actual outer radius R2' is compared with the theoretical outer radius R2 to check whether the ball milling process is appropriate. If R2'>R2, the ball milling process is adjusted. If R2'<R2 and the base 100 of the CNC blade is exposed, the ball milling process does not need to be adjusted.

[0043]

[0044] Where R is the radius of the grinding ball, T is the standard film thickness;

[0045] T'=(R2' 2 -R1' 2 ) / D=(R2'+R1')(R2'-R1') / D (II);

[0046] Where T' is the actual film thickness; R2' is the actual outer radius; R1' is the actual inner radius; and D is the grinding ball diameter, D = 2R. Combined with Formula II, it can be seen that for a given coating thickness, if the ball milling time is too long, the inner and outer radii of the ball milling pit will be too long, and the difference between the inner and outer radii will be too small, almost overlapping. In other words, if the milling time is not controlled, the inner and outer radii of the blade grinding pit will almost overlap, making it impossible to detect the actual film thickness. Therefore, the ball milling process is very important.

[0047] Based on the basic information of existing coatings (category, thickness), accurate calculation is carried out to develop fast and effective ball milling parameters, so as to quickly detect the film thickness and adhesion of CNC blades, greatly improving the detection efficiency. Specifically, under a microscope, the grinding pits of the ground CNC blade are magnified 50-100 times. You will see a decomposition line between the coating and the substrate. Figure 3-4 Observe the shape of this dividing line to judge whether the bonding between the coating and the substrate is good or not. If this boundary line is very clear and neat, the coating bonding is good. Figure 3 If the dividing line is jagged or faulty, the coating adhesion is poor. Figure 4 .

[0048] As a preferred embodiment of the present invention, it may also have the following additional technical features:

[0049] The ball milling process uses a grinding ball 300 to rotate and grind the surface of the film layer 200 of the CNC blade, and at the same time, abrasives are applied to the surface of the grinding ball 300.

[0050] The empirical parameters of the ball milling process include the ball milling time, the rotation speed of the grinding balls 300 and the particle size of the grinding agent.

[0051] The grinding ball 300 has a density of 6-8 g / cm 3 Steel balls or ceramic balls, specifically, the steel balls are made of carbon steel with a density of 7.85g / cm 3 The ceramic ball is made of zirconia ceramic, with a density of 6.05g / cm 3 .

[0052] The grinding agent is diamond powder. When used, anhydrous ethanol is sprayed on the surface of the grinding ball for lubrication.

[0053] The basic information includes film thickness, film type and film hardness. After a product is prepared, the range of film thickness can be roughly determined. Then, the film thickness is tested using the following ball milling process. If the actual value meets the test value, it is judged to be a qualified product.

[0054] When the film type is PVD coating, the film hardness is 30-38GPa;

[0055] The film thickness range is 1-3μm, using the first grinding process; the film thickness range is 3-10μm, using the second grinding process;

[0056] When the film type is CVD coating, the film hardness is 20-30GPa;

[0057] The film thickness range is 6-10μm, and the third grinding process is adopted; the film thickness range is 10-20μm, and the fourth grinding process is adopted.

[0058] The first grinding process is as follows: abrasive particle size 1-3 μm, rotation speed 800-1000 n / min, ball milling time 10-20 s;

[0059] The second grinding process is as follows: the grinding agent particle size is 1-3 μm, the rotation speed is 800-1000 n / min, and the ball milling time is 20-40 s;

[0060] The third grinding process is as follows: grinding agent particle size 3-5 μm, rotation speed 500-900 n / min, ball milling time 60-80 s;

[0061] The fourth grinding process is as follows: grinding agent particle size 3-5 μm, rotation speed 500-900 n / min, ball milling time 80-100 s.

[0062] In specific applications, according to the standard, when the grinding depth reaches twice the thickness of the film layer, stop grinding and wipe the surface of the specimen. When the depth of the ground pit reaches twice the thickness of the film, the outer radius of the pit can be calculated according to the formula The theoretical values of the outer radius of pits with different film thicknesses can be obtained, as shown in Table 1 below. The ball milling time can be guided according to the theoretical value and the actual value (using Formula II). When the actual value of the outer radius is greater than the theoretical value in the table below, it means that the ball milling time is too long and the above-mentioned ball milling process needs to be adjusted. When the actual value of the outer radius is less than the theoretical value in the table below and the base 100 of the CNC blade is exposed (this condition can be judged with the naked eye), it means that the above-mentioned ball milling process meets the detection standard and the ball milling process can be directly used to detect the film thickness in the subsequent detection process, which greatly saves the detection time.

[0063] Table 1 Theoretical values of outer radius for different film thicknesses

[0064]

[0065]

[0066] Under the premise that no conflict occurs, those skilled in the art may freely combine and superimpose the above-mentioned additional technical features.

[0067] The above descriptions are merely preferred embodiments of the present invention. Any technical solution that achieves the purpose of the present invention by substantially the same means shall fall within the scope of protection of the present invention.

Claims

1. A ball milling detection method for CNC blade coating, characterized in that: The following steps are involved: First, the basic information of the CNC blade is determined, and then the corresponding CNC blade ball milling process is adopted according to the basic information. After the ball milling is completed, a ball milling pit is generated on the surface of the CNC blade film layer (200). The actual outer circle radius R2' and the actual inner circle radius R1' of the film layer at the ball milling pit are measured. According to the following formula (II), the actual film layer (200) thickness T' is calculated, and T' is taken as the standard film layer thickness T. The formula (I) is used to establish the outer circle theoretical radius R2 of the film layer (200) when the ball milling pit depth is twice the standard film layer thickness. The outer circle actual radius R2' is compared with the outer circle theoretical radius R2 to check whether the ball milling process is appropriate. If R2'>R2, the ball milling process is adjusted; if R2'<R2, and the base (100) of the CNC blade is exposed, the ball milling process does not need to be adjusted; （I）； Where R is the radius of the grinding ball, T is the standard film thickness; T'=(R2'²-R1'²) / D(II); Where T' is the actual film thickness; R2' is the actual radius of the outer circle; R1' is the actual radius of the inner circle; D is the diameter of the grinding ball, D=2R; The basic information includes film thickness, film type and film hardness; When the film type is PVD coating, the film hardness is 30-38GPa; The film thickness range is 1-3μm, using the first grinding process; the film thickness range is 3-10μm, using the second grinding process; When the film type is CVD coating, the film hardness is 20-30GPa; The film thickness range is 6-10μm, using the third grinding process; the film thickness range is 10-20μm, using the fourth grinding process; The first grinding process is as follows: abrasive particle size 1-3 μm, rotation speed 800-1000 n / min, ball milling time 10-20 s; The second grinding process is as follows: the grinding agent particle size is 1-3 μm, the rotation speed is 800-1000 n / min, and the ball milling time is 20-40 s; The third grinding process is as follows: grinding agent particle size 3-5 μm, rotation speed 500-900 n / min, ball milling time 60-80 s; The fourth grinding process is as follows: grinding agent particle size 3-5 μm, rotation speed 500-900 n / min, ball milling time 80-100 s.

2. The ball milling detection method for CNC blade coating according to claim 1, characterized in that: The ball milling process uses a grinding ball (300) to rotate and grind the surface of the film layer (200) of the numerical control blade, and simultaneously applies a grinding agent to the surface of the grinding ball (300).

3. The ball milling detection method for CNC blade coating according to claim 2, characterized in that: The ball milling process includes ball milling time, rotation speed of the grinding balls (300) and grinding agent particle size.

4. The ball milling detection method for CNC blade coating according to claim 3 is characterized in that: The grinding ball (300) has a density of 6-8 g / cm 3 steel balls or ceramic balls.

5. The ball milling detection method for CNC blade coating according to claim 3, characterized in that: The abrasive is diamond powder.

6. The ball milling detection method for CNC blade coating according to claim 1, characterized in that: If R2'>R2, shorten the ball milling time.

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