A tool multi-layer coating and a method for producing and using the same

Abstract

This invention discloses a multilayer coating for cutting tools, its preparation method, and its application, belonging to the field of surface treatment technology. The multilayer coating comprises a deposited bonding layer, a support layer, and a functional surface layer. The functional surface layer is composed of alternating layers of a wear-resistant layer and a high-hardness self-lubricating layer. The wear-resistant layer is a TiCN layer, and the high-hardness self-lubricating layer is a DLC layer. The bonding layer is a Me layer, and the support layer is a MeC layer; Me is any one of Cr, Ti, or W. This coating material exhibits integrated multifunctional characteristics of high hardness, wear resistance, and long service life in PCB micro-drilling tool environments. Prepared using a combination of magnetron sputtering and plasma-enhanced chemical vapor deposition (PECVD) technology, this coating material can be used as a surface protection for PCB micro-drilling tools, significantly improving their service life and showing promising prospects for industrial application.

Description

Technical Field

[0001] This invention relates to the field of surface treatment technology, and more specifically, to a multilayer coating for cutting tools, its preparation method, and its application. Background Technology

[0002] Printed Circuit Boards (PCBs) serve as the support structure for electronic components, providing connections between them and offering insulation and heat protection. Drilling accounts for 30-40% of the total cost of PCB manufacturing. Currently, micro-drills used in PCB manufacturing primarily utilize CNC drilling machines for high-speed cutting, typically employing carbide shank tools. These tools require high cutting speeds, high chip removal rates, high hole position accuracy, good hole wall quality, and long tool life.

[0003] Currently, the main methods for improving the overall performance of micro-drills include: improving micro-drill materials, drilling methods, micro-drill groove shapes, and using micro-drill surface strengthening technology. Among these, the development of micro-drill surface strengthening technology is the most promising technology. This involves coating various lubricating coatings onto PCB micro-drills to solve the problem of rapid tool wear or workpiece material adhesion during micro-machining. Currently, coatings used on PCB micro-drills include diamond coatings, diamond-like carbon (DLC), WC, and TiAlN. DLC has been studied as a solid lubricant for nearly 30 years and is widely used in mechanical protective coatings. Its high hardness and wear resistance can maintain the sharpness and integrity of the tool for a long time, while its low coefficient of friction and adhesion effect facilitate smooth chip removal. Furthermore, it has advantages such as simple preparation equipment and low manufacturing cost, making it suitable for various steel, non-ferrous metals, and cemented carbide materials, and applicable in aerospace, electronic components, biomedical materials, and other fields. However, the adhesion between DLC coatings and metal surfaces is currently relatively low. When applied to drilling processes, the film is prone to peeling, leading to poor drilling quality and short tool life. Furthermore, the small size and numerous sharp edges and grooves in micro-drills further exacerbate the problem of poor adhesion between the coating and the drill bit. Typically, poor adhesion between the coating and the substrate is due to high internal stress, which is directly proportional to the coating's hardness. Therefore, balancing the adhesion and hardness between the coating and the drill bit, while ensuring good cutting quality and a long cutting life, has become a major challenge that urgently needs to be addressed when applying DLC ​​coatings to the field of mechanical protective coatings.

[0004] In summary, the existing PCB tool surface coatings still have technical problems such as low hardness, poor wear resistance, high coefficient of friction, poor adhesion, and short service life.

[0005] In view of this, the present invention is proposed. Summary of the Invention

[0006] The purpose of this invention is to provide a multi-layer coating for cutting tools, its preparation method and application, so as to improve the problems of low hardness, poor wear resistance, high friction coefficient, poor adhesion and short service life of micro-drilling tools in the prior art.

[0007] This invention is implemented as follows:

[0008] In a first aspect, the present invention provides a multilayer coating for cutting tools, the coating comprising a deposited bonding layer, a support layer and a functional surface layer;

[0009] The aforementioned functional surface layer is composed of alternating layers of wear-resistant layer and high-hardness self-lubricating layer; the wear-resistant layer is a TiCN layer, and the high-hardness self-lubricating layer is a DLC layer;

[0010] The aforementioned bonding layer is a Me layer; the aforementioned support layer is a MeC layer; Me is any one of Cr, Ti, or W.

[0011] In some implementations, the thickness of the functional surface layer is 40–500 nm. Specifically, the thickness of a single TiCN layer is 20–200 nm, and the thickness of a single DLC layer is 20–300 nm.

[0012] In some implementations, the thickness of the TiCN layer is 50–150 nm; the thickness of the DLC layer is 50–150 nm.

[0013] In some implementations, the number of alternating stacking cycles of TiCN layers and DLC layers is 1 to 4.

[0014] In some implementations, the thickness of the bonding layer is 40–100 nm.

[0015] In some implementations, the thickness of the support layer is 40–100 nm.

[0016] Secondly, the present invention provides a method for preparing the above-mentioned multilayer coating of cutting tools, which includes sequentially depositing a bonding layer, a support layer and a functional surface layer on the surface of the cutting tool substrate, and completing the coating preparation after cooling.

[0017] In some embodiments, the deposited bonding layer includes: forming a Me layer by DC magnetron sputtering of a metal target in an Ar atmosphere with a gas flow rate of 80-200 sccm;

[0018] The metal target power is 5 kW, the bias voltage is -200 to -800 V, the chamber temperature is 80 to 300 °C, and the thickness of the Me layer is 40 to 100 nm; Me is any one of Cr, Ti, or W.

[0019] In some embodiments, the deposition of the support layer includes: maintaining a constant Ar flow rate, and forming a MeC layer by DC magnetron sputtering of a metal target and a graphite target, wherein the power of the metal target gradually decreases and the power of the graphite target gradually increases.

[0020] In some embodiments, the power of the metal target is gradually reduced from 5 kW to 0.5 kW, and the power of the graphite target is gradually increased from 0.5 kW to 5 kW. The bias voltage is -300 to -800 V, and the chamber temperature is 100 to 300 °C, forming a gradient MeC coating. The thickness of the MeC coating is 40 to 100 nm.

[0021] In some implementations, the deposited functional surface layer includes alternating deposits of a wear-resistant layer and a high-hardness self-lubricating layer.

[0022] In some embodiments, depositing the wear-resistant layer includes: forming a TiCN coating on the surface of the MeC layer by DC magnetron sputtering of a TiC target in an N2 atmosphere.

[0023] In some embodiments, depositing a high-hardness self-lubricating layer includes forming a DLC coating on the surface of a TiCN layer using plasma-enhanced chemical vapor deposition in a C2H2 atmosphere.

[0024] In some embodiments, the process parameters for depositing the wear-resistant layer include: sputtering target power adjusted to 5kW to 25kW, bias voltage of -200V to -500V, and chamber temperature of 100 to 300°C, with a TiCN coating thickness of 20 to 200nm.

[0025] In some embodiments, the process parameters for depositing the high-hardness self-lubricating layer include: sputtering under the following conditions: a C2H2 atmosphere with a gas flow rate of 100–600 sccm, a bias voltage of -500–-900V, a chamber temperature of 100–350°C, and a DLC coating thickness of 20–300 nm.

[0026] In some embodiments, the purity of the Cr target is higher than 99.98%, the purity of the TiC target is higher than 99.8%, and the purity of the C target is higher than 99.5%.

[0027] Thirdly, the present invention provides the application of the above-mentioned multilayer coating of cutting tools in PCB micro-drilling tools.

[0028] The present invention has the following beneficial effects:

[0029] (1) The TiCN / / DLC functional surface layer in the multilayer coating of the PCB micro-drill tool of the present invention fully utilizes the high hardness and self-lubricating properties of the DLC coating, as well as the wear resistance of the TiCN coating. A Cr layer and a CrC layer are sandwiched between the TiCN / / DLC functional surface layer and the cemented carbide surface as a bonding layer and a support layer, which can buffer and eliminate the residual internal stress between the cemented carbide substrate and the coating, improve the impact resistance of the coating, and prevent the TiCN / / DLC coating from cracking and falling off when the PCB micro-drill tool is rubbed, thereby improving the adhesion of the coating. The Cr bonding layer can control the compatibility of the cemented carbide substrate, and the overall coating can achieve the integrated multi-functional characteristics of high hardness, wear resistance and long life.

[0030] (2) The multilayer coating of the PCB micro-drilling tool of the present invention significantly improves the integrated multi-functional performance of the PCB micro-drilling tool component, which combines high hardness, wear resistance, and long life. This is because the multilayer DLC coating provided by the present invention contains a large amount of sp... 3 The key can improve the hardness of the coating, giving it better wear resistance and a longer service life.

[0031] (3) The present invention adopts a gradient coating design, with the coating transitioning from the surface to the interior, from the high-concentration TiCN / / DLC coating to the low-concentration cemented carbide substrate surface, which alleviates the performance mismatch between coatings and between coatings and substrate, reduces the generation of cracks, and improves the bonding strength between coating and substrate. Attached Figure Description

[0032] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a schematic diagram of the multilayer coating of the PCB micro-drill tool of the present invention;

[0034] Figure 2 This is a comparison chart of wear conditions in the drilling test in the experimental example. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0036] To prepare a multilayer coating with high hardness, wear resistance, and long lifespan on the surface of cemented carbide, this invention employs a composite deposition method combining magnetron sputtering and plasma-enhanced chemical vapor deposition (PECVD) to prepare a multilayer coating material for PCB micro-drill tools. For example... Figure 1 As shown:

[0037] The multilayer coating of the PCB micro-drill tool in this invention includes a bonding layer, a support layer and a functional surface layer deposited sequentially on the substrate surface.

[0038] The bonding layer is a Me layer with a thickness of 40–100 nm. In this invention, Me is any one of Cr, Ti, or W, and the bonding layer mainly controls the compatibility of the cemented carbide surface.

[0039] In this invention, the support layer is a MeC layer, where MeC corresponds to the bonding layer. When the bonding layer is a Cr layer, the support layer is CrC; when the bonding layer is a Ti layer, the support layer is TiC; and when the bonding layer is W, the support layer is WC. The presence of the support layer enhances the adhesion between the coating and the substrate, buffers residual internal stress in the coating, and prevents coating peeling during machining.

[0040] The thickness of the functional surface layer is 40–500 nm. The functional surface layer includes a wear-resistant layer and a high-hardness self-lubricating layer. The wear-resistant layer is a TiCN layer with a thickness of 20–200 nm; the high-hardness self-lubricating layer is a DLC layer with a thickness of 20–300 nm.

[0041] The TiCN layer not only improves the tool's hardness but also provides excellent wear resistance; the DLC layer combines the high hardness of diamond with the lubricity of graphite. The TiCN / / DLC coating, as a functional surface layer, enables the multi-layer coating of the PCB micro-drill tool of this invention to simultaneously achieve high hardness and wear resistance.

[0042] As a general technical concept, the present invention also provides a method for preparing the above-mentioned multilayer coating of PCB micro-drill tool, which includes the following steps:

[0043] (1) Pretreatment: The surface of the cemented carbide is ground and polished to remove the oxide film on the sample surface; the cemented carbide substrate is ultrasonically cleaned with acetone and ethanol for 15 minutes in sequence to remove grease and contaminants from the sample surface, and then dried to make the surface of the cemented carbide substrate smooth. After drying, it is placed on the workpiece rotator in the vacuum coating chamber and fixedly installed.

[0044] (2) Sputter cleaning: Close the inlet and outlet of the vacuum chamber and evacuate to a pressure below 4 × 10⁻⁶. -3At Pa, argon gas with a flow rate of 80-200 sccm is introduced, and the bias voltage of the workpiece support is adjusted to -300 to -800V. The substrate and target are cleaned and etched through the anolyte ion source.

[0045] Sputter cleaning removes the oxide layer and contaminants from the sample surface, thereby improving the adhesion between the substrate and the coating.

[0046] (3) Deposition of bonding layer: The coating chamber is evacuated to below 10°C. -3 At Pa, argon gas with a flow rate of 80-200 sccm is introduced to deposit a Me coating as a bonding layer on the surface of the cemented carbide substrate. Me is any one of Cr, Ti or W, and the thickness of the bonding layer is 40-100 nm.

[0047] (4) Deposition of support layer: After the Me bonding layer is deposited, the argon flow rate is maintained and the Ar is adjusted to 0.5 Pa. The power of the Me target is gradually reduced (5 kW to 0.5 kW) and the power of the graphite target is gradually increased (0.5 kW to 5 kW) to form a gradient MeC coating. The MeC coating is deposited on the surface of the bonding layer as a support layer with a thickness of 40 to 100 nm.

[0048] (5) Deposit wear-resistant layer: Close the argon valve and open the nitrogen valve. In the nitrogen atmosphere, form a TiCN coating by magnetron sputtering a TiC target. Deposit the wear-resistant TiCN coating on the surface of the transition layer as a functional surface layer.

[0049] The deposition process parameters for the above-mentioned wear-resistant layer are as follows: the sputtering target power is adjusted to 5-25 kW, the bias voltage is -200 to -500 V, the flow rate of N2 gas is 300-600 sccm, the sputtering is carried out under the process conditions of chamber temperature of 100-300℃, and the thickness of the wear-resistant layer is 20-200 nm.

[0050] (6) Deposition of a high-hardness self-lubricating layer: Close the nitrogen valve and open the C2H2 valve. In a C2H2 atmosphere, form a DLC coating using a PECVD device. Deposit a high-hardness, self-lubricating DLC ​​coating as a functional surface layer on the wear-resistant TiCN coating surface. Then repeat steps (5) and (6) to alternately deposit TiCN coating and DLC coating to obtain a TiCN / / DLC multilayer functional surface layer. After the coating preparation is complete, turn off the power supply and bias voltage, and turn off the gas. After the cemented carbide substrate cools to room temperature, open the vacuum coating chamber and remove the cemented carbide substrate to obtain the TiCN / / DLC functional surface layer.

[0051] The deposition process parameters for the high-hardness self-lubricating layer are as follows: C2H2 gas flow rate 100~600sccm, bias voltage -500~-900V, and sputtering is performed under the process conditions of chamber temperature 100~350℃. The thickness of the DLC coating is 20~300nm.

[0052] In this invention, when the number of alternating stacking cycles of TiCN layer and DLC layer is 1 to 4, the prepared PCB micro-drill tool multilayer coating has better hardness, wear resistance and bonding strength.

[0053] After composite deposition using magnetron sputtering and PECVD technology, the coating exhibits extremely high adhesion to the cemented carbide, achieving the preparation of an integrated coating with synergistic surface / interface functions. This coating also meets the integrated multi-functional characteristics of high hardness, wear resistance, and long lifespan.

[0054] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0055] In the embodiments of the present invention, the purity of the Cr target is higher than 99.98%, the purity of the TiC target is higher than 99.8%, and the purity of the C target is higher than 99.5%.

[0056] Example 1

[0057] This embodiment provides a multilayer coating for PCB micro-drilling tools that combines high hardness, wear resistance, and long lifespan. It uses cemented carbide as the substrate material and is prepared using magnetron sputtering and PECVD deposition methods. The specific steps are as follows:

[0058] (1) Pre-preparation of matrix material: Grind and polish the surface of cemented carbide to remove the oxide film on the sample surface.

[0059] (2) Surface cleaning of the substrate material: The cemented carbide substrate was ultrasonically cleaned with acetone and ethanol for 15 minutes in sequence to remove grease and contaminants from the sample surface, and then dried to make the surface of the cemented carbide substrate smooth. After drying, it was placed on the workpiece gantry in the vacuum coating chamber and fixed in place.

[0060] (3) Close the inlet and outlet of the vacuum chamber and evacuate until the pressure is below 4 × 10⁻⁶. -3 Argon gas with a flow rate of 130 sccm is introduced at Pa. The bias voltage of the workpiece support is adjusted to -500V. The substrate and target are cleaned and etched through the anodic layer ion source to remove the oxide layer and contaminants on the sample surface, thereby improving the adhesion between the substrate and the coating.

[0061] (4) Prepare the Cr coating by evacuating the coating chamber to a vacuum level below 1×10⁻⁶. -3At a pressure of Pa, argon gas with a flow rate of 130 sccm was introduced to deposit a Cr coating as a bonding layer on the surface of the cemented carbide substrate. The deposition process parameters were: Cr target power of 5 kW, bias voltage of -200 V, cavity temperature of 200 °C, and Cr coating thickness of 80 nm.

[0062] (5) Prepare CrC coating. After the Cr bonding layer is deposited, keep the argon flow rate, gradually decrease the Cr target power (5Kw to 0.5Kw), gradually increase the graphite target power (0.5Kw to 5Kw), set the bias voltage to -300V, and the chamber temperature to 180℃ to form a gradient CrC coating. Deposit the CrC coating on the bonding layer surface as a support layer. The thickness of the CrC coating is 50nm.

[0063] (6) To prepare the TiCN coating in the multi-period functional surface layer, close the argon valve and open the nitrogen valve. In the nitrogen atmosphere, deposit the wear-resistant TiCN coating on the surface of the support layer as the functional surface layer by magnetron sputtering of the TiC target. The deposition process parameters are: sputtering target power is adjusted to 20Kw, bias voltage is -200V, and sputtering is carried out under the process conditions of chamber temperature at 180℃. The thickness of the TiCN coating is 80nm.

[0064] (7) To prepare the DLC coating in the multi-period functional surface layer, the nitrogen valve was closed and the C2H2 valve was opened. In a C2H2 atmosphere, a DLC coating was formed using a PECVD device. A high-hardness, self-lubricating DLC ​​coating was deposited on the wear-resistant TiCN coating surface as the functional surface layer. The deposition process parameters were: C2H2 gas flow rate of 500 sccm, power of 10 kW, bias voltage of -500 V, and chamber temperature of 150 °C. The thickness of the DLC coating was 100 nm. Steps 6 and 7 were then repeated three times to obtain alternating deposition of the TiCN and DLC coatings, i.e., a TiCN / / DLC multilayer functional surface layer. After the coating preparation was completed, the power supply and bias voltage were turned off, and the gas was shut off. After the cemented carbide substrate cooled to room temperature, the vacuum deposition chamber was opened to remove the cemented carbide substrate, thus obtaining the TiCN / / DLC functional surface layer.

[0065] Example 2

[0066] This embodiment provides a multilayer coating for PCB micro-drilling tools that combines high hardness, wear resistance, and long lifespan. Its preparation method and structure are the same as in Embodiment 1, but the difference lies in the deposition process parameters of the Cr coating, CrC coating, TiCN coating, and DLC coating, resulting in different thicknesses. In this embodiment:

[0067] (6) To prepare the TiCN coating in the multi-period functional surface layer, the argon valve was closed and the nitrogen valve was opened. In the nitrogen atmosphere, the wear-resistant TiCN coating was deposited on the surface of the support layer as the functional surface layer by magnetron sputtering of the TiC target. The deposition process parameters were: sputtering target power was adjusted to 15Kw, bias voltage was -200V, and cavity temperature was 160℃. The thickness of the TiCN coating was 76nm.

[0068] (7) To prepare the DLC coating in the multi-period functional surface layer, the nitrogen valve was closed and the C2H2 valve was opened. In the C2H2 atmosphere, the DLC coating was formed by PECVD. A high-hardness, self-lubricating DLC ​​coating was deposited on the wear-resistant TiCN coating surface as the functional surface layer. The deposition process parameters were: C2H2 gas flow rate of 550 sccm, power of 15 kW, bias voltage of -600 V, and cavity temperature of 160 °C. The thickness of the DLC coating was 134 nm. Then, steps 6 and 7 were repeated 3 times to deposit the TiCN coating and DLC coating alternately to obtain the TiCN / / DLC multilayer functional surface layer.

[0069] Example 3

[0070] This embodiment provides a multilayer coating for PCB micro-drilling tools that combines high hardness, wear resistance, and long lifespan. Its preparation method and structure are the same as in Example 1, but the difference lies in the deposition process parameters of the Cr coating, CrC coating, TiCN coating, and DLC coating, resulting in different thicknesses. In this embodiment:

[0071] (6) To prepare the TiCN coating in the multi-period functional surface layer, the argon valve was closed and the nitrogen valve was opened. In the nitrogen atmosphere, the wear-resistant TiCN coating was deposited on the surface of the support layer as the functional surface layer by magnetron sputtering of the TiC target. The deposition process parameters were: sputtering target power was adjusted to 10Kw, bias voltage was -250V, and cavity temperature was 150℃. The thickness of the TiCN coating was 59nm.

[0072] (7) To prepare the DLC coating in the multi-period functional surface layer, the nitrogen valve was closed and the C2H2 valve was opened. In the C2H2 atmosphere, the DLC coating was formed by PECVD. A high-hardness, self-lubricating DLC ​​coating was deposited on the wear-resistant TiCN coating surface as the functional surface layer. The deposition process parameters were: C2H2 gas flow rate of 600 sccm, power of 20 kW, bias voltage of -900 V, and cavity temperature of 210 °C. The thickness of the DLC coating was 151 nm. Then, steps 6 and 7 were repeated 3 times to deposit the TiCN coating and DLC coating alternately to obtain the TiCN / / DLC multilayer functional surface layer.

[0073] Example 4

[0074] This embodiment provides a multilayer coating for PCB micro-drill tools that combines high hardness, wear resistance, and long lifespan. Its preparation method and structure are the same as in Embodiment 1, except that the Cr and CrC coatings are replaced with Ti and TiC coatings, while the deposition process parameters for the TiCN and DLC coatings are the same. In this embodiment:

[0075] (4) Prepare the Ti coating by evacuating the coating chamber to a vacuum level below 1×10⁻⁶. -3 At a pressure of Pa, argon gas with a flow rate of 130 sccm was introduced to deposit a Ti coating as a bonding layer on the surface of the cemented carbide substrate. The deposition process parameters were: Ti target power of 10 kW, bias voltage of -200 V, cavity temperature of 200 °C, and Ti coating thickness of 67 nm.

[0076] (5) Prepare TiC coating. After the Ti bonding layer is deposited, keep the argon flow rate, gradually decrease the power of the Ti target (5Kw to 0.5Kw), gradually increase the power of the graphite target (0.5Kw to 5Kw), set the bias voltage to -300V, and the chamber temperature to 180℃ to form a gradient TiC coating. Deposit the TiC coating on the surface of the bonding layer as a support layer. The thickness of the TiC coating is 56nm.

[0077] Example 5

[0078] This embodiment provides a multilayer coating for PCB micro-drill tools that combines high hardness, wear resistance, and long lifespan. Its preparation method and structure are the same as in Embodiment 1, except that the Cr and CrC coatings are replaced with W and WC coatings, while the deposition process parameters for the TiCN and DLC coatings are the same. In this embodiment:

[0079] (4) Prepare the W coating by evacuating the coating chamber to a vacuum level below 1×10⁻⁶. -3 At a pressure of Pa, argon gas with a flow rate of 130 sccm was introduced to deposit a W coating as a bonding layer on the surface of the cemented carbide substrate. The deposition process parameters were: W target power of 10 kW, bias voltage of -200 V, cavity temperature of 200 °C, and W coating thickness of 81 nm.

[0080] (5) Prepare WC coating. After the W bonding layer is deposited, keep the argon flow rate, gradually decrease the W target power (5Kw to 0.5Kw), gradually increase the graphite target power (0.5Kw to 5Kw), bias voltage -300V, chamber temperature 180℃, form gradient WC coating, deposit WC coating on the bonding layer surface as support layer, the thickness of WC coating is 73nm.

[0081] Comparative Example 1

[0082] This comparative example provides a single-layer DLC coating for a PCB micro-drill tool, which differs from Example 1 in that it does not contain Cr coating, CrC coating, or TiCN coating, but only has a 100nm thick DLC coating deposited on the cemented carbide tool substrate.

[0083] Comparative Example 2

[0084] This comparative example provides a single-layer DLC coating for a PCB micro-drill tool, which differs from Example 1 in that it does not contain Cr coating, CrC coating and DLC coating, but only has a 40nm thick TiCN coating and a 100nm thick DLC coating deposited on the cemented carbide tool substrate.

[0085] Comparative Example 3

[0086] This comparative example provides a single-layer coating for a PCB micro-drill tool, which differs from Example 1 in that it does not contain a DLC coating, but only has a Cr coating with a thickness of 80 nm, a CrC coating with a thickness of 50 nm, and a TiCN coating with a thickness of 80 nm deposited on the carbide tool substrate.

[0087] Comparative Example 4

[0088] This comparative example provides a single-layer DLC coating for a PCB micro-drill tool, which differs from Example 1 in that it does not contain a TiCN coating, but only has an 80nm thick Cr coating, a 50nm thick CrC coating, and a 100nm thick DLC coating deposited on the cemented carbide tool substrate.

[0089] Comparative Example 5

[0090] This comparative example provides a single-layer DLC coating for a PCB micro-drill tool, which differs from Example 1 in that it does not contain a Cr coating or a CrC coating, but only has an 80nm thick TiCN coating and a 100nm thick DLC coating deposited on the cemented carbide tool substrate.

[0091] Comparative Example 6

[0092] This comparative example provides a single-layer DLC coating for a PCB micro-drill tool, which differs from Example 1 in that the thickness of the DLC coating is 400 nm.

[0093] Comparative Example 7

[0094] This comparative example provides a single-layer DLC coating for a PCB micro-drill tool, which differs from Example 1 in that the number of TiCN / / DLC cycles is 5.

[0095] Experimental Example

[0096] The coatings prepared in Comparative Examples 1-7 and Examples 1-5 were subjected to hardness and film-substrate adhesion tests and drilling tests.

[0097] (1) Hardness and film-substrate adhesion test

[0098] According to current testing standards, the hardness and film-substrate adhesion of the multilayer coatings deposited on the cemented carbide substrates obtained in Comparative Examples 1-7 and 1-5 were tested. The test results are shown in the table below:

[0099]

[0100]

[0101] The data in the table above shows that the coating of Example 3 has higher hardness and greater film-substrate adhesion compared to Examples 1, 2, 4, 5 and Comparative Examples 1 to 7. This indicates that the multilayer coating of the PCB micro-drill tool with high hardness, wear resistance and long life provided by the present invention can effectively improve the hardness of the tool, and at the same time, greatly increase the adhesion between the cemented carbide tool substrate and the DLC coating.

[0102] (2) Drilling test

[0103] The cutting tools used in Comparative Examples 1-7 and the tools with multi-layer coatings deposited on the cemented carbide substrate obtained in Examples 1-5 were used to drill holes in a double-layer PCB board. The PCB board used was a compressed plate mainly composed of Al2O3 and SiO2 ceramics, with a total thickness of 8 mm. The drilling experiment was conducted under dry conditions, and the drilling parameters were: rotational speed (S) = 1.6 × 10⁻⁶. 5 r / min, feed rate (F) = 1.5 × 10 3 mm / min, retraction speed (U) = 2.5 × 10 4 mm / min. Figure 2 This shows the tool wear of each tool after 2000 drilling cycles. Figure 2 It can be seen that the multilayer coating of the PCB micro-drill tool prepared by the method in Example 3 has the least surface wear and the longest service life after 2000 drilling cycles.

[0104] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A tool multilayer coating, characterized by, The coating comprises a bonding layer, a support layer, and a functional surface layer deposited sequentially; The functional surface layer is composed of alternating layers of a wear-resistant layer and a high-hardness self-lubricating layer; the wear-resistant layer is a TiCN layer, and the high-hardness self-lubricating layer is a DLC layer. The bonding layer is a Me layer; the support layer is a MeC layer; The Me is any one of Cr, Ti or W; The TiCN layer has a single-layer thickness of 20~200nm; the DLC layer has a single-layer thickness of 20~300nm; The number of cycles in which the TiCN layer and DLC layer are alternately stacked is 1 to 4.

2. The tool multi-layer coating according to claim 1, characterized in that The thickness of the bonding layer is 40~100nm.

3. The tool multilayer coating according to claim 1, characterized in that The thickness of the support layer is 40~100nm.

4. The method for preparing a multilayer coating for a cutting tool according to any one of claims 1-3, characterized in that, A bonding layer, a support layer, and a functional surface layer are sequentially deposited on the surface of the tool substrate, and the coating preparation is completed after cooling.

5. The method for preparing a multilayer coating for a cutting tool according to claim 4, characterized in that, The deposition of the bonding layer includes: forming a Me layer by DC magnetron sputtering of a metal target in an Ar atmosphere with a gas flow rate of 80~200 sccm; The metal target power is 5 kW, the bias voltage is -200 V to -800 V, and the deposition temperature in the chamber is 80 to 300 ℃; the thickness of the Me layer is 40 to 100 nm. The Me is any one of Cr, Ti, or W.

6. The method of producing a tool multi-layer coating according to claim 5, characterized in that The deposition of the support layer includes: maintaining a constant Ar flow rate, and forming a MeC layer by DC magnetron sputtering of a metal target and a graphite target, wherein the power of the metal target gradually decreases and the power of the graphite target gradually increases.

7. The method of producing a tool multi-layer coating according to claim 6, characterized in that The power of the metal target material is gradually reduced from 5kW to 0.5kW, and the power of the graphite target material is gradually increased from 0.5kW to 5kW. The bias voltage is -300~-800V, and the chamber temperature is 100~300℃, forming a gradient MeC coating. The thickness of the MeC coating is 40~100 nm.

8. The method of producing a tool multi-layer coating according to claim 6, characterized in that The functional surface layer is deposited by alternating layers of wear-resistant and high-hardness self-lubricating layers. Depositing the wear-resistant layer includes: forming a TiCN coating by DC magnetron sputtering of a TiC target in an N2 atmosphere and depositing it on the surface of the MeC layer; Depositing the high-hardness self-lubricating layer includes: forming a DLC coating in a C2H2 atmosphere using plasma-enhanced chemical vapor deposition technology and depositing it on the surface of the TiCN layer.

9. The method of producing a tool multi-layer coating according to claim 8, characterized in that The process parameters for depositing the wear-resistant layer include: sputtering target power adjusted to 5 kW to 25 kW, N2 gas flow rate of 300 to 600 sccm, bias voltage of -200 to -500 V, and sputtering performed under the process conditions of chamber temperature of 100 to 300 ℃, with a TiCN coating thickness of 20 to 200 nm.

10. The method of producing a tool multi-layer coating according to claim 8, characterized in that The process parameters for depositing the high-hardness self-lubricating layer include: sputtering under the following conditions: C2H2 gas flow rate of 100~600 sccm, bias voltage of -500~-900 V, and chamber temperature of 100~350 ℃, and the thickness of the DLC coating is 20~300 nm.

11. The method of producing a tool multi-layer coating according to claim 8, characterized in that The purity of the Cr target in the metal target is higher than 99.98%, the purity of the TiC target is higher than 99.8%, and the purity of the graphite target is higher than 99.5%.

12. The application of the multilayer coating of cutting tools as described in any one of claims 1-3 in PCB micro-drilling tools.

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