Cutting tool with electric detection function and cutting method

Abstract

The invention relates to a cutting tool with an electric detection function and a cutting method. The cutting tool with the electric detection function comprises a tool handle and a tool body connected with the tool handle, the tool handle is used for being connected with a machine tool spindle, the tool body comprises a depth sensing part and a cutting part, the surface of the depth sensing part and the surface of the cutting part are each coated with a wear-resistant insulating coating, and the cutting part is used for drilling a circuit board; a groove is formed in the surface of the depth sensing part, an annular conductive band is installed in the groove, an insulated wire matched with the annular conductive band is embedded in the knife handle and the knife body, one end of the insulated wire is electrically connected with the annular conductive band, and the other end of the insulated wire is electrically connected with the annular conductive band. The other end of the insulated wire extends out of the end of the cutter handle and is electrically connected with a machine tool controller, and the position of the groove corresponds to the theoretical depth of an inner copper foil layer in the circuit board. According to the cutting tool with the electric detection function, a copper foil layer in a circuit board can be accurately sensed in real time on line in the drilling process.

Description

Technical Field

[0001] This invention relates to the field of drilling technology, and in particular to a cutting tool and cutting method with electrical detection function. Background Technology

[0002] In the manufacturing process of printed circuit boards, with the high-density integration of electronic components and the significant increase in signal transmission rates, unprecedented requirements have been placed on the processing precision of blind and buried vias. These vias need to stop precisely on a certain internal conductive layer (such as a power layer, signal layer, or ground layer), without penetrating the layer to ensure electrical isolation, while also making sufficient contact to ensure electrical connection. The depth control accuracy is usually required to be within ±50 micrometers or even ±25 micrometers.

[0003] However, existing drilling depth control technologies have many limitations: traditional methods rely on contact detection between the drill tip and the copper foil on the PCB surface to determine the drilling start point, and then control the feed stroke through preset depth. However, factors such as PCB thickness tolerance, material inhomogeneity, and board warpage can cause significant deviations between the actual internal layer positions and the design values. Existing technologies cannot achieve real-time, online, and accurate sensing of the internal layer positions during drilling, making it difficult to meet the process requirements of high-precision blind and buried via machining. Summary of the Invention

[0004] Therefore, it is necessary to provide a cutting tool and cutting method with electrical detection function to address the problem that existing drilling depth control technology cannot achieve real-time, online, and accurate perception of the position of the internal layer during the drilling process, which makes it difficult to meet the process requirements of high-precision blind buried hole machining.

[0005] A cutting tool with electrical detection function includes a tool holder and a tool body connected to the tool holder. The tool holder is used to connect to a machine tool spindle. The tool body includes a depth sensing part and a cutting part. The surfaces of the depth sensing part and the cutting part are coated with a wear-resistant insulating coating. The cutting part is used to drill holes in a circuit board. The surface of the depth sensing unit is provided with a groove, and an annular conductive strip is installed in the groove. An insulated wire that matches the annular conductive strip is embedded inside the tool holder and the tool body. One end of the insulated wire is electrically connected to the annular conductive strip, and the other end of the insulated wire extends from the end of the tool holder and is electrically connected to the machine tool controller. The position of the groove corresponds to the theoretical depth of the internal copper foil layer in the circuit board.

[0006] The aforementioned cutting tool with electrical detection function incorporates an annular conductive strip corresponding to the copper foil layer inside the circuit board within its depth sensing section. This annular conductive strip is led out to the machine tool controller via insulated wires. During drilling, when the annular conductive strip contacts the copper foil layer inside the circuit board, an electrical path is instantly formed and detected in real time by the machine tool controller. This enables real-time, online, and precise sensing of the copper foil layer inside the circuit board during drilling. Furthermore, because the annular conductive strip is embedded in the groove of the depth sensing section, and the depth sensing section is coated with a wear-resistant insulating coating, the annular conductive strip is reliably insulated from the tool body and is protected by both the groove sidewall and the wear-resistant insulating coating. This prevents the annular conductive strip from wearing or peeling off due to friction with the hole wall during drilling, ensuring the long-term stability and reliability of the electrical detection function. Moreover, placing the annular conductive strip behind the depth sensing section avoids the high-temperature, high-friction conditions of the main cutting area. Simultaneously, the wear-resistant insulating coating on the surface of the cutting section ensures the hardness and lifespan of the cutting edge, allowing the cutting tool to maintain excellent cutting performance and machining accuracy while possessing depth sensing capabilities. Furthermore, by embedding insulated wires inside the tool holder and tool body, interference from external wiring during the drilling process is avoided. The annular conductive strip is installed via an embedded method, simplifying the process and controlling costs. This allows the cutting tool of this invention to directly replace existing standard drill bits without requiring complex modifications to the machine tool spindle, demonstrating excellent industrial applicability. Since the cutting tool itself possesses depth sensing capabilities, there is no need to design a dedicated step-through drilling test structure on the circuit board, thereby saving board space, simplifying the process, and reducing circuit board production costs.

[0007] In one embodiment, the circuit board includes a first inner copper foil layer and a second inner copper foil layer, and the groove includes a first groove and a second groove. A first annular conductive strip that matches the first inner copper foil layer is installed in the first groove, and a second annular conductive strip that matches the second inner copper foil layer is installed in the second groove. The position of the first groove corresponds to the theoretical depth of the first inner copper foil layer, and the position of the second groove corresponds to the theoretical depth of the second inner copper foil layer.

[0008] In one embodiment, the end of the cutting part is provided with a wear-resistant conductive layer, and the inside of the tool holder and the tool body is provided with an insulating wire that matches the wear-resistant conductive layer.

[0009] In one embodiment, the thickness of the wear-resistant conductive layer is greater than 1 micrometer and less than 50 micrometers.

[0010] In one embodiment, the wear-resistant conductive layer is made of at least one of boron-doped diamond, diamond-like carbon, and titanium carbide-based cermet.

[0011] A cutting method for a cutting tool with electrical detection function, comprising: The cutting tool is controlled to rotate and feed on the circuit board surface by a drive motor and a feed motor to process cutting holes. A test signal is applied to the first insulated wire, and a detection signal is obtained through the first insulated wire to determine whether the annular conductive strip is in contact with the internal copper foil layer of the circuit board, wherein the first insulated wire is the insulated wire corresponding to the annular conductive strip; If it is determined that the annular conductive strip is in contact with the internal copper foil layer of the circuit board, the cutting tool is controlled to perform a preset action.

[0012] In one embodiment, the method further includes: The cutting tool is controlled to rotate and feed at a first feed rate on the surface of the circuit board to process a cutting hole; When the cutting tool is fed to a preset warning depth, the rotational feed speed of the cutting tool is switched to a second feed speed, wherein the second feed speed is less than the first feed speed.

[0013] In one embodiment, after switching the rotary feed rate of the cutting tool to a second feed rate, the method further includes: Determine the signal-to-noise ratio or pulse width of the detected signal; If the signal-to-noise ratio is lower than a first preset threshold or the pulse width is greater than a second preset threshold, the rotational feed speed of the cutting tool is switched to a third feed speed, wherein the third feed speed is less than the second feed speed.

[0014] In one embodiment, the method further includes: When the first annular conductive strip comes into contact with the first inner copper foil layer, the actual depth of the first inner copper foil layer is determined. The preset warning depth corresponding to the second inner copper foil layer is dynamically adjusted based on the actual depth of the first inner copper foil layer and the theoretical depth of the first inner copper foil layer.

[0015] In one embodiment, before applying a test signal to the first insulated wire and acquiring a detection signal through the first insulated wire to determine whether the annular conductive strip is in contact with the internal copper foil layer of the circuit board, the method further includes: A test signal is applied to the second insulated wire, and a detection signal is obtained through the second insulated wire to determine whether the wear-resistant conductive layer at the end of the cutting part is in contact with the surface copper foil of the circuit board, wherein the second insulated wire is the insulated wire corresponding to the wear-resistant conductive layer; When it is determined that the wear-resistant conductive layer is in contact with the surface copper foil of the circuit board, the feed depth of the cutting tool is initialized. Attached Figure Description

[0016] Fig. 1 This is a schematic diagram of the overall structure of the cutting tool with electrical detection function according to the present invention; Fig. 2 This is a cross-sectional structural diagram of the cutting tool with electrical detection function according to the present invention; Fig. 3 This is a schematic flowchart of the cutting method of the cutting tool with electrical detection function according to the present invention; Among them, 10 is the tool holder, 20 is the tool body, 21 is the depth sensing part, 22 is the cutting part, 23 is the annular conductive strip, 231 is the first annular conductive strip, 232 is the second annular conductive strip, 30 is the first insulated wire, and 40 is the second insulated wire. Detailed Implementation

[0017] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0018] It should be noted that when an element is said to be "fixed to" another element, it can be directly on the other element or there may be an intervening element. When an element is said to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. Conversely, when an element is said to be "directly on" another element, there is no intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0020] This invention discloses a cutting tool with electrical detection function.

[0021] like Figs. 1 to 3As shown, the cutting tool with electrical detection function includes a tool holder 10 and a tool body 20 connected to the tool holder 10. The tool holder 10 is used to connect to the machine tool spindle. The tool body 20 includes a depth sensing part 21 and a cutting part 22. The surfaces of the depth sensing part 21 and the cutting part 22 are coated with a wear-resistant insulating coating. The cutting part 22 is used to drill holes in the circuit board. The surface of the depth sensing part 21 is provided with a groove, in which an annular conductive strip 23 is installed. An insulated wire that matches the annular conductive strip 23 is embedded inside the tool holder 10 and the tool body 20. One end of the insulated wire is electrically connected to the annular conductive strip 23, and the other end of the insulated wire extends from the end of the tool holder 10 and is electrically connected to the machine tool controller. The position of the groove corresponds to the theoretical depth of the internal copper foil layer in the circuit board.

[0022] The aforementioned cutting tool with electrical detection function incorporates an annular conductive strip corresponding to the copper foil layer inside the circuit board within its depth sensing section. This annular conductive strip is led out to the machine tool controller via insulated wires. During drilling, when the annular conductive strip contacts the copper foil layer inside the circuit board, an electrical path is instantly formed and detected in real time by the machine tool controller. This enables real-time, online, and precise sensing of the copper foil layer inside the circuit board during drilling. Furthermore, because the annular conductive strip is embedded in the groove of the depth sensing section, and the depth sensing section is coated with a wear-resistant insulating coating, the annular conductive strip is reliably insulated from the tool body and is protected by both the groove sidewall and the wear-resistant insulating coating. This prevents the annular conductive strip from wearing or peeling off due to friction with the hole wall during drilling, ensuring the long-term stability and reliability of the electrical detection function. Moreover, placing the annular conductive strip behind the depth sensing section avoids the high-temperature, high-friction conditions of the main cutting area. Simultaneously, the wear-resistant insulating coating on the surface of the cutting section ensures the hardness and lifespan of the cutting edge, allowing the cutting tool to maintain excellent cutting performance and machining accuracy while possessing depth sensing capabilities. Furthermore, by embedding insulated wires inside the tool holder and tool body, interference from external wiring during the drilling process is avoided. The annular conductive strip is installed via an embedded method, simplifying the process and controlling costs. This allows the cutting tool of this invention to directly replace existing standard drill bits without requiring complex modifications to the machine tool spindle, demonstrating excellent industrial applicability. Since the cutting tool itself possesses depth sensing capabilities, there is no need to design a dedicated step-through drilling test structure on the circuit board, thereby saving board space, simplifying the process, and reducing circuit board production costs.

[0023] The circuit board includes a first internal copper foil layer and a second internal copper foil layer. The groove includes a first groove and a second groove. A first annular conductive strip 231 that matches the first internal copper foil layer is installed in the first groove. A second annular conductive strip 232 that matches the second internal copper foil layer is installed in the second groove. The position of the first groove corresponds to the theoretical depth of the first internal copper foil layer, and the position of the second groove corresponds to the theoretical depth of the second internal copper foil layer.

[0024] When a circuit board contains multiple different internal copper foil layers, by setting multiple annular conductive strips with different axial positions, the cutting tool with electrical detection function can detect the depth of multiple internal copper foil layers, meeting the complex requirements of blind and buried via machining in multilayer circuit boards. Different annular conductive strips are led out to different electrode terminals at the end of the tool holder via independent insulated wires, thus forming multiple independent detection channels. The detection signals of each layer do not interfere with each other, allowing the cutting tool with electrical detection function to accurately identify which internal copper foil layer it is currently reaching. Real-time detection data of multiple layer depths can be used for dynamic compensation during machining, quality traceability after machining, and can also provide a reference for machining other circuit boards in the same batch.

[0025] The cutting section 22 has a wear-resistant conductive layer at its end, and insulated wires that match the wear-resistant conductive layer are embedded inside the tool holder 10 and the tool body 20. By setting the wear-resistant conductive layer at the end of the cutting section 22, when drilling the circuit board, the wear-resistant conductive layer first contacts the copper foil on the circuit board surface. The contact signal is led out through independent insulated wires, which can accurately detect the first contact between the drill bit and the circuit board surface, providing an accurate starting zero point for subsequent depth measurement. The use of a wear-resistant conductive layer material (such as boron-doped diamond) ensures that the hardness of the drill tip can resist the wear of high-filler PCBs, and also ensures reliable electrical conduction when in contact with the surface copper foil, solving the problem that traditional diamond drill bits cannot detect surface contact due to insulation. Since the surface contact detection channel and the internal layer detection channel are independent of each other, different detection signals or different signal processing algorithms can be applied to optimize detection sensitivity and anti-interference ability.

[0026] The thickness of the wear-resistant conductive layer is greater than 1 micrometer and less than 50 micrometers. Setting the thickness of the wear-resistant conductive layer to be greater than 1 micrometer ensures its continuity and density, preventing localized non-conductivity or excessive resistance due to excessive thinness, which would affect detection sensitivity. Setting the thickness to less than 50 micrometers prevents the cutting edge from becoming dull due to an excessively thick layer, maintaining the drill bit's original sharpness and geometric accuracy, and avoiding increased cutting resistance and decreased machining quality. Because the thickness of the wear-resistant conductive layer is greater than 1 micrometer and less than 50 micrometers, it has sufficient wear resistance to complete thousands of drilling cycles, while material costs remain controllable.

[0027] The wear-resistant conductive layer is made of at least one of boron-doped diamond, diamond-like carbon (DLC), and titanium carbide-based cermet. Boron-doped diamond, DLC, and titanium carbide-based cermet all exhibit good wear resistance and conductivity. Boron-doped diamond combines the ultra-high hardness of diamond (>80 GPa) with semiconductor-grade conductivity (resistivity 0.01-0.1 Ω·cm), making it an ideal material for advanced conductive layers, especially suitable for difficult-to-process PCBs with high filler and high glass fiber content. Diamond-like carbon (DLC) has high hardness and good conductivity (which can be controlled through doping), low film-forming temperature, low internal stress, good adhesion to hard alloy substrates, and relatively low cost. Titanium carbide-based cermet has high hardness, good wear resistance, and good conductivity, making it a low-cost alternative suitable for applications requiring moderate conductivity and wear resistance. In this embodiment, the type of conductive and wear-resistant material can be selected based on the material characteristics of the circuit board being processed, the required processing precision, and the cost budget.

[0028] The present invention also discloses a cutting method for the above-mentioned cutting tool with electrical detection function, comprising steps S101 to S103: Step S101: Control the cutting tool to rotate and feed on the circuit board surface by the drive motor and the feed motor to process the cutting hole.

[0029] In this step, the drive motor drives the cutting tool to rotate, and the feed motor drives the cutting tool to move linearly. The drive motor and feed motor work together to allow the cutting tool to rotate and feed across the circuit board surface, thus machining cutting holes. Cutting holes include various types such as through holes, blind holes, and buried holes.

[0030] In a preferred embodiment, during step S101, the cutting tool is first controlled to rotate and feed at a first feed speed on the circuit board surface to process the cutting hole. When the cutting tool reaches a preset warning depth, the rotational feed speed of the cutting tool is switched to a second feed speed, which is lower than the first feed speed. By using a higher first feed speed in the stage far from the inner copper foil layer of the circuit board, processing efficiency can be ensured. Switching to a lower second feed speed when approaching the inner copper foil layer can improve detection accuracy and control response speed, achieving an optimized balance between efficiency and accuracy. The reduced feed speed of the cutting tool can prolong the contact time between the annular conductive strip and the inner copper foil layer, increasing the chance of the detection system capturing the signal and avoiding missed detection due to brief contact caused by high-speed feed. When the cutting tool feeds at a low speed using the second feed speed, even if there is a slight delay in the control system response, the depth increment of the drill bit during the delay period is small, thereby keeping the over-drilling within a minimum range.

[0031] In a preferred embodiment, during step S101, after switching the rotary feed speed of the cutting tool to the second feed speed, the signal-to-noise ratio (SNR) or pulse width of the detection signal can be determined first. If the SNR is lower than a first preset threshold or the pulse width is greater than a second preset threshold, the rotary feed speed of the cutting tool is switched to a third feed speed, which is lower than the second feed speed. When the SNR is lower than the first preset threshold or the pulse width is greater than the second preset threshold, it often indicates that factors such as uneven circuit board material, copper foil oxidation, and drill wear have led to a decrease in the quality of the detection signal. In this case, further reducing the cutting tool speed can extend the detection window, ensuring reliable detection even under harsh working conditions and improving the robustness of the process. By dynamically adjusting the feed speed of the cutting tool according to the real-time signal quality, a complete closed-loop control of the cutting tool is constructed. By adopting a three-level feed speed, refined and intelligent control of the drilling process is achieved.

[0032] Step S102: Apply a test signal to the first insulated wire 30 and obtain a detection signal through the first insulated wire 30 to determine whether the annular conductive strip is in contact with the internal copper foil layer of the circuit board. The first insulated wire 30 is the insulated wire corresponding to the annular conductive strip.

[0033] In this step, the test signal can be a DC voltage signal, a low-frequency square wave pulse, or a high-frequency carrier signal. By applying the test signal to the first insulated wire, an electrical reference state of the detection channel can be established so as to identify the signal changes caused by the contact between the annular conductive strip and the internal copper foil layer of the circuit board.

[0034] In a preferred embodiment, before step S102, a test signal can be applied to the second insulated wire 40, and a detection signal can be obtained through the second insulated wire 40 to determine whether the wear-resistant conductive layer at the end of the cutting part is in contact with the surface copper foil of the circuit board. The second insulated wire is the insulated wire corresponding to the wear-resistant conductive layer. When it is determined that the wear-resistant conductive layer is in contact with the surface copper foil of the circuit board, the feed depth of the cutting tool is initialized. By detecting the contact between the wear-resistant conductive layer at the end of the cutting part and the surface copper foil, the first contact moment between the drill bit and the board surface can be accurately captured, and this position can be set as the zero point of the depth count, providing an accurate reference for all subsequent depth measurements. Furthermore, the thickness difference of different circuit boards, board warping, and drill bit installation length error will all affect the absolute depth control. By dynamically determining the starting point through surface contact detection, the above errors can be eliminated.

[0035] Step S103: If it is determined that the annular conductive strip is in contact with the internal copper foil layer of the circuit board, then control the cutting tool to perform a preset action.

[0036] In this step, the preset actions can be selected from various options such as stopping the feed, stopping after a small feed, immediately retracting the tool, or continuing the feed after recording the depth. These can be flexibly set according to the process requirements of the circuit board to adapt to different application scenarios.

[0037] In a preferred embodiment, when performing step S103, when the first annular conductive strip contacts the first inner copper foil layer, the actual depth of the first inner copper foil layer is determined; based on the actual depth of the first inner copper foil layer and the theoretical depth of the first inner copper foil layer, the preset warning depth corresponding to the second inner copper foil layer is dynamically adjusted.

[0038] By analyzing the deviation between the actual depth and theoretical depth of the first internal copper foil layer, the preset warning depth corresponding to the second internal copper foil layer is dynamically adjusted. This makes the preset warning depth of the second internal copper foil layer more accurate, solving the problem of interlayer position deviation caused by factors such as thickness tolerance, warpage, and uneven lamination on the circuit board, and achieving self-adaptation of the drilling process. For different drilling positions on the same circuit board, since the thickness distribution may be uneven, the depth parameters of subsequent holes can be dynamically adjusted by feedback of the actual depth of each hole or area, significantly improving the consistency of the entire board processing. By acquiring the layer depth deviation information of the circuit board during processing and performing dynamic compensation, the dependence on dedicated testing structures is eliminated, saving costs and processes.

[0039] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0040] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A cutting tool with electrical detection function, characterized in that, The tool includes a tool holder and a tool body connected to the tool holder. The tool holder is used to connect to a machine tool spindle. The tool body includes a depth sensing part and a cutting part. The surfaces of the depth sensing part and the cutting part are coated with a wear-resistant insulating coating. The cutting part is used to drill holes in a circuit board. The surface of the depth sensing unit is provided with a groove, and an annular conductive strip is installed in the groove. An insulated wire that matches the annular conductive strip is embedded inside the tool holder and the tool body. One end of the insulated wire is electrically connected to the annular conductive strip, and the other end of the insulated wire extends from the end of the tool holder and is electrically connected to the machine tool controller. The position of the groove corresponds to the theoretical depth of the internal copper foil layer in the circuit board.

2. The cutting tool with electrical detection function according to claim 1, characterized in that, The circuit board includes a first internal copper foil layer and a second internal copper foil layer. The groove includes a first groove and a second groove. A first annular conductive strip that matches the first internal copper foil layer is installed in the first groove, and a second annular conductive strip that matches the second internal copper foil layer is installed in the second groove. The position of the first groove corresponds to the theoretical depth of the first inner copper foil layer, and the position of the second groove corresponds to the theoretical depth of the second inner copper foil layer.

3. The cutting tool with electrical detection function according to claim 2, characterized in that, The end of the cutting part is provided with a wear-resistant conductive layer, and the inside of the tool holder and the tool body is provided with an insulating wire that matches the wear-resistant conductive layer.

4. The cutting tool with electrical detection function according to claim 3, characterized in that, The thickness of the wear-resistant conductive layer is greater than 1 micrometer and less than 50 micrometers.

5. The cutting tool with electrical detection function according to claim 4, characterized in that, The wear-resistant conductive layer is made of at least one of boron-doped diamond, diamond-like carbon, and titanium carbide-based metal ceramics.

6. A cutting method for a cutting tool with electrical detection function as described in any one of claims 1 to 5, characterized in that, include: The cutting tool is controlled to rotate and feed on the circuit board surface by a drive motor and a feed motor to process cutting holes. A test signal is applied to the first insulated wire, and a detection signal is obtained through the first insulated wire to determine whether the annular conductive strip is in contact with the internal copper foil layer of the circuit board, wherein the first insulated wire is the insulated wire corresponding to the annular conductive strip; If it is determined that the annular conductive strip is in contact with the internal copper foil layer of the circuit board, the cutting tool is controlled to perform a preset action.

7. The cutting tool with electrical detection function according to claim 6, characterized in that, The method further includes: The cutting tool is controlled to rotate and feed at a first feed rate on the surface of the circuit board to process a cutting hole; When the cutting tool is fed to a preset warning depth, the rotational feed speed of the cutting tool is switched to a second feed speed, wherein the second feed speed is less than the first feed speed.

8. The cutting tool with electrical detection function according to claim 7, characterized in that, After switching the rotary feed rate of the cutting tool to the second feed rate, the method further includes: Determine the signal-to-noise ratio or pulse width of the detected signal; If the signal-to-noise ratio is lower than a first preset threshold or the pulse width is greater than a second preset threshold, the rotational feed speed of the cutting tool is switched to a third feed speed, wherein the third feed speed is less than the second feed speed.

9. The cutting tool with electrical detection function according to claim 7, characterized in that, The method further includes: When the first annular conductive strip comes into contact with the first inner copper foil layer, the actual depth of the first inner copper foil layer is determined. The preset warning depth corresponding to the second inner copper foil layer is dynamically adjusted based on the actual depth of the first inner copper foil layer and the theoretical depth of the first inner copper foil layer.

10. The cutting tool with electrical detection function according to claim 9, characterized in that, Before applying a test signal to the first insulated wire and obtaining a detection signal through the first insulated wire to determine whether the annular conductive strip is in contact with the internal copper foil layer of the circuit board, the method further includes: A test signal is applied to the second insulated wire, and a detection signal is obtained through the second insulated wire to determine whether the wear-resistant conductive layer at the end of the cutting part is in contact with the surface copper foil of the circuit board, wherein the second insulated wire is the insulated wire corresponding to the wear-resistant conductive layer; When it is determined that the wear-resistant conductive layer is in contact with the surface copper foil of the circuit board, the feed depth of the cutting tool is initialized.

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