A discardable milling tool for high-gloss mobile phone cameras and its manufacturing method

Abstract

This invention relates to the field of cutting tool technology, and in particular discloses a high-gloss mobile phone camera insert milling discard tool and its manufacturing method, including a tool holder, a tool body, and fasteners. The bottom of the tool holder is provided with a receiving groove, and a first threaded hole is opened in the receiving groove. A second threaded hole is opened on the tool body. The fasteners are installed on the tool holder through the second threaded hole on the tool body and fixedly mounted on the tool holder by the first threaded hole. The tool body includes a mounting part and a cutting insert integrally formed with the mounting part. When the tool holder rotates, the cutting insert on the mounting part contacts the machining surface of the external component to perform a cutting operation.

Description

Technical Field

[0001] This invention relates to the field of cutting tool technology, and in particular discloses a high-gloss mobile phone camera milling discard tool and its manufacturing method. Background Technology

[0002] In the milling of precision components such as high-gloss mobile phone cameras, existing disposable cutting tools face multiple technical bottlenecks: the cutting structure design of the tool has defects, the connection strength between the cutting insert and the mounting part is insufficient, and the cutting edge is prone to wear or breakage due to vibration during high-speed cutting. Moreover, the chip removal path is not smooth, which can easily cause chip accumulation and affect the machining accuracy. The fixing method of the tool holder and the tool body relies on a single thread connection. After long-term use, the torque generated by the cutting force can easily cause the fastener to loosen. When the countersunk hole depth is not properly matched with the thickness of the component, the screw head may protrude from the surface of the tool body, causing machining interference. The heat dissipation and coating technology is backward. The cutting fluid circulation path is single and cannot effectively remove cutting heat. In addition, the wear resistance and corrosion resistance of the coating on the surface of the cutting insert are insufficient, making it difficult to meet the stringent requirements for tool life in high-gloss surface machining. Summary of the Invention

[0003] In order to overcome the shortcomings and deficiencies of the existing technology, the purpose of this invention is to provide a high-gloss mobile phone camera milling discard tool and its manufacturing method.

[0004] To achieve the above objectives, the present invention provides a high-gloss mobile phone camera insert milling discard-type tool, comprising a tool holder, a tool body, and a fastener. The tool holder has a receiving groove at its bottom, and a first threaded hole is formed in the receiving groove. The tool body has a second threaded hole. The fastener is installed onto the tool holder via the second threaded hole on the tool body and onto the first threaded hole on the tool holder, thereby fixing the tool body onto the tool holder. The tool body includes a mounting part and a cutting insert integrally formed with the mounting part. When the tool holder rotates, the cutting insert on the mounting part contacts the machining surface of an external component to perform a cutting operation.

[0005] The free end of the blade has a notch, and the notch is provided with a first cutting edge and a first holding part integrally formed with the first cutting edge. The included angle between the first holding part and the first cutting edge is 0-180°. The first holding part is used to hold the external component, and the first cutting edge performs a cutting operation on the side of the external component.

[0006] The tool body's mounting portion is embedded into a receiving groove at the bottom of the tool holder. A fastener (such as a screw) passes through the second threaded hole in the tool body and connects to the first threaded hole in the tool holder, achieving a secure assembly between the tool body and the tool holder. The insert and mounting portion are integrally formed, with a notch at its free end forming a first cutting edge and a first holding portion that are perpendicular to each other. During cutting, the first holding portion first contacts and holds the surface of the external component, providing a stable support reference for the first cutting edge. Subsequently, the cutting edge precisely cuts the side of the component. This design brings significant benefits: in terms of structural stability, the integrally formed insert and mounting portion enhance the overall strength of the cutting structure, reducing vibration deformation during high-speed rotation; in terms of machining accuracy, the vertically positioned holding portion and cutting edge form a "holding-cutting" linkage structure. The holding portion effectively counteracts the lateral displacement generated by the cutting force, ensuring that the cutting edge precisely cuts along a predetermined trajectory, avoiding machining deviations caused by workpiece wobbling.

[0007] The cutting tool is also provided with an inclined guide surface, which is located on the side of the first cutting edge. The inclined guide surface forms an angle of 15°-30° with the axis of the cutting tool, and the inclined guide surface forms a chip removal path.

[0008] An inclined guide surface with an angle of 15°-30° to the axis of the cutting edge is machined on the side of the first cutting edge, forming a continuous chip removal path. When the tool rotates at high speed, the inclined guide surface uses its specific angle to guide the chips generated during the cutting process to be discharged along the inclined surface, avoiding chip retention between the cutting edge and the machined surface. This design brings significant benefits: improved chip removal efficiency, the guiding effect of the inclined guide surface allows chips to quickly leave the cutting area, reducing scratches on the machined surface or tool blockage caused by chip accumulation; optimized machining quality, the smooth discharge of chips reduces secondary friction between the cutting edge and chips, and with the stable support of the holding part, it can effectively improve the surface finish and precision of the machined surface; extended tool life, the inclined guide surface reduces the compression and wear of chips on the cutting edge, and at the same time reduces the local accumulation of cutting heat. Especially under the high precision requirements of high-gloss surface machining, it can significantly improve tool durability, reduce frequent tool changes due to cutting edge wear, and improve production efficiency.

[0009] The fastener is a screw. The receiving groove is provided with a first countersunk hole and a first threaded hole is connected to the first countersunk hole. The cutter body is provided with a second countersunk hole and a second threaded hole is connected to the second countersunk hole. The depth of the first countersunk hole is the same as the depth of the mounting part of the cutter body, and the depth of the second countersunk hole is the same as the depth of the screw head. After the screw head is sunk into the second countersunk hole, it is flush with the surface of the cutter body.

[0010] A first countersunk hole, with the same depth as the tool body mounting section, is machined within the tool holder's receiving groove, and a first threaded hole is formed at the bottom of the countersunk hole. Simultaneously, a second countersunk hole, matching the depth of the screw head, is machined within the tool body mounting section, connecting the second threaded hole to the second countersunk hole. During assembly, the screw is passed through the second countersunk hole in the tool body and screwed into the first threaded hole in the tool holder until the screw head is completely recessed into the second countersunk hole and flush with the tool body surface. This design offers significant advantages: in terms of structural reliability, the precise matching of the countersunk hole depth to the component thickness ensures the screw head is flush with the tool body surface, preventing workpiece scratches or equipment interference caused by screw protrusion during machining; in terms of connection stability, the coaxial connection between the countersunk hole and the threaded hole ensures the screw preload is evenly transmitted to the contact surfaces of the tool holder and the tool body.

[0011] An elastic washer is provided between the screw head and the second countersunk hole. The outer diameter of the elastic washer is larger than the diameter of the second countersunk hole and smaller than the annular step on the outer edge of the second countersunk hole. This is used to prevent the screw from loosening and to evenly distribute the preload.

[0012] During assembly, the elastic washer is first placed in the second countersunk hole, with its outer diameter slightly larger than the countersunk hole diameter, so that the edge of the washer engages with the lower part of the annular step on the outer edge of the second countersunk hole. Then, the screw is passed through the washer and screwed into the second threaded hole and the first threaded hole. Under the preload of the screw, the elastic washer undergoes elastic deformation, tightly fitting the screw head, the bottom surface of the countersunk hole, and the step surface. This design offers significant advantages: an anti-loosening mechanism where the elastic restoring force of the washer creates continuous friction between the screw head and the countersunk hole, effectively counteracting the axial loosening tendency caused by high-speed cutting vibrations and preventing tool body displacement or detachment due to screw loosening; uniform preload distribution where the washer's flexible contact characteristics evenly distribute the screw's preload to the tool body surface, preventing deformation or cracking of the mounting section caused by localized stress concentration and improving the reliability of the connection between the tool holder and the tool body; and enhanced dynamic stability where the buffering effect of the elastic washer absorbs impact loads during cutting in high-frequency vibration machining environments, reducing rigid collisions between fasteners and the countersunk hole, extending the service life of the screw, countersunk hole, and annular step. It is particularly suitable for high-precision, high-gloss surface machining scenarios, ensuring the stability and consistency of the tool structure during long-term machining.

[0013] The cutting tool body is also provided with a heat dissipation channel for filling cutting fluid. The heat dissipation channel includes a first heat dissipation port on the side of the cutting tool insert, a second heat dissipation port on the bottom surface of the first holding part, and an internal flow channel connecting the first heat dissipation port and the second heat dissipation port. The first heat dissipation port is an elliptical through hole with a major axis diameter of 1.2-2.0 mm and a minor axis diameter of 0.8-1.5 mm. The second heat dissipation port is a circular through hole with a diameter of 0.6-1.0 mm. The diameter of the internal flow channel gradually decreases from the first heat dissipation port to the second heat dissipation port.

[0014] The tapered flow channel utilizes the Venturi effect to increase the flow rate of the cutting fluid, thereby increasing the heat exchange efficiency with the cutting tool and quickly removing the heat generated during the cutting process. This prevents the cutting tool from softening or deforming due to high temperatures, making it particularly suitable for high-gloss machining of temperature-sensitive precision components. The elliptical first heat dissipation port expands the cutting fluid intake area, while the circular second heat dissipation port is precisely aligned with the contact area between the cutting edge and the machined surface. The high-speed sprayed cutting fluid can effectively flush away chips, and the inclined guide surface forms a dual chip removal path to prevent surface scratches caused by chip retention.

[0015] The tool holder has a mounting shaft at the end away from the tool body. The mounting shaft includes a first shaft body and a snap-fit ​​part at the end of the first shaft body away from the tool holder. The snap-fit ​​part includes a first boss and a second boss disposed on the first boss. The diameter of the first boss is larger than the diameter of the second boss. The second boss and the first boss are connected by a first transition fillet. The top of the second boss is provided with a second transition fillet. The first transition fillet and the second transition fillet can reduce the contact stress between the mounting shaft and the inner hole of the machining equipment spindle during installation and rotation.

[0016] The double transition fillet structure eliminates the stress concentration problem of the right-angle edge of the traditional stepped shaft. Finite element analysis has verified that it can reduce the contact stress by 30%-40%, effectively avoiding fatigue cracks or fractures caused by stress concentration when the mounting shaft rotates at high speed (such as 10,000-20,000 rpm), thus extending the overall tool life.

[0017] The inner wall of the heat dissipation channel is provided with a spiral guide pattern, the pitch of which is 0.3-0.6 mm. The spiral guide pattern can guide the cutting fluid to form a spiral flow within the internal channel, increasing the contact area and contact time between the cutting fluid and the tool, thereby improving heat dissipation efficiency.

[0018] Spiral guide patterns (such as right-hand or left-hand spiral structures, 0.1-0.2 mm deep) with a pitch of 0.3-0.6 mm are machined on the inner wall of the internal flow channel of the heat dissipation channel using laser etching, electrolytic machining, or micro-milling processes. The patterns are uniformly distributed along the flow channel axis, forming a synergistic flow guiding structure with the tapered flow channel (claim 5). After flowing in from the first heat dissipation port, the cutting fluid is guided by the spiral patterns to generate a rotating flow, and after being accelerated by the tapered flow channel, it is ejected from the second heat dissipation port. The spiral flow increases the contact area between the cutting fluid and the inner wall of the flow channel by 20%-30% and extends the contact time by 15%-20%.

[0019] The cutting edge is coated with a composite coating, which includes a titanium aluminum nitride layer coated on the surface of the cutting edge, a transition layer coated on the titanium aluminum nitride layer, and a diamond-like carbon layer coated on the transition layer.

[0020] A 2-5 μm thick titanium aluminum nitride (TiAlN) layer is deposited on the surface of the cutting edge using physical vapor deposition (PVD) to form a high-hardness (HV3000-3500) wear-resistant substrate. A 0.5-1 μm transition layer (such as a Cr / CrN gradient structure) is then deposited using ion plating to mitigate the difference in thermal expansion coefficients between the TiAlN and diamond-like carbon (DLC) layers. Finally, a 1-3 μm DLC layer is deposited at 300-400℃ using plasma-enhanced chemical vapor deposition (PECVD), with the acetylene to hydrogen flow ratio controlled at 1:3 and the deposition pressure at 0.5-1.0 Pa. These three coating layers form a gradient hardness structure.

[0021] The transition layer comprises a pure metallic chromium (Cr) layer with a thickness of approximately 0.2-0.5 μm, which is tightly adhered to the surface of the TiAlN layer using ion plating technology. The chromium and TiAlN exhibit high lattice matching (thermal expansion coefficient approximately 6.5 × 10⁻⁶). -6 / ℃, close to 7×10⁻⁶ for TiAlN. -6 The chromium nitride (CrN) layer attached to Cr, approximately 0.3-0.5 μm thick, forms a CrN ceramic phase during deposition by gradually introducing nitrogen (N2). The hardness of CrN (HV 1200-1500) is between that of TiAlN (HV 3000+) and DLC (HV 2000-3000), and its coefficient of thermal expansion (approximately 9 × 10⁻⁶) is also relatively low. -6 / ℃) close to DLC (6-8×10 -6 / ℃), forming a "buffer zone" between hardness and thermal properties.

[0022] A method for manufacturing a discardable milling tool for high-gloss mobile phone cameras, characterized by the following steps:

[0023] S1. Manufacturing the tool holder: Select metal raw materials, use a lathe to rough machine the tool holder raw materials to initially form the outline of the tool holder, including the main body of the tool holder, the bottom receiving groove and the mounting shaft, and use a milling machine to machine the first threaded hole and the first countersunk hole in the receiving groove.

[0024] S2. Manufacturing the cutter body: Select cemented carbide and use milling to rough machine the cemented carbide blank to form the mounting part and the prototype of the cutting insert. Pre-machine the second countersunk hole and the second threaded hole in the mounting part. Open a notch at the free end of the cutting insert and machine the first cutting edge and the first holding part at the notch.

[0025] S3. Tool body finishing: By adjusting the angle of the milling tool, an inclined guide surface is machined on the side of the first cutting edge. A heat dissipation channel is opened on the side of the cutting edge using a laser processing mechanism. A spiral guide pattern is processed on the inner wall of the heat dissipation channel using a laser etching process.

[0026] S4. Surface treatment of cutting edge: A titanium aluminum nitride layer is deposited on the surface of the cutting edge using physical vapor deposition (PVD), a transition layer is deposited on the titanium aluminum nitride layer using ion plating, and a diamond-like carbon (DLC) layer is deposited on the transition layer using chemical vapor deposition (CVD).

[0027] S5. Assembly of components; Insert the mounting part of the tool body into the receiving groove of the tool holder, so that the second threaded hole is coaxially aligned with the first threaded hole; place an elastic washer in the second countersunk hole, and use a torque wrench to screw the screw into the first threaded hole, applying a torque of 0.8 to 1.2 N·m, so that the screw head sinks into the second countersunk hole and is flush with the surface of the tool body.

[0028] The diamond-like carbon layer was deposited using plasma-enhanced chemical vapor deposition (PECVD) at a deposition temperature of 300-400℃, an acetylene to hydrogen flow rate ratio of 1:3, and a deposition pressure of 0.5-1.0 Pa.

[0029] The tool holder is made of metal (such as high-speed steel or cemented carbide), and is machined with receiving grooves, threaded holes, and countersunk holes using lathes and milling machines to form a composite positioning structure of "mounting shaft + receiving groove". This design allows the tool body and tool holder to be rigidly connected by screws, with a large contact area and high fitting accuracy. It can withstand the high axial loads in plunge milling, avoiding the problem of traditional one-piece tools being scrapped due to local wear, and reducing operating costs.

[0030] The combination of countersunk holes and flexible washers allows for precise control of the installation force (0.8–1.2 N·m) using a torque wrench, preventing overtightening that could deform the tool body or undertightening that could cause vibration. It also ensures the screw head is flush with the tool body surface, preventing interference with the workpiece surface during machining and guaranteeing a smooth, high-gloss finish. Laser processing creates heat dissipation channels on the side of the cutting insert, and spiral guide lines with a pitch of 0.3–0.6 mm are etched on the inner wall. This design creates a spiral flow of cutting fluid within the channels, significantly increasing the contact area and residence time between the fluid and the tool's inner wall (heat exchange efficiency is improved by more than 30% compared to straight channels). This enhances the conduction and removal of cutting heat, suppresses thermal deformation of the tool due to high temperatures, and extends its service life, making it particularly suitable for high-speed, high-load continuous machining scenarios.

[0031] Titanium aluminum nitride (TiAlN) is deposited through physical vapor deposition (PVD) process, achieving a hardness of up to HV3000+ and a high-temperature oxidation temperature of up to 1100℃. It can effectively protect the cutting tool from chemical wear during high-temperature cutting (such as adhesive wear with aluminum alloys). At the same time, its low coefficient of friction (0.3-0.4) reduces cutting resistance, making it suitable for machining non-ferrous metals such as aluminum and copper.

[0032] A pure chromium (Cr) layer, 0.2-0.5 μm thick, is formed with the TiAlN layer via ion plating to create a strong metallic bond. The coefficients of thermal expansion of Cr and TiAlN are close (6.5 × 10⁻⁶).-6 / ℃ vs. 7×10 -6 / ℃), with high lattice matching, can eliminate stress concentration at the coating interface and avoid the problems of cracking and peeling that are common with traditional single coatings.

[0033] Chromium nitride (CrN) layer: thickness 0.3-0.5 μm, hardness HV1200-1500, intermediate between TiAlN and diamond-like carbon (DLC) layer, forming a hardness gradient buffer zone. Its coefficient of thermal expansion (9×10⁻⁶) is... -6 / ℃) close to DLC (6-8×10 -6 ( / ℃), further reducing the adhesion stress of the DLC layer and improving the overall bonding strength of the multilayer coating.

[0034] Diamond-like carbon (DLC) layer: Deposited using plasma-enhanced chemical vapor deposition (PECVD) at a low temperature of 300-400℃ to avoid softening of the cemented carbide substrate due to high-temperature annealing. Optimized process parameters, including an acetylene to hydrogen flow ratio of 1:3 and a pressure of 0.5-1.0 Pa, result in a DLC layer hardness of HV2000-3000 and a low coefficient of friction of 0.05-0.1. This combination of high wear resistance and self-lubrication significantly reduces tool sticking during aluminum alloy machining, ensuring a workpiece surface roughness Ra≤0.2μm, meeting the high-gloss requirements of mobile phone camera modules.

[0035] The beneficial effects of this invention are as follows: This invention utilizes a multi-technology synergy, including modular threaded connection between the tool holder and the tool body, a vertical "press-cut" structure for the cutting insert, inclined guide surface for chip removal, a gradually narrowing heat dissipation channel combined with a spiral guide pattern, stress optimization of the double transition fillet of the mounting shaft, and a gradient coating system of titanium-aluminum nitride layer / transition layer / diamond-like layer. This results in a comprehensive performance improvement mechanism that is "structurally stable, with smooth chip removal, efficient heat dissipation, and wear-resistant and vibration-resistant." It has advantages such as a stable structure to prevent interference, precise machining and smooth surface, high chip removal and heat dissipation efficiency, long tool life, and strong process compatibility. It is suitable for high-gloss and high-efficiency machining of precision components such as mobile phone cameras. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0037] Figure 2 For the present invention Figure 1 Enlarged structural diagram of structure A in the middle;

[0038] Figure 3 This is an exploded view of the entire invention;

[0039] Figure 4 This is a schematic diagram of the blade body of the present invention;

[0040] Figure 5 This is a schematic diagram of the structure of the knife handle of the present invention;

[0041] Figure 6 This is a cross-sectional view of the blade body of the present invention;

[0042] Figure 7 This is a schematic diagram of the composite coating structure of the present invention;

[0043] Figure 8 This is a flowchart of the manufacturing method of the present invention.

[0044] The reference numerals in the figures include:

[0045] 1. Handle; 2. Tool body; 3. Fastener; 4. Receiving groove; 5. First threaded hole; 6. Second threaded hole; 7. Mounting part; 8. Cutting insert; 9. Notch; 11. First cutting edge; 12. First holding part; 13. Inclined guide surface; 14. First countersunk hole; 15. Second countersunk hole; 16. Elastic washer; 18. First heat dissipation vent; 19. Second heat dissipation vent; 21. Internal flow channel; 22. Mounting shaft; 23. First shaft body; 24. Snap-fit ​​part; 25. First boss; 26. Second boss; 27. First transition fillet; 28. Second transition fillet; 29. ​​Spiral guide pattern; 31. Composite coating; 32. Titanium aluminum nitride layer; 33. Transition layer; 34. Diamond-like carbon layer; 100. External component. Detailed Implementation

[0046] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to embodiments and accompanying drawings. The content mentioned in the embodiments is not intended to limit the present invention.

[0047] Please see Figures 1 to 8 As shown, a high-gloss mobile phone camera insert milling discard tool of the present invention includes a tool holder 1, a tool body 2, and a fastener 3. The tool holder 1 has a receiving groove 4 at its bottom, and a first threaded hole 5 is formed in the receiving groove 4. The tool body 2 has a second threaded hole 6. The fastener 3 is installed on the tool holder 1 through the second threaded hole 6 on the tool body 2 and fixedly installed on the tool holder 1 by the first threaded hole 5 on the tool holder 1. The tool body 2 includes a mounting part 7 and a cutting insert 8 integrally formed with the mounting part 7. When the tool holder 1 rotates, the cutting insert 8 on the mounting part 7 contacts the machining surface of the external component 100 to perform a cutting operation.

[0048] The free end of the blade 8 has a notch 9, at which a first cutting edge 11 and a first holding part 12 integrally formed with the first cutting edge 11 are provided. The included angle between the first holding part 12 and the first cutting edge 11 is 0-180°. Preferably, the included angle between the first holding part 12 and the first cutting edge 11 is 90°. The first holding part 12 is used to hold the external component 100, and the first cutting edge 11 performs a cutting operation on the side of the external component 100.

[0049] The mounting portion 7 of the cutter body 2 is embedded into the receiving groove 4 at the bottom of the tool holder 1. A fastener 3 (such as a screw) passes through the second threaded hole 6 of the cutter body 2 and connects to the first threaded hole 5 of the tool holder 1, achieving a stable assembly of the cutter body 2 and the tool holder 1. The insert 8 is integrally formed with the mounting portion 7, and a first cutting edge 11 and a first holding portion 12 are formed perpendicularly at the notch 9 at its free end. During cutting, the first holding portion 12 first contacts and holds the surface of the external component 100, providing a stable support reference for the first cutting edge 11. Subsequently, the cutting edge performs precision cutting on the side of the component. This design brings significant benefits: in terms of structural stability, the integrally formed insert 8 and mounting portion 7 enhance the overall strength of the cutting structure and reduce vibration deformation during high-speed rotation; in terms of machining accuracy, the vertically arranged holding portion and cutting edge form a "holding-cutting" linkage structure. The holding portion can effectively counteract the lateral displacement generated by the cutting force, ensuring that the cutting edge accurately cuts along a predetermined trajectory and avoiding machining deviations caused by workpiece wobbling.

[0050] The cutting blade 8 is also provided with an inclined guide surface 13, which is located on the side of the first cutting edge 11. The inclined guide surface 13 forms an angle of 15°-30° with the axis of the cutting blade 8, and the inclined guide surface 13 forms a chip removal path.

[0051] An inclined guide surface 13, forming an angle of 15°-30° with the axis of the cutting insert 8, is machined on the side of the first cutting edge 11, creating a continuous chip removal path. When the tool rotates at high speed, the inclined guide surface 13 uses its specific angle to guide the chips generated during the cutting process to be discharged along the inclined direction, preventing chips from accumulating between the cutting edge and the machined surface. This design brings significant benefits: improved chip removal efficiency, the guiding effect of the inclined guide surface 13 allows chips to quickly leave the cutting area, reducing scratches on the machined surface or tool blockage caused by chip accumulation; optimized machining quality, the smooth discharge of chips reduces secondary friction between the cutting edge and chips, and with the stable support of the holding part, it can effectively improve the surface finish and precision of the machined surface; extended tool life, the inclined guide surface 13 reduces the compression and wear of chips on the cutting edge, and at the same time reduces the local accumulation of cutting heat. Especially under the high precision requirements of high-gloss surface machining, it can significantly improve tool durability, reduce frequent tool changes due to cutting edge wear, and improve production efficiency.

[0052] The fastener 3 is a screw. The receiving groove 4 is provided with a first countersunk hole 14 and a first threaded hole 5 connected to the first countersunk hole 14. The cutter body 2 is provided with a second countersunk hole 15 and a second threaded hole 6 connected to the second threaded hole 6. The depth of the first countersunk hole 14 is the same as the depth of the mounting part 7 of the cutter body 2, and the depth of the second countersunk hole 15 is the same as the depth of the screw head. After the screw head is sunk into the second countersunk hole 15, it is flush with the surface of the cutter body 2.

[0053] A first countersunk hole 14, with the same depth as the mounting portion 7 of the tool body 2, is machined in the receiving groove 4 of the tool holder 1, and a first threaded hole 5 is opened at the bottom of the countersunk hole. Simultaneously, a second countersunk hole 15, matching the depth of the screw head, is machined in the mounting portion 7 of the tool body 2, so that the second threaded hole 6 communicates with the second countersunk hole 15. During assembly, the screw is passed through the second countersunk hole 15 of the tool body 2 and screwed into the first threaded hole 5 of the tool holder 1 until the screw head is completely recessed into the second countersunk hole 15 and flush with the surface of the tool body 2. This design brings significant benefits: in terms of structural reliability, the precise matching of the countersunk hole depth and the component thickness ensures that the screw head is flush with the surface of the tool body 2, avoiding workpiece scratches or equipment interference caused by screw protrusion during machining; in terms of connection stability, the coaxial connection structure of the countersunk hole and the threaded hole ensures that the screw preload is evenly transmitted to the contact surfaces of the tool holder 1 and the tool body 2.

[0054] An elastic washer 16 is provided between the screw head and the second countersunk hole 15. The outer diameter of the elastic washer 16 is larger than the diameter of the second countersunk hole 15 and smaller than the annular step on the outer edge of the second countersunk hole 15, which is used to prevent the screw from loosening and to evenly distribute the preload.

[0055] During assembly, the elastic washer 16 is first placed inside the second countersunk hole 15, with its outer diameter slightly larger than the diameter of the countersunk hole, so that the edge of the washer engages with the lower part of the annular step on the outer edge of the second countersunk hole 15. Then, the screw is screwed through the washer into the second threaded hole 6 and the first threaded hole 5. Under the preload of the screw, the elastic washer 16 undergoes elastic deformation, tightly fitting the screw head, the bottom surface of the countersunk hole, and the step surface. This design brings significant benefits: an anti-loosening mechanism, where the elastic restoring force of the elastic washer 16 creates continuous friction between the screw head and the countersunk hole, effectively counteracting the axial loosening tendency caused by high-speed cutting vibration and preventing displacement or detachment of the tool body 2 due to screw loosening; uniform preload, where the flexible contact characteristics of the washer evenly distribute the screw preload to the surface of the tool body 2, preventing deformation or cracking of the mounting part 7 caused by localized stress concentration, and improving the reliability of the connection between the tool holder 1 and the tool body 2; and enhanced dynamic stability, where the buffering effect of the elastic washer 16 absorbs impact loads during cutting in high-frequency vibration machining environments, reducing rigid collisions between the fastener 3 and the countersunk hole, extending the service life of the screw, countersunk hole, and annular step, especially suitable for high-precision, high-gloss surface machining scenarios, ensuring the stability and consistency of the tool structure during long-term machining.

[0056] The cutter body 2 is also provided with a heat dissipation channel for filling cutting fluid. The heat dissipation channel includes a first heat dissipation port 18 opened on the side of the cutting insert 8, a second heat dissipation port 19 on the bottom surface of the first holding part 12, and an internal flow channel 21 connecting the first heat dissipation port 18 and the second heat dissipation port 19. The first heat dissipation port 18 is an elliptical through hole with a major axis diameter of 1.2-2.0 mm and a minor axis diameter of 0.8-1.5 mm. The second heat dissipation port 19 is a circular through hole with a diameter of 0.6-1.0 mm. The diameter of the internal flow channel 21 gradually decreases from the first heat dissipation port 18 to the second heat dissipation port 19.

[0057] The tapered flow channel utilizes the Venturi effect to increase the flow rate of the cutting fluid, thereby increasing the heat exchange efficiency with the cutting tool 8 and quickly removing the heat generated during the cutting process. This prevents the cutting tool 8 from softening or deforming due to high temperatures, making it particularly suitable for high-gloss machining of temperature-sensitive precision components. The elliptical first heat dissipation port 18 expands the cutting fluid intake area, while the circular second heat dissipation port 19 is precisely aligned with the contact area between the cutting edge and the machined surface. The high-speed sprayed cutting fluid can effectively flush away chips, and together with the inclined guide surface 13, a dual chip removal path is formed to prevent surface scratches caused by chip retention.

[0058] The tool holder 1 is provided with a mounting shaft 22 at the end away from the tool body 2. The mounting shaft 22 includes a first shaft body 23 and a snap-fit ​​part 24 at the end of the first shaft body 23 away from the tool holder 1. The snap-fit ​​part 24 includes a first boss 25 and a second boss 26 provided on the first boss 25. The diameter of the first boss 25 is larger than the diameter of the second boss 26. The second boss 26 is connected to the first boss 25 by a first transition fillet 27. The top of the second boss 26 is provided with a second transition fillet 28. The first transition fillet 27 and the second transition fillet 28 can reduce the contact stress between the mounting shaft 22 and the inner hole of the machining equipment spindle during installation and rotation.

[0059] The double transition fillet structure eliminates the stress concentration problem of the right-angle edge of the traditional stepped shaft. Finite element analysis has verified that it can reduce the contact stress by 30%-40%, effectively avoiding fatigue cracks or fractures caused by stress concentration when the mounting shaft 22 rotates at high speed (such as 10,000-20,000 rpm), thus extending the overall tool life.

[0060] The inner wall of the internal flow channel 21 of the heat dissipation channel is provided with a spiral guide pattern 29, the pitch of which is 0.3-0.6mm. The spiral guide pattern 29 can guide the cutting fluid to form a spiral flow within the internal flow channel 21, increasing the contact area and contact time between the cutting fluid and the tool, thereby improving heat dissipation efficiency.

[0061] Spiral guide patterns 29 with a pitch of 0.3-0.6 mm (such as right-handed or left-handed structures, with a depth of 0.1-0.2 mm) are machined on the inner wall of the internal flow channel 21 of the heat dissipation channel using laser etching, electrolytic machining, or micro-milling processes. The patterns are uniformly distributed along the axial direction of the flow channel, forming a synergistic flow guiding structure with the tapered flow channel (claim 5). After the cutting fluid flows in from the first heat dissipation port 18, it is guided by the spiral patterns to generate a rotating flow, and after being accelerated by the tapered flow channel, it is ejected from the second heat dissipation port 19. The spiral flow increases the contact area between the cutting fluid and the inner wall of the flow channel by 20%-30% and prolongs the contact time by 15%-20%.

[0062] The cutting edge 8 is coated with a composite coating 31, which includes a titanium aluminum nitride layer 32 coated on the surface of the cutting edge 8, a transition layer 33 coated on the titanium aluminum nitride layer 32, and a diamond-like carbon layer 34 coated on the transition layer 33.

[0063] A 2-5 μm thick titanium aluminum nitride (TiAlN) layer is deposited on the surface of the blade 8 using physical vapor deposition (PVD) to form a high-hardness (HV3000-3500) wear-resistant substrate. A 0.5-1 μm transition layer 33 (e.g., a Cr / CrN gradient structure) is deposited using ion plating to mitigate the difference in thermal expansion coefficients between the TiAlN layer and the diamond-like carbon (DLC) layer 34. Finally, a 1-3 μm thick DLC layer is deposited at 300-400℃ using plasma-enhanced chemical vapor deposition (PECVD), with the acetylene to hydrogen flow ratio controlled at 1:3 and the deposition pressure at 0.5-1.0 Pa. These three coating layers form a gradient hardness structure.

[0064] The transition layer 33 comprises a pure metallic chromium (Cr) layer with a thickness of approximately 0.2-0.5 μm, which is tightly adhered to the surface of the TiAlN layer using ion plating technology. The chromium and TiAlN exhibit high lattice matching (thermal expansion coefficient approximately 6.5 × 10⁻⁶). -6 / ℃, close to 7×10⁻⁶ for TiAlN. -6 The chromium nitride (CrN) layer attached to Cr, approximately 0.3-0.5 μm thick, forms a CrN ceramic phase during deposition by gradually introducing nitrogen (N2). The hardness of CrN (HV 1200-1500) is between that of TiAlN (HV 3000+) and DLC (HV 2000-3000), and its coefficient of thermal expansion (approximately 9 × 10⁻⁶) is also relatively low. -6 / ℃) close to DLC (6-8×10 -6 / ℃), forming a "buffer zone" between hardness and thermal properties.

[0065] A method for manufacturing a discardable milling tool for high-gloss mobile phone cameras, characterized by the following steps:

[0066] S1. Manufacturing tool holder 1: Select metal raw materials, use a lathe to rough machine the raw materials of tool holder 1 to initially form the outline of tool holder 1, including the main body of tool holder 1, bottom receiving groove 4 and mounting shaft 22, and use a milling machine to machine the first threaded hole 5 and the first countersunk hole 14 in the receiving groove 4.

[0067] S2. Manufacturing the cutter body 2: Select cemented carbide and use milling to rough machine the cemented carbide blank to form the mounting part 7 and the cutting insert 8 of the cutter body 2. Pre-machine the second countersunk hole 15 and the second threaded hole 6 in the mounting part 7. Open a notch 9 at the free end of the cutting insert 8. Machine the first cutting edge 11 and the first holding part 12 at the notch 9.

[0068] S3. Finishing of the cutter body 2: By adjusting the angle of the milling cutter, an inclined guide surface 13 is machined on the side of the first cutting edge 11. A heat dissipation channel is opened on the side of the cutting edge 8 using a laser processing mechanism. A spiral guide pattern 29 is processed on the inner wall of the heat dissipation channel by laser etching process.

[0069] S4. Surface treatment of blade 8: A titanium aluminum nitride layer 32 is deposited on the surface of blade 8 using physical vapor deposition. A transition layer 33 is deposited on the titanium aluminum nitride layer 32 using ion plating. A diamond-like carbon layer 34 is deposited on the transition layer 33 using chemical vapor deposition.

[0070] S5. Assembly of components; Insert the mounting part 7 of the blade body 2 into the receiving groove 4 of the handle 1, so that the second threaded hole 6 is coaxially aligned with the first threaded hole 5; Place the elastic washer 16 in the second countersunk hole 15, and use a torque wrench to screw the screw into the first threaded hole 5, applying a torque of 0.8 to 1.2 N·m, so that the screw head sinks into the second countersunk hole 15 and is flush with the surface of the blade body 2.

[0071] The diamond-like carbon layer 34 was deposited using plasma-enhanced chemical vapor deposition (PECVD) at a temperature of 300-400℃, an acetylene to hydrogen flow rate ratio of 1:3, and a deposition pressure of 0.5-1.0 Pa.

[0072] The tool holder 1 is made of metal (such as high-speed steel or cemented carbide), and the receiving groove 4, threaded hole, and countersunk hole are machined by lathe and milling machine to form a composite positioning structure of "mounting shaft 22 + receiving groove 4". This design allows the tool body 2 and the tool holder 1 to be rigidly connected by screws, with a large contact area and high fitting accuracy. It can withstand the high axial load in plunge milling and avoids the problem of traditional one-piece tools being scrapped due to local wear, thus reducing the cost of use.

[0073] The combination of countersunk hole and elastic washer 16 allows for precise control of the installation force (0.8–1.2 N·m) using a torque wrench, preventing deformation of the tool body 2 due to overtightening or vibration caused by undertightening. It also ensures the screw head is flush with the surface of the tool body 2, preventing interference with the workpiece surface during machining and guaranteeing a smooth, high-gloss finish. Heat dissipation channels are laser-machined on the side of the cutting insert 8, and spiral guide lines 29 with a pitch of 0.3–0.6 mm are etched on the inner wall. This design creates a spiral flow of cutting fluid within the channel, significantly increasing the contact area and residence time between the fluid and the tool's inner wall (heat exchange efficiency is improved by more than 30% compared to a straight channel). This enhances the conduction and removal of cutting heat, suppresses thermal deformation of the tool due to high temperatures, and extends its service life, making it particularly suitable for high-speed, high-load continuous machining scenarios.

[0074] The titanium aluminum nitride layer 32 (TiAlN) is deposited through physical vapor deposition (PVD) process, with a hardness of up to HV3000+ and a high-temperature oxidation temperature of up to 1100℃. It can effectively protect the cutting bit 8 from chemical wear during high-temperature cutting (such as adhesive wear with aluminum alloys). At the same time, its low coefficient of friction (0.3-0.4) reduces cutting resistance, making it suitable for machining non-ferrous metals such as aluminum and copper.

[0075] A pure chromium (Cr) layer, 0.2-0.5 μm thick, is formed with the TiAlN layer via ion plating to create a strong metallic bond. The coefficients of thermal expansion of Cr and TiAlN are close (6.5 × 10⁻⁶). -6 / ℃ vs. 7×10 -6 / ℃), with high lattice matching, can eliminate stress concentration at the coating interface and avoid the problems of cracking and peeling that are common with traditional single coatings.

[0076] Chromium nitride (CrN) layer: thickness 0.3-0.5 μm, hardness HV1200-1500, between TiAlN and diamond-like carbon (DLC) layer 34, forming a hardness gradient buffer zone. Its coefficient of thermal expansion (9×10⁻⁶) is... -6 / ℃) close to DLC (6-8×10 -6 ( / ℃), further reducing the adhesion stress of the DLC layer and improving the overall bonding strength of the multilayer coating.

[0077] Diamond-like carbon (DLC) layer 34: Deposited using plasma-enhanced chemical vapor deposition (PECVD) at a low temperature of 300-400℃ to avoid softening of the cemented carbide substrate due to high-temperature annealing. Optimized process parameters, including an acetylene to hydrogen flow ratio of 1:3 and a pressure of 0.5-1.0 Pa, result in a DLC layer hardness of HV2000-3000 and a low coefficient of friction of 0.05-0.1. This combination of high wear resistance and self-lubrication significantly reduces tool sticking during aluminum alloy machining, ensuring a workpiece surface roughness Ra≤0.2μm, meeting the high-gloss requirements of mobile phone camera modules.

[0078] The above description is only a preferred embodiment of the present invention. For those skilled in the art, there will be changes in the specific implementation and application scope based on the ideas of the present invention. The content of this specification should not be construed as a limitation of the present invention.

Claims

1. A high light mobile phone camera insert-milling disposable tool, characterized by: The tool includes a handle (1), a blade (2), and a fastener (3). The handle (1) has a receiving groove (4) at its bottom, and a first threaded hole (5) is provided in the receiving groove (4). The blade (2) has a second threaded hole (6). The fastener (3) is installed on the handle (1) through the second threaded hole (6) on the blade (2) and fixedly mounted on the handle (1) by the first threaded hole (5). The blade (2) includes a mounting part (7) and a cutting insert (8) integrally formed with the mounting part (7). The handle (1) rotates. At that time, the cutting edge (8) on the mounting part (7) contacts the machining surface to perform a cutting operation; the free end of the cutting edge (8) has a notch (9), and the notch (9) is provided with a first cutting edge (11) and a first holding part (12) integrally formed with the first cutting edge (11). The included angle between the first holding part (12) and the first cutting edge (11) is 0-180°. The first holding part (12) is used to hold the external component (100), and the first cutting edge (11) performs a cutting operation on the side of the external component (100). The cutting edge (8) is also provided with an inclined guide surface (13), which is located on the side of the first cutting edge (11). The inclined guide surface (13) forms an angle of 15°-30° with the axis of the cutting edge (8), and the inclined guide surface (13) forms a chip removal path. The fastener (3) is a screw. The receiving groove (4) is provided with a first countersunk hole (14), and the first threaded hole (5) is connected to the first countersunk hole (14). The cutting body (2) is provided with a second countersunk hole (15), which is connected to the second threaded hole (6). The depth of the first countersunk hole (14) is the same as the depth of the mounting part (7) of the cutting body (2), and the depth of the second countersunk hole (15) is the same as the depth of the screw head. After the screw head is sunk into the second countersunk hole (15), it is flush with the surface of the cutting body (2). The cutter body (2) is also provided with a heat dissipation channel for filling cutting fluid. The heat dissipation channel includes a first heat dissipation port (18) opened on the side of the cutting insert (8), a second heat dissipation port (19) on the bottom surface of the first holding part (12), and an internal flow channel (21) connecting the first heat dissipation port (18) and the second heat dissipation port (19). The first heat dissipation port (18) is an elliptical through hole with a major axis diameter of 1.2-2.0 mm and a minor axis diameter of 0.8-1.5 mm. The second heat dissipation port (19) is a circular through hole with a diameter of 0.6-1.0 mm. The diameter of the internal flow channel (21) gradually decreases from the first heat dissipation port (18) to the second heat dissipation port (19). The tool holder (1) is provided with a mounting shaft (22) at one end away from the tool body (2). The mounting shaft (22) includes a first shaft body (23) and a snap-fit ​​part (24) at one end away from the tool holder (1). The snap-fit ​​part (24) includes a first boss (25) and a second boss (26) provided on the first boss (25). The diameter of the first boss (25) is larger than the diameter of the second boss (26). The second boss (26) is connected to the first boss (25) by a first transition fillet (27). The top of the second boss (26) is provided with a second transition fillet (28). The first transition fillet (27) and the second transition fillet (28) can reduce the contact stress between the mounting shaft (22) and the inner hole of the machining equipment spindle during installation and rotation.

2. The high-gloss mobile phone camera milling discard tool according to claim 1, characterized in that: An elastic washer (16) is provided between the screw head and the second countersunk hole (15). The outer diameter of the elastic washer (16) is larger than the diameter of the second countersunk hole (15) and smaller than the annular step on the outer edge of the second countersunk hole (15), which is used to prevent the screw from loosening and to evenly distribute the preload.

3. The high-gloss mobile phone camera milling discard tool according to claim 1, characterized in that: The inner wall of the internal flow channel (21) of the heat dissipation channel is provided with a spiral guide pattern (29), and the pitch of the spiral guide pattern (29) is 0.3-0.6mm. The spiral guide pattern (29) can guide the cutting fluid to form a spiral flow in the internal flow channel (21), increase the contact area and contact time between the cutting fluid and the tool, and improve the heat dissipation efficiency.

4. The high-gloss mobile phone camera milling discard tool according to claim 1, characterized in that: The blade (8) is coated with a composite coating (31), which includes a titanium aluminum nitride layer (32) coated on the surface of the blade (8), a transition layer (33) coated on the titanium aluminum nitride layer (32), and a diamond-like layer (34) coated on the transition layer (33).

5. A method for manufacturing a high-gloss mobile phone camera milling cutter according to any one of claims 1-4, characterized in that, The steps are as follows: S1. Manufacturing tool holder (1): Select metal raw materials and use a lathe to rough machine the tool holder (1) raw materials to initially form the outline of the tool holder (1), including the main body of the tool holder (1), the bottom receiving groove (4) and the mounting shaft (22). Use a milling machine to machine the first threaded hole (5) and the first countersunk hole (14) in the receiving groove (4). S2. Manufacturing the cutter body (2): Select cemented carbide and use milling to rough machine the cemented carbide blank to form the initial shape of the mounting part (7) and the cutting insert (8) of the cutter body (2). Pre-machine the second countersunk hole (15) and the second threaded hole (6) in the mounting part (7). Open a notch (9) at the free end of the cutting insert (8). Machin the first cutting edge (11) and the first holding part (12) at the notch (9). S3. Finishing of the cutter body (2): By adjusting the angle of the milling cutter, an inclined guide surface (13) is machined on the side of the first cutting edge (11). A heat dissipation channel is opened on the side of the cutting edge (8) using a laser processing mechanism. A spiral guide pattern (29) is processed on the inner wall of the heat dissipation channel by laser etching process. S4. Surface treatment of blade (8): A titanium aluminum nitride layer (32) is deposited on the surface of blade (8) by physical vapor deposition, a transition layer (33) is deposited on the titanium aluminum nitride layer (32) by ion plating, and a diamond-like carbon layer (34) is deposited on the transition layer (33) by chemical vapor deposition. S5. Assembly of components; embed the mounting part (7) of the tool body (2) into the receiving groove (4) of the tool holder (1) so that the second threaded hole (6) is coaxially aligned with the first threaded hole (5); place an elastic washer (16) in the second countersunk hole (15), use a torque wrench to screw the screw into the first threaded hole (5), apply a torque of 0.8 to 1.2 N·m, so that the screw head sinks into the second countersunk hole (15) and is flush with the surface of the tool body (2).

6. The manufacturing method of a high-gloss mobile phone camera milling discard tool according to claim 5, characterized in that: The diamond-like layer (34) in S4 is deposited using plasma-enhanced chemical vapor deposition (PECVD) at a temperature of 300-400°C, with an acetylene to hydrogen flow rate ratio of 1:3 and a deposition pressure of 0.5-1.0 Pa.

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