Composite multifunctional forming tool

Abstract

The application relates to a composite multifunctional forming cutter and relates to the technical field of metal cutting processing. The cutter comprises a cutter handle and a cutting part. The cutting part is coaxially integrated with a drilling section, a milling section, a chamfering section and a finishing forming section in sequence along a cutter axis from a cutter tip to the cutter handle. Circular arcs are adopted for transition between the sections, and annular chip removal grooves are arranged in the transition areas. At least one internal cooling hole is arranged in the cutter, and the outlet of the internal cooling hole is connected to the cutting areas of the sections. During machining, drilling is completed by the drilling section, milling is completed by the milling section through radial feeding, chamfering is completed by the chamfering section through axial feeding, and finally, the finishing forming section is used to complete the finishing of the final surface with small cutting depth and high rotating speed. The application realizes the completion of drilling, milling, chamfering and finishing forming multiple processes in one clamping by the single cutter, and the cutter does not need to be replaced, positioning errors caused by multiple cutter replacements are effectively eliminated, and the machining precision and efficiency are significantly improved.

Description

Technical Field

[0001] This application relates to the field of metal cutting technology, and in particular to a composite multi-functional forming tool that integrates drilling, milling, chamfering and finishing functions. Background Technology

[0002] In traditional machining, multiple processes such as drilling, reaming, milling planes or cavities, chamfering hole openings, and final finishing are typically performed on a workpiece using a sequential machining method, where each process uses a separate dedicated tool. A typical process flow is as follows: First, a center drill or twist drill is used to drill a pilot hole; then, a milling cutter is used to mill the hole wall, hole bottom, or workpiece end face; next, a chamfering cutter is used to chamfer the hole opening edges, removing burrs and providing guidance for subsequent assembly; finally, a reamer or dedicated forming cutter is used for finishing to achieve the required dimensional accuracy and surface roughness.

[0003] While this traditional multi-blade, multi-sequence processing mode can be organized through dedicated machine production lines in single-product mass production, its inherent drawbacks become apparent when facing the demands of modern flexible manufacturing with multiple products, small batches, and rapid changeover. First, frequent tool changes consume a significant amount of non-cutting time. Each tool change involves starting and stopping the spindle, rotating the tool magazine to select the tool, and the robot arm changing the tool. These auxiliary times accumulate, severely reducing the actual effective operating rate of the machine tool. Second, each tool change introduces a repetitive positioning error between the tool and the workpiece. These errors accumulate with the increase in processes, ultimately making it difficult to guarantee the form and position tolerances between the machined features, especially the coaxiality of the hole system, the perpendicularity of each stepped surface, and the symmetry of the chamfer relative to the hole. Third, for compact machining centers or small CNC machine tools with limited tool magazine capacity, a single part occupies multiple tool positions. When machining complex parts or performing multi-face machining in a single clamping, the tool magazine capacity becomes insufficient, and manual tool changes may even be required, severely restricting the continuity of automated production. In addition, the design, manufacturing, inventory management, and life monitoring of multiple independent tools also bring higher operating costs and management complexity.

[0004] Therefore, how to integrate the functions of multiple machining processes into a single tool, enabling it to continuously complete the entire process chain from drilling to final shaping in a single setup without tool changes, has become a key technical requirement for improving machining efficiency, ensuring machining accuracy, and reducing overall costs. Summary of the Invention

[0005] The purpose of this application is to provide a composite multi-functional forming tool that integrates four functional sections along the axial direction: drilling, milling, chamfering, and finishing. Multiple processes can be completed in one tool setup, thereby significantly reducing tool change time, eliminating repetitive positioning errors, and improving machining accuracy and efficiency.

[0006] To solve the above-mentioned technical problems, this application provides a composite multi-functional forming tool, including a tool holder and a cutting part connected to the tool holder. The cutting part includes, along the axis of the tool from the tool tip to the tool holder, a drilling section, a milling section, a chamfering section and a finishing forming section in sequence.

[0007] The drilling section is located at the very front of the cutting tool and is configured as a drill bit with spiral grooves and a drill tip;

[0008] The milling section is configured as a milling cutter with multiple side cutting edges;

[0009] The chamfered section is constructed in the form of a chamfering tool with a tapered cutting edge;

[0010] The finishing section is constructed as a forming milling cutter with a profile that matches the final surface of the workpiece and a finishing edge.

[0011] The transition between the drilling section and the milling section, the milling section and the chamfering section, and the chamfering section and the finishing section are all made of arc, and annular chip removal grooves are provided in the transition areas between these sections.

[0012] The tool has at least one internal cooling hole inside, and the outlet of the internal cooling hole leads to the drill tip of the drilling section, the cutting edge area of ​​the milling section, the cutting edge area of ​​the chamfering section, and the cutting edge area of ​​the finishing section.

[0013] Furthermore, the drilling section is a double- or triple-flute twist drill with a drill tip angle of 118°-140° and a helix angle of 25°-30° for its spiral groove. The drill tip is thinned with a chisel edge or an S-shaped chisel edge to achieve self-centering and reduce axial force. The axial length of the drilling section is greater than the depth of the bottom hole to be machined.

[0014] Furthermore, the milling section is a four- or six-flute end mill structure with a helical groove. The helix angle of the helical groove is 15°-20°. To reduce resonance during machining, the helical direction of the helical groove of the milling section is preferably set to be opposite to the direction of the helical groove of the drilling section.

[0015] Furthermore, the diameter of the milling section is greater than or equal to the diameter of the drilling section to meet the milling allowance requirements; a transition arc with a radius of 0.5-1.0 mm is provided at the junction of the drilling section and the milling section, and the transition radius of the arc between the milling section and the chamfering section and between the chamfering section and the finishing section is 0.5-1.5 mm, so as to eliminate stress concentration at the step; the cutting edge of the milling section is preferably a wave-shaped edge or a chip-breaking edge to improve the stability during side milling.

[0016] Furthermore, the chamfered section is conical or spherical-tipped, with a cone angle of 90° or 120°, corresponding to a chamfer of 45° or 30° respectively; the chamfered section is provided with multiple cutting edges, with a clearance angle of 5°-8° and a rake angle of 0°-5°; the large end diameter of the chamfered section is equal to the diameter of the milling section plus twice the chamfer width, and the small end diameter is equal to the diameter of the milling section, ensuring a smooth transition from the milling section to the chamfered section.

[0017] Furthermore, the finishing section has a micro-finishing cutting edge with a width of 0.10-0.20 mm and a clearance angle of 1°-2°, which enables high-quality surface finishing. The surface of the finishing section is coated with a diamond-like carbon coating or a nano-composite coating, and the coefficient of friction of the coating is ≤0.1, thereby reducing the cutting force and extending the tool life. The diameter of the finishing section is the final finished product size.

[0018] Furthermore, the annular chip removal grooves provided in the transition area between each functional section have a depth of 0.3-0.5 mm and a width of 1-2 mm. These annular grooves can effectively guide the cutting fluid and break the chips, preventing the chips from entangled.

[0019] Furthermore, the internal cooling holes inside the tool are single-hole or double-helix holes, and their outlets are precisely aligned with the drill tip, the milling section cutting edge, the chamfering section cutting edge, and the finishing section cutting edge, respectively, to ensure effective cooling and lubrication of each cutting area.

[0020] Furthermore, the cutting tool is made of solid cemented carbide or high-speed steel to ensure overall rigidity and wear resistance.

[0021] In addition, this application also provides a machining method using the above-mentioned composite multifunctional forming tool, including the following steps:

[0022] Drilling step: Rotate the tool and feed it axially, and use the drilling section to drill a pilot hole in the workpiece to a predetermined depth;

[0023] Milling steps: On the drilled bottom hole or workpiece surface, control the tool to feed radially and use the side edge of the milling section to perform milling.

[0024] Chamfering step: Move the tool axially so that the chamfering section contacts the edge of the hole to be chamfered or the edge of the workpiece, and feed axially to complete the chamfering;

[0025] Finishing and forming step: The tool is axially fed to the final profile position, and the finishing and forming section is used to perform finishing with a small depth of cut and high speed to form the final profile;

[0026] Furthermore, throughout the drilling, milling, chamfering, and finishing processes, coolant is supplied to the cutting area through the internal cooling hole of the tool.

[0027] In summary, this application includes at least one of the following beneficial technical effects:

[0028] 1. This application integrates the drilling section, milling section, chamfering section, and finishing section along the tool axis, enabling a single tool to sequentially complete the drilling, milling, chamfering, and finishing process chain in a single clamping and feed. This eliminates the frequent tool changes required in traditional processes, significantly shortens machining auxiliary time, and greatly improves overall production efficiency. At the same time, the use of arc transitions between functional sections, combined with an annular chip removal groove design, effectively avoids structural stress concentration, ensures smooth chip removal, and makes the multi-process continuous machining process stable and reliable.

[0029] 2. Since all machining processes are completed by the same tool under the same clamping conditions, this application fundamentally eliminates the cumulative errors caused by multiple tool changes and repeated positioning, thereby ensuring extremely high coaxiality, positional accuracy and surface quality consistency between the machined holes or profiles; the micro-repairing blade strip set in the finishing section, combined with the low friction coefficient coating, can achieve a smoothing effect in the finishing steps, meeting the machining requirements of high-precision mating surfaces.

[0030] 3. The tool structure of this application has a high degree of design flexibility. The length, diameter and final profile of each functional section can be customized according to the specific surface of the workpiece. It can machine simple straight holes and stepped holes, as well as complex internal cavity profiles such as sealing grooves and curved surfaces, making it widely applicable. In addition, the internal cooling holes opened inside the tool can accurately deliver coolant to the cutting hot spots in each cutting area, effectively reducing the cutting temperature and extending the tool life, further ensuring the stable operation of efficient and high-precision machining. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the overall structure of the composite multifunctional forming tool of this application;

[0032] Figure 2 This is an internal axial sectional view of the composite multifunctional forming tool of this application;

[0033] Figure 3 This is a flowchart illustrating the processing method of this application.

[0034] Explanation of reference numerals in the attached diagram: 1. Tool holder; 2. Drilling section; 3. Milling section; 4. Chamfering section; 5. Finishing section; 6. Annular chip removal groove; 7. Internal cooling hole. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of this application.

[0036] Example 1

[0037] Please see Figure 1 and Figure 2 This embodiment provides a composite multi-functional forming tool made of solid cemented carbide. The tool includes a tool holder 1 for clamping and a cutting section for performing cutting tasks. Along the axis of the tool, the cutting section is coaxially arranged from the tool tip toward the tool holder 1 with a drilling section 2, a milling section 3, a chamfering section 4, and a finishing forming section 5.

[0038] The drilling section 2 is located at the very front of the tool and is constructed as a three-flute twist drill with a drill tip angle of 135° and a helix angle of 28° for the spiral groove. The drill tip adopts an S-shaped chisel edge structure, which has good self-centering ability. In this embodiment, the diameter of the drilling section 2 is 10.0 mm, its axial length is 30 mm, and it can machine bottom holes with a depth not exceeding 28 mm.

[0039] Milling section 3 immediately follows drilling section 2. Milling section 3 is a six-flute end mill structure with a helical groove of 18°. The helix direction of this groove is left-handed, opposite to the right-handed helical groove of drilling section 2, to counteract cutting torque and reduce vibration. Milling section 3 has a diameter of 12.0 mm, larger than that of the drilling section, allowing for subsequent chamfering and finishing. The cutting edge of milling section 3 uses a chip-breaking edge design.

[0040] At the junction of drilling section 2 and milling section 3, a circular arc with a radius of 0.8 mm is used for smooth transition to avoid stress concentration at right angles. Similarly, a circular arc with a radius of 1.0 mm is also provided between milling section 3 and chamfering section 4, and between chamfering section 4 and finishing section 5.

[0041] The chamfering section 4 has a conical structure with a cone angle of 90°, used for machining a 45° chamfer of C0.5. Six cutting edges are evenly distributed on the chamfering section 4, with a rake angle of 3° and a clearance angle of 6°. The small end diameter of the chamfering section 4 is the same as that of the milling section, which is 12.0 mm; the large end diameter is 13.0 mm.

[0042] The finishing section 5 is located after the chamfering section 4 and near the tool holder 1. The contour of this section is designed according to the final surface profile required by the workpiece. In this embodiment, it is a straight-walled cylindrical surface used to ream the final precision hole. The diameter of the finishing section 5 is 12.02 mm, which is the nominal size of the final finished hole. This section has six cutting edges evenly distributed circumferentially and is provided with a micro-finishing edge band with a width of 0.15 mm and a clearance angle of 1.5°. The surface of the finishing section 5 is coated with a diamond-like carbon coating by physical vapor deposition. This coating has a friction coefficient as low as 0.08, which greatly reduces the generation of built-up edge.

[0043] In the transition area between each of the aforementioned drilling section 2, milling section 3, chamfering section 4, and finishing section 5, an annular chip removal groove 6 is provided. The annular chip removal groove 6 has a depth of 0.4 mm and a width of 1.5 mm, which can effectively accommodate and guide the chips out, preventing blockage.

[0044] A single-hole internal cooling hole 7 is provided at the central axis of the tool, extending through to the tool holder 1. This internal cooling hole 7 branches out into various functional sections inside the tool, and its outlets 7a, 7b, 7c, and 7d are accurately pointed to the drill tip of the drilling section 2, the side cutting edge of the milling section 3, the tapered cutting edge of the chamfering section 4, and the finishing edge area of ​​the finishing section 5, respectively, ensuring that the coolant can reach the cutting hot spot directly throughout the machining process.

[0045] Machining method using the tool of this embodiment, such as Figure 3 As shown, it includes the following steps:

[0046] S1. Drilling step: The tool is clamped on the spindle of the CNC machine tool. The tool is driven to rotate and feed downward with a speed of 3000 r / min and an axial feed speed of 200 mm / min. The drilling section 2 contacts the workpiece first and drills the bottom hole to the predetermined depth of 28 mm.

[0047] S2. Milling steps: After drilling is completed, the spindle continues to rotate and the tool is controlled by the CNC program to perform helical interpolation motion, that is, it moves in a circular motion while lifting upwards; at this time, the six side edges of the milling section 3 enlarge and finish mill the drilled hole wall, and process the hole diameter from 10.0mm to close to the final size.

[0048] S3. Chamfering step: Quickly lift the tool axially to position the tapered cutting edge of chamfering section 4 to the edge of the hole, and then feed downwards by a small amount of 0.5mm at a feed speed of 100mm / min to complete the chamfering of the hole C0.5.

[0049] S4. Finishing and forming step: Finally, feed the tool axially to the starting position of the finishing and forming section 5. Using parameters of high speed 4000r / min, small depth of cut (0.01mm allowance on one side) and low feed speed 50mm / min, the finishing and forming section 5 passes through the entire hole depth from top to bottom or from bottom to top. The micro-finishing cutting edge on it performs finishing on the hole wall, and finally forms a finished hole with qualified dimensions and high surface finish.

[0050] Throughout all the above steps, the machine tool's cooling system continuously supplies cutting fluid at a pressure of 7MPa to the tool's internal cooling hole 7 through the tool holder 1, and the cutting fluid is precisely sprayed into the cutting zone from each outlet 7a-7d.

[0051] The tool in this embodiment completes four processes—drilling, reaming, chamfering, and precision reaming—in one operation without changing tools, achieving extremely high coaxiality and surface quality, and significantly shortening the machining cycle time for a single piece.

[0052] Example 2

[0053] This embodiment is basically the same as Embodiment 1 in structure and working principle, the difference being that the cutting tool is made of cobalt-containing high-speed steel, suitable for machining lightweight materials such as aluminum alloys. The drilling section 2 is a double-edged twist drill with a drill tip angle of 118°. The internal cooling holes 7 are two spiral holes, distributed along the back of the spiral grooves of the drilling section, providing better cooling. The finishing and forming section 5 has a stepped surface with a sealing groove, specifically designed for machining certain valve body holes.

[0054] Example 3

[0055] This embodiment is basically the same as Embodiment 1 in structure and working principle, the difference being that the tool in this embodiment is specifically designed for machining workpieces with stepped holes. The contour of the finishing forming section 5 is designed as a two-stage stepped shape, with the front end being the first-stage finishing edge and the rear end being the second-stage finishing edge, with a conical transition between the two stages. During machining, after completing the drilling, milling, and chamfering steps, the tool continues to feed axially, allowing the two-stage stepped edges of the finishing forming section 5 to sequentially finish the two-stage inner walls of the stepped hole, thereby completing the precision forming of the two-stage hole in one pass, eliminating the need for segmented machining or tool changes, further improving the coaxiality and efficiency of the stepped hole machining.

[0056] The above description is merely a preferred embodiment of this application and is not intended to limit the scope of protection of this application. Any equivalent substitutions or modifications made to the length, diameter, contour shape, and machining parameters of each functional segment of the tool within the scope of the technical concept and claims of this application shall be included within the scope of protection of this application.

Claims

1. A composite multi-functional forming tool, comprising a tool holder (1) and a cutting portion connected to the tool holder (1), characterized in that, The cutting section includes, along the axis of the tool from the tip to the shank (1), a drilling section (2), a milling section (3), a chamfering section (4), and a finishing section (5). The drilling section (2) is located at the front end of the tool and is constructed in the form of a drill bit with spiral grooves and a drill tip; The milling section (3) is constructed in the form of a milling cutter with multiple side cutting edges; The chamfered section (4) is constructed as a chamfering tool with a tapered cutting edge; The finishing section (5) is constructed as a forming milling cutter with a profile that matches the final surface of the workpiece and a finishing edge. A circular arc transition is used between the drilling section (2) and the milling section (3), between the milling section (3) and the chamfering section (4), and between the chamfering section (4) and the finishing section (5), and an annular chip removal groove (6) is provided in the transition area between these sections. The tool has at least one internal cooling hole (7) inside, and the outlet of the internal cooling hole (7) leads to the drill tip of the drilling section (2), the cutting edge area of ​​the milling section (3), the cutting edge area of ​​the chamfering section (4), and the cutting edge area of ​​the finishing section (5).

2. The composite multifunctional forming tool according to claim 1, characterized in that, The drilling section (2) is a double-edged or triple-edged twist drill with a drill tip angle of 118°-140° and a spiral angle of 25°-30° for its spiral groove. The drill tip is thinned with a transverse cutting edge or an S-shaped transverse cutting edge, and the axial length of the drilling section (2) is greater than the depth of the bottom hole to be machined.

3. The composite multifunctional forming tool according to claim 2, characterized in that, The milling section (3) is a four- or six-flute end mill structure with a spiral groove. The spiral angle of the spiral groove is 15°-20°, and the spiral direction of the spiral groove of the milling section (3) is opposite to that of the spiral groove of the drilling section (2).

4. The composite multifunctional forming tool according to claim 3, characterized in that, The diameter of the milling section (3) is greater than or equal to the diameter of the drilling section (2). A transition arc with a radius of 0.5-1.0 mm is provided at the junction of the drilling section (2) and the milling section (3). The arc transition radius between the milling section (3) and the chamfering section (4) and between the chamfering section (4) and the finishing section (5) is 0.5-1.5 mm. The cutting edge of the milling section (3) is a wave-shaped edge or a chip-breaking edge.

5. A composite multifunctional forming tool according to claim 4, characterized in that, The chamfered section (4) is conical or spherical cone with a cone angle of 90° or 120°. The chamfered section (4) is provided with multiple cutting edges with a back angle of 5°-8° and a front angle of 0°-5°. The large end diameter of the chamfered section (4) is equal to the diameter of the milling section (3) plus twice the chamfer width, and the small end diameter is equal to the diameter of the milling section (3).

6. The composite multifunctional forming tool according to claim 1, characterized in that, The finishing section (5) has a micro-refined cutting edge with a width of 0.10-0.20 mm and a back angle of 1°-2°. The surface of the finishing section (5) is coated with a diamond-like coating or a nano-composite coating, and the coefficient of friction of the coating is ≤0.

1. The diameter of the finishing section (5) is the final finished product size.

7. A composite multifunctional forming tool according to claim 1, characterized in that, The annular chip removal groove (6) has a depth of 0.3-0.5 mm and a width of 1-2 mm.

8. A composite multifunctional forming tool according to claim 1, characterized in that, The internal cooling hole (7) is a single hole or a double spiral hole.

9. A composite multifunctional forming tool according to any one of claims 1 to 8, characterized in that, The cutting tool is made of solid cemented carbide or high-speed steel.

10. A machining method using a composite multifunctional forming tool as described in any one of claims 1 to 9, characterized in that, Includes the following steps: Drilling steps: Rotate the tool and feed it axially, and use the drilling section (2) to drill a bottom hole to a predetermined depth on the workpiece; Milling steps: On the drilled bottom hole or workpiece surface, control the tool to feed radially and use the side edge of the milling section (3) to perform milling. Chamfering step: Move the tool along the axial direction so that the chamfering segment (4) contacts the edge of the hole to be chamfered or the edge of the workpiece, and feed along the axial direction to complete the chamfering; Finishing and forming steps: The tool is axially fed to the final profile position, and the finishing and forming section (5) is used to perform finishing with a small depth of cut and high speed to form the final profile; Furthermore, during the drilling, milling, chamfering, and finishing steps, coolant is supplied to the cutting area through the internal cooling hole (7) of the tool.

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