A profile milling cutter for machining a stepped profile and a contoured surface and a method of machining

Abstract

The present application belongs to the technical field of cutters, and particularly relates to a profile milling cutter for machining stepped profiles and special-shaped surfaces and a machining method. The machining method specifically comprises the following steps: S1: selecting materials, S2: blanking and rough grinding, S3: handle reference grinding, S4: spiral cutting edge groove and rake angle, spiral angle grinding, S5: drill point angle, stepped end edge and multiple peripheral relief angle combined grinding, S6: segmented ultra-thin core thickness precision grinding, S7: blade edge passivation and surface treatment, S8: dynamic balance and radial runout active compensation, S9: precision detection and warehouse storage. The present application adopts segmented variable parameter grinding and intermittent cooling between fine grinding, through the reserved allowance, the fine grinding is split into 2-3 knives of trace feed, and a cooling interval is set after each feed, so that the thermal stress can be fully released and dissipated after each extremely small cutting, and the generation of thermal cracks is completely eliminated.

Description

Technical Field

[0001] This invention relates to the field of cutting tool technology, specifically to a forming milling cutter and machining method for machining stepped contours and irregular surfaces. Background Technology

[0002] Cutting tools are tools used for cutting processes in mechanical manufacturing. Since the vast majority of cutting tools are machine-made and are primarily used for cutting metal materials, the term "cutting tool" is generally understood to refer to metal cutting tools.

[0003] Forming tools are an important type of metal cutting tool. When machining 4.3mm tools with a core thickness of only 0.1mm using traditional processes, the contact force of the grinding wheel can easily cause the workpiece to bend, generating high-frequency vibration, resulting in edge chipping or excessive radial runout. Moreover, with a core thickness of 0.1mm, grinding heat is difficult to dissipate in conventional one-step forming grinding, which can easily generate microcracks in the core, leading to breakage during processing and batch scrapping. Therefore, it is particularly important to design a forming milling cutter and machining method for stepped contours and irregular surfaces to solve the above problems. Summary of the Invention

[0004] To solve the above problems, this invention designs a forming milling cutter and processing method for machining stepped contours and irregular surfaces. By using the "tailstock internal support grinding method" to transform the cantilever beam into a simply supported beam, and combining "CBN grinding wheel sharp shearing" and "0.002mm / time micro-feed", the radial grinding pressure is greatly reduced, and tool deflection and high-frequency chatter are completely eliminated.

[0005] To solve the above-mentioned technical problems, the present invention provides a machining method for a forming milling cutter for machining stepped contours and irregular surfaces, specifically including the following steps: S1: Material selection: Select 55° cemented carbide round bars with a grain size of 0.6μm and a bending strength of ≥4200MPa. The diameter of the bar stock should meet the machining allowance of the shank. S2: Cutting and rough grinding: Use a cutting detection device to cut the bar material to the specified dimensions according to the total length. After cutting, grind both ends of the bar material flat. S3: Shank reference grinding: The shank diameter is finely ground to 8 (-0.008, 0) using a high-precision centerless grinder to form a preform milling cutter blank. The surface roughness of the shank is controlled below Ra0.2, serving as the sole positioning reference surface for all subsequent machining. S4: Grinding of spiral chip grooves and rake angle and helix angle: Using a six-axis five-linkage CNC tool grinder, with a shaped grinding wheel, three-tooth spiral grooves are ground, with the rake angle controlled at 16° and the helix angle at 20°. During rough grinding, 40% of the core thickness is retained for finishing. S5: Combined grinding of drill tip, stepped end edge and multiple clearance angles on the outer periphery: Using a double-cone angle composite grinding wheel, in one clamping and feed: first grind the 130° drill tip at the front end, and simultaneously grind the radial double clearance angles on the outer periphery to 12°±1° and 28°±2° and the axial double clearance angles to 4° and 8° respectively; then use a small-diameter diamond grinding wheel to perform micro-area precision contouring on the end edge, controlling the double clearance angles of the end edge to 8°±1° and 20°±2° respectively, and ensuring that the step difference of 0.1mm and 0.3mm between the inner and outer cutting edge widths of the double clearance angles of the end edge is flush; S6: Segmented ultra-thin core thickness precision grinding: The internal hole support grinding method is adopted, and a specially made high-rigidity mandrel is held against the core area from the tail of the tool; the precision grinding is completed by 2-3 micro-feeds, with a single feed amount ≤0.002mm / time, and a cooling interval is set after each feed. Finally, the core thickness is controlled to 0.1mm (+0, +0.1) to prevent thermal stress accumulation from causing micro-cracks. S7: Edge passivation and surface treatment: A combination of weak directional airflow sandblasting and soft brush is used to strictly control the passivation radius between 0.01 and 0.02 mm, remove grinding burrs and improve the micro-smoothness of the cutting edge; S8: Dynamic balancing and radial runout active compensation: The grinding wheel vibration is eliminated by using an online dynamic balancing instrument on the grinding machine, and the first and second step cutting diameters are measured in real time by a laser tool setter; based on the measured 360° high and low point data, the rotation phase of the C-axis is automatically calculated and compensated, and the final cutting diameter runout is controlled within 0.008mm. S9: Precision inspection and storage: Use inspection equipment to measure various diameters and angles, and store them in the shell after the measurements are correct.

[0006] Furthermore, in step S2, after the bar stock is cut, it is subjected to ultrasonic non-destructive testing to remove blanks with internal micro-cracks.

[0007] Furthermore, the cutting and testing device includes a base, a first bar conveying bracket, a second bar conveying bracket, an ultrasonic non-destructive testing instrument, a guide fixing seat, a transport seat, and a cutting blade. The first bar conveying bracket, the guide fixing seat, the transport seat, and the second bar conveying bracket are arranged sequentially from left to right on the top of the base. The cross-sections of the first bar conveying bracket and the second bar conveying bracket are V-shaped and both are horizontally arranged. The right end of the first bar conveying bracket is close to the left end face of the guide fixing seat, and the left and right end faces of the guide fixing seat are relatively close to the first bar conveying bracket. A first guide hole is provided at the position. The cutting tool is set between the guide fixing seat and the transport seat and is driven downward by the cutting drive hydraulic cylinder installed on the top of the guide fixing seat. The transport seat is connected to the top of the base through a telescopic elastic component. The height of the second bar material conveying bracket is lower than that of the first bar material conveying bracket. The second bar material conveying bracket passes through the ultrasonic non-destructive testing instrument. The right end of the second bar material conveying bracket is connected to the inclined feeding guide bracket. The bottom of the first bar material conveying bracket and the second bar material conveying bracket, as well as the transport seat, are provided with roller structures for bar material conveying.

[0008] Furthermore, in step S4, during the grinding of the spiral grooves, a 3D dresser is used to dress the irregular grinding wheel online, so that the shape of the grinding wheel perfectly matches the 3 teeth and the forming contour. The three teeth are ground in turn using a layered oscillating grinding method to ensure that the helix angle of the three spiral grooves is consistent, which is conducive to chip removal.

[0009] Furthermore, in step S7, the passivation radius is strictly controlled between 0.01 and 0.02 mm during the edge passivation and surface treatment. Polishing paste is used to perform mirror treatment on the edge, which can greatly reduce the sticking phenomenon during cutting.

[0010] Further, the testing equipment in step S9 includes a testing platform, an arc-shaped guide bracket, a fixed bracket, a magnifying detector, a Zoller tool detector, and a rotating plate. The testing platform is suspended in mid-air, with a magnifying detection station and a dimensional detection station respectively set on its top. The top of the testing platform also has a countersunk groove that matches the rotating plate. The rotating plate is connected to the countersunk groove by a bearing mounted on the outer side and is connected to a rotary drive mechanism. Two tool fixing fixtures are set on the rotating plate. The two tool fixing fixtures are driven by the rotary drive mechanism to pass through the magnifying detection station and the dimensional detection station in sequence. The tool fixing fixtures are rotated by a servo motor installed at the bottom of the rotating plate. The arc-shaped guide bracket is installed directly above the magnifying detector through the fixed bracket. The magnifying detector is electrically connected to a first display set on one side of the fixed bracket and is slidably connected to the inner wall of the arc-shaped guide bracket by a slide block. The slide block slides up and down along the inner wall of the arc-shaped guide bracket by a telescopic electric cylinder. The Zoller tool detector is set on the dimensional detection station and electrically connected to a second display. This invention also provides a forming milling cutter for machining stepped contours and irregular surfaces. The structure consists of a shank portion and a cutting portion integrated together. The cutting portion, at its end away from the shank portion, is sequentially provided with a drill tip cutting area, a first stepped cutting diameter area, and a second stepped cutting diameter area. Three helical chip grooves are evenly distributed on the outer circumference of the cutting portion. The end of the drill tip cutting area has a 130° drill tip angle. The outer diameter of the first stepped cutting diameter area is 4.3 mm, and the outer diameter of the second stepped cutting diameter area is 3.6 mm. The core thickness inside the cutting portion is 0.1 mm. The outer circumferential surface of the cutting portion has an axial double clearance angle and a radial double clearance angle. The axial double clearance angles are 4° and 8°, and the radial double clearance angles are 12° and 28°. Corresponding to the axial and radial double clearance angles, the outer circumferential surface of the cutting portion has a double-width outer circumferential cutting band with widths of 0.4 mm and 0.6 mm, respectively.

[0011] Furthermore, the end face of the drill tip cutting area is provided with an end-edge rake angle and an end-edge double-stage clearance angle, wherein the end-edge rake angle is 3°, and the end-edge double-stage clearance angles are 8° and 20° respectively.

[0012] Furthermore, the end face of the double-stage rear angle of the end blade is provided with end face support blade bands of unequal width. The end face support blade bands include a first blade band located on the inner side and a second blade band located on the outer side. The width of the first blade band is 0.1 mm and the width of the second blade band is 0.3 mm.

[0013] Furthermore, the spiral chip groove has a helix angle of 20°, a rake angle of 16°, and a groove length of 15mm.

[0014] With the above structure, the present invention has the following beneficial effects: This invention transforms a cantilever beam into a simply supported beam through the "tailstock internal support grinding method," and by combining "CBN grinding wheel sharp shearing" with "extremely small feed of 0.002 mm / cycle," it significantly reduces radial grinding pressure and completely eliminates tool deflection and high-frequency chatter.

[0015] The present invention employs the above-described structure to automatically perform flaw detection on each cut bar, eliminating the need for a separate inspection process later, thus greatly improving practicality.

[0016] The testing equipment used in this invention can simultaneously perform magnified appearance inspection and dimensional inspection on two forming milling cutters, and the inspection items can be changed by rotating the rotating plate without re-clamping, which facilitates inspection and improves inspection efficiency. Attached Figure Description

[0017] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0018] Figure 1 This is a schematic diagram of the main structure of the forming milling cutter in this invention.

[0019] Figure 2 for Figure 1 Enlarged schematic diagram of the middle cutting section Figure 3 This is a schematic diagram of the left-side structure of the forming milling cutter in this invention.

[0020] Figure 4 for Figure 3 A magnified view of A in the middle.

[0021] Figure 5 This is a schematic diagram of the cutting detection device.

[0022] Figure 6 for Figure 5 A magnified view of B in the middle.

[0023] Figure 7 This is a schematic diagram of the transporter.

[0024] Figure 8 This is a schematic diagram of the testing equipment.

[0025] In the diagram: 1-1 is the tool holder, 1-2 is the cutting section, 1-2-1 is the drill tip cutting area, 1-2-2 is the first stepped cutting diameter area, 1-2-3 is the second stepped cutting diameter area, 1-2-4 is the spiral chip groove, 2 is the base, 3 is the guide fixing seat, 4 is the conveying seat, 5 is the first bar stock conveying support, 6 is the ultrasonic non-destructive testing instrument, 7 is the second bar stock conveying support, 8 is the inclined unloading guide support, 9 is the clamping electric cylinder, 10 is the cutting drive hydraulic cylinder, 11 is the cutting tool, 12 is the first vertical guide rail, 13 is the first slider, and 14 is the guide link. 15 is the second vertical guide rail, 16 is the push transmission block, 17 is the translation drive cylinder, 18 is the sliding frame, 19 is the lifting cylinder, 20 is the horizontal slide rail, 21 is the telescopic elastic component, 22 is the detection platform, 23 is the rotating plate, 24 is the external gear ring, 25 is the servo motor, 26 is the drive servo motor, 27 is the drive gear, 28 is the arc-shaped guide bracket, 29 is the magnifying detector, 30 is the first display, 31 is the telescopic cylinder, 32 is the Zoller tool detector, 33 is the second display, 36 is the fixed bracket, and 37 is the tool fixing fixture. Detailed Implementation

[0026] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] In the description of this invention, it should be noted that certain terms indicating orientation or positional relationships are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting this invention.

[0028] In the description of this invention, it should be noted that the term "connection" should be interpreted broadly. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0029] The present invention will be further described in detail below through specific embodiments.

[0030] This invention provides a machining method for a forming milling cutter for machining stepped contours and irregular surfaces, specifically including the following steps: S1: Material selection: Select 55° cemented carbide round bars with a grain size of 0.6μm and a bending strength of ≥4200MPa. The diameter of the bar stock should meet the machining allowance of the tool holder. S2: Cutting and rough grinding: Use a cutting detection device to cut the bar material to the specified dimensions according to the total length. After cutting, grind both ends of the bar material flat. S3: Shank reference grinding: The shank diameter is finely ground to 8 (-0.008, 0) using a high-precision centerless grinder to form a preform milling cutter blank. The surface roughness of the shank is controlled below Ra0.2, serving as the sole positioning reference surface for all subsequent machining. S4: Grinding of spiral chip grooves and rake angle and helix angle: Using a six-axis five-linkage CNC tool grinder, with a shaped grinding wheel, three-tooth spiral grooves are ground, with the rake angle controlled at 16° and the helix angle at 20°. During rough grinding, 40% of the core thickness is retained for finishing. S5: Combined grinding of drill tip, stepped end edge and multiple clearance angles on the outer periphery: Using a double-cone angle composite grinding wheel, in one clamping and feed: first grind the 130° drill tip at the front end, and at the same time grind the radial double clearance angles of the outer periphery to 12°±1° and 28°±2° and the axial double clearance angles to 4° and 8° respectively; then use a small-diameter diamond grinding wheel to perform micro-area precision contouring on the end edge, control the double clearance angles of the end edge to 8°±1° and 20°±2° respectively, and ensure that the step difference of 0.1mm and 0.3mm between the inner and outer cutting edge widths of the double clearance angles of the end edge is flush; S6: Segmented ultra-thin core thickness precision grinding: The internal hole support grinding method is adopted, and a specially made high-rigidity mandrel is held against the core area from the tail of the tool; the precision grinding is completed by 2-3 micro-feeds, with a single feed amount ≤0.002mm / time, and a cooling interval is set after each feed. Finally, the core thickness is controlled to 0.1mm (+0, +0.1) to prevent thermal stress accumulation from causing micro-cracks. S7: Edge passivation and surface treatment: A combination of weak directional airflow sandblasting and soft brush is used to strictly control the passivation radius between 0.01 and 0.02 mm, remove grinding burrs and improve the micro-smoothness of the cutting edge; S8: Dynamic balancing and radial runout active compensation: The grinding wheel vibration is eliminated by using an online dynamic balancing instrument on the grinding machine, and the first-step cutting diameter (4.3mm) and the second-step cutting diameter (3.6mm) are measured in real time by a laser tool setter; based on the measured 360° high and low point data, the rotation phase of the C-axis is automatically calculated and compensated (i.e., the principle of eccentric grinding is used to grind more in the high point area and less in the low point area), so that the final cutting diameter runout is controlled within 0.008mm; S9: Precision inspection and storage: Use inspection equipment to measure various diameters and angles, and store them in the shell after the measurements are correct.

[0031] This invention transforms a cantilever beam into a simply supported beam through the "tailstock internal support grinding method," and by combining "CBN grinding wheel sharp shearing" with "extremely small feed of 0.002 mm / cycle," it significantly reduces radial grinding pressure and completely eliminates tool deflection and high-frequency chatter.

[0032] In step S3, during the rough grinding of the spiral groove, a larger feed rate and depth of cut are used, but a 40% core thickness allowance is intentionally retained (keeping the core thickness at approximately 0.15-0.2 mm). At this point, the tool body cross-section is thicker, capable of withstanding greater cutting forces. In step S5, during the ultra-thin core thickness fine grinding, the rough grinding parameters are switched to an "extremely small feed" mode (0.002 mm / pass), and the final 0.05-0.1 mm allowance is divided into 2-3 passes. This design achieves segmented variable parameter grinding. When performing the "2-3 pass micro-feed" in S5, after each extremely small (0.002 mm) cut, the machine is not immediately allowed to proceed with the next cut; instead, the grinding wheel is allowed to idle in place for a few seconds (or the feed is paused). During this interval, high-pressure grinding fluid continuously washes over the surface, effectively removing the heat accumulated on the 0.1 mm ultra-thin core thickness. This invention employs segmented variable parameter grinding and intermittent cooling for fine grinding. By retaining allowance and dividing fine grinding into 2-3 micro-feeds, and setting a cooling interval after each feed, thermal stress is fully released and dissipated after each extremely small cut, completely eliminating the generation of thermal cracks.

[0033] After the bar stock is cut in step S2 above, it is inspected by an ultrasonic non-destructive testing instrument set in the cutting and testing device to remove blanks with internal micro-cracks.

[0034] like Figure 5 and Figure 6 The cutting and testing device shown includes a base 2, a first bar conveying support 5, a second bar conveying support 7, an ultrasonic non-destructive testing instrument 6, a guide fixing seat 3, a transport seat 4, and a cutting blade 11. The first bar conveying support 5, the guide fixing seat 3, the transport seat 4, and the second bar conveying support 7 are arranged sequentially from left to right on the top of the base. The cross-sections of the first bar conveying support 5 and the second bar conveying support 7 are V-shaped and both are horizontally positioned. The right end of the first bar conveying support 5 is close to the left end face of the guide fixing seat 3. A first guide hole is formed between the left and right end faces of the guide fixing seat 3 relative to the position of the first bar conveying support. The left and right ends of the transport seat... A second guide hole matching the first guide hole is also provided between the end faces. The cutting tool 11 is set between the guide fixing seat 3 and the transport seat 4 and is driven by the cutting drive hydraulic cylinder 10 installed on the top of the guide fixing seat 3. The transport seat 4 is connected to the top of the base 2 through the telescopic elastic component 21. The height of the second bar material conveying bracket 7 is lower than that of the first bar material conveying bracket 5. The second bar material conveying bracket 7 passes through the ultrasonic non-destructive testing instrument 6. The right end of the second bar material conveying bracket 7 is connected to the inclined feeding guide bracket 8. The bottom of the first bar material conveying bracket 5 and the second bar material conveying bracket 7, as well as the transport seat 4, are provided with roller structures for bar material conveying. During cutting, the bar stock is conveyed to the right along the first bar stock conveying bracket. Its right end passes through the guide fixing seat along the first guide hole and extends into the transport seat. The cutting length is adjusted by moving the baffle inside the transport seat. When the bar stock stops moving forward, the clamping electric cylinder 9 on the top of the guide fixing seat is activated. The clamping head, which is located in the guide fixing seat and connected to the clamping electric cylinder, fixes the bar stock. After fixing, the cutting drive hydraulic cylinder 10 is activated to cut the bar stock using the cutting blade 11. After cutting, as the cutting drive hydraulic cylinder 10 continues to press down, the transport seat will be lowered horizontally to a position flush with the second bar stock conveying bracket 7. At this time, the baffle is removed, and the cut bar stock will automatically move into the second bar stock conveying bracket 7 under the action of the roller structure. It then enters the ultrasonic non-destructive testing instrument 6 for testing. After testing, it moves along the second bar stock conveying bracket 7 into the inclined unloading guide bracket. The present invention, using the above structure, can automatically perform flaw detection on each cut bar stock without the need for a special subsequent testing process, greatly improving practicality.

[0035] like Figure 6The cutting tool 11 is shown with a first vertical guide rail 12 on the right end face of the guide fixing seat 3 on both sides. The cutting tool 11 is connected to the two first vertical guide rails 12 by the first sliders 13 on both sides. This design allows the cutting tool to cut downwards along the right end face of the guide fixing seat 3. A second vertical guide rail 15 is provided on the left end face of the transport seat above the second guide hole. The cutting tool 11 is slidably connected to the second vertical guide rail 15 by the guide connector 14. A push transmission block 16 is fixed at the lower end of the second vertical guide rail 15. As the cutting drive hydraulic cylinder continues to press down after cutting, the push transmission block 16 will bring the transport seat down under the action of the guide connector 14, thereby reducing the height of the cut bar and enabling the inclined feeding guide bracket 8 to transport the bar to the base in a shorter distance, which reduces the footprint and increases practicality.

[0036] like Figure 7 A translation drive cylinder 17 is mounted on the top of the conveying seat. The output shaft of the translation drive cylinder 17 is connected to a lifting cylinder mounting base. The lifting cylinder mounting base is horizontally slidably connected to the top of the right end of the conveying seat via a sliding frame 18. A horizontal slide rail 20 matching the sliding frame 18 is provided on the outer wall of the conveying seat. A long strip-shaped notch is opened at the top of the right end of the conveying seat. The lifting cylinder 19 is fixed on the lifting cylinder mounting base, and its output shaft passes through the lifting cylinder mounting base and the sliding frame 18 and extends along the notch into the second guide hole to connect with the baffle. By adopting the above design, the position of the baffle can be adjusted, thereby cutting the bar stock to the appropriate length as needed.

[0037] In step S4 above, during the grinding of the spiral groove, a 3D dresser is used to dress the irregular grinding wheel online, so that the shape of the grinding wheel perfectly matches the 3 teeth and the forming contour. The three teeth are ground in turn by a layered oscillating grinding method to ensure that the helix angle of the three spiral grooves is consistent, which is conducive to chip removal.

[0038] In step S7 above, the blunting radius is strictly controlled between 0.01 and 0.02 mm during the blunting and surface treatment of the cutting edge. Polishing paste is used to perform mirror treatment on the cutting edge, which can greatly reduce the sticking phenomenon during cutting.

[0039] like Figure 8The testing equipment in step S9 includes a testing platform 22, an arc-shaped guide bracket 28, a fixed bracket 36, a magnifying detector 29, a Zoller tool detector 32, and a rotating plate 23. The testing platform is suspended in the air, and its top is provided with a magnifying detection station and a dimensional detection station. The top of the testing platform also has a countersunk groove that matches the rotating plate. The rotating plate 23 is connected to the countersunk groove by a bearing mounted on the outer side and is connected to the rotary drive mechanism. Two tool fixing fixtures 37 are provided on the rotating plate 23. The two tool fixing fixtures are driven by the rotary drive mechanism to pass through the countersunk groove in sequence. The tool holder 37 rotates via a servo motor 25 mounted on the bottom of the rotating plate, passing through the magnification and dimensional inspection stations. An arc-shaped guide bracket 28 is mounted directly above the magnification inspection instrument 29 via a fixed bracket 36. The magnification inspection instrument 29 is electrically connected to a first display 30 located on one side of the fixed bracket 36 and slidably connected to the inner wall of the arc-shaped guide bracket via a slide block. The slide block slides up and down along the inner wall of the arc-shaped guide bracket via a telescopic electric cylinder 31. The Zoller tool inspector 32 is located at the dimensional inspection station and electrically connected to a second display 33. During operation, two forming milling cutters to be inspected are loaded into the two tool holders 37. This design allows for simultaneous magnification and dimensional inspection of both tools. After one aspect of the inspection is completed, the rotating plate can be rotated 180° to continue the inspection of the other aspect. This invention, through this design, facilitates inspection, eliminates the need for repeated clamping, and improves inspection efficiency.

[0040] like Figure 8 The rotary drive mechanism shown includes an external gear ring 24 mounted on the upper end of the rotating plate, a drive gear 27, and a drive servo motor 26. The drive servo motor 26 is fixed to the detection platform, and the drive gear 27 is mounted on the output shaft of the drive servo motor 26 and meshes with the external gear ring 24. This design has the advantages of simple structure, ease of manufacture, and convenient use.

[0041] like Figure 1 , Figure 2 and Figure 3The milling cutter shown is a form milling cutter for machining stepped contours and irregular surfaces. Its structure consists of a shank portion 1-1 and a cutting portion 1-2 integrated together. The cutting portion 1-2, at its end away from the shank portion 1-1, is sequentially provided with a drill tip cutting area 1-2-1, a first stepped cutting diameter area 1-2-2, and a second stepped cutting diameter area 1-2-3. Three helical chip grooves 1-2-4 are evenly distributed on the outer circumference of the cutting portion. The end of the drill tip cutting area has a 130° drill tip angle. The outer circumference of the first stepped cutting diameter area... The cutting diameter is 4.3 mm, the outer diameter of the second stepped cutting diameter region is 3.6 mm, the core thickness inside the cutting part is 0.1 mm, and the outer circumferential surface of the cutting part is provided with axial double clearance angles and radial double clearance angles. The axial double clearance angles are 4° and 8°, and the radial double clearance angles are 12° and 28°. Corresponding to the axial and radial double clearance angles, the outer circumferential surface of the cutting part is provided with a double-width outer circumferential cutting band, the widths of which are 0.4 mm and 0.6 mm, respectively. This invention solves the cutting problem of "insufficient chip removal space and easy chip adhesion and entanglement in small-diameter tools" by using the above structure.

[0042] The cutting area of ​​the drill tip is provided with a rake angle and a double clearance angle, wherein the rake angle is 3° and the double clearance angles are 8° and 20° respectively. The aforementioned end face of the double-stage rear angle of the end blade is provided with end face support blade strips of unequal width. The end face support blade strips include a first blade strip located on the inner side and a second blade strip located on the outer side. The width of the first blade strip is 0.1 mm and the width of the second blade strip is 0.3 mm.

[0043] The spiral chip groove has a helix angle of 20°, a rake angle of 16°, and a groove length of 15mm.

[0044] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A machining method for a forming milling cutter for machining stepped contours and irregular surfaces, characterized in that: Specifically, the following steps are included: S1: Material selection: Select 55° cemented carbide round bars with a grain size of 0.6μm and a bending strength of ≥4200MPa. The diameter of the bar stock should meet the machining allowance of the shank. S2: Cutting and rough grinding: Use a cutting detection device to cut the bar material to the specified dimensions according to the total length. After cutting, grind both ends of the bar material flat. S3: Shank reference grinding: Using the end face for positioning, the shank diameter is finely ground to 8(-0.008, 0) mm using a high-precision centerless grinder, and the surface roughness of the shank is controlled below Ra0.

2. This is used as the sole positioning reference surface for all subsequent machining. S4: Grinding of spiral chip grooves and rake angle and helix angle: Using a six-axis five-linkage CNC tool grinder, with a shaped grinding wheel, three-tooth spiral grooves are ground, with the rake angle controlled at 16° and the helix angle at 20°. During rough grinding, 40% of the core thickness is retained for finishing. S5: Combined grinding of drill tip, stepped end edge and multiple clearance angles on the outer periphery: Using a double-cone angle composite grinding wheel, in one clamping and feed: first grind the 130° drill tip at the front end, and at the same time grind the radial double clearance angles of the outer periphery of 12°±1° and 28°±2° and the axial double clearance angles of 4° and 8° respectively; then use a small-diameter diamond grinding wheel to perform micro-area precision contouring on the end edge, control the double clearance angles of the end edge of 8°±1° and 20°±2° respectively, and ensure that the step difference between the inner and outer cutting edge widths of the double clearance angles of the end edge is 0.1mm and 0.3mm respectively. S6: Segmented ultra-thin core thickness precision grinding: The internal hole support grinding method is adopted, and a specially made high-rigidity mandrel is held against the core area from the tail of the tool; the precision grinding is completed by 2-3 micro-feeds, with a single feed amount ≤0.002mm / time, and a cooling interval is set after each feed. Finally, the core thickness is controlled to 0.1mm (+0, +0.1) to prevent thermal stress accumulation from causing micro-cracks. S7: Edge passivation and surface treatment: A combination of weak directional airflow sandblasting and soft brush is used to strictly control the passivation radius between 0.01 and 0.02 mm, remove grinding burrs and improve the micro-smoothness of the cutting edge; S8: Dynamic balancing and radial runout active compensation: The grinding wheel vibration is eliminated by using an online dynamic balancing instrument on the grinding machine, and the first and second step cutting diameters are measured in real time by a laser tool setter; based on the measured 360° high and low point data, the rotation phase of the C-axis is automatically calculated and compensated, and the final cutting diameter runout is controlled within 0.008mm. S9: Precision inspection and storage: Use inspection equipment to measure various diameters and angles, and store them in the shell after the measurements are correct.

2. The machining method of a forming milling cutter for machining stepped contours and irregular surfaces according to claim 1, characterized in that: In step S2, after the bar stock is cut, it is inspected by an ultrasonic non-destructive testing instrument set in the cutting and testing device to remove blanks with internal micro-cracks.

3. A machining method for a forming milling cutter for machining stepped contours and irregular surfaces according to any one of claims 1 or 2, characterized in that: The cutting and testing device includes a base, a first bar conveying bracket, a second bar conveying bracket, an ultrasonic non-destructive testing instrument, a guide fixing seat, a transport seat, and a cutting blade. The first bar conveying bracket, the guide fixing seat, the transport seat, and the second bar conveying bracket are arranged sequentially from left to right on the top of the base. The cross-sections of the first and second bar conveying brackets are V-shaped and both are horizontally positioned. The right end of the first bar conveying bracket is close to the left end face of the guide fixing seat. A first guide hole is formed between the left and right end faces of the guide fixing seat relative to the position of the first bar conveying bracket. The cutting blade is positioned between the guide fixing seat and the transport seat and is driven downward by a cutting drive hydraulic cylinder installed on the top of the guide fixing seat. The transport seat is connected to the top of the base through a telescopic elastic component. The height of the second bar conveying bracket is lower than that of the first bar conveying bracket. The second bar conveying bracket passes through the ultrasonic non-destructive testing instrument. The right end of the second bar conveying bracket is connected to the inclined feeding guide bracket. Roller structures for bar conveying are provided at the bottom of the first and second bar conveying brackets and inside the transport seat.

4. The machining method of a forming milling cutter for machining stepped contours and irregular surfaces according to claim 1, characterized in that: In step S4, during the spiral groove grinding, a 3D dresser is used to dress the irregular grinding wheel online, so that the shape of the grinding wheel perfectly matches the three teeth and the forming contour. The three teeth are ground in turn using a layered oscillating grinding method to ensure that the helix angle of the three spiral grooves is consistent, which is conducive to chip removal.

5. The machining method of a forming milling cutter for machining stepped contours and irregular surfaces according to claim 1, characterized in that: In step S7, the passivation radius is strictly controlled between 0.01 and 0.02 mm during the edge passivation and surface treatment. Polishing paste is used to perform mirror treatment on the edge, which can greatly reduce the sticking phenomenon during cutting.

6. The machining method of a forming milling cutter for machining stepped contours and irregular surfaces according to claim 1, characterized in that: The testing equipment in step S9 includes a testing platform, an arc-shaped guide bracket, a fixed bracket, a magnifying detector, a Zoller tool detector, and a rotating plate. The testing platform is suspended in the air, with a magnifying detection station and a dimensional detection station respectively set on its top. The top of the testing platform also has a countersunk groove that matches the rotating plate. The rotating plate is connected to the countersunk groove by a bearing mounted on the outer side and is connected to a rotary drive mechanism. Two tool fixing fixtures are set on the rotating plate. The two tool fixing fixtures are driven by the rotary drive mechanism to pass through the magnifying detection station and the dimensional detection station in sequence. The tool fixing fixtures are rotated by a servo motor installed at the bottom of the rotating plate. The arc-shaped guide bracket is installed directly above the magnifying detector through the fixed bracket. The magnifying detector is electrically connected to a first display set on one side of the fixed bracket and is slidably connected to the inner wall of the arc-shaped guide bracket by a slide block. The slide block slides up and down along the inner wall of the arc-shaped guide bracket by a telescopic electric cylinder. The Zoller tool detector is set on the dimensional detection station and is electrically connected to a second display.

7. A forming milling cutter for machining stepped contours and irregular surfaces, characterized in that: The structure comprises a shank portion and a cutting portion integrated into one unit. The cutting part, located away from the tool holder, is sequentially provided with a drill tip cutting area, a first-step cutting diameter area, and a second-step cutting diameter area. Three spiral chip-receiving grooves are evenly distributed on the outer circumference of the cutting part. The end of the drill tip cutting area is provided with a drill tip angle of 130°. The outer diameter of the first-step cutting diameter area is 4.3 mm, and the outer diameter of the second-step cutting diameter area is 3.6 mm. The core thickness inside the cutting part is 0.1 mm. The outer circumferential surface of the cutting part is provided with an axial double clearance angle and a radial double clearance angle. The axial double clearance angles are 4° and 8°, and the radial double clearance angles are 12° and 28°, respectively. The outer circumferential surface of the cutting part corresponding to the axial double clearance angle and the radial double clearance angle is provided with a double-width outer circumferential cutting band. The widths of the double-width outer circumferential cutting band are 0.4 mm and 0.6 mm, respectively.

8. A forming milling cutter for machining stepped contours and irregular surfaces according to claim 7, characterized in that: The end face of the cutting zone of the drill tip is provided with an end-edge rake angle and an end-edge double-stage clearance angle. The end-edge rake angle is 3°, and the end-edge double-stage clearance angles are 8° and 20° respectively.

9. A forming milling cutter for machining stepped contours and irregular surfaces according to claim 8, characterized in that: The end face of the double-stage rear angle of the end blade is provided with end face support blade bands of different widths. The end face support blade bands include a first blade band located on the inner side and a second blade band located on the outer side. The width of the first blade band is 0.1 mm and the width of the second blade band is 0.3 mm.

10. A forming milling cutter for machining stepped contours and irregular surfaces according to claim 7, characterized in that: The spiral chip-receiving groove has a helix angle of 20°, a rake angle of 16°, and a groove length of 15mm.

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