Spiral fluted tap

Abstract

The utility model provides a spiral fluted tap which is provided with a thick handle part, a neck part and a thick-head thread part which are coaxially arranged, the helical angle beta of the thread part is greater than 40 degrees; the groove profile of the thread part is of a three-groove structure and is in a straight-line three-arc form; the screw tap is made of a high-speed steel material subjected to vacuum heat treatment and subzero treatment and is subjected to passivation treatment. The spiral fluted tap solves the technical problems that a spiral fluted tap is unsmooth in chip rolling and discharging, short in service life, prone to being broken, unstable in performance and low in working efficiency. The cutter is beneficial to numerical control multi-line grinding machining, sharp in cutting, beneficial to tight chip rolling, long in service life, high in machining stability and high in efficiency.

Description

Technical Field

[0001] The utility model belongs to the technical field of taps and relates to a spiral groove tap. Background Art

[0002] Spiral-flute taps are typically made of high-speed tool steel. The chip flutes in the working section of the tap are helical, significantly enhancing chip flow control and guidance. Chips are continuously discharged in a spiral pattern, preventing chip blockage and improving working conditions. Furthermore, spiral-flute taps eliminate the need for multiple chip removal operations during threading, allowing the tap to reach the end in a single pass. Therefore, spiral-flute taps offer higher productivity than straight-flute taps. Furthermore, spiral-flute taps increase the effective rake angle and chip clearance, resulting in a sharper cutting edge, making the tap easier to work, reducing cutting torque, and increasing its durability. These advantages make spiral-flute taps particularly suitable for deep-hole threads in mild steel, alloy steel, stainless steel, heat-resistant alloys, and non-ferrous metals. They are also suitable for threads in holes with grooves or intermittent surfaces.

[0003] The selection of the helix angle for spiral-flute taps is crucial; the proper helix angle significantly impacts the tap's performance. The larger the helix angle, the greater the chip guidance and evacuation, the larger the actual working rake angle, and the smoother the tapping process.

[0004] However, if the helix angle is too large, the strength of the tap teeth will be weakened, and the tap will be more difficult to manufacture. Therefore, the helix angle of the tap should be reasonably selected according to the processing conditions and the material being processed.

[0005] When the helix angle (β) is between 10° and 20°, the tap achieves optimal chip removal when machining hard, low-toughness materials, high-carbon steel, titanium alloys, and nickel-based alloys, reducing cutting resistance and tool wear. When the helix angle (β) is between 30° and 40°, the tap is most effective when machining low- and medium-carbon steels and alloy steels, producing the longest chips and minimizing chip accumulation in the flute. When the helix angle (β) is greater than 40°, it is most effective when machining ductile nonferrous metals and stainless steel. Furthermore, spiral-fluted taps are primarily used for blind hole threads, so their rake and relief angles are smaller than those of ordinary straight-fluted taps, and their cutting cone is shorter.

[0006] While spiral-flute taps offer the aforementioned advantages, they also have some drawbacks. For example, their cutting edge strength is lower than that of straight-flute taps, making them unsuitable for tapping high-strength or brittle materials. Their characteristic closed-cutting nature is that the tool features multiple cutting edges distributed circumferentially, working together during tapping. The back of the blade cuts into the bottom hole wall, leaving only a semi-enclosed cutting space between the groove and the hole wall. This makes chip removal and cooling more difficult. Therefore, resolving the conflict between tap strength and chip space is a key aspect of tap optimization.

[0007] When processing carbon steel workpieces, ordinary spiral groove taps usually choose a helix angle (β) of 30°~40º, a cutting rake angle (γ) of 2°~6º, a cutting edge width of 0.4 times the nominal diameter (mm), and a cutting cone relief angle (α) of 100°~100°. 切削锥 ) Select a tap with a thread diameter of 3° to 5° and a nominal thread diameter greater than or equal to 6mm. The thread profile should be relief ground, and the mid-diameter relief amount (α 中径 ) is 0.01-0.02mm, and the shank is a thin structure. While this existing tap structure is light and agile during manual tapping, and produces stable threaded holes, it suffers from poor chip removal during high-efficiency tapping on CNC machines such as machining centers and drilling and milling centers, resulting in a short service life and, in severe cases, even tap breakage, affecting thread production. This leads to unstable performance and low efficiency, often becoming a difficult problem to overcome in practical applications. To address this, the following improved technical solution is proposed. Utility Model Content

[0008] The technical problem solved by the utility model is to provide a spiral groove tap to solve the technical problems of poor chip winding and removal, short life, easy breakage, unstable performance and low working efficiency of spiral groove taps.

[0009] The utility model adopts the following technical solution: a spiral groove tap, comprising a coaxially arranged thick shank tapered shank, a thin neck tapered neck and a coarse head threaded portion; the helix angle β of the threaded portion is greater than 40°; the groove of the threaded portion is a three-groove structure, and is in the form of three arcs in a straight line; the tap is made of high-speed steel material subjected to vacuum heat treatment, cryogenic treatment and passivation treatment.

[0010] Among the above technical solutions, as a preferred technical solution of the present invention: the helix angle β of the threaded portion is 45°.

[0011] Among the above technical solutions, as the preferred technical solution of the present invention, the groove rake angle γ of the threaded portion is set to 6° to 8° in the M6 ​​specification; the front arc R1 is set to R0.85mm in the M6 ​​specification; the core diameter φd is set to 2.42mm in the M6 ​​specification; and the cutting edge width f is set to 1.4mm in the M6 ​​specification.

[0012] Among the above technical solutions, as the preferred technical solution of the present invention: the high-speed steel is a high-vanadium high-speed steel material; the high-vanadium high-speed steel material has a bending strength of 4200 MPa and an impact energy resistance of 38J.

[0013] Among the above technical solutions, as the preferred technical solution of the present invention: the threaded portion is shoveled in the middle diameter, and the threaded portion M6 specification middle diameter relief grinding amount α 中径 0.015~0.025mm; cutting cone relief angle α 切削锥 It is 4°~6º.

[0014] Among the above technical solutions, as the preferred technical solution of the present invention: the cutting cone length L of the threaded portion is 2 to 3 pitches P; the cutting cone diameter φdx length is 4.8 mm in the M6 ​​specification.

[0015] Among the above technical solutions, as the preferred technical solution of the present invention, the arc R1 of the three arcs in a straight line is 0.85 mm; R2 is 2.30 mm; and R3 is 9.12 mm.

[0016] The advantages of this utility model compared with the prior art are:

[0017] 1. The utility model adopts a thick shank with a neck. The thick shank is conducive to clamping and transmitting large torque. The tap with a neck is conducive to processing deep holes and sufficient flow of coolant during tapping, and is conducive to CNC multi-line grinding during the grinding process of the tap thread.

[0018] 2. The utility model has a large right-hand 45° helix angle, which makes chip removal smoother and increases the actual rake angle for sharp cutting.

[0019] 3. The chip removal groove of the utility model has a three-groove structure and is distributed symmetrically around the center. The groove shape is optimized into a straight line with three arcs. The arcs are connected smoothly, which increases the chip holding space and is conducive to tight chip rolling.

[0020] 4. The high-vanadium high-speed steel material of this utility model has a bending strength of 4200MPa and an impact energy resistance of 38J. It has high hardness and wear resistance, sufficient strength and toughness, high heat resistance, and high thermal conductivity, which can greatly improve the life of CNC tools. This alone can double the life of the tool compared to the original.

[0021] 5. The vacuum heat treatment process of this utility model provides good protection for the surface of the tap, preventing oxidation and decarburization, improving mechanical properties, minimizing deformation, achieving high processing precision, reducing volatility of alloy elements, and ensuring quality; the cryogenic treatment process transforms the retained austenite of the tap material into martensite after heat treatment, resulting in uniform and consistent structure, and the dispersion and precipitation of ultrafine carbides, which more than doubles the wear resistance; the passivation treatment process resists physical wear of the tool, maintains the smoothness of the workpiece, and facilitates chip removal from the groove.

[0022] 6. The utility model uses a CNC multi-line thread grinder to perform spading on the mid-diameter of the threaded part. The spading position is accurately input through the spiral angle to calculate its lead. The processed thread spading amount and spading position are accurate and reliable; the mid-diameter spading amount α 中径 The angle of relief grinding is 0.015~0.025mm, which effectively achieves the purpose of hanging shovel, reduces cutting resistance and prolongs product life. Reasonable relief grinding angle can ensure both reasonable distribution of cutting amount and sharpness and wear resistance. After multiple life verifications, the relief grinding angle of cutting cone α 切削锥The angle is 4°~6º, and the product life is stable. Through the above optimization, high-performance spiral groove tap products overcome the adverse factors in the processing process, and their life is nearly doubled in the efficient thread processing of CNC equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic diagram of the structure of the utility model;

[0024] Figure 2 For this utility model Figure 1 Detailed enlarged view of the S part;

[0025] Figure 3 This is a schematic diagram of the groove-shaped cross-section structure and the relief angle diagram of the utility model;

[0026] Figure 4 This is a schematic diagram of the relief angle of the mid-diameter threaded portion of the utility model;

[0027] Figure 5 This is a cross-sectional groove processing diagram of the utility model;

[0028] In the figure: 1-shank, 2-neck, 3-threaded part, 4-cutting cone, 5-chip groove. DETAILED DESCRIPTION

[0029] The following is a combination of the appended examples of the present invention Figure 1-5 The technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort shall fall within the scope of protection of the present invention.

[0030] (like Figure 1 A spiral-fluted tap (shown in FIG. 1 ) comprises a coaxially arranged thick shank portion 1, a narrow neck 2, and a thick-start threaded portion 3. The thick shank with a neck facilitates clamping and transmitting high torque. The neck facilitates deep hole machining and sufficient coolant flow during tapping, and facilitates CNC multi-thread grinding during thread grinding.

[0031] The helix angle β of the threaded portion 3 is greater than 40°. In the above embodiment, as a preferred embodiment of the present invention, the helix angle β of the threaded portion 3 is 45°. This makes chip removal smoother, increases the actual rake angle, and ensures sharp cutting.

[0032] The groove of the threaded portion 3 is a three-groove structure, forming a straight line with three arcs. In the above-mentioned embodiment, which is a preferred embodiment of the present invention, the arc R1 of the three arcs is 0.85 mm; R2 is 2.30 mm; and R3 is 9.12 mm. Compared to a double-groove structure, a three-groove structure can more effectively distribute cutting forces, making the cutting process smoother and improving cutting efficiency. The straight-line, three-arc groove design allows chips to be easily discharged from the hole during cutting along the spiral groove's upward rotation, preventing chips from remaining or clogging in the groove and reducing the risk of tap breakage and blade cracking caused by chip blockage. Due to smooth chip evacuation and a stable cutting process, spiral-groove taps can produce high-precision threads that meet the requirements of precision machining. This smooth chip evacuation reduces friction and heat accumulation during cutting, helping to reduce surface roughness and improve machining quality. Due to the smooth cutting process and chip evacuation, spiral-groove taps experience less blade wear, thereby extending the tap's service life. Smooth chip evacuation prevents chip accumulation within the grooves, reducing the risk of chip blockage and tap breakage. Spiral-fluted taps are suitable for machining a wide range of materials and are particularly well-suited for blind hole machining due to their superior chip evacuation, ensuring smooth chip evacuation and preventing accumulation at the bottom of the hole. The helix angle of spiral-fluted taps can be adjusted to suit different machining conditions and materials.

[0033] In the above embodiment, which is a preferred embodiment of the present invention, the flute rake angle γ of the chip flute 5 is set at an M6 specification of 6° to 8°. The size of the rake angle γ directly affects the sharpness of the cutting edge. Within the range of 6° to 8°, the cutting edge maintains sufficient sharpness while also ensuring edge strength. A sharp cutting edge reduces cutting forces, improves cutting efficiency, and reduces friction and heat accumulation during the cutting process, thereby extending the service life of the tap.

[0034] The front arc R1 value for the M6 ​​specification is R0.85mm. The front arc R1 design optimizes chip formation and evacuation during cutting, promoting tight chip curling. An appropriate arc radius helps form continuous chips, reduces vibration and impact during cutting, and improves machining accuracy and surface quality. A reasonable arc radius also strengthens the cutting edge, reduces the risk of chipping and breakage, and increases the durability and service life of the tap.

[0035] The core diameter φd for the M6 ​​tap is 2.42mm. The size of the core diameter φd significantly impacts the tap's cutting stability and stiffness. For the M6 ​​tap, a 2.42mm core diameter ensures sufficient stiffness and stability during cutting, minimizing machining errors caused by vibration and deformation.

[0036] The cutting edge width f is 1.4mm for the M6 ​​specification. The optimized flute shape increases chip space. The cutting edge width f directly affects the blade strength. In the M6 ​​specification, a 1.4mm cutting edge width ensures sufficient chip volume while maintaining cutting edge stability and durability.

[0037] The tap is made of high-speed steel that has undergone vacuum heat treatment, cryogenic treatment, and passivation. In the above-mentioned embodiment, as a preferred embodiment of the present invention, the high-speed steel is high-vanadium high-speed steel; this high-vanadium high-speed steel has a bending strength of 4200 MPa and an impact energy resistance of 38 J. High-vanadium high-speed steel offers high hardness and wear resistance, sufficient strength and toughness, high heat resistance, and high thermal conductivity, significantly extending the life of CNC tools. This alone can double the tool life of existing tools.

[0038] High-vanadium high-speed steel (HSS) is renowned for its exceptional hardness and wear resistance. Research has shown that its wear resistance far exceeds that of conventional high-chromium cast iron and high-manganese steel, making it an excellent performer in cutting environments subject to high loads and frequent friction. Despite its extreme hardness, HSS maintains considerable toughness, making it less susceptible to fracture under impact loads, enhancing tool durability and safety. Heat treatment in a vacuum effectively prevents the steel from reacting with oxygen in the air at high temperatures, reducing oxidation and decarburization, thereby maintaining the steel's purity and performance stability. Vacuum heat treatment also allows for more precise control of the heating and cooling processes, optimizing the steel's microstructure and properties. Cryogenic treatment, by cooling the steel to extremely low temperatures (such as liquid nitrogen), further refines the steel's grain structure, reduces internal stresses and defects, and enhances its hardness and wear resistance. Cryogenic treatment also improves the steel's toughness and fatigue resistance. Passivation treatment forms a dense oxide film on the steel surface to enhance its corrosion resistance. For high-vanadium high-speed steel, passivation treatment can protect its surface from erosion by media such as cutting fluid and coolant, thereby extending the service life of the tool.

[0039] The high-vanadium high-speed steel material has a flexural strength of 4200 MPa, indicating its exceptional resistance to deformation and fracture under bending loads. This is crucial for taps that must withstand complex cutting forces and impact loads, ensuring stability and reliability under harsh operating conditions. The impact energy resistance is 38J, a key indicator of a material's resistance to fracture under impact loads. This high impact energy resistance of high-vanadium high-speed steel means it maintains its integrity during sudden impacts, reducing the risk of damage and failure caused by shock.

[0040] Therefore, the vacuum heat treatment process of this utility model effectively protects the tap surface, preventing oxidation and decarburization. This improves mechanical properties, minimizes deformation, achieves high machining precision, reduces alloy element volatility, and ensures quality. A newly added cryogenic treatment process transforms the retained austenite of the tap material into martensite after heat treatment, resulting in a uniform and consistent structure and the dispersion and precipitation of ultrafine carbides, more than doubling wear resistance. A newly added passivation treatment process resists physical wear of the tool, maintains workpiece finish, and facilitates chip removal from the grooves.

[0041] (like Figure 3 、 Figure 4 As shown in the above embodiment, as a preferred embodiment of the present invention: the threaded portion 3 is shovel-geared in the middle diameter, and the threaded portion 3M6 specification is shovel-geared in the middle diameter. Figure 4 α 中径 The cutting cone 4 is ground to a relief angle of 0.015 to 0.025 mm. Figure 3 α 切削锥 It is 4°~6º.

[0042] Reasonable machining process: First, the thread part is shoveled in the middle diameter. The middle diameter is shoveled by CNC multi-line thread grinder. The shovel position is accurately input through the spiral angle to calculate its lead. The processed thread shovel back amount and shovel position are accurate and reliable. The M6 ​​specification middle diameter shovel grinding amount α 中径 When the angle is 0.015-0.025mm, the purpose of hanging the shovel is effectively achieved, the cutting resistance is reduced, and the product life is increased; secondly, a reasonable relief angle is selected. It is more difficult to process the cutting cone with a large helix angle spiral groove tap. It is necessary to ensure the reasonable distribution of the cutting amount and its sharpness and wear resistance. After multiple life verifications, the relief angle α was finally determined. 切削锥 When the angle is 4° to 6°, the product life is more stable.

[0043] Through the above optimization, high-performance spiral groove tap products overcome the adverse factors in the processing process, and their service life is nearly doubled in the efficient thread processing of CNC equipment.

[0044] (like Figure 2 As shown in the above embodiment, as a preferred embodiment of the present invention: the cutting cone length of the cutting cone 4 Figure 2 L is 2 to 3 pitches P; the cutting cone 4 end diameter Figure 2 The length of φdx is 4.8mm for M6 specification.

[0045] The selection of cutting cone length, L, is crucial for the stability of the cutting process. When L is 2 to 3 pitches, P, the cutting cone can more effectively guide the tap into the workpiece, reducing vibration and deflection during cutting, thereby improving cutting accuracy and stability. A longer cutting cone can more evenly distribute cutting forces and reduce stress concentration on the cutting edge. This helps reduce cutting forces and temperatures during cutting, extending the life of the tap. Different materials and working conditions have different requirements for cutting cone length. Spiral-fluted taps are designed specifically for blind holes. By selecting an appropriate cutting cone length (such as 2 to 3 pitches, P), the tap can be better adapted to different processing requirements, achieving an efficient and stable cutting process.

[0046] The size of the cutting cone end diameter (φdx) directly affects the cutting area and cutting efficiency. For an M6 tool, a φ4.8mm cutting cone diameter ensures sufficient cutting area, improves cutting efficiency, and maintains cutting edge stability and durability. An appropriate cutting cone diameter helps form continuous chips, reducing friction and heat buildup during cutting. This helps reduce surface roughness and improve machining quality. The selection of a cutting cone diameter also requires consideration of cutting edge strength. For an M6 tool, a φ4.8mm cutting cone end diameter ensures cutting efficiency while ensuring sufficient cutting edge strength, reducing the risk of chipping and breakage.

[0047] From the above description, it can be found that the utility model adopts a thick shank with a neck. The thick shank is conducive to clamping and transmitting large torque. The tap with a neck is conducive to processing deep holes and sufficient flow of coolant during the tapping process, and is conducive to CNC multi-line grinding during the grinding process of the tap thread.

[0048] The utility model has a right-hand 45° large helix angle, which makes chip removal smoother and increases the actual rake angle for sharp cutting.

[0049] The chip removal groove of the utility model has a three-groove structure and is symmetrically distributed in the center. The groove shape is optimized into a straight line with three arcs. The arcs are smoothly connected, which increases the chip holding space and is conducive to tight chip rolling.

[0050] The high-vanadium high-speed steel material of this utility model has a bending strength of 4200MPa and an impact energy resistance of 38J. It has high hardness and wear resistance, sufficient strength and toughness, high heat resistance, and high thermal conductivity, which can greatly improve the life of CNC tools. This alone can double the life of the tool compared to the original.

[0051] The vacuum heat treatment process of the utility model provides good protection for the surface of the tap, preventing oxidation and decarburization, thereby improving mechanical properties, minimizing deformation, achieving high processing precision, reducing volatility of alloy elements, and ensuring quality; the cryogenic treatment process transforms the retained austenite of the tap material into martensite after heat treatment, achieving uniform and consistent structure, and dispersing and precipitating ultrafine carbides, thereby more than doubling the wear resistance; the passivation treatment process resists physical wear of the tool, maintains the smoothness of the workpiece, and facilitates chip removal from the groove.

[0052] The utility model is to carry out spading on the middle diameter of the thread part by using a CNC multi-line thread grinder. The spading position is accurately inputted through the spiral angle to calculate its lead. The spading amount and spading position of the processed thread are accurate and reliable. The spading amount of the middle diameter is α 中径 The angle of relief grinding is 0.015~0.025mm, which effectively achieves the purpose of hanging shovel, reduces cutting resistance and prolongs product life. Reasonable relief grinding angle can ensure both reasonable distribution of cutting amount and sharpness and wear resistance. Through multiple life verifications, the relief grinding angle of thread part α 切削锥 The angle is 4°~6º, and the product life is stable. Through the above optimization, high-performance spiral groove tap products overcome the adverse factors in the processing process, and their life is nearly doubled in the efficient thread processing of CNC equipment.

[0053] In summary, the utility model solves the technical problems of poor chip winding and evacuation, short life, easy breakage of the spiral groove tap, unstable performance and low work efficiency; it is beneficial to CNC multi-line grinding processing, has sharp cutting, is conducive to tight chip winding, long tool life, high processing stability and high efficiency.

[0054] Each embodiment in this specification is described in a related manner. The same or similar parts between the embodiments can be referred to each other. Each embodiment focuses on the differences from other embodiments.

[0055] The above description is only a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications and equivalent replacements made within the spirit and principles of the present invention are included in the scope of protection of the present invention.

Claims

1. A spiral groove tap, characterized in that: The tap comprises a coaxially arranged thick shank portion (1), a thin neck (2) and a coarse head thread portion (3); the helix angle β of the chip groove (5) is greater than 40°; the groove type of the chip groove (5) is a three-groove structure, and is in the form of three arcs in a straight line; the tap is made of high-speed steel material that has been vacuum heat treated and deep-cold treated and is passivated.

2. The spiral groove tap according to claim 1, characterized in that: The helix angle β of the chip removal groove (5) is 45°.

3. The spiral groove tap according to claim 1, characterized in that: The flute rake angle γ of the chip removal groove (5) is set to 6° to 8° in M6 specification; the front arc R1 is set to R0.85mm in M6 specification; the core diameter φd is set to 2.42mm in M6 specification; and the cutting edge width f is set to 1.4mm in M6 specification.

4. The spiral groove tap according to claim 1, characterized in that: The high-speed steel is a high-vanadium high-speed steel material; the high-vanadium high-speed steel material has a bending strength of 4200 MPa and an impact energy resistance of 38J.

5. The spiral groove tap according to claim 1, characterized in that: When the tap is machined, the threaded portion (3) is shoveled at the middle diameter, and the threaded portion (3) is shoveled at the middle diameter of M6 specification. 中径 0.015~0.025mm; cutting cone (4) relief angle α 切削锥 It is 4°~6º.

6. The spiral groove tap according to claim 5, characterized in that: The cutting cone length L of the cutting cone (4) is 2 to 3 pitches P; the cutting cone diameter φdx length is M6 and the specification is 4.8 mm.

7. The spiral groove tap according to claim 1, characterized in that: The arc R1 of the three arcs in the straight line is 0.85 mm; R2 is 2.30 mm; and R3 is 9.12 mm.

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