Spiral fluted tap

Abstract

The invention 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 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 are solved. 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 invention belongs to the technical field of taps and relates to a spiral groove tap. Background Art

[0002] Spiral groove taps are usually made of high-speed tool steel. The chip groove in the working part of the tap is made into a spiral shape, which greatly enhances the control of chip flow and chip guiding. The chips are discharged continuously in a spiral shape, avoiding chip blockage and improving working conditions. In addition, when tapping, the spiral groove tap does not need to withdraw the chip multiple times, and can be processed to the end in one go. Therefore, the production efficiency of spiral groove taps is higher than that of straight groove taps. In addition, the spiral groove tap increases the actual rake angle and chip space of the tap, the blade is sharper, the tap works more quickly, the cutting torque is reduced, and the durability of the tap is improved. Because the spiral groove tap has these advantages, the tap is particularly suitable for processing deep hole threads of low carbon steel, alloy steel, stainless steel, heat-resistant alloys and non-ferrous metals, and is also suitable for processing hole threads with grooves or intermittent surfaces.

[0003] The selection of helix angle for spiral groove taps is very important. Whether the helix angle is reasonable has a great influence on the use effect of the tap. The larger the helix angle, the stronger the chip guiding and chip removal effect of the tap, the larger the actual working front angle, and the easier 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 10° to 20°, the tap has the best chip removal effect when processing hard-to-process materials with high hardness and low toughness, high carbon steel, titanium alloy and nickel-based alloy workpieces, which can reduce cutting resistance and reduce tool wear; when the helix angle (β) is 30° to 40°, the tap has the best effect when processing low- and medium-carbon steel and alloy steel, with the longest chips and the least chips in the groove. When the helix angle (β) is greater than 40°, the best effect is achieved when processing non-ferrous metals and stainless steel workpieces with good ductility. In addition, spiral groove taps are mainly used to process blind hole threads, so the front angle and back angle are smaller than those of ordinary straight groove taps, and the cutting cone is shorter than that of ordinary taps.

[0006] Although spiral groove taps have the above advantages, they also have some shortcomings. For example, the cutting edge strength of spiral groove taps is lower than that of straight groove taps, so they are not suitable for processing screw holes of high-strength materials or brittle materials. Its processing characteristics are closed cutting tools. When tapping, multiple cutting edges distributed in the circumferential direction work together, and the back of the blade cuts into the bottom hole wall, leaving only a semi-closed cutting space between the groove and the screw hole wall, making it more difficult to remove chips and cool them. Therefore, solving the contradiction between tap strength and chip space is an important part of tap optimization.

[0007] When processing carbon steel workpieces, ordinary spiral groove taps usually choose a helix angle (β) of 30° to 40°, a cutting front angle (γ) of 2° to 6°, a cutting edge width of 0.4 times the nominal diameter mm, and a cutting cone back angle (α 切削锥 ) Select a tap with a thread diameter of 3° to 5° and a nominal thread diameter greater than or equal to 6 mm. The thread profile should be ground, and the mid-diameter grinding amount (α 中径 ) is 0.01-0.02mm, and the handle is a thin handle structure. Although the tap of the existing structure is light and fast in the manual tapping process, and the size of the processed threaded hole is stable, it is not smooth in the high-efficiency tapping of CNC equipment such as machining centers and drilling and milling centers. The service life is short, and even the tap is broken in severe cases, affecting the thread processing. The use performance is unstable and the work efficiency is low, which often becomes a difficult problem to overcome in actual work. In this regard, the following improved technical solutions are proposed. Summary of the invention

[0008] The technical problem solved by the present invention 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 technical solution adopted by the present invention is as follows: a spiral groove tap has 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 type 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, deep cryogenic treatment and passivation treatment.

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

[0011] In the above technical scheme, as the preferred technical scheme of the present invention: the value of the groove front angle γ of the threaded portion is 6°~8°; the value of the front arc R1 is R0.85mm; the core diameter φd is 2.42mm; the cutting edge width f is 1.4mm.

[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 4200MPa and an impact resistance of 38J.

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

[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 M6 specification of 4.8 mm.

[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 the present invention compared with the prior art are:

[0017] 1. The present invention 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 inflow of coolant during tapping, and is conducive to CNC multi-line grinding during the grinding process of the tap thread.

[0018] 2. The invention has a large right-hand helix angle of 45°, which makes chip removal smoother and increases the actual front angle, making the cutting sharper.

[0019] 3. The chip removal groove of the present invention has a three-groove structure and is centrally symmetrically distributed. 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.

[0020] 4. The high-vanadium high-speed steel material of the present invention has a bending strength of 4200MPa and an impact energy of 38J. It has high hardness and wear resistance, sufficient strength and toughness, high heat resistance, and high thermal conductivity, and can greatly increase 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 the present invention can well protect the surface of the tap, prevent oxidation and decarburization, improve mechanical properties, reduce deformation, increase processing accuracy, reduce volatility of alloy elements, and ensure quality; the cryogenic treatment process can transform the residual austenite of the tap material into martensite after heat treatment, achieve uniform and consistent structure, disperse and precipitate ultrafine carbides, and improve wear resistance by more than double; the passivation treatment process can resist physical wear of the tool, maintain the smoothness of the workpiece, and facilitate chip removal from the groove.

[0022] 6. The threaded part of the present invention is shoveled in the middle diameter. The middle diameter is shoveled by a CNC multi-line thread grinder. The shovel position is accurately input through the spiral angle to calculate its lead. The processed thread backing amount and shovel position are accurate and reliable; the middle diameter shovel grinding amount α 中径 The grinding back angle is 0.015-0.025mm, which effectively achieves the purpose of hanging the shovel, reduces cutting resistance and prolongs product life. Reasonable grinding back angle should ensure both the reasonable distribution of cutting amount and its sharpness and wear resistance. Through multiple life verifications, the grinding back angle of the cutting cone is α 切削锥The angle is 4°~6°, and the product life is stable. Through the above optimization, high-performance spiral groove tap products overcome the unfavorable 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 It is a schematic diagram of the structure of the present invention;

[0024] Figure 2 For the present invention Figure 1 The enlarged detail of the S part;

[0025] Figure 3 It is a schematic diagram of the groove cross-section structure and the back angle relief diagram of the present invention;

[0026] Figure 4 Schematic diagram of the relief angle of the mid-diameter of the threaded portion of the present invention;

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

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

[0029] The following will be combined with the attached embodiment 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. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] (like Figure 1 A spiral groove tap (shown in the figure) has a coaxially arranged thick shank portion 1, a thin neck 2 and a thick head thread portion 3. The thick shank with a neck is adopted. The thick shank is conducive to clamping and transmitting large torque. The tap with a neck is conducive to machining deep holes and sufficient inflow of coolant during tapping, and is conducive to CNC multi-line grinding during the grinding process of the tap thread.

[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°. The chip removal is smoother, the actual front angle is increased, and the cutting is sharp.

[0032] The groove type of the threaded portion 3 is a three-groove structure, and is in the form of three arcs in a straight line; in the above embodiment, as a preferred embodiment of the present invention: the arc R1 of the three arcs in the straight line is 0.85mm; R2 is 2.30mm; and R3 is 9.12mm. Compared with the double-groove structure, the three-groove structure can more effectively disperse the cutting force, making the cutting process more stable, thereby improving the cutting efficiency. The groove design in the form of three arcs in a straight line enables the chips to be easily discharged out of the hole along the rising rotation of the spiral groove during the cutting process, avoiding the chips from remaining or clogging in the groove, and reducing the risk of tap breakage and blade collapse caused by chip clogging. Due to smooth chip removal and smooth cutting process, the spiral groove tap can process high-precision threads to meet the needs of precision machining. The smooth discharge of chips reduces friction and heat accumulation during the cutting process, helps to reduce the roughness of the machined surface, and improves the machining quality. Due to the smooth cutting process and smooth chip removal, the blade wear of the spiral groove tap is reduced, thereby extending the service life of the tap. The smooth discharge of chips avoids the accumulation of chips in the grooves, reducing the risk of chipping or breaking of the tap due to chip blockage. Spiral groove taps are suitable for processing a variety of materials, especially for blind hole processing, because their excellent chip evacuation performance can ensure smooth chip discharge and avoid accumulation at the bottom of the blind hole. The helix angle of spiral groove taps can be adjusted according to different processing requirements to adapt to different working conditions and materials.

[0033] In the above embodiment, as a preferred embodiment of the present invention: the flute rake angle γ of the chip groove 5 has a value M6 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 taking into account the strength of the cutting edge. A sharp cutting edge can reduce cutting force, improve cutting efficiency, and reduce friction and heat accumulation during the cutting process, which helps to extend the service life of the tap.

[0034] The value of the front arc R1 is R0.85mm for M6 specification; the design of the front arc R1 can optimize the chip formation and discharge during the cutting process, which is conducive to tight chip curling. The appropriate arc radius helps to form continuous chips, reduce vibration and impact during the cutting process, and improve machining accuracy and surface quality. A reasonable arc radius can also enhance the strength of the cutting edge, reduce the risk of chipping and breakage, and improve the durability and service life of the tap.

[0035] The core diameter φd is 2.42mm for M6 specification. The size of the core diameter φd has an important influence on the cutting stability and rigidity of the tap. Under the M6 ​​specification, the core diameter of 2.42mm can ensure that the tap maintains sufficient rigidity and stability during the cutting process, reducing the processing error caused by vibration and deformation.

[0036] The cutting edge width f is 1.4mm for M6. The optimized groove shape increases the chip space. The size of the cutting edge width f directly affects the blade strength. Under the M6 ​​specification, the 1.4mm cutting edge width can ensure sufficient chip volume while maintaining the stability and durability of the cutting edge.

[0037] The tap is made of high-speed steel material that has been subjected to vacuum heat treatment and deep cold treatment and is passivated. In the above embodiment, as a preferred embodiment 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 4200MPa and an impact energy of 38J. High-vanadium high-speed steel material 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.

[0038] High vanadium high-speed steel is known for its extremely high hardness and wear resistance. Studies have shown that its wear resistance is much higher than that of traditional high-chromium cast iron and high-manganese steel, which makes it perform well in cutting environments with high loads and frequent friction. Despite its extremely high hardness, high vanadium high-speed steel still maintains considerable toughness, which makes it less likely to break when subjected to impact loads, improving the durability and safety of the tool. Heat treatment in a vacuum environment can effectively prevent the steel from reacting with oxygen in the air at high temperatures, reduce oxidation and decarburization, and thus maintain the purity and performance stability of the steel. At the same time, vacuum heat treatment can also more accurately control the heating and cooling process and optimize the microstructure and properties of the steel. Cryogenic treatment can further refine the grain structure of the steel, reduce internal stress and defects, and improve the hardness and wear resistance of the material by cooling the steel to extremely low temperatures (such as liquid nitrogen temperature). In addition, cryogenic treatment can also improve the toughness and fatigue resistance of the steel. Passivation treatment is to form a dense oxide film on the surface of the steel to improve 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 bending strength of the high-vanadium high-speed steel material is 4200MPa, which indicates that the high-vanadium high-speed steel has a very high ability to resist deformation and fracture when subjected to bending loads. This is crucial for taps that need to withstand complex cutting forces and impact loads, ensuring their stability and reliability under harsh working conditions. The impact energy resistance is 38J, which is an important indicator to measure the material's ability to resist fracture when subjected to impact loads. The high impact energy resistance of high-vanadium high-speed steel means that it can maintain integrity when subjected to sudden impacts, reducing the risk of damage and failure caused by impacts.

[0040] Therefore, the vacuum heat treatment process of the present invention can well protect the surface of the tap, prevent oxidation and decarburization, improve mechanical properties, reduce deformation, increase processing precision, reduce volatility of alloy elements, and ensure quality. The newly added cryogenic treatment process can transform the residual austenite of the tap material into martensite after heat treatment, achieve good uniformity and consistency of structure, disperse and precipitate ultrafine carbides, and improve wear resistance by more than double. The newly added passivation treatment process can resist physical wear of the tool, maintain the finish of the workpiece, and facilitate chip removal in the groove.

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

[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 backing 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 can overcome the unfavorable factors in the processing process, and their service life in high-efficiency thread processing of CNC equipment is nearly doubled.

[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 end diameter of the cutting cone 4 Figure 2 The φdx length value of M6 specification is 4.8mm.

[0045] The selection of the cutting cone length L is crucial to 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, reduce vibration and offset during the cutting process, and thus improve cutting accuracy and stability. A longer cutting cone can distribute the cutting force more evenly and reduce stress concentration on the cutting edge. This helps to reduce the cutting force and cutting temperature during the cutting process and extend the service life of the tap. Different materials and working conditions have different requirements for the cutting cone length. Spiral groove taps are specially designed 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 and achieve an efficient and stable cutting process.

[0046] The size of the cutting cone end diameter φdx directly affects the cutting area and cutting efficiency. Under the M6 ​​specification, selecting a cutting cone diameter of φ4.8mm can ensure sufficient cutting area, improve cutting efficiency, and maintain the stability and durability of the cutting edge. The appropriate cutting cone diameter helps to form continuous chips and reduce friction and heat accumulation during the cutting process. This helps to reduce the roughness of the machined surface and improve the machining quality. The selection of the cutting cone diameter also needs to consider the strength of the cutting edge. Under the M6 ​​specification, the cutting cone end diameter of φ4.8mm can ensure that the cutting edge has sufficient strength while ensuring cutting efficiency, reducing the risk of chipping and breaking.

[0047] From the above description, it can be found that the present invention 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 inflow of coolant during tapping, and is conducive to CNC multi-line grinding during the grinding process of the tap thread.

[0048] The invention has a right-handed 45° large helix angle, which makes chip removal smoother, increases the actual front angle, and ensures sharp cutting.

[0049] The chip removal groove of the present invention has a three-groove structure and is centrally symmetrically distributed. 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 the present invention has a bending strength of 4200MPa and an impact resistance of 38J. It has high hardness and wear resistance, sufficient strength and toughness, high heat resistance, and high thermal conductivity, and can greatly increase 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 present invention can well protect the surface of the tap, prevent oxidation and decarburization, improve mechanical properties, reduce deformation, increase processing precision, reduce volatility of alloy elements, and ensure quality; the deep cold treatment process can transform the residual austenite of the tap material into martensite after heat treatment, achieve good uniformity and consistency of structure, disperse and precipitate ultrafine carbides, and improve wear resistance by more than double; the passivation treatment process can resist physical wear of the tool, maintain the smoothness of the workpiece, and facilitate chip removal of the groove.

[0052] The threaded part of the present invention is shoveled in the middle diameter, and the middle diameter is shoveled by a CNC multi-line thread grinder. The shovel position is accurately input through the spiral angle to calculate its lead, and the processed thread back shovel amount and shovel position are accurate and reliable; the middle diameter shovel grinding amount α 中径 The grinding back angle of the threaded part is 0.015-0.025 mm, which effectively achieves the purpose of hanging the shovel, reduces the cutting resistance and prolongs the product life. The reasonable grinding back angle must ensure the reasonable distribution of the cutting amount and its sharpness and wear resistance. Through multiple life verifications, the grinding back angle of the threaded part α 切削锥 The angle is 4°~6°, and the product life is stable. Through the above optimization, high-performance spiral groove tap products overcome the unfavorable factors in the processing process, and their life is nearly doubled in the efficient thread processing of CNC equipment.

[0053] In summary, the present invention solves the technical problems of poor chip winding and removal, 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, and the same or similar parts between the embodiments can be referenced to each other, and 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 protection scope of the present invention. Any modification and equivalent replacement made within the spirit and principle of the present invention are included in the protection scope of the present invention.

Claims

1. A spiral groove tap, characterized in that: The invention comprises a coarse shank portion (1), a thin neck (2) and a coarse head thread portion (3) which are coaxially arranged; 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 which has been subjected to vacuum heat treatment and deep cryogenic treatment and has been 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 front angle γ of the chip removal groove (5) is set at M6 specification of 6° to 8°; the front arc R1 is set at M6 specification of R0.85 mm; the core diameter φd is set at M6 specification of 2.42 mm; and the cutting edge width f is set at M6 specification of 1.4 mm.

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 4200MPa and an impact 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 ground with a middle diameter, and the threaded portion (3) is ground with a middle diameter of M6 specification (Fig. 4) α 中径 The cutting cone (4) has a relief angle (Fig. 3) α 切削锥 It is 4°~6°.

6. The spiral groove tap according to claim 1, 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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