A novel high-efficiency chip removal and anti-chipping spiral groove tap

Abstract

This utility model discloses a novel high-efficiency chip removal and anti-chipping spiral groove tap, relating to the field of metal cutting technology. It includes a cutting section, a calibration section, and a shank connected in sequence, with the cutting section and the calibration section constituting the working section. Multiple spiral grooves are uniformly formed on the outer circumference of the working section. The spiral grooves include a first spiral groove on the cutting section and a second spiral groove on the calibration section. The depth of the first spiral groove is greater than the depth of the second spiral groove. The lead of the first spiral groove decreases along the cutting direction, while the lead of the second spiral groove remains constant. Furthermore, the cross-sectional shape of the spiral groove is a smooth transition of three circular arcs. This utility model, through a design of variable lead, variable groove depth, and a three-segment circular arc groove, achieves gradient chip containment, forced pushing, and stress-free guidance, solving the chip clogging problem in blind hole and deep hole machining. Simultaneously, the large core thickness ensures that the tap has sufficient torsional and bending stiffness.

Description

Technical Field

[0001] This utility model relates to the field of metal cutting technology, and in particular to a novel high-efficiency chip removal and anti-chipping spiral groove tap. Background Technology

[0002] Spiral flute taps are the mainstream cutting tools for internal thread machining and are widely used in industries such as automotive, aerospace, and mold manufacturing. However, with the increasing application of difficult-to-machine materials such as titanium alloys, stainless steel, and high-strength steel, as well as the increase in complex machining conditions such as blind holes and deep holes, higher requirements are placed on the chip removal performance and cutting edge strength of taps.

[0003] Existing spiral flute taps mostly employ a design with constant lead and constant flute depth. In deep hole machining, chips easily accumulate and clog within the limited spiral flutes, leading to a sharp increase in cutting torque, which can cause chipping or even tap breakage. Although some improvements attempt to improve chip removal by increasing the flute width or changing the helix angle, these measures often weaken the tool body strength, making it difficult to balance chip removal and strength, and failing to fundamentally solve the technical problems of chip accumulation and clogging. Furthermore, while some existing technologies use taps with variable lead or specific flute shapes, none of them simultaneously resolve the contradiction between chip removal and strength, nor have they formed a synergistically optimized system solution.

[0004] Therefore, it is necessary to design a spiral groove tap that can simultaneously take into account chip removal performance and tool body strength. Utility Model Content

[0005] The purpose of this invention is to provide a novel high-efficiency chip removal and anti-chipping spiral groove tap to address the aforementioned problems. Through a three-in-one design of variable lead, variable groove depth, and three-segment circular arc groove, the chip removal efficiency is significantly improved, achieving gradient chip containment, forced pushing, and stress-free guidance, thus solving the chip clogging problem in blind hole and deep hole machining.

[0006] The technical solution adopted in this utility model is as follows: A novel high-efficiency chip removal and anti-chipping spiral groove tap includes a cutting part, a calibration part, and a shank connected in sequence. The cutting part and the calibration part constitute a working part. Multiple spiral grooves are uniformly opened on the outer circumference of the working part. The spiral grooves include a first spiral groove on the cutting part and a second spiral groove on the calibration part. The groove depth of the first spiral groove is greater than the groove depth of the second spiral groove. The lead of the first spiral groove decreases along the cutting direction, while the lead of the second spiral groove is constant. Furthermore, the cross-section of the spiral groove is a three-circular-arc smooth transition groove type.

[0007] Furthermore, the three-circular-arc smooth transition groove type has R1=(0.6~0.65)d, R2=(0.138~0.15)d, and R3=(0.8~1)d, where d is the nominal diameter of the tap.

[0008] Furthermore, the helix angle ω of the helical groove is 30° to 45°.

[0009] Furthermore, the ratio of the width of the spiral groove to the core thickness is 0.6 to 0.8.

[0010] Furthermore, the ratio of the core thickness of the working part to the outer diameter of the tap is ≥0.45.

[0011] Furthermore, the cutting edge of the cutting part is provided with a micro-chamfer and a rounded blunt structure; and / or the calibration part is provided with an inverted conical structure.

[0012] Furthermore, the micro-chamfer size of the cutting part is 0.02 to 0.05 mm, the radius of the arc passivation structure of the cutting part is 0.01 to 0.03 mm, and the inverted cone angle of the calibration part is 0.5° to 1°.

[0013] Furthermore, the connection between the calibration part and the handle is configured as a large circular arc transition structure, wherein R4=(0.2~0.3)d, R5=(0.25~0.35)d, and d is the nominal diameter of the tap.

[0014] Furthermore, the cutting cone length of the cutting part is 2.5P to 3P, where P is the tap pitch.

[0015] Furthermore, the spiral groove is machined as a right-handed adaptive blind hole.

[0016] In summary, due to the adoption of the above technical solution, the beneficial effects of this utility model are:

[0017] 1. The novel high-efficiency chip removal and anti-chipping spiral groove tap provided by this utility model has significantly improved chip removal efficiency through the three-in-one design of variable lead, variable groove depth and three-segment circular arc groove, realizing gradient containment, forced pushing and stress-free guidance of chips, and solving the chip clogging problem in blind hole and deep hole machining.

[0018] 2. The novel high-efficiency chip removal and anti-chipping spiral flute provided by this utility model has a thick core to ensure that the tap has sufficient torsional and bending stiffness. The micro-beveling and arc-blunting structure of the cutting edge improves the ability of the cutting edge to resist chipping and impact. The inverted cone structure of the calibration part can reduce friction and jamming during tool retraction. Through multiple protection structures, the cutting edge is strengthened throughout the entire process from entry, cutting to exit, which significantly extends the tool life and effectively solves the problem of easy chipping of the cutting edge of existing taps.

[0019] 3. The novel high-efficiency chip-removing and anti-chipping spiral flute tap provided by this utility model features smooth chip removal and strong tool body rigidity, resulting in an extremely stable cutting process, consistent machining quality, thread accuracy up to H6 grade, and surface roughness Ra≤0.8μm. Furthermore, continuous cutting eliminates the need for frequent tool retraction, thus improving machining efficiency. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of this utility model;

[0021] Figure 2 for Figure 1 Enlarged view of point a in the middle;

[0022] Figure 3 This is a schematic diagram of the groove-shaped transverse section structure of this utility model;

[0023] Figure 4 for Figure 3 Enlarged view of point b in the middle;

[0024] The markings in the diagram are: 1-cutting part, 2-calibration part, 3-shank part, 4-working part, 5-spiral groove, 6-cutting edge, 7-micro chamfer, 8-circular arc passivation structure. Detailed Implementation

[0025] The present invention will now be described in detail with reference to the accompanying drawings.

[0026] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this utility model and are not intended to limit this utility model.

[0027] A new type of high-efficiency chip removal and anti-chipping spiral groove tap, such as Figures 1-4As shown, the workpiece includes a cutting section 1, a calibration section 2, and a shank 3 connected in sequence. The cutting section 1 and the calibration section 2 constitute the working section 4. The cutting section 1 is used to remove most of the metal excess and perform preliminary machining on the internal thread. The calibration section 2 is used to calibrate the internal thread, thereby increasing the accuracy of the internal thread. The shank 3 is used to cooperate with related tapping equipment to facilitate the cooperation between the spiral groove tap 5 and the related tapping equipment. Multiple spiral grooves 5 are uniformly formed on the outer circumference of the working section 4. The spiral grooves 5 include a first spiral groove 5 provided on the cutting section 1 and a second spiral groove 5 provided on the calibration section 2. The spiral grooves 5 provide a chip outflow channel to avoid chip blockage. The groove depth of the first spiral groove 5 is greater than the groove depth of the second spiral groove 5. The increased groove depth of the cutting section 1 can provide a larger chip space. Furthermore, the groove depth of the working section 4 decreases linearly along the cutting direction. The lead of the first helical groove 5 decreases along the cutting direction. This decrease in lead generates a continuous axial thrust on the chips, effectively guiding them and ensuring their smooth discharge within the cutting zone, thus preventing chip accumulation that can occur due to variations in groove depth. Furthermore, the variable lead of the first helical groove 5 decreases linearly. The lead of the second helical groove 5 remains constant because thread forming ultimately occurs at the calibration section 2. If the lead of the calibration section 2 also decreases, the actual pitch will continuously change, resulting in a non-standard thread pitch that cannot be screwed into standard bolts / nuts. Moreover, the cross-section of the helical groove 5 is a three-arc smooth transition groove shape. This three-arc groove shape eliminates stress concentration points caused by abrupt changes in groove shape due to variable lead and groove depth, ensuring the structural integrity of the tool body under complex geometry and providing a foundation for subsequent edge strengthening 6. In summary, through the integrated design of variable lead, variable groove depth, and three-arc groove shape, gradient chip containment, forced pushing, and stress-free guidance are achieved, solving the chip clogging problem in blind hole and deep hole machining.

[0028] Furthermore, the base material of the tap is made of powder high-speed steel or cemented carbide; when powder high-speed steel is used, its hardness is HRC 65-69; when cemented carbide is used, its hardness is HRA 90-93. The surface of the working part 4 is coated with a high-performance coating, which is a TiAlN / TiCN composite coating or a DLC diamond-like carbon coating; the TiAlN / TiCN composite coating has a thickness of 2-4μm, a hardness of HV 3000+, and is suitable for difficult-to-machine materials; the DLC diamond-like carbon coating is suitable for aluminum alloys and copper alloys, and can prevent chip adhesion and improve thread surface finish.

[0029] In one alternative implementation, the three-circular-arc smooth transition groove type is R1=(0.6~0.65)d, R2=(0.138~0.15)d, R3=(0.8~1)d, where d is the nominal diameter of the tap.

[0030] In one alternative embodiment, the helix angle ω of the helical groove 5 is 30° to 45°.

[0031] In one alternative implementation, the ratio of the groove width to the core thickness of the spiral groove 5 in the working part 4 is 0.6 to 0.8. This ratio reflects the relative proportion between the core thickness and the groove opening width, directly affecting chip removal smoothness and rigidity. This ratio provides adequate chip space while ensuring sufficient core thickness and guaranteeing the tool's torsional and bending strength, allowing for smooth chip removal, while avoiding excessively wide grooves that result in insufficient core thickness and rigidity. This ratio is suitable for most general-purpose taps, balancing tool life and chip removal performance.

[0032] In one alternative implementation, the ratio of the core thickness of the working section 4 to the outer diameter of the tap is ≥0.45 to ensure that the tool body still has sufficient strength after increasing the chip clearance space. The large core thickness design not only enhances the torsional and bending stiffness of the tool body, but also matches the variable groove depth structure, so that the working section 4 achieves a balance between chip clearance space and strength. Specifically, the cutting section 1 has a large groove depth, so it is necessary to ensure that the core thickness is relatively large at the same time to avoid the core becoming too thin due to the increase in groove depth; the calibration section 2 has a small groove depth and a relatively larger core thickness, which further enhances the rigidity of the guiding part.

[0033] In one alternative embodiment, the cutting edge 6 of the cutting section 1 is provided with a micro-chamfer 7 and an arc-shaped blunting structure 8; and / or the calibration section 2 is provided with a tapered structure. The micro-chamfer 7 is an extremely narrow second bevel ground on the cutting edge 6, adjacent to the main cutting edge, which can enhance the "blunt body" effect of the cutting edge 6 against impact and extend the tap life; the arc-shaped blunting structure 8 is to grind the tip of the cutting edge 6 into a tiny arc, eliminating the micro-notches and stress concentrations generated by grinding, and preventing the cutting edge 6 from chipping prematurely; the combination of the two allows the cutting edge 6 to obtain extremely high chipping resistance while maintaining the necessary sharpness. The tapered structure of the calibration section 2 starts from the end of the calibration section 2 near the cutting section 1 and gradually decreases the outer diameter of the tap towards the shank 3. The tapered structure can reduce the friction of the tool retraction and avoid damage to the cutting edge 6 caused by friction.

[0034] In one alternative embodiment, the micro-chamfer 7 of the cutting part 1 has a size of 0.02 to 0.05 mm, the radius of the arc passivation structure 8 of the cutting part 1 is 0.01 to 0.03 mm, and the inverted cone angle of the calibration part 2 is 0.5° to 1°.

[0035] In one alternative implementation, the connection between the calibration part 2 and the shank 3 is configured as a large circular arc transition structure. After tapping, the large circular arc transition structure, compared to a sharp step or right angle, can avoid scraping burrs; at the same time, it protects the last few teeth of the through-hole thread, preventing chipping or scratches; furthermore, it makes the transition from the calibration part 2 to the shank 3 smooth, facilitating smooth tap withdrawal and reducing jamming. The large circular arc transition structure has R4 = (0.2~0.3)d and R5 = (0.25~0.35)d, where d is the nominal diameter of the tap.

[0036] In one alternative embodiment, the cutting cone length of the cutting part 1 is 2.5P to 3P, where P is the tap pitch.

[0037] In one alternative implementation, the spiral groove 5 is machined as a right-handed adaptive blind hole.

[0038] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model. The present utility model extends to any new features or combinations disclosed in this specification, and any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model. It is obvious to those skilled in the art that the present utility model is not limited to the details of the above exemplary embodiments, and that detailed technical features not disclosed in this embodiment, such as specific structures and connection methods, are all prior art, which can be obtained by those skilled in the art from the prior art. The present disclosure does not specifically limit these aspects.

[0039] In the description of the embodiments of this utility model, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first" and "second" may explicitly or implicitly include one or more of that feature.

Claims

1. A novel high-efficiency chip removal and anti-chipping spiral groove tap, characterized in that: The device includes a cutting part (1), a calibration part (2), and a shank (3) connected in sequence. The cutting part (1) and the calibration part (2) constitute a working part (4). Multiple spiral grooves (5) are uniformly opened on the outer circumferential surface of the working part (4). The spiral grooves (5) include a first spiral groove (5) provided on the cutting part (1) and a second spiral groove (5) provided on the calibration part (2). The groove depth of the first spiral groove (5) is greater than the groove depth of the second spiral groove (5). The lead of the first spiral groove (5) decreases along the cutting direction, while the lead of the second spiral groove (5) is constant. The cross-section of the spiral groove (5) is a three-circular-arc smooth transition groove type.

2. The novel high-efficiency chip removal and anti-chipping spiral groove tap as described in claim 1, characterized in that: The three-circular-arc smooth transition groove type is R1=(0.6~0.65)d, R2=(0.138~0.15)d, R3=(0.8~1)d, where d is the nominal diameter of the tap.

3. The novel high-efficiency chip removal and anti-chipping spiral groove tap as described in claim 1, characterized in that: The helix angle ω of the spiral groove (5) is 30° to 45°.

4. The novel high-efficiency chip removal and anti-chipping spiral groove tap as described in claim 1, characterized in that: The ratio of the groove width to the core thickness of the spiral groove (5) is 0.6 to 0.

8.

5. The novel high-efficiency chip removal and anti-chipping spiral groove tap as described in claim 1, characterized in that: The ratio of the core thickness of the working part (4) to the outer diameter of the tap is ≥0.

45.

6. The novel high-efficiency chip removal and anti-chipping spiral groove tap as described in claim 1, characterized in that: The cutting edge (6) of the cutting part (1) is provided with a micro chamfer (7) and an arc passivation structure (8); and / or the calibration part (2) is provided with an inverted cone structure.

7. The novel high-efficiency chip removal and anti-chipping spiral groove tap as described in claim 6, characterized in that: The micro-chamfer (7) of the cutting part (1) has a size of 0.02 to 0.05 mm, and the radius of the arc passivation structure (8) of the cutting part (1) is 0.01 to 0.03 mm; the inverted cone angle of the calibration part (2) is 0.5° to 1°.

8. The novel high-efficiency chip removal and anti-chipping spiral groove tap as described in claim 1, characterized in that: The connection between the calibration part (2) and the handle (3) is set as a large circular arc transition structure, wherein R4=(0.2~0.3)d, R5=(0.25~0.35)d, and d is the nominal diameter of the tap.

9. The novel high-efficiency chip removal and anti-chipping spiral groove tap as described in claim 1, characterized in that: The cutting cone length of the cutting part (1) is 2.5P to 3P, where P is the tap pitch.

10. The novel high-efficiency chip removal and anti-chipping spiral groove tap as described in claim 1, characterized in that: The spiral groove (5) is a right-handed adaptive blind hole.

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