A multi-layer stepped drill tip twist drill

Abstract

This invention discloses a multi-layer stepped twist drill tip, relating to the field of cutting tool technology. It comprises a shank and a working part, the working part having a helical groove and a cutting back; the top of the working part has a chisel edge and a cutting edge, and a stepped groove is provided on the flank face connected to the cutting edge; the stepped groove divides the cutting edge into several segments; the groove spacing of the stepped groove gradually decreases from the top of the working part towards the shank. Compared with existing stepped drills, this invention not only reduces drill wear, extending its lifespan, but also increases cutting speed.

Description

Technical Field

[0001] This invention relates to the field of cutting tool technology, and in particular to a multi-layer stepped twist drill tip. Background Technology

[0002] Conventional twist drills rely on two symmetrically distributed, straight cutting edges to simultaneously remove a certain amount of metal during drilling. This results in higher power requirements and greater reaction forces on the cutting edges, making them prone to damage. Currently, a stepped-tip twist drill has emerged on the market. Its stepped cutting mechanism facilitates positioning during layered drilling, reduces cutting resistance and heat generation, increases drilling efficiency, and extends service life. This significantly improves the drill bit's performance and produces high-precision holes with minimal burrs on the cutting edge, making it highly favored by machining professionals.

[0003] Conventional stepped-tip twist drills have parallel steps spaced along the drill bit axis, with the step surfaces perpendicular to the axis. This arrangement leads to machining overlap without improving cutting efficiency, and the step surfaces easily trap cutting debris, affecting subsequent machining. To address this issue, Chinese Patent CN214720850U discloses a helical stepped-tip twist drill with a helical cutting groove and a pitch that gradually increases from the top of the working part towards the shank, reducing machining overlap and significantly improving cutting speed. However, correspondingly, the cutting depth also gradually increases, accelerating drill bit wear and reducing drill bit life. Summary of the Invention

[0004] The main objective of this invention is to provide a multi-layer stepped twist drill tip to solve the above-mentioned problems.

[0005] To achieve the above objectives, the present invention provides a multi-layer stepped twist drill tip, comprising a shank and a working part, wherein the working part is provided with a spiral groove and a cutting back; the top of the working part is provided with a transverse cutting edge and a cutting edge, and a stepped groove is provided on the back face connected to the cutting edge; the stepped groove divides the cutting edge into several segments; the groove spacing of the stepped groove gradually decreases from the top of the working part toward the shank.

[0006] Furthermore, the stepped groove is spiral-shaped; the spiral direction of the stepped groove is the same as that of the spiral groove; the slope of the stepped groove gradually decreases from the top of the working part towards the handle.

[0007] Furthermore, the slope of the stepped groove decreases from 17° to 8°.

[0008] The present invention has the following beneficial effects:

[0009] Compared with existing step drills, this invention not only reduces drill bit wear, extending its lifespan, but also increases cutting speed. Attached Figure Description

[0010] Figure 1 This is a schematic diagram of a multi-layer stepped twist drill tip according to the present invention.

[0011] Figure 2 This is a perspective view of the working part of a multi-step twist drill tip according to the present invention.

[0012] Figure 3 This is a front view of the working part of a multi-step twist drill tip according to the present invention.

[0013] Among them, 1-shank; 2-working part; 3-spiral groove; 4-back of the cutting edge; 5-cutting edge; 6-chasm edge; 7-flank face; 8-stepped groove. Detailed Implementation

[0014] To achieve the above objectives and effects, the technical means and structure adopted by the present invention will be described in detail with reference to the accompanying drawings, focusing on the features and functions of the preferred embodiments of the present invention.

[0015] like Figure 1-3 As shown, this invention provides a multi-layer stepped twist drill tip, comprising a shank 1 and a working part 2. The working part 2 is provided with a helical groove 3 and a cutting edge 4; the top of the working part 2 is provided with a chisel edge 6 and a cutting edge 5, and a stepped groove 8 is provided on the flank face 7 connected to the cutting edge 5; the stepped groove 8 divides the cutting edge 5 into several segments; the groove spacing of the stepped groove 8 gradually decreases from the top of the working part 2 towards the shank 1. Figure 2 As shown, the spacing is a > b > c.

[0016] Cutting with as much distance as possible at the small outer diameter position results in less resistance and faster cutting speed for products with small heads. By following the principle and rules of gradual progress, the cutting characteristics of the product are met. After the first step enters the test block, due to the characteristics of the spiral groove at the product head, the second step, the third step, and so on can be cut automatically with very little force. Under reasonable operation, the cutting speed and efficiency of the drill bit are guaranteed, and the wear of the drill bit is reduced, making its life longer. When cutting with a pistol drill, the operator saves more effort, and the positioning is better, resulting in better roundness and surface finish of the machined workpiece.

[0017] In another embodiment, the stepped groove 8 is spiral-shaped; the spiral direction of the stepped groove 8 is the same as that of the spiral groove 3; the slope of the stepped groove 8 gradually decreases from the top of the working part 2 towards the handle 1, such as... Figure 3 As shown.

[0018] Because the angle of the stepped groove 8 is determined by the resistance of the drill bit during cutting, a larger angle results in faster cutting speed and less force under the same conditions. Therefore, a larger angle is set at the step with a smaller outer diameter of the head, allowing the product to quickly position itself into the workpiece. After the first step is entered, subsequent steps only require some auxiliary force to easily cut and feed into the workpiece. Thus, the angle of the stepped groove 8 decreases accordingly. The specific decrease refers to the angle requirements range for each specification of twist drill head, normally decreasing within the range of 17°-8°. This ensures the product's optimal performance. Simultaneously, at the step with the largest outer diameter of the product, due to the decreasing angle, the step distance is short and the front and rear angles are small, thus ensuring both speed and wear resistance.

[0019] The cutting speed was tested by cutting a 5mm thick German ST37 test block with a hand drill.

[0020] Using a standard 6mm step drill with a load of 8KG, 201 holes were drilled, with an average cutting time of 3.65 seconds. However, using the same specification product of this invention under the same conditions, the average cutting time was 3.3 seconds, which is faster and about 10% faster than the standard step drill.

[0021] Using a standard 10mm step drill to drill 201 holes with a 10kg weight, the average cutting time was 5.5 seconds. However, using the same specification product of this invention under the same conditions, the average cutting time was 5.03 seconds, which is faster and about 9% faster than the standard step drill.

[0022] The lifespan was tested by cutting 4mm thick 304 stainless steel with a hand drill.

[0023] When drilling with a standard 6mm step drill under 8kg load, 32 holes were cut before the drill bit burned, and cutting was stopped. However, when drilling with the same specification product of this invention under the same conditions, 38 holes were cut before the drill bit burned, and cutting was stopped. The product has better lifespan and wear resistance, which is about 19% better than the standard step drill.

[0024] When drilling with a standard 10mm step drill under 10kg weight, 30 holes were cut before the drill bit burned, and cutting was stopped. However, when drilling with the same specification product of this invention under the same conditions, 36 holes were cut before the drill bit burned, and cutting was stopped. The product has better lifespan and wear resistance, which is about 20% better than the standard step drill.

[0025] The above description is only a preferred embodiment of the present invention and not all embodiments. Anyone should know that structural changes made under the guidance of the present invention, and any technical solutions that are the same as or similar to the present invention, are within the protection scope of the present invention.

Claims

1. A multi-layer stepped twist drill bit, comprising a shank and a working part, wherein the working part is provided with a helical groove and a cutting back; the top of the working part is provided with a transverse cutting edge and a cutting edge, characterized in that, A stepped groove is provided on the flank face connected to the cutting edge; the stepped groove divides the cutting edge into several segments; the groove spacing of the stepped groove gradually decreases from the top of the working part to the shank. The stepped groove is spiral-shaped; the spiral direction of the stepped groove is the same as that of the spiral groove; the slope of the stepped groove gradually decreases from the top of the working part towards the handle.

2. The multi-layer stepped twist drill as described in claim 1, characterized in that, The slope of the stepped groove decreases from 17° to 8°.

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