Multilayer step drill compound tap

Abstract

The application discloses a multilayer step head drilling composite tap, and relates to the technical field of cutters. The tap comprises a shank and a working part, the working part is provided with a spiral groove and a land, the top of the working part is provided with a cross blade and a cutting edge, the land in the middle of the working part is provided with a tap structure, the rear surface connected with the cutting edge is provided with a step groove, and the step groove divides the cutting edge into several sections. The tap structure is arranged on the land in the middle of the working part, the working of the drill bit is not affected, the spiral groove is smooth, and the tap has better chip removal effect; the drill bit adopts the step structure, the cutting speed is improved, the wear of the drill bit is reduced, and the service life of the drill bit is longer.

Description

Technical Field

[0001] This invention relates to the field of cutting tool technology, and in particular to a multi-layer stepped head drilling composite tap. Background Technology

[0002] The machining of threaded holes typically involves first drilling a pilot hole with a drill bit for positioning and pre-machining, followed by tapping with a tap. This requires two different tools, leading to wasted time and reduced efficiency due to tool changes, and also necessitating repeated positioning, which lowers accuracy. Chinese patents with publication numbers CN2855605Y, CN107971533A, and CN201632690U disclose a multi-layer stepped head composite tap to address these issues. However, in these patents, the tap structure is located after the drill bit structure, resulting in poor chip removal; furthermore, the drill bit structure is a standard twist drill, which has a slow cutting speed and is prone to wear. Summary of the Invention

[0003] The main objective of this invention is to provide a multi-layer stepped head drilling composite tap to solve the above-mentioned problems.

[0004] To achieve the above objectives, the present invention provides a multi-layer stepped head drilling composite tap, comprising a shank and a working part, wherein the working part is provided with a spiral groove and a cutting edge; the top of the working part is provided with a transverse cutting edge and a cutting edge, and a tap structure is provided on the cutting edge in the middle of the working part; a stepped groove is provided on the flank face connected to the cutting edge; the stepped groove divides the cutting edge into several segments.

[0005] Furthermore, the spacing between the stepped grooves gradually decreases from the top of the working part towards the handle.

[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] This invention places the tap structure on the back of the cutting edge in the middle of the working part, which does not affect the operation of the drill bit. The spiral groove is unobstructed, resulting in better chip removal. The drill bit adopts a stepped structure, which not only improves the cutting speed but also reduces the wear of the drill bit, making it last longer. Attached Figure Description

[0010] Figure 1 This is a schematic diagram of the overall structure of a multi-layer stepped head drilling composite tap according to the present invention.

[0011] Figure 2 This is a perspective view of the working part of a multi-layer stepped head drilling composite tap according to the present invention.

[0012] Figure 3 This is a front view of the working part of a multi-layer stepped head drilling composite tap 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-chistle edge; 7-flank face; 8-stepped groove; 9-tap structure. 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 head drilling composite tap, comprising a shank 1 and a working part 2. The working part 2 is provided with a spiral 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; a tap structure 9 is provided on the cutting edge 4 in the middle of the working part 2; 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 a > b > c. This invention places the tap structure on the back of the cutting edge in the middle of the working section, which does not affect the drill bit's operation. The spiral groove is unobstructed, resulting in better chip removal. The drill bit adopts a stepped structure, which not only improves the cutting speed but also reduces drill bit wear, extending its lifespan.

[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 head drilling composite tap, comprising a shank and a working part, wherein the working part is provided with a helical groove and a cutting edge; the top of the working part is provided with a transverse cutting edge and a cutting edge, and a tap structure is provided on the cutting edge in the middle of the working part; 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 spacing between the stepped grooves gradually decreases from the top of the working part towards the handle. 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 head drilling composite tap as described in claim 1, characterized in that, The slope of the stepped groove decreases from 17° to 8°.

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