Ultra-short lead thread tap and manufacturing method thereof

Abstract

The invention discloses a manufacturing method of a screw tap with ultra-short lead teeth, which comprises the following steps of: 1, grinding the lead teeth of a standard screw tap by a screw pitch; secondly, cutting edges are ground, the width of the cutting edges is 0.3 mm, and three cutting edges are ground and arranged in a three-fork star shape; and thirdly, the clearance relief angle is ground, and the angle of the relief angle is-5 degrees. By optimizing the manufacturing process of the ultra-short thread leading screw tap, the machining problem of a specific shallow screw hole with the effective thread and bottom hole depth difference smaller than or equal to 1P is effectively solved, meanwhile, the thread surface quality is remarkably improved, the defects of roughness, out-of-tolerance and the like caused by direct short grinding are overcome, and cooperative improvement of the machining quality and the service life of a tool is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of machining tools, in particular to an ultra-short lead tap and a manufacturing method thereof. BACKGROUND

[0002] A tap (or called a screw tap) is a common cutting tool for machining internal threads, widely used in the fields of mechanical manufacturing, electronic equipment, automobile industry, etc.

[0003] According to industry standards, the length of the lead is usually divided into short lead (1.5-2.5P), standard lead (3.5-4.5P) and long lead (6-8P) according to the pitch (P). The short lead is suitable for through holes or easy-to-cut materials, the standard lead is suitable for most through holes and part of blind holes, and the long lead is suitable for blind holes or difficult-to-cut materials.

[0004] However, in some specific application occasions, such as high-voltage relay terminal hole, precision electronic component mounting hole, etc., due to the limitation of structural space, the difference between the bottom hole depth and the effective thread depth is very small, usually less than or equal to one pitch. In this case, using a standard lead tap will cause the following problems: 1. The complete thread part of the tap cannot fully enter the hole bottom, and the effective thread length is insufficient; 2. If a short lead tap is used directly, although it can quickly cut in, the cutting force is concentrated and the torque is large, which easily leads to tap fracture, rough thread surface or size out-of-tolerance; 3. If the lead of the standard tap is simply ground to adapt to the shallow hole, the cutting performance and service life of the tap will be significantly weakened. In the prior art, the common method is to directly grind the lead of the standard tap by 1.0 pitch, but this method is not optimized, which leads to a sharp decline in the service life of the tap, only about 10% of the original tap, and the surface of the processed thread is rough, which seriously affects the product quality and production efficiency. SUMMARY

[0005] The purpose of the present application is to provide an ultra-short lead tap and a manufacturing method thereof, which solves the problems raised in the background art.

[0006] To achieve the above purpose, the present application provides the following technical solution: a manufacturing method of an ultra-short lead tap, comprising the following steps: Step 1: grind the lead of the standard tap by 1.0 pitch; Step 2: grind the cutting edge, the blade width is 0.3mm, and there are three edge openings, which are arranged in the shape of a trident; Step 3: grind the relief angle, the relief angle is-5 degrees.

[0007] Preferably, the length of the ground lead is the length of the standard lead minus 1.0 pitch.

[0008] Preferably, the cutting edge is located at the leading part of the tap, for dispersing cutting force and improving chip shape.

[0009] Preferably, the relief angle is arranged at the thread tooth back of the tap, for enhancing chip removal ability and heat dissipation efficiency.

[0010] Preferably, the tap is suitable for machining a threaded hole with a difference between effective thread depth and hole depth less than or equal to one pitch.

[0011] Preferably, the tap is suitable for M3 to M6 threaded holes.

[0012] An ultra-short pilot tap, the pilot length of which is shorter than that of a standard tap by one pitch, is provided with three cutting edges at the pilot end, the three edges are arranged in a trident star shape, the cutting edge width is 0.3 mm, and the relief angle is -5 degrees.

[0013] Preferably, it is used for machining high-voltage relay terminal threaded holes or other similar threaded holes.

[0014] Compared with the prior art, the present application has the following beneficial effects: The present application optimizes the manufacturing process of the ultra-short pilot tap, on the basis of grinding the pilot by one pitch, precisely grinds the 0.3 mm cutting edge and the -5° relief angle, successfully increases the tap life from 10% of the simple grinding process to more than 50% of the standard tap, effectively solves the problem of machining specific shallow threaded holes with a difference between effective thread depth and hole depth less than or equal to one pitch, significantly improves the thread surface quality, overcomes the defects such as roughness and excess error caused by direct grinding, and realizes the coordinated improvement of machining quality and tool life. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 The block flowchart of the present application. DETAILED DESCRIPTION

[0016] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0017] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "horizontal", "vertical", "top", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application. In addition, the terms "first", "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0018] Please refer to Figure 1 The present application provides an embodiment: an ultra-short lead tap and its manufacturing method, first, select M4x0.7 high speed steel tap as the processing base, the standard tap lead length is 3.5 times the pitch, which is calculated as 2.45mm.

[0019] Then the processing base standard tap is made into an ultra-short lead tap, including the following steps: Step one: the standard tap is ground short by one pitch on the precision numerical control tool grinder, that is, 0.7mm length is removed, the speed of the diamond grinding wheel is kept at 25m / s, the workbench feeding speed is set to 100mm / min, and cooling liquid is used for continuous cooling to prevent overheating during grinding which may cause material annealing; after grinding, the tool microscope is used to measure and confirm that the lead length is 1.75mm.

[0020] Step two: three evenly distributed cutting edges are precisely ground on the lead-in part of the tap front end which has been ground short, the three edges are symmetrically arranged in a trident star shape, the width of each edge is accurately controlled at 0.3mm, the symmetry error of the edges is not more than 0.02mm, and the surface roughness of the edges is required to reach Ra≤0.4μm; the special trident star-shaped edge design can evenly disperse the cutting force in three directions, effectively improving the chip shape and preventing chip jamming.

[0021] Step three: a-5° clearance relief angle is ground on the tap thread tooth back part, a special angle clamp is used to ensure the consistency of the angle during grinding, the angle tolerance is strictly controlled within ±0.5°, and the roughness of the relief angle surface is required to reach Ra≤0.8μm, so as to ensure smooth chip removal and improve heat dissipation conditions.

[0022] The ultra-short pilot tap prepared by the above process has the following determined geometric parameters: the pilot tap length is 1.75 mm, shorter than a standard tap by one pitch; the cutting edge is in a three-prong star shape, each edge width is 0.3 mm ± 0.02 mm; the clearance relief angle is -5° ± 0.5°; this unique structural design significantly improves the cutting performance and chip removal capacity while maintaining sufficient strength.

[0023] By machining a workpiece with the prepared ultra-short pilot tap, the cutting parameters of the ultra-short pilot tap are set as a rotation speed of 200 r / min and a feed rate of 0.7 mm / r, and water-based emulsion is used for continuous cooling; after the cutting is completed, the thread surface roughness of the workpiece is stabilized in the range of Ra 1.4-1.6 μm; in terms of chip removal performance, the chip is in a continuous spiral shape and no jamming occurs; in terms of dimensional stability, the thread pitch diameter variation is controlled within 0.02 mm, showing good machining consistency.

[0024] It is apparent for those skilled in the art that the present application is not limited to the details of the above exemplary embodiments, but can be implemented in other concrete forms without departing from the spirit or essential characteristics of the present application. Therefore, the embodiments should be considered in all respects as illustrative and not restrictive, the scope of the present application being defined by the appended claims rather than the above description, and it is intended to embrace all changes and modifications that fall within the meaning and scope of the equivalent elements of the claims. Any reference signs in the claims should not be construed as limiting the claims to which they belong.

Claims

1. A method for manufacturing an ultra-short threaded tap, characterized in that: Includes the following steps: Step 1: Grind the lead thread of the standard tap to shorten it by one pitch; Step 2: Grind the cutting edge with a width of 0.3mm. There are three cutting edges, which are arranged in a trident shape. Step 3: Grind the clearance angle to -5 degrees.

2. The method for manufacturing an ultra-short threaded tap according to claim 1, characterized in that: The length of the threaded tooth after grinding is the standard threaded tooth length minus one pitch.

3. The method for manufacturing an ultra-short threaded tap according to claim 1, characterized in that: The cutting edge is located at the front guide portion of the tap and is used to disperse the cutting force and improve the chip shape.

4. The method for manufacturing an ultra-short threaded tap according to claim 1, characterized in that: The clearance angle is set on the back of the tap thread to enhance chip removal capability and heat dissipation efficiency.

5. The method for manufacturing an ultra-short threaded tap according to claim 1, characterized in that: The tap is suitable for machining threaded holes where the difference between the effective thread depth and the bottom hole depth is less than or equal to one pitch.

6. The method for manufacturing an ultra-short threaded tap according to claim 5, characterized in that: The tap is applicable to threaded holes from M3 to M6.

7. A type of ultra-short threaded tap, characterized in that: The product is manufactured by the production process described in any one of claims 1 to 6. The length of the lead thread is shorter than that of a standard tap by one pitch. The lead thread end is provided with three cutting edges, which are arranged in a trident shape. The width of the cutting edges is 0.3 mm, and the clearance angle is -5 degrees.

8. The ultra-short thread tap according to claim 7, characterized in that: It is used to machine threaded holes for high-voltage relay terminals or other similar structures.

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