JP4618680B2 - Broach manufacturing method - Google Patents

Description

The present invention relates to a method for manufacturing a broach that performs hole cutting or surface cutting .

Conventional cutting tool flank wear is a typical wear pattern that determines the tool life, but broaching flank wear, especially when drilling holes or surface cutting, appears more prominently than other cutting tools and prevents this. Is required. It has been reported that the flank wear of such a conventional broach is generally larger at the corner than at the center. The reason for the increased corner wear is that the corner portion is easily affected by heat during cutting, has a sharp edge shape, has low strength, and easily causes minute chipping. In general, re-grinding of broach is carried out on the rake face of the cutting edge. However, grinding burrs generated by rake face grinding of the cutting edge fall off during machining and chipping is performed on the cutting edge of the broach cutting edge. May cause troubles such as low life of brooches. FIG. 5 is a perspective view of a single blade of a round broach showing flank wear of a conventional broach, as shown in FIG. 5, chipping of the cutting edge a of the broach cutting edge 1 due to corner wear or re-grinding of the cutting edge of the broach. Grinding burrs are generated on the rake face at the corner ridge line c that forms the cutting edge 1 of the cutting edge 1 and the side face 4, and these grinding burrs fall off at the initial stage of workpiece processing, and the cutting edge 1 a and the side face 4 of the cutting edge 1 of the broach Chipping was generated at the corner ridgeline c to be formed, causing troubles such as a low life of the broach.
Furthermore, broach troubles include welding on the broach surface, which is likely to occur mainly when the affinity between the broach material and the work material is strong, and further when the work material is soft. Therefore, it was necessary to add a surface treatment such as nitriding or coating, or to use a cutting oil having a high extreme pressure.
Japanese Utility Model Publication No. 63-30427 JP 2000-5904 A Japanese Patent Publication No. 02-17607

In Patent Document 1, in order to prevent chipping from occurring at the cutting edge of such a broach, 30-250 μm radius is applied to the corner of the cutting edge by sandblasting and liquid honing. It has been proposed that the cutting edge is subjected to rake face grinding except for a rounded shape to form a sharp edge (Patent Document 1, page 3, lines 10 to 18). However, since the sharp edge of the cutting edge of the cutting edge remains and grinding burrs are generated by the rake face grinding, the above problem cannot be solved. Further, in claim 10 of Patent Document 2, it is proposed to provide a cutting edge surface (chamfered chamfering surface) of 30 to 250 μm at the cutting edge of the cutting edge of the broach. However, the cutting depth of one blade of broach is several μm to 50 μm, and such a large cutting edge surface (chamfered chamfered surface) is subject to a large cutting resistance, which may lead to a short life such as cutting of the broach, and has high cutting accuracy. There is no disclosure as to whether it is satisfactory.
In the conventional broach, there has been no means for preventing chipping at the cutting edge of the broaching blade, disclosing an appropriate rounding amount that can satisfy the cutting accuracy, or ensuring a stable and appropriate rounding amount. Patent Document 3 proposes a heat treatment of a metal product by shot peening, but it is a heat treatment that heats the metal product to around 900 ° C. and cannot be applied to a broach cutting edge after quenching.

The problem of the present invention is that the tip of the cutting edge of the broach due to the flank wear of the broach, especially the corner wear, or the broach cutting edge due to the removal of the grinding burr generated by the rake face grinding of the cutting edge when the broach is reground. It is an object of the present invention to provide a method for manufacturing a broach that prevents chipping of the blade edge and causing troubles such as a low life of the broach. Another object of the present invention is to provide a method for manufacturing a broach that prevents welding of the broach surface without adding a surface treatment such as nitriding or coating.

For this reason, the present invention provides a cutting edge of the cutting edge of the broach by grinding a cutting edge of a high-speed steel or cemented carbide broach after shot peening to give a fine roundness of 5 to 10 μm to the cutting edge of the cutting edge. The above problems have been solved by providing a method for manufacturing a broach characterized in that the flank face and the cutting edge side flank face have a satin finish with a surface roughness R _max of 0.5 to 1.5 μm .

In the present invention, after grinding the cutting edge of a high speed steel or cemented carbide broach , the cutting edge of the cutting edge of the broach and the cutting edge are cut by shot peening to give a 5-10 μm roundness to the cutting edge of the cutting edge. Because the broach manufacturing method has a flank finish with a surface roughness R _max of 0.5 to 1.5 μm on the flank side of the blade, the cutting edge of the broach and each edge of the corner ridge line do not affect the cutting accuracy Broaching due to chipping of the cutting edge of the broaching edge due to flank wear of the broach, especially corner wear, or the removal of grinding burrs generated by rake face grinding of the cutting edge when re-grinding the broach. The present invention provides a method for manufacturing a broach that prevents chipping of the cutting edge of the cutting edge to cause troubles such as a low life of the broach .

In addition, the surface of the cutting edge of the broach and the side of the flank of the cutting edge are treated with a uniform textured surface, which is different from the grinding bar, to create a textured surface asperity on the flank of the cutting edge and the flank of the cutting edge. It is possible to provide a method for manufacturing a broach that is formed, improves the permeability of the cutting oil, and prevents welding of the broach surface without adding a surface treatment such as nitriding or coating .

The present invention will be described with reference to FIGS. FIG. 1 is a perspective view of two blades of a round broach showing a first embodiment of the present invention, and FIG. 2 (a) is a perspective view of one blade of a round broach showing a second embodiment of the present invention. The cutting edge state after the surface modification by shot peening is shown, and (b) shows the cutting edge state having a grinding line immediately after grinding before shot peening .

As shown in FIG. 1, the broach according to the first embodiment of the present invention is 5 to 10 μm by shot peening on a cutting edge 1 of a cutting edge 1 of a high speed steel (or may be made of carbide) broach. A small roundness was added to improve the wear resistance of the broach cutting edge. 3 is a cutting edge flank, 2 is a rake face, and 4 is a side flank. Preferably, such shot peening is performed every time after the re-grinding of the broach, thereby generating chipping of the cutting edge of the broaching edge due to the removal of a grinding burr generated by grinding the rake face of the cutting edge at the time of regrinding the broach. It is possible to prevent problems such as low life of the broach.

As shown in FIG. 2 (a), the broach of the second embodiment of the present invention is a cutting edge of the cutting edge 1 of the high speed steel (may be made of carbide) broach of the first embodiment. By applying the same shot peening to the flank 3 and the cutting edge side flank 4 as in the first embodiment of the present invention, a uniform satin texture having a surface roughness Rmax of 0.5 to 5 μm, which is different from a grinding bar. Finished (similar pear ground is formed under the rake face 2 and side face 4). This uniform matte finish is clearly different from the grinding stripes shown in FIG. 2B (similar grinding stripes are also formed below the rake face 2 and the side face 4). A broach that forms a satin-like irregularity on the flank and side flank of the cutting edge, improves the penetration of the cutting oil, and prevents welding of the broach surface without adding surface treatment such as nitriding or coating The manufacturing method of can be provided.

  FIG. 3 shows processing data when a fine roundness of 0 to 30 μm is added to the cutting edge a of the cutting edge 1 of the broach. The inventor appropriately changes the fine particle diameter of the shot, the injection pressure, the injection speed, and the injection distance to the cutting edge a of the cutting edge 1 of the high-speed steel broach shown in FIG. FIG. 3 shows the results of plotting the number of machining until a cutting edge flank 3 of the broaching cutting edge 1 is worn 0.1 mm from experimental values, with a small roundness of 0 to 30 μm added to a. If the chamfer of 3 to 25 μm is rounded on the cutting edge a of the cutting edge 1, the number of processing will be longer and the life of the broach will be longer. As a result, the life of the broach was shortened. The chamfering of a minute roundness of 3 to 25 μm stabilized the cutting state of the broach and had no effect on the cutting accuracy. The number of processing was larger when chamfered with a fine roundness of 5 to 10 μm.

  FIG. 4 shows the same shot peening used in the experiment of Example 1 of FIG. 3 on a high-speed steel plate, and 10 uniform satin finish surfaces having a surface roughness Rmax of 0.5 to 8 μm. The data of the scrape friction test between these 10 high-speed steel plates and the workpiece are shown. As a comparison, a scraping friction test was performed between 10 workpieces having a surface roughness of Rmax 0.5 to 7 μm and a high-speed steel plate having a ground surface shown in FIG. 2B and a workpiece. As a result, as shown in FIG. 4, the reduction amount of the workpiece was less than 5 μm on the uniform finish surface of the product of the present invention, but the reduction amount of the workpiece on the finished surface of the comparative product was as large as 8 μm, and The amount of reduction was always greater than the uniform satin finish. Even on the cutting edge flank and cutting edge side flank of the broach cutting edge, the matte finish surface reduces the contact surface with the workpiece. This is considered to improve the workability and, as a result, reduce the amount of workpiece reduction. Therefore, the broach which prevents the welding of a broach surface without adding surface treatments, such as a nitriding process and a coating, was provided. The reduction amount of the workpiece of the high-speed steel plate having a satin finish surface of Rmax 0.5 to 5 μm was more favorable.

With this configuration, in the embodiment of the present invention, after grinding the cutting edge of a high-speed steel or cemented carbide broach , the edge of the cutting edge is finely rounded by 5 to 10 μm by shot peening so that the broach is cut. Since the cutting edge flank and cutting edge side flank of the blade have a matte finish with a surface roughness R _max of 0.5 to 1.5 μm , the cutting edge of the broach and the corner ridgeline Each edge is rounded by a stable amount within a range that does not affect the cutting accuracy, stabilizes the cutting state of the broach, tips the tip of the broach cutting edge due to flank wear on the broach, especially corner wear, or When cutting the rake face of the cutting edge during re-grinding, chipping of the tip of the broaching edge due to the removal of grinding burrs occurs, causing trouble such as a low life of the broach. It was intended to provide a broach manufacturing method of preventing Succoth.

Further, when the cutting edge flank and the cutting edge side flank of the cutting edge of the broach are subjected to a uniform satin finish different from the grinding line, the surface of the broach is subjected to surface treatment such as nitriding or coating. Therefore, it is possible to provide a method for manufacturing a broach that can prevent the above-mentioned problem without adding.

The perspective view of 2 blades of the round broach which shows the 1st Embodiment of this invention (A) is a perspective view of one blade of a round broach showing the second embodiment of the present invention, showing the state of the blade edge after surface modification by shot peening of the present invention, (b) grinding before shot peening The cutting edge state which has the grinding line immediately after is shown. Processing data when a fine roundness of 0 to 30 μm is attached to the cutting edge a of the cutting edge 1 of the broach is shown. When the same shot peening as used in the experiment of Example 1 in FIG. 3 is applied to a high-speed steel plate to obtain 10 uniform satin finish surfaces having a surface roughness R _{max of} 0.5 to 8 μm. The data of the scraping friction test of these 10 high-speed steel plates and a workpiece | work are shown. The perspective view of 1 blade of a round broach showing the flank wear of the conventional broach.

Explanation of symbols

1: Cutting edge of broach 3: Cutting edge flank 4: Side flank a: Cutting edge of broaching edge

Claims (1)

For high-speed steel or cemented carbide broaches, shot peening is performed after grinding the cutting edge of the broach, so that the edge of the cutting edge of the broach is rounded to 5 to 10 μm, and at the same time, the broaching Roughness R of 0.5 to 1.5 μm between the cutting edge flank and the side flank of the cutting edge _max A broach manufacturing method characterized by having a satin finish.

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