JPH06285535A - Forming of back relief on drawing die tip - Google Patents

Abstract

PURPOSE:To improve productivity, forming precision and reliability of a back relief by providing small projections on the upper surface end parts of a lower metallic mold punch, centering and mounting the lower punch on a lathe chuck to be a working axis and improving centering and mounting precision of the small hole of a powder compression molding body. CONSTITUTION:Small projections 7a are provided on the upper surface end parts of lower metallic mold punch 3 as marks, powder material 1 is compressed to be formed by the lower metallic mold punch 3 and an upper metallic mold punch 5 in a metallic mold 2 and the powder compression molding body 10 of drawing die tip is formed. After small projection and small recessed part 7b are formed on one surface end part of the powder compression molding body 10, the lower punch 3 is centered and mounted on the lathe chuck 16 to be the working axis, the molding body 10 is positioned according to the marks and mounted on the lower punch 3 and the back relief 15 is formed by grinding on the molding body 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wire drawing die chip which is formed by turning a back relief into a powder compression molding of a wire drawing die chip obtained by compression molding raw material powders of cemented carbide, thermite, ceramics and the like. The present invention relates to a relief molding method.

[0002]

2. Description of the Related Art Conventionally, wire drawing die chips are produced by compressing and molding raw material powders of various compositions such as cemented carbide, thermite, and ceramics in a mold by a lower die punch and an upper die punch, as shown in FIG. As shown, a powder compression molded body a having a mouth b, a pore c and a back hole d is molded, the powder compression molded body a is mounted on a lathe chuck f, and the back relief e is turned by a tool g to mold. After that, the back relief e is manufactured by sintering, and the back relief e is coaxially formed with respect to the pore c and is formed by turning at a predetermined acute angle with high precision. It becomes an extremely important factor in wire drawing and greatly affects the accuracy and reliability of wire drawing with a die for wire drawing.

[0003]

Conventionally, the wire drawing die chip is formed by mounting the powder compression molded product compression-molded by the die as described above on the lathe chuck, turning the back relief, and then molding. Although manufactured by binding, the powder compression-molded body is liable to cause variations in the placement accuracy of its pores due to the clearance generated between the powder and the mold, strain deformation after the completion of compression molding, etc. There is a problem in the accuracy of turning molding of the back relief with respect to the pores, that is, its coaxial accuracy and reliability, such that it is difficult to center the pores when it is mounted on.

The present invention was developed in order to solve the above-mentioned problems. The object of the present invention is to attach a small convex portion to the upper end portion of the lower die punch, The lower die punch is centered and mounted on the lathe chuck to be used as the processing axis, and the accuracy of centering and mounting the pores of the powder compression molded product is improved to improve productivity as well as back relief molding accuracy and reliability for wire drawing. An object is to provide a back relief forming method of a die chip.

[0005]

According to the present invention, a small convex portion of a mark is attached to an upper end portion of a lower die punch, and a raw material powder is produced by the lower die punch and the upper die punch in the die. After compression molding to form a powder compression molding of wire drawing die chip, and forming a small recessed part at one end of one surface of the powder compression molding, the lower die punch is centered and mounted on the lathe chuck. As a machining axis, the above powder compression molded body is aligned and mounted on the lower die punch by the above-mentioned both marks, and a back relief is turned on the powder compression molded body to form a lathe chuck. In addition to facilitating the attachment of the powder compression molded body to the core, the precision of centering and attaching the pores is improved to improve the precision and reliability of the turning relief of the back relief.

[0006]

[Function] A small convex portion of a mark is attached to the upper end of the lower die punch, and the raw material powder is compression-molded by the lower die punch and the upper die punch in the die to form a die die for wire drawing. By forming into a powder compression molded product, a small recessed portion of a mark is formed at one surface end of the powder compression molded product, and the lower die punch is centered and attached to the lathe chuck to form a processing shaft. When the above-mentioned powder compression molded body is aligned and mounted on the die punch, the pores of the powder compression molded body can be easily centered and mounted together with the lower die punch. The back relief is easily and accurately turned on the body and formed, and excellent back relief turning accuracy and reliability are obtained.

[0007]

FIG. 1 shows an embodiment of the present invention. In the figure, 1 is a raw material powder of cemented carbide, thermite, ceramics, etc., 2 is a die, 3 is a lower die punch with protrusions 4, 5 is an upper die punch with protrusions 6, and 7a is an upper surface of the lower die die 3. A small convex portion of a mark attached to the end portion, 7b is a small concave portion of the mark on one end of the powder compression molded body 10 formed by the small convex portion 7a, 10 is a mouth 11 and pores 12 and back holes 13 are formed. The powder compression molded body of the wire drawing die chip, 15 is a back relief which is turned into the powder compression molded body 10, 16 is a lathe chuck, 17 is a fixing tape, and 18 is a back relief 15.
1A, a protrusion 4 for forming a mouth 11 and a hole 12 is integrally provided at the upper end portion of the lower die punch 3 as shown in FIG. A small convex portion 7a serving as a mark is provided with a commercially available strong adhesive or the like, a predetermined amount of the raw material powder 1 is filled in the die 2, and the lower die punch with the protrusion 4 is provided as shown in FIG. 1 (B). 3 and the upper die punch 5 with the protrusion 6 to form the raw material powder 1 into a powder compression molded body 10 of a wire drawing die chip, and the powder compression molded body 10 is molded into a die as shown in FIG. 1 (C). Then, a large number of powder compression moldings 10 are molded continuously. The powder compression molding 10 has a mouse 11 and pores 1 as shown in the figure.
2 and the back hole 13 are formed, and a small concave portion 7b as a mark is formed by the small convex portion 7a attached to the end of one surface thereof.
The back relief 15 is turned and formed in the next step.

As described above, the desired number of powder compression moldings 1
After molding 0, the tip of the protrusion 4 of the lower die punch 3 is slightly cut off as shown in FIG. 1 (D), the lower die punch 3 is centered and attached to the lathe chuck 16, and the machining axis is set. Then, the powder compression molding 10 is mounted on the front end portion (upper surface side) of the lower die punch 3 by aligning it with the small convex portion 7a and the small concave portion 7b, and if necessary, the lower die punch 3 and the powder. Fixing tape (adhesive tape) 17 between the periphery of the compression molded body 10
Then, the bite 18 is advanced by advancing as shown by the arrow, and the back relief 15 is precisely turned and molded on the powder compression molded body 10 which is rotating. The front end portion (upper surface side) of the lower die punch 3 serving as a processing axis may be provided with a mark by an appropriate means, if necessary, to replace the small convex portion 7a.

As described above, the lower die punch 3 mounted on the lathe chuck 16 is easily and accurately centered and mounted on the lathe machining axis by the projection 4 projecting from the front end thereof.
The runout accuracy of the lower die punch 3 with respect to the machining axis of the lathe is 0-
It can be secured within 1/1000 mm. Further, the powder compression molded body 10 can be easily aligned with the front end portion of the lower die punch 3 by the above-mentioned both marks and can be mounted almost in the same manner as during the compression molding. The accuracy of centering and mounting the fine holes 12 is remarkably improved, and the back relief 15 formed by turning with the cutting tool 18 is accurately formed coaxially with the fine holes 12.

When the lower die punch 3 and the periphery of the powder compression molded body 10 are closely fixed by a fixing tape (adhesive tape) 17, the coaxial precision of the back relief 15 with respect to the pores 12 is further enhanced, and FIG. As shown in (D), the tip portion of the projection 4 projecting from the front end portion (upper surface side) of the lower die punch 3 is appropriately cut and rounded to prevent contact with the tip portion of the cutting tool 18. To facilitate turning and fine holes 1
The extension accuracy with 2 can be improved. Preferably, the cutting edge dimension d of the cutting tool 18 is set to about 1 / 3D or less with respect to the diameter D of the pores 12.

[0011]

As described above, according to the present invention, a small convex portion of a mark is attached to the upper end portion of the lower die punch as described above, and the raw material powder is produced by the lower die punch and the upper die punch in the die. By compressing and forming into a powder compression molded product of wire drawing die chip, a small concave part of a mark is formed at one end of one surface of the powder compression molded product, and the lower die punch is centered on the lathe chuck. When it is mounted as a processing shaft, and the powder compression molded product is mounted on the lower die punch by aligning the powder compression molded product with the two marks, the lower die punch and the powder compression molded product's pores with respect to the lathe processing shaft are attached. Centering and mounting can be performed easily and accurately, and a back relief can be easily turned and formed on the powder compression molded product with high precision, so that not only the productivity but also the turning precision and reliability of the back relief are significantly improved.

[Brief description of drawings]

FIG. 1 is a sectional view (A) showing a compression step of the present invention.
(C) and a side-view mechanism diagram showing the turning process (D)

FIG. 2 is a side view mechanism diagram showing a turning process of a conventional example.

[Explanation of symbols]

 1 Raw material powder 2 Mold 3 Lower mold punch 5 Upper mold punch 7a Small convex portion (mark) 7b Small concave portion (mark) 10 Powder compression molded body 15 Back relief 16 Lathe check

Claims (1)

[Claims] 1. A wire for wire drawing by forming a small convex portion of a mark at the upper end of the lower die punch, and compression-molding the raw material powder in the die by the lower die punch and the upper die punch. After forming into a powder compression molded body of a die chip and forming a small recessed part at one end of the powder compression molded body, the lower die punch is centered and attached to the lathe chuck to form a machining axis. A back relief molding of a die die for wire drawing, characterized in that the powder compression molding is arranged and mounted on the die punch by the both marks, and a back relief is turned on the powder compression molding. Processing method.