JPH08260006A - Method for manufacturing drill and device therefor - Google Patents

Abstract

PURPOSE: To provide a manufacturing method of a drill capable of reducing the number of processes for manufacturing the drill and reducing the manufacturing time and the manufacturing cost without causing the deformation and deterioration in strength of the drill, and to provide a manufacturing device thereof. CONSTITUTION: A cavity 36 of a die 34 is demarcated of a shank part 38 and a edge part 40, and is provided with an upper punch 46 freely insertible into the shank part 38 and a lower punch 28 having the same shape of screw grooves 30a, 30b as that of the groove part of the drill. Uniaxial pressure formation is applied to the granular raw material in the cavity 36 under descending action of the upper punch 46 to form a preform. The lower punch 28 is inserted into the edge part 40 in the cavity 36 while being rotated to be matched with the pinch of the drill to separate the preform from the die.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drill manufacturing method and a manufacturing apparatus for manufacturing the drill by uniaxial pressure molding. More specifically, the present invention relates to a drill manufacturing method for simultaneously forming a drill blade portion and a shank portion. And a manufacturing apparatus thereof.

[0002]

2. Description of the Related Art Conventionally, as disclosed in Japanese Patent Laid-Open No. 2-4905, a conventional method for manufacturing a drill is to form a spiral blade portion by an extrusion molding method, sinter it, and then form a shank portion. In order to do so, a method has been proposed in which a part of the groove portion of the blade portion is filled with a metal powder material, which is pressed and sintered. At this time, by molding so as to leave holes in the powder layer of the shank portion, the difference in the thermal contraction rate between the blade portion and the shank portion is absorbed, and the occurrence of cracks or the like in the sintering process is prevented. There is.

[0003]

However, in the above-described conventional method for manufacturing a drill, the step of extruding the blade portion, the step of sintering the blade portion, the step of filling the groove portion with the granular material, and the shank. A large number of steps are required, such as a step of press-molding the portion and a step of sintering the shank portion. For this reason,
The manufacturing time was long and the manufacturing cost could not be reduced. Also, a large amount of binder is required to maintain the shape of the extruded blade. For this reason, there is a concern that the drill may be deformed during sintering or the strength of the drill after sintering may be reduced, and thus a step of removing the binder was required before sintering. Furthermore, during the step of filling the groove portion of the blade portion with the granular material, it is difficult to uniformly fill the granular material along the complicated shape of the groove portion, and the density of the granular material becomes uneven. However, there is a concern that the strength of the drill after sintering may decrease.

The present invention has been made in order to overcome the above problems, and it is possible to reduce the manufacturing time and manufacturing cost by reducing the manufacturing process of the drill, and also to prevent deformation and strength reduction of the drill. An object of the present invention is to provide a drill manufacturing method and a manufacturing apparatus for the drill, which eliminates concerns.

[0005]

In order to achieve the above-mentioned object, the present invention is a method for manufacturing a drill in which a drill is formed by uniaxial pressure forming, in which raw materials in the form of powder or granules are used in the mold cavity. And a second step of forming a preform having a blade portion and a shank portion of a drill by performing uniaxial pressure forming on the raw material under the displacement action of the first punch. And a third step of inserting the second punch into the mold while rotating according to the pitch of the drill, and releasing the preform from the mold, and sintering the preform. And a fourth step of obtaining a formed body of the drill.

In this case, the method has a step of forming a thin film on the surface of the preform taken out in the third step.

Further, the present invention is a drill manufacturing apparatus for forming a drill by uniaxial pressure forming, comprising a mold having cavities defined corresponding to the shapes of a blade portion and a shank portion of the drill, and A first punch insertable in the shank portion of the cavity and a second punch having a spiral groove of the same shape as the drill are provided, and the second punch rotates on the blade portion of the cavity according to the pitch of the drill. It is characterized by inserting while.

In this case, a spiral wire rod and / or a spiral pipe, which is disposed inside the cavity and is held by the first punch and the second punch, is provided.

Further, a spraying means is provided above the mold, and a material for forming a thin film is sprayed onto the preformed body immediately after being pulled out from the mold by the spraying means.

[0010]

According to the present invention, the preform having the drill blade and shank integrated with each other can be easily formed by uniaxial pressure forming, and the preform is formed by forming a thin film on the preform. The shape of the body is retained, it can be prevented from collapsing or breaking, and a binder is not required. As a result, it is possible to obtain a drill in which the blade and the shank are integrated by sintering the preform. Therefore, the step of separately molding the shank portion is not required, and the drill can be manufactured by omitting some steps as compared with the conventional technique.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A drill manufacturing method according to the present invention will be described in detail below with reference to the accompanying drawings, with reference to preferred embodiments in relation to an apparatus for carrying out the method.

FIG. 1 is a sectional view of a drill manufacturing apparatus according to this embodiment, FIG. 2 is a perspective view of a first bevel gear of the drill manufacturing apparatus of FIG. 1, and FIGS. 3 to 5 are drill manufacturing of FIG. It is sectional drawing explaining the usage method of an apparatus.

In FIG. 1, reference numeral 10 indicates a drill manufacturing apparatus according to this embodiment. This drill manufacturing device 10
A base plate 16 having a hole 14 defined therein is fixed to the upper surface of a plate-shaped base 12. At the top of the hole 14, the first
Of the first bevel gear 18 is rotatably provided.
A second bevel gear 20 meshes with the motor, and a motor 22 is axially attached to the second bevel gear 20. A hole portion 24 is defined at the center of the first bevel gear 18, and convex portions 26a and 26b are provided on the inner wall that defines the hole portion 24 (see FIG. 2). The hole 2
4, a lower punch 28 is inserted, and spiral grooves 30a and 30b having the same shape as the blade portion of the drill are defined in the lower punch 28. The spiral grooves 30a and 30b have the convex portions 26a,
When the first bevel gear 18 is rotated, the spiral grooves 30a and 30b and the convex portions 26a and 26b convert the rotational movement into linear movement, and the lower punch 28 is displaced in the vertical direction. On the upper surface of the lower punch 28, holes 32a and 32b are defined along the axial direction of the lower punch 28. The upper end of the lower punch 28 has the cavity 3 of the mold 34.
6 is inserted. The upper portion of the cavity 36 is provided with a shank portion 38 for forming a shank of a drill, and the lower portion of the cavity 36 is provided with a blade portion 40 for forming a blade of a drill. The blade portion 40 is provided with spiral convex portions 42a and 42b for forming the groove of the blade, and the spiral grooves 30a and 30b of the lower punch 28 are slidably engaged with the convex portions 42a and 42b. . The mold 34 is supported by columns 44a and 44b, and the columns 44a and 44b are fixed to the upper portion of the base plate 16. An upper punch 46 that is displaced relative to the cavity 36 is provided above the cavity 36.
It is configured to be freely inserted into the shank portion 38. On the lower surface of the upper punch 46, holes 48a and 48b are defined along the axial direction of the upper punch 46.

The drill manufacturing apparatus 10 according to this embodiment is basically constructed as described above, and its operation will be described below in connection with the drill manufacturing method according to this embodiment. .

First, the lower punch 28 is inserted into the lower end of the blade portion 40 of the cavity 36 by a predetermined length (see FIG. 3). Then, inside the cavities 36, the spiral wire rods 50a, 50
b is provided, and the lower ends of the wire rods 50a and 50b are inserted into the hole portions 32a and 32b of the lower punch 28. This wire 50a, 5
0b is a rod made of iron, copper, or cobalt and its alloy having a diameter of 1.5 mm, and the spiral pitch of the wire rods 50a and 50b is the same as that of the drill.

At that time, as a raw material corresponding to JIS K-10, a powdery or granular material 10 composed of 92% by weight of tungsten carbide, 6% by weight of cobalt, and 2% by weight of tantalum carbide was previously prepared.
20 g of ethyl alcohol was added to 0 g, and the mixture was wet-mixed in a ball mill for 24 hours, and after mixing, the obtained granular material 1
A raw material is prepared in which the amount of ethyl alcohol is adjusted to 5 g with respect to 00 g, and 0.2 g of ammonium stearate is added as a lubricant to 100 g of the granular material and mixed. The raw material prepared in this manner is used as a mold 34.
The cavities 36 are filled.

Next, the upper ends of the wire rods 50a and 50b are inserted into the hole portions 48a and 48b of the upper punch 46, and the raw material in the cavity 36 is uniaxially pressure-molded by the lowering action of the upper punch 46, and the blade of the drill. A preformed body 52 in which the portion and the shank portion are integrally formed is obtained (see FIG. 4).

Next, when the motor 22 is energized, the second bevel gear 20 rotates, and the rotational movement thereof is transmitted to the first bevel gear 18. Then, the convex portions 26a and 26b and the spiral groove 30a,
The rotary motion is converted into a linear motion by 30b, and the lower punch 28 rises. Therefore, the lower punch 28 is inserted into the blade portion 40 of the cavity 36. At this time, the spiral grooves 30a and 30b of the lower punch 28 slide on the spiral convex portions 42a and 42b of the blade portion 40, and the lower punch 28 moves to the cavity 3
It is inserted in the inside of 6 while rotating. As a result, the preform 52 in the cavity 36 is pressed by the lower punch 28 and pushed out from the upper opening of the cavity 36, and the preform 52 is released from the mold 34 (see FIG. 5). At this time, if the lower punch 28 is inserted into the cavity 36 while pulling up the upper ends of the wire rods 50a and 50b, the preform 52 can be easily taken out.

At this time, it is preferable to spray the thin film forming agent onto the preformed body 52 by the sprayer 54 while extruding the preformed body 52. This thin film forming agent is nitrocellulose 2
% By weight, 5% by weight of ethyl cellosolve, 5 butyl benzoate
%, Ethyl alcohol 10% by weight, acetone 78% by weight. As a result, a thin film is formed on the surface of the preform 52, and it is possible to prevent the shape of the preform 52 from being destroyed or broken even when the preform 52 is dried. Therefore, the preform is formed without using a binder. The shape of the body 52 can be maintained.

Next, the wire rods 50a and 50b are attached to the preform 5.
Pull out from 2. Since the holes after the wire rods 50a and 50b are pulled out remain in the preform 52, the holes become oil holes for supplying the cutting oil of the completed drill.

Then, the preform 52 is dried,
Furthermore, a drill is completed through a sintering process.

In this embodiment, wire rods 50a and 50b formed of metal rods are used, and after uniaxial pressure molding, the wire rods 50a and 50b are pulled out to define an oil hole. At this time, if a metal pipe is used instead of the wire rods 50a and 50b to form a drill, and the pipe protruding from the drill is cut after uniaxial pressure molding or after sintering,
The inner wall of the pipe becomes an oil hole. In addition, when forming a drill without oil holes, the metal rod wire 5
0a, 50b is used to form a drill, and the wire rod 50a protruding from the drill after uniaxial pressure forming or after sintering,
Cut 50b. Alternatively, the drill may be formed without using the wire rods 50a and 50b.

[0023]

According to the drill manufacturing method and the manufacturing apparatus thereof according to the present invention, the following effects can be obtained.

Since the drill in which the blade portion and the shank portion are integrated can be manufactured in a small number of steps, the manufacturing time can be reduced, the manufacturing cost can be reduced, and the production efficiency can be improved. Further, since a thin film is formed on the surface of the preform, it is possible to maintain the shape of the preform without using a binder, wipe off the fear of deformation and strength reduction of the drill, and improve the strength. It is possible to manufacture excellent high quality drills.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a drill manufacturing apparatus according to this embodiment.

2 is a perspective view of a first bevel gear of the drill manufacturing apparatus of FIG. 1. FIG.

FIG. 3 is a cross-sectional view illustrating a drill manufacturing method using the drill manufacturing apparatus of FIG.

FIG. 4 is a cross-sectional view illustrating a drill manufacturing method using the drill manufacturing apparatus of FIG.

5 is a cross-sectional view illustrating a method of manufacturing a drill using the drill manufacturing apparatus of FIG.

[Explanation of symbols]

10 ... Drill manufacturing device 18, 20 ... Bevel gear 28 ... Lower punch 30a, 30b ... Spiral groove 36 ... Cavity 38 ... Shank part 40 ... Blade part 42a, 42b ... Convex part 46 ... Upper punch

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mitsuo Kuwahara 1-10-1 Shin-Sayama, Sayama-shi, Saitama Honda Engineering Co., Ltd.

Claims (6)

[Claims] 1. A method of manufacturing a drill for forming a drill by uniaxial pressure forming, comprising: a first step of filling powdery raw material into a cavity of a mold; and a displacement action of a first punch. Uniaxial pressure molding is performed on the raw material to form a preform having a drill blade portion and a shank portion, and the second punch is rotated according to the pitch of the drill. A third step of inserting the preform into a mold and releasing the preform from the mold; and a fourth step of sintering the preform to obtain a drill compact. Manufacturing method of the drill. 2. The method for manufacturing a drill according to claim 1, further comprising the step of forming a thin film on the surface of the preform taken out in the third step. 3. A drill manufacturing apparatus for forming a drill by uniaxial pressure molding, comprising a mold having cavities defined corresponding to the shapes of a blade portion and a shank portion of the drill, and a shank portion of the cavity. A second punch having a spiral groove having the same shape as the drill, and the second punch is inserted into the blade portion of the cavity while rotating according to the pitch of the drill. A drill manufacturing device characterized by the above. 4. The drill manufacturing apparatus according to claim 3, further comprising a spiral wire rod disposed inside the cavity and held by the first punch and the second punch. Drill manufacturing equipment. 5. The drill manufacturing apparatus according to claim 3, further comprising a spiral pipe arranged inside the cavity and held by the first punch and the second punch. Drill manufacturing equipment. 6. The drill manufacturing apparatus according to claim 3, wherein a spraying unit is provided above the mold, and the preform immediately after being pulled out from the mold by the spraying unit. A drill manufacturing apparatus, characterized in that a material for forming a thin film is sprayed onto the drill.