JP3537367B2 - Milling tools - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a milling tool using diamond abrasive grains, and more particularly to a milling tool capable of simultaneously performing heavy grinding and finish grinding.

[0002]

2. Description of the Related Art Conventionally, as a milling tool for performing surface processing of a cast alloy, a ceramic compact, etc., a chip using a super-abrasive such as a diamond abrasive grain or a CBN abrasive together with a cemented carbide chip, or a grinding tool. A tool having a granular layer is used.

For example, Japanese Patent Publication No. 59-50449 discloses that a cutting edge made of polycrystalline diamond formed by sintering diamond powder under a high temperature and a high pressure is brazed to a cutting edge of a chip body as a cutting edge for finish cutting. A face milling cutter is described. According to this milling cutter, the life of the milling cutter can be greatly improved compared to a conventional milling cutter using only a carbide tip, and even if used for a long time, a good cutting surface can always be obtained as expected. I have.

Japanese Patent Application Laid-Open No. 61-265207 describes an electrodeposition milling tool in which diamond abrasive grains are adhered to a cutting edge portion by plating. According to this milling tool, it is said that the cutting efficiency of a fragile material can be improved.

By the way, in the surface processing of, for example, an aluminum casting alloy, there are portions that require both heavy grinding and finish grinding in relation to the shape and dimensions of the final product. In order to machine such a part, separate milling tools suitable for heavy grinding and finish grinding are used. The milling tool described in Japanese Patent Publication No. 59-50449 has excellent wear resistance and a long life because the cutting edge is made of a diamond sintered body, but is suitable for heavy grinding because the cutting edge is large. However, it is not suitable for finish grinding. The milling tool described in JP-A-61-265207 is suitable for finish grinding but not for heavy grinding since the cutting edge is an abrasive layer in which diamond abrasive grains are firmly fixed by electrodeposition. It is.

[0006] In heavy grinding and finish grinding, there is a grain size of the abrasive grains and an interval between the abrasive grains suitable for each of the machining. JP-B-59-50449 and JP-A-61-26
In the milling tool described in Japanese Patent No. 5207, since the grain size and spacing of the abrasive grains cannot be changed in one tool, the milling tool is necessarily a tool dedicated to either heavy grinding or finish grinding. Not get.

[0007]

On the other hand, concrete,
For heavy or finish grinding of hard materials such as rock, there are tools in which diamond abrasive grains are brazed to a substrate. For example, Japanese Unexamined Patent Publication No. Hei 6-210571 discloses a tool in which diamond abrasive grains are bonded by solder to a thickness-reduced region in which the thickness of a disk-shaped support is reduced toward the outer periphery. In this tool, the abrasive grains are arranged apart from each other by a predetermined pitch, and can be effectively used as a cutter disk and a groove milling mill.

However, in the case of this tool as well, since the size of the cutting edge made of abrasive grains is substantially uniform over the entire surface of the support, the action of the abrasive grains is either heavy grinding or finish grinding. A single tool cannot perform both heavy and finish grinding operations. That is, when the pitch of the abrasive grains is large, the abrasive grains act on heavy grinding, and as a result, processing accuracy is reduced. On the other hand, if the pitch of the abrasive grains is small, the abrasive grains act on the finish grinding, and as a result, the processing efficiency decreases.

An object of the present invention is to make it possible to simultaneously perform heavy grinding and finish grinding with one tool in a milling tool for machining an aluminum alloy, an aluminum composite material, or the like.

[0010]

A milling tool according to the present invention is a milling tool in which a cutting edge is formed on an end face of a cup-shaped base metal, wherein an inclined portion is formed at a portion near an outer peripheral portion of the end face, A hard material is attached to the inclined portion as a region for heavy grinding, and a super-abrasive such as a diamond abrasive or a CBN abrasive is provided for a flat portion on the end surface as a region for finish grinding.

In the milling tool of the present invention, the cutting edge is divided into a heavy grinding area and a finish grinding area, and a hard material is attached to the heavy grinding area under conditions suitable for heavy grinding, and the finishing is applied to the finish grinding area. By arranging the abrasive grains under conditions suitable for grinding, both heavy grinding and finish grinding can be performed simultaneously with one tool.

Here, as the hard material to be attached to the heavy grinding area, diamond abrasive grains or CBN abrasive grains are used.
Either a sintered body and a cemented carbide containing at least volume% alone or a mixture of both can be used. Heavy grinding requires characteristics such as a large cutting edge, high load and enduring impact, and the use of such a sintered body makes it possible to perform heavy grinding in which rough cutting is performed with a large cut.

[0013] 25 diamond abrasive grains or CBN abrasive grains
As a sintered body containing at least% by volume, for example,
A sintered body containing 0 to 70% by volume, 4 to 15% by volume of Co, and 25 to 75% by volume of diamond abrasive grains can be used. In order to manufacture these sintered bodies, it is possible to manufacture sintered bodies having excellent wear resistance by increasing the content of diamond abrasive grains and WC. As the cemented carbide, WC-Co, WC-TiC-Co, WC-T
Cemented carbide such as iC-TaC-Co can be used.

In order to attach the hard material to the inclined portion of the end face of the base metal, it is brazed directly to the surface of the inclined portion with an active metal brazing material, or a recess is formed at a predetermined position of the inclined portion and embedded. Can be attached.

In the finishing grinding area, the cutting edge is small.
Since properties such as obtaining a good processed surface are required, use super-abrasive grains such as diamond abrasive grains and CBN abrasive grains, for example, using abrasive grains having a small grain size, and reduce the arrangement intervals of the abrasive grains. For example, it is arranged under conditions suitable for finish grinding.

Specifically, the abrasive grain size is 0.1 to 0.3 m
m, and the intervals between the abrasive grains are preferably in the range of 4 to 8 times the grain diameter of the abrasive grains. If the abrasive grain size exceeds 0.3 mm, the bite will increase and the surface roughness will increase,
If it is less than m, the protrusion amount of the abrasive grains becomes small and the surface roughness also becomes large. If the spacing of the abrasive grains exceeds 8 times the grain diameter of the abrasive grains, the entire machined surface is not uniformly machined, resulting in poor surface roughness.
If the ratio is less than twice, the heat dissipation and the ability to discharge chips are deteriorated. In addition, it is desirable that the heights of the abrasive grains are made uniform so that the abrasive grains in the finish grinding area uniformly hit the processing surface. Height alignment is obtained by truing.

Whether the abrasive grains are arranged in one layer, two layers or three or more layers can be determined depending on the use of the milling tool. For example, one layer is suitable when emphasizing the machining surface, two layers are appropriate when both the machining surface accuracy and the tool life are required, and three or more layers when emphasizing the tool life. Are suitable. The brazing method can be performed by a conventionally known method.
It is fixed using a brazing filler metal containing an active metal such as a or V, or a self-fluxing alloy such as a Ni—Cr alloy.

The milling tool according to the present invention is manufactured by, for example, the following steps. -An inclined portion is formed in a portion near the outer peripheral portion of the end face of the base metal. -A concave portion is formed at a predetermined position on the inclined portion. Fill the recess with an active metal-containing brazing material.・ Embed a hard material. A paste-like silver brazing material containing titanium is applied to the flat portion of the end face of the base metal, and diamond abrasive grains having a particle diameter of 250 μm are applied to 1.8.
They are arranged at mm intervals. -Heat in a non-oxidizing atmosphere to fix diamond abrasive grains on the base metal.・ True is applied to the flat part to make the height of the abrasive grains in the flat part uniform.

[0019]

FIG. 1 is a perspective view showing a milling tool according to an embodiment of the present invention, and FIG. 2 is an enlarged sectional view of a cutting edge of the milling tool shown in FIG.

The milling tool 10 includes a cup-shaped base 11
An inclined portion 12 is formed in a portion of the end face near the outer peripheral portion, a hard material 14 is attached with the inclined portion 12 as an area 13 for heavy grinding, and a flat portion 15 on the end face is used as an area 16 for finish grinding, suitable for finish grinding. The diamond abrasive grains 17 are provided.

The base metal 11 is a steel base metal having a short overall cylindrical shape, and has a mounting hole 11a at the center of the bottom for mounting on a rotating shaft of a power tool. The dimensions of each part of the tool are 100 mm outside diameter and 78 m inside diameter of the base metal 11.
m, the width of the inclined part 12 is 5 mm, and the inclination angle of the inclined part 12 is 20
Degree, flat part 15 width 6 mm, base metal 11 overall height 50 m
m.

On the inclined portion 12 of the heavy grinding area 13, a diamond material 50
Eight chips of a mixed sintered body of 30% by volume, 48% by volume of WC, and 2% by volume of Co are attached at equal intervals in the circumferential direction, and one diamond abrasive 17 having a particle size of 250 μm They are arranged at intervals of 0.8 mm and are fixed with a Ti-containing brazing material.

As described above, the milling tool 10 includes a heavy grinding area 13 to which a hard material 14 suitable for heavy grinding is attached,
Since the edge portion is composed of the finish grinding area 16 in which diamond abrasive grains are arranged under conditions suitable for the finish grinding,
One tool can perform both heavy grinding and finish grinding simultaneously. For example, as shown in FIG. 3, in the surface processing of the aluminum casting alloy 20, the milling tool 10 is fed to the left in the drawing while rotating, so that the surface of the aluminum casting alloy 20 is deeply removed in the heavy grinding area 13. Then, the surface is finish-ground in the finish grinding area 16.

[0024]

EXAMPLE A milling tool (invention) of the present embodiment and a milling tool in which the basic shape of a base metal is the same as in FIG. 1 and diamond abrasive grains are fixed to both inclined and flat portions by electrodeposition (comparative product) ) And a milling tool with a diamond sintered compact tip (conventional product) were subjected to a grinding test. [Test conditions] Machine used: Okuma Vertical shaft milling machine Rotation speed: 8000 min ^-1 Cutting depth: 3.0 mm / pass Work material: Aluminum die-cast alloy (ADC-40)

[Test Results] Table 1 shows power consumption, tool durability and surface roughness of the ground surface, which are indicators of the grinding ability.

[Table 1] The power consumption and tool durability are indicated by indices when the conventional product is set to 100.

As can be seen from Table 1, the power consumption of the invention product is reduced by 10 to 36% and the durability is 1.1 to 2.7 times as compared with the comparison product and the conventional product, and the grinding ability and tool life are excellent. ing. Also, the roughness of the finished ground surface is small, and the processing accuracy is excellent. In this test, the depth of cut was set in accordance with the comparative product for finish grinding. However, in the case of the invention product, since the depth of cut can be actually increased because it is also used for heavy grinding, overall The grinding ability will be even higher.

FIG. 4 is a graph showing the power consumption and surface roughness of each tool when the feed speed per rotation is changed. In the drawing, the solid line represents power consumption, and the broken line represents surface roughness. As can be seen from the figure, the invention product showed good results in power consumption and surface roughness at any feed speed.

[0028]

According to the present invention, the following effects can be obtained.

(1) The cutting edge is divided into an area for heavy grinding and an area for finish grinding, and a hard material is attached to the area for heavy grinding under conditions suitable for heavy grinding. By disposing the abrasive grains under the conditions, both heavy grinding and finish grinding can be performed simultaneously with one tool.

(2) As a hard material to be attached to the heavy grinding area, either a sintered body containing diamond abrasive grains or CBN abrasive grains in an amount of 25% by volume or more and a cemented carbide or a mixture of both are used. Heavy grinding with a large cutting depth can be performed.

(3) By setting the grain size of the abrasive grains in the finish grinding area and the arrangement interval in a specific range, a good surface roughness can be obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a milling tool according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a cutting edge of the milling tool of FIG. 1;

FIG. 3 is a diagram showing a use state of the milling tool of FIG. 1;

FIG. 4 is a graph showing a grinding test result.

[Explanation of symbols]

10 Milling tools 11 base 11a Mounting hole 12 Slope 13 Area for heavy grinding 14 Hard material 15 Flat part 16 Finish grinding area 17 diamond abrasive 20 Aluminum casting alloy

Continuation of the front page (56) References JP-A-3-202276 (JP, A) JP-A-52-121890 (JP, A) JP-A-2000-326234 (JP, A) JP-A-2001-79772 (JP, A) 6-42064 (JP, U) 61-92509 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) B23C 5/06 B24D 3/00 320

Claims (2)

(57) [Claims] 1. A milling tool in which a cutting edge is formed on an end surface of a cup-shaped base metal, wherein an inclined portion is formed near an outer peripheral portion of the end surface, and the inclined portion is used as a heavy grinding area .
Contains 25% by volume or more of diamond abrasive grains or CBN abrasive grains
One or a mixture of both
A milling tool in which united hard materials are attached at intervals, and super-abrasive grains such as diamond abrasive grains and CBN abrasive grains are disposed using the flat portion of the end face as a region for finish grinding. 2. The abrasive grain size of the superabrasive grains provided in the finish grinding area is in the range of 0.1 to 0.3 mm, and the spacing between the abrasive grains is 4 to 8 times the abrasive grain size. The milling tool according to claim 1, wherein