KR20180076029A - Milling cutter having wedge type blade - Google Patents

Abstract

Disclosed is a milling cutter having a wedge type blade, preventing a poor process caused by position variation or shaking of a blade coming in contact with multi-face of a pocket and fixed on the multi-face. The milling cutter comprises: a cartridge; and a blade mounted on a pocket formed on a side surface of the cartridge. Moreover, the blade comes in contact with both lateral surfaces of the pocket and having a column shape. Furthermore, the both lateral surfaces of the blade have a wedge shape having a width getting narrower to the center-point direction while coupled to the cartridge by a fastening screw. Accordingly, a poor process caused by position variation and shaking of the blade can be prevented.

Description

Technical Field [0001] The present invention relates to a milling cutter having a wedge-

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a milling cutter, and more particularly, to a milling cutter in which a blade is held firmly fixed to a cartridge in a process of mounting a wedge-shaped blade to machine a workpiece.

A milling cutter is a cutting tool having a plurality of blades on the outer circumference or cross section of a cylindrical or conical body. The material, shape and machining technology of the milling cutter have been continuously developed, and the machining precision for the workpiece has been increased and the production efficiency has been improved, and the milling cutter has been widely and widely applied. The blade of the milling cutter is fixed in contact with one or more faces of the pocket. Most of the one surface is in contact with either the top surface or the side surface of the pocket. In the multifaceted case, it is fixed to the cartridge in such a manner as to be inserted into and fastened to the multi-side of the pocket, and is fastened to the front face, for example, a face connected to the side face of the pocket. Blades that contact multiple faces of the pocket are described in detail in U.S. Patent Publication No. 2014-0003872.

On the other hand, the blade mounted on the milling cutter is subjected to a force applied in a radially outward direction by centrifugal force due to high-speed rotation. This centrifugal force acts as a force to push the blade away from the pocket of the milling cutter, affecting the feed and cutting depth of the cutting tip and causing the positional variation of the blade in the pocket. In addition, the blades may cause blade shake due to the working load generated during machining of the workpiece, and the quality of the workpiece may be deteriorated. For this reason, a method of fixing the blade in contact with the multiple faces of the pocket is preferred. Nevertheless, it is difficult to prevent processing defects due to fluctuations in the position of the blades or shaking, so that methods such as adding additional fixing means have been proposed. However, the blades which are still in contact with the multi-faces of the pocket are not fixed in a stable manner, so that they are not firmly held in the process of machining the workpiece, resulting in defective machining.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a milling cutter equipped with a wedge-shaped blade for blocking processing defects due to positional fluctuations or shaking of blades which are brought into contact with and fixed to multiple faces of a pocket.

SUMMARY OF THE INVENTION [0008] In order to solve the problems of the present invention, a milling cutter equipped with a blocking wedge-shaped blade includes a cartridge and a blade mounted on a pocket formed on the side surface of the cartridge. At this time, the blade comes in contact with both sides of the pocket and is in the form of a column, and both side surfaces of the blade are wedge-shaped in the direction of the center point of the cartridge and are coupled to the cartridge by a fastening screw.

In the cutter of the present invention, the blade has a ridge between both sides, and the ridge forms a gap (G) with a front surface existing between both sides of the pocket. Both sides of the pocket form a contact angle?, And the contact angle? May be 90 degrees or more and less than 180 degrees. As the contact angle? Increases, the contact area between both sides of the pocket and both side surfaces of the blade becomes large. The triangle formed by both side surfaces of the pocket and the side surface of the cartridge is preferably an isosceles triangle.

In the preferred cutter of the present invention, one side of the blade may include a second chip discharge groove for discharging chips generated during the cutting of the workpiece. And a cutting tip for cutting the workpiece may be attached to one side of the second chip discharge groove. And a height adjusting screw for adjusting a height of the blade in a lower portion of the blade in the pocket.

In the preferred cutter of the present invention, the pockets are different in distance from the center point according to roughing, centering and finishing, and the distance between the pocket and the center point may become smaller as the roughing, the centering and finishing are performed. The height at which the blade protrudes from the cartridge may become larger as the roughing, the medium cutting, and the finishing. It is preferable that the first to third pockets have the largest number of the first pockets and the smallest number of the third pockets.

According to the milling cutter equipped with the wedge-shaped blades of the present invention, the wedge-shaped blades are fixed to the pockets, so that the machining failure due to the fluctuation of the positions of the blades fixed by contact with the multi- .

1 is a perspective view showing a milling cutter equipped with a wedge-shaped blade according to the present invention.
2 is a cross-sectional view taken along the line II-II in FIG.
3 is a plan view for explaining a modification of a milling cutter equipped with a wedge-shaped blade according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The embodiments described below can be modified into various other forms, and the scope of the present invention is not limited to the embodiments described below. The embodiments of the present invention are provided to enable those skilled in the art to more fully understand the present invention. Terms pointing to positions, such as top, bottom, front, etc., are only relevant to those shown in the figures. In practice, the blades are used in any optional orientation, and the spatial orientation in actual use varies with the direction and rotation of the milling cutter.

The embodiment of the present invention proposes a milling cutter for cutting off the defective machining due to the fluctuation of position of the blade fixed or contacting with the multi-sided surface of the pocket by fixing the wedge-shaped blade to the pocket. To this end, a detailed description will be given of the structure of a milling cutter in which a wedge-shaped blade is fixed to a pocket, and a process for blocking a machining defect due to fluctuation of position of the blade or shaking or the like will be described in detail. In a typical milling cutter, the blades are secured to the cartridge in a variety of ways, such as being fastened on one side, such as the side or top of the pocket, or fastened on multiple sides of the pocket. Embodiments of the present invention are limited in such a way that they are held in contact with the multiple faces of the pocket. Here, the polyhedron means at least two faces among the faces forming the pocket.

1 is a perspective view showing a milling cutter 100 equipped with a wedge-shaped blade according to an embodiment of the present invention. 2 is a cross-sectional view taken along line II-II in FIG. The structure of the milling cutter 100 shown herein may further include elements that add other functions within the scope of the present invention.

Referring to FIGS. 1 and 2, a milling cutter 100 includes a cartridge 10, a cooling module 20, and a blade 30. The cartridge 10 is cylindrical in radius R and constitutes a cartridge body 11 made of a material such as aluminum, titanium or steel. The cartridge 10 may include a first chip discharge groove 12 for discharging a chip generated during cutting of a workpiece. The first chip discharge groove 12 is a part of the cartridge side surface 14 is removed. The cooling module 20 includes a cooling water flow path 22 between the screw neck 21 and the screw neck 21 and the cartridge 10 and supplies cooling water to the blade 30 through the cooling water flow path 22 . The manner of supplying the cooling water is not limited to that shown in the present invention, and various methods can be applied.

There are a plurality of pockets 13 in the cartridge side 14 along the circumference to receive and secure the wedge-shaped blades 30. The pocket 13 has at least three sides. Concretely, the front face 13b of the pocket is formed between both sides 13a and 13c and both sides 13a and 13c of the pocket where the width becomes narrower toward the cartridge center point CP. Here, the front face 13b of the pocket is a face facing the cartridge 10 when the cartridge 10 is viewed from the circumference toward the center point CP. The blade 30 contacts both sides 13a and 13c of the pocket and is spaced apart from the front face 13b by the gap G. [ As described above, it can be said that the manner in which the blade 30 is held in contact with both side surfaces 13a and 13c of the pocket is fixed in contact with the multiple surfaces of the pocket.

The blade 30 partially protrudes outside the cartridge 10 and includes a fastening hole 34 into which the blade body 31, the second chip discharge groove 33 and the fastening screw 35 are inserted. The blade body 31 is in the form of a column and has ridges 31b of the body facing both sides 31a and 31c of the body contacting the both sides 13a and 13c of the pocket and a front face 13b of the pocket. . Both side surfaces 31a and 31c of the body are tapered in a manner that their width becomes narrower toward the center point CP. Accordingly, the cross section of the blade 30 becomes a wedge shape. As the blades 30 are brought into close contact with the pockets 13 by the fastening screws 35, both side surfaces 31a and 31c of the body are tapered on both sides 13a and 13b of the pockets, 13c.

The blades 30 of the milling cutter 100 of the present invention are fixed in a tapered manner, thereby making it possible to prevent machining defects due to fluctuations in the position of the blades 30 or shaking. Specifically, the blade mounted on a general milling cutter is subjected to a force exerted radially outwardly by centrifugal force due to high-speed rotation. This centrifugal force acts as a force to push the blade away from the pocket of the milling cutter, affecting the feed and cutting depth of the cutting tip and causing the positional variation of the blade in the pocket. Further, the blades may be shaken due to the machining load generated during machining of the workpiece, and the quality of the workpiece may be deteriorated.

Since the blade 30 according to the embodiment of the present invention is firmly fixed to the pocket 13, it is possible to prevent machining defects occurring in the conventional milling cutter. Both side surfaces 13a and 13b of the pocket form a contact angle?. The contact angle? Is determined in consideration of the size of the milling cutter 100, the kind of the workpiece, the shape of the cutting tip 32, and the like according to the embodiment of the present invention. The contact angle θ is determined within a range of 90 degrees or more and smaller than 180 degrees and the contact area between both sides 31a and 31c of the blade and both sides 13a and 13c of the pocket becomes The smaller the contact area becomes, the smaller the contact area becomes. The contact area induces a uniform dispersion of the force to which the blade 30 is fixed, thereby minimizing the fluctuation of the position of the blade 30, shaking, and the like, thereby preventing machining failure. Preferably, the triangle is an isosceles triangle, considering the triangle consisting of both sides 13a, 13c of the pocket and the side 14 of the cartridge.

The blade 30 is recessed with a second chip discharge groove 33 for discharging a chip generated in the process of cutting the workpiece. The second chip discharge groove 33 is open to the outside of the blade 30 and is attached to the cutting tip 32 on one side. The cutting tip 32 is in the shape of a plate and has an abrasive layer with abrasive particles such as diamond adhered on the end thereof and is soldered or bonded to the one side surface. The second chip discharge groove 33 communicates with the first chip discharge groove 12 formed in the cartridge 10 and the chip discharged through the cutting process is connected to the first and second chip discharge grooves 12, And is discharged to the outside of the milling cutter 100 together with the cooling water.

A method of fixing the blade (30) to the pocket (13) is as follows. First, the blade 30 is aligned with the pocket 13, and the fastening screw 35 is inserted into the fastening hole 34. The blade 30 is mounted on the pocket 13 by rotating the fastening screw 35 by a predetermined degree. At this time, the gap G between the front face 13b of the pocket and the ridge 31b of the blade provides a tightening margin. That is, the gap G absorbs impact generated during the fastening of the blade 30, and helps to achieve more precise mounting. If the gap G does not exist and the ridge 31b of the blade touches the front face 13b of the pocket, the fastening screw 35 can not be further rotated, which makes it difficult to mount the blade 30 precisely. It is preferable that the front face 13b is rounded in order to sufficiently maintain the distance from the ridge 31b of the blade.

The pocket 13 under the blade 30 includes a space in which the adjusting screw 40 for adjusting the height of the blade 30 is to be mounted. Here, the height refers to the degree to which the blade 30 protrudes from the upper surface of the cartridge 10. The height adjusting screw (40) includes a plurality of adjusting grooves (41). When a tool such as a stick is inserted into the adjusting groove 41 and the adjusting screw 40 is rotated, the blade 30 moves up and down. Since the method of adjusting the height of the blade 30 is known in the art, detailed description thereof will be omitted here.

3 is a plan view for explaining a modification of the milling cutter 100 equipped with the wedge-shaped blades according to the embodiment of the present invention. At this time, the milling cutter 100 is as described with reference to FIG. 1 and FIG. 2, and a detailed description of the overlapping portions will be omitted.

Referring to FIG. 3, the milling cutter 100 of the present invention can realize roughing, medium cutting, and finishing. The cutting of the workpiece by the milling cutter usually proceeds in the order of rough cutting, semi-finishing cutting and finishing cutting. However, the conventional milling cutter is provided with a cutter for performing the roughing, the medium cutting or the finishing process separately. As described above, when the milling cutters are different from each other and the workpiece is cut using the same, it is necessary to change the cutter every roughing, medium cutting or finishing. When the milling cutter is exchanged, a separate time is required for exchanging and setting the milling cutter, and there is a problem that a place for storing the milling cutter is required.

The distance between the center point CP and the pocket 13 is adjusted in the milling cutter 100 according to the modification of the present invention. Specifically, the first pocket 13a for roughing is located at a first distance L1 from the center point CP, the second pocket 13b for medium cutting is located at the second distance L2, And the third pocket 13c is located at the third distance L3. At this time, the first to third distances L1, L2, and L3 have a difference of 1 mm, for example. In other words, the first distance L1 for roughing is the largest, and the third distance L3 for finishing is the smallest. The first to third distances L1, L2 and L3 are different from each other and the distance is short in the order of the first distance L1, the second distance L2 and the third distance L3 for roughing, When cutting a workpiece on the ground, roughing occurs first, followed by mid-cutting, and finally finishing. Accordingly, the first milling cutter 100 can perform roughing, medium cutting, and finishing at once.

The heights H1, H2 and H3 of the respective blades 30 can be adjusted in accordance with the first to third distances L1, L2 and L3. For example, the height H1 of the blade 30 of the first pocket 13a is the lowest and the height H3 of the blade 30 of the third pocket 13c is the highest. The first to third pockets 13a, 13b, and 13c are appropriately combined in a condition that they are not located adjacent to each other. That is, the second or third pockets 13b and 13c are located on the sides of the first pockets 13a, the first or third pockets 13a and 13c are located on the sides of the second pockets 13b, The first or second pockets 13a and 13b are located beside the three pockets 13c. At this time, it is preferable that at least two or more of the first to third pockets 13a, 13b, and 13c are disposed. The arrangement of the first to third pockets 13a, 13b, and 13c is for smoothly performing roughing, medium cutting, and finishing, which will be described below.

The first pocket 13a on which the blade 30 of the first height H1 is mounted, the second pocket 13b on which the blade 30 of the second height H2 is mounted, and the blade of the third height H3, It is preferable that the number of the third pockets 13c on which the first pockets 30 are mounted is not uniform. That is, the number of the first pockets 13a is the largest, the number of the second pockets 13b is the next, and the number of the third pockets 13c is the smallest. This is because, in the process of cutting the workpiece, the roughing reduces the thickness of the workpiece while flattening the surface, and the roughing and finishing serve to form the surface roughness. In the case of finishing, since the surface roughness is relatively small, a smaller number of blades 30 are applied than in the case of the middle cutting.

As an example of cutting the workpiece using the embodiment of the present invention, the cartridge body 11 has a diameter of 250 mm, a rotation speed of 7,500 rpm and a movement speed of 6,000 mm / min, and the number of blades 30 is 21 . At this time, the number of blades 30 mounted on the first pocket 13a is 11, the number of blades 30 on the second pocket 13b is 7, and the number of blades 30 on the third pocket 13c is three .

The roughing smoothes the surface of the blade 30 of the optional first pocket 13a while reducing the thickness of the workpiece. At this time, since the first milling cutter 100 moves at a moving speed of 6,000 mm / min while rotating at a rotating speed of 7,500 rpm, the middle pocket is formed in the second pocket 13b adjacent to the blade 30 of any first pocket 13a, Not the blade 30 of the first pocket 13a but the blade 30 of the second pocket 13b that is not adjacent to the blade 30 of the first pocket 13a. The finishing is not performed by the blade 30 of the third pocket 13c adjacent to the blade 30 of the second pocket 13b but also by the blade 30 of the second pocket 13b And is embodied as a blade 30 of the third pocket 13c which is not adjacent. The process of roughing, centering, and finishing as described above depends on the rotational speed and the moving speed of the first milling cutter 100.

In some cases, the milling cutter 100 according to the embodiment of the present invention implements roughing and finishing, and the middle cutting can be selectively implemented. This is determined in consideration of the degree of processing of the workpiece. The drawings are merely examples that can implement both roughing, centering, and finishing.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but many variations and modifications may be made without departing from the spirit and scope of the invention. It is possible.

10; A cartridge 11; Cartridge body
12, 33; The first and second chip discharge grooves
13; Pocket 20; Cooling module
21; Screw neck 22; Cooling water flow path
30; Blade 31; Blade body
32; Cutting tip 34; Fastening hole
35; Fastening screws 40; Height adjustment screw
41; Adjusting groove
100; Milling cutter

Claims (11)

cartridge; And
And a blade mounted on a pocket formed in the side surface of the cartridge,
The blade
Wherein the cartridge is in the form of a wedge which contacts both sides of the pocket and is in the form of a column and both sides of the blade are narrowed toward the center of the cartridge and are coupled to the cartridge by a fastening screw Milling cutter with blade. 2. The milling machine according to claim 1, wherein the blade has a ridge between both sides, and the ridge forms a gap (G) with a front surface existing between both sides of the pocket. cutter. The milling cutter as set forth in claim 1, wherein both sides of the pocket form a contact angle (?), And the contact angle (?) Is 90 degrees or more and less than 180 degrees. 4. The milling cutter according to claim 3, wherein when the contact angle (?) Increases, a contact area between both sides of the pocket and both side surfaces of the blade is increased. 2. The milling cutter as set forth in claim 1, wherein the triangle consisting of both sides of the pocket and the side of the cartridge is an isosceles triangle. The milling cutter as set forth in claim 1, further comprising a second chip discharge groove formed at one side of the blade for discharging chips generated during cutting of the workpiece. The milling cutter according to claim 6, wherein a cutting tip for cutting the workpiece is attached to one side of the second chip discharge groove. The milling cutter as set forth in claim 1, wherein a height adjustment screw is provided at a lower portion of the blade in the pocket to adjust a height of the blade. [2] The method of claim 1, wherein the pockets are spaced apart from the center point by roughing, centering, and finishing, and the distance between the pocket and the center point is reduced as the roughing, Milling cutter with blade. 10. The milling cutter as set forth in claim 9, wherein a height of the blade protruding from the cartridge increases as the roughing, the centering, and the finishing become greater. 10. The milling cutter as set forth in claim 9, wherein the number of the first to third pockets is the largest number of the first pockets and the smallest number of the third pockets.

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