JPH0760524A - Cemented carbide tip for cutting tool - Google Patents

Abstract

PURPOSE:To provide a cemented carbide tip which can be installed to/removed from a milling cutter to be capable of separate replacement and regenerative usage. CONSTITUTION:A chevron-shape protruding part 8 is provided at an outer circumference of a steel body to form a tip base seat 9. A cemented carbide tip 1 having an outer circumferential cutting edge 3 and a side edge, and having a screw through-hole 7 directed from an outer circumferential flank 2 to the tip base seat 9 is fixed on the chevron-shape protruding part 8 by a fixing screw 16 to be an integrated milling cutter. Flanges 12, 13 are formed in a bottom surface and a back surface of the cemented carbide tip 1 to be engaged with grooves 14, 15 of the tip base seat 9, and it is composed to be prevented from moving even when external force is applied.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is known as a side milling cutter, a groove milling cutter, etc., for flattening the surface of a work material,
The present invention relates to an improved structure of a cemented carbide tip used in a milling cutter which is a cutting tool used for drilling a groove.

[0002]

2. Description of the Related Art It is attached to a main shaft of a milling machine by using a complementary shaft (referred to as an arbor), and while being rotated, it smoothly cuts the surface of a work material or cuts grooves. As a cutting tool for this, side milling cutters and groove milling cutters that have a cylindrical or disk-shaped steel body, and have angle-shaped protrusions formed on the outer periphery of which are fixed to a rectangular tip having an outer peripheral cutting edge and side blades are commonly used. ing. These are generally called milling cutters and are high speed steels (high speed steels) used for cutting cast iron and soft alloy steels.
There is a brazing and milling cutter with a cemented carbide tip fixed to machine hard alloy steel or hardened hard work material.

As shown in FIG. 4, a conventional brazing and milling cutter has an axial hole (3
0) having a cylindrical or disc-shaped body (31) having a diameter of 50 to 200 mm and provided with chevron protrusions (32),
A stepped chip pedestal (33) for fixing a flat-plate chip (34) made of a cemented carbide is cut out on the surface of the chevron projection (32) facing the rotational direction, and the chip pedestal (33) is cut out. ), The cemented carbide tip (34) is fixed by brazing such as silver brazing to form an integrated cutter. The cemented carbide tip (34) of this milling cutter is ground with a rake face using a tool grinder, the outer periphery is flanked with a peripheral flank face (35), and the side face is further side polished. A blade (36) is formed and used for cutting.

In the case of the brazing type, the special skill of oxyacetylene welding is required, and the work piece is 70
There is a working problem of a bad environment due to a high temperature exceeding 0 ° C. Further, stress is generated in the cemented carbide chip (34) due to the difference in linear expansion coefficient between the steel body (31) and the cemented carbide chip (34) during the process of cooling from the high temperature to the room temperature.
There are manufacturing difficulties such as cracking of the cemented carbide tip (34).

Generally, the brazing type steel body (31) is hardened prior to the brazing operation.
Due to the brazing temperature of over 700 ° C, the hardened steel is annealed and the pedestal (33) supporting the cemented carbide tip (34) becomes soft, and it cannot be used for cutting of high hardness work materials. There is also.

In the milling cutter integrally formed by brazing as described above, the angle of the outer peripheral flank and the angle of the rake face are formed constant, and it is desired to change these depending on the nature of the work material. However, it was almost impossible to change it, and it was necessary to create a new one with a different shape. Normally, for cast iron and alloy steel, the rake angle is about 0 degrees, and the clearance angle is a small value of 5 to 6 degrees. For cutting soft work materials such as copper and aluminum, the rake angle is about 10 degrees. , The clearance angle is 7 ~
The value is as large as 10 degrees and the cutting edge is sharpened. Therefore 1
Even if you try to cut both types of work materials with a single milling cutter, it is difficult to combine them.

Further, since the cemented carbide tip (34) protrudes only about 1 mm outward in the radial direction from the chevron projection (32), it can be re-polished even if the tip (34) is worn or damaged. However, once the outer peripheral cutting edge (35) was worn, it was necessary to discard the entire milling cutter including the body (31). Further, when the cemented carbide tip (34) is brazed, when the cemented carbide tip (34) is heated to melt the silver solder in order to be replaced,
The body (31) is distorted by the high temperature of about 00 degrees C,
There are problems such as incorrect dimensions.

There are throwaway type face milling cutters and segment type cutting tools in which the cemented carbide tips (34) can be replaced. However, these are rake angles and clearance angles depending on the nature of the work material. It does not have the function of changing the, and is not used as a side milling cutter or groove milling cutter.

Further, regarding the size of the peripheral clearance angle, for example, when grinding is performed using a profiler tool grinder, it does not collide with the adjacent blade due to the locus of the outer circumference of the grindstone of the tool grinder during the grinding stroke. Therefore, it is limited to a certain value or less. That is, when the clearance surface is linear, the maximum value of the clearance angle is less than half the value obtained by dividing the circumference of 360 degrees by the number of blades of the milling cutter. For example, a 26-blade milling cutter must have a value less than 6.92 degrees. This means that when trying to make copper or aluminum for a milling cutter with a large number of blades, it is not possible to easily form an outer peripheral flank with a large clearance angle with a conventional structure, and with an extremely small diameter. It is necessary to use a grindstone to prevent collision with the adjacent blade and to increase the rotation speed in order to maintain the peripheral speed.

Further, in recent years, work materials such as high hardness materials and special alloy steels, which are difficult to cut, are often used. Therefore, a reinforcing coating layer of titanium, boron or diamond is formed on the surface of the cemented carbide chip (34). However, in the case of the brazing type, it is necessary to load the entire cutter into the coating furnace, which has a drawback that the furnace volume efficiency is low and the coating cost is high.

[0011]

In the above-mentioned conventional milling cutter, it is impossible to change the rake angle according to the work material, and it is difficult to form a large peripheral clearance angle. It is uneconomical because the entire milling cutter needs to be discarded because the tip cannot be partially replaced when it is worn out, and the coating cost is increased when forming a reinforcing coating layer such as titanium, alumina or diamond on the tip. There are drawbacks such as being expensive.

The present invention eliminates the difficulties associated with the manufacture and use of the above-mentioned conventional side milling cutters and groove milling cutters, and makes it possible to obtain cemented carbide grades and arbitrary rake and clearance angles according to the work material. , It is possible to partially replace the tip and change the tip width,
The purpose of the present invention is to provide a cemented carbide tip for use in an economical slow-away type milling cutter, which can be used only for forming the reinforcing coating layer even during coating.

[0013]

The present invention provides a milling cutter for a cemented carbide chip having a blade portion, that is, an outer peripheral cutting edge and a side blade, and having a screw through hole extending from the outer peripheral flank toward a steel body. Of the steel body, the chip pedestal for supporting the above-mentioned cemented carbide chip is provided on the chevron-shaped projection formed on the outer periphery of the steel body, and the screw hole for fixing the screw is formed through the screw through hole. The above-mentioned problem is solved by screwing the above-mentioned cemented carbide chips and fixing the cemented carbide chips.

Further, the cemented carbide chip is formed with a projecting flange on the bottom surface and / or the back surface which come into contact with the chip pedestal, and is fitted in a groove of the same shape drilled on the chip pedestal. There is. As a result, even if a cutting resistance or an external force in the lateral direction acts on the cemented carbide chip during cutting, the cemented carbide chip is held more firmly and does not move.

As described above, the cemented carbide tip of the present invention is an assembly type throwaway tip,
No special skill required for brazing work is required, and problems such as cracks due to high temperature or thermal stress do not occur. Even when the body is hardened, the phenomenon of annealing due to the brazing temperature does not occur, so form a high-performance milling cutter that maintains the strength of the body and can withstand the processing of high hardness work materials. Is possible. Further, even if the cemented carbide tips are partially worn, it is easy to replace them one by one, so that there is no waste such as discarding the entire milling cutter.

Since the cemented carbide tip of the present invention has the above-mentioned structure, every other cemented carbide tip is assembled on the tip pedestal of the steel body, and the outer peripheral flank and the rake face are processed at an arbitrary angle. , By alternately assembling all the blades after polishing, a large peripheral clearance angle and rake face angle can be easily obtained, so even a multi-blade structure can easily create a milling cutter with a large peripheral clearance angle for aluminum. It has the feature of being able to do.

Since the cemented carbide tip of the present invention has the above-described structure, when the need arises to make the blade width a little wider, the milling cutter as a whole is not replaced with a new one but has a wider width. Since it is sufficient to prepare and replace the chips, it becomes possible to easily perform the applied work such as exchanging only the cemented carbide chips on the machine and cutting the grooves having different groove widths. Further, even when the work material is changed to cast iron, alloy steel, stainless steel, etc., by exchanging the cemented carbide chip material with a material corresponding to the work material, it is possible to perform cutting under optimum conditions.

The cemented carbide to be applied to the cemented carbide chip of the present invention is not particularly limited, and an alloy obtained by appropriately mixing widely used metal carbide powder and metal powder and sintering, for example, , W (tungsten) 70% or more of WC-Co type, WC-TiC-Co type or WC-
TiC-TaC-Co system is mentioned. A cermet can also be used.

On the surface of the cemented carbide tip having the cutting edge and the side edge formed, a superhard reinforcing coating layer of titanium, boron, diamond or the like is formed, which can be used for cutting a work material having a higher hardness. I can. That is, TiN (titanium) is formed on the surface of the chip including the blade by PVD (Physical Vapor Deposition), CVD (Chemical Vapor Deposition), IVD (Ion Implantation Deposition), Ion Platetainer, etc. Nitride), TiC (titanium carbide), SiC (silicon carbide), CBN (cubic boron nitride), TiCN (titanium carbonitride), TiA
By forming a reinforced coating layer of 1N (titanium aluminum nitride), diamond, etc., it is possible to improve wear resistance and chipping resistance (blade spill resistance) during cutting of highly hard work materials. .

[0020]

As described above, according to the present invention, since the cemented carbide tip is attached and detachable, even if the cemented carbide tip is worn during cutting, it is recovered and the body of the milling cutter with a small single-step width is used. It is possible to re-use after mounting on the flank and polishing the flank face and rake face again. In this way, the blades are played in order of smaller blade width,
Conventionally, the entire milling cutter was discarded once used, but by applying the cemented carbide chip of the present invention, the cost required for cutting can be greatly reduced.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings showing an embodiment of the present invention, FIG. 1 shows a cemented carbide chip (1) of the present invention.
2 is a front view showing a mode in which the steel body is attached to the chevron projection (8), FIG. 2 is a plan view of the same and FIG. 3 is a side view of the cemented carbide tip (1) seen from the rake face.

The cemented carbide tip (1) of the present invention is shown in FIG.
As shown in 2 and 3, the outer peripheral flank (2) is ground and the rake face (4) is ground to form the outer peripheral cutting edge (3), and the side grinding (6) is formed to form the side blade (5). Is formed,
The bottom surface and the back surface are brought into contact with the chip pedestal (9) formed on the chevron protrusion (8) provided on the outer periphery of the steel body,
A screw hole formed in the chevron protrusion (8) through a screw through hole (7) formed in the center of the cemented carbide chip (1) from the flank (2) toward the chip pedestal (9). By screwing the fixing screw (16) to (11),
It is mechanically fixed. Since the flange (12) on the bottom surface and the semi-circular flange (13) on the back surface of the cemented carbide chip (1) are fitted to the chip pedestal (9), these flanges (12), (1)
Grooves (14) and (15) shaped to match 3) are perforated. This collar (12), (13) and groove (14),
The fitting of (15) prevents the cemented carbide tip (1) from moving rearward and leftward and rightward even if a resistance force during cutting is applied, and the cemented carbide tip (1) is firmly fixed.

The angles of the flank surface (2) and the rake surface (4) are fixed to every other cemented carbide chip (1) and polished to perform tool grinding on the adjacent cemented carbide chips (1). Since the obstacle such as the diamond grindstone of the board coming into contact can be prevented, it can be selected in an arbitrary range. A single milling cutter can be obtained by sequentially polishing the cemented carbide tips (1) and finally assembling all the blades integrally with the steel body.

Since the cemented carbide tip (1) of the present invention has the above-mentioned structure, it can be attached to and detached from the tip pedestal (9) at any time, and by cutting,
Even if the cemented carbide tip (1) is partially damaged or worn, it is possible to replace only the cemented carbide tip (1), and the situation where the entire milling cutter is discarded like the brazing type There is an effect that it can be prevented and the cost required for cutting can be reduced.

The cemented carbide tip (1) is ground on the flank face and rake face with a dedicated steel body to form the outer peripheral cutting edge (3) and the side edge (5), and then mounted on another body. It is also free to use. Even if it is necessary to slightly change the width of the groove to be drilled in the work material, it is not necessary to separately prepare a milling cutter, and if the cemented carbide tip (1) with different width is prepared, it will be on the machine. , Cemented carbide chips (1)
By exchanging, grooves with different widths can be cut. Furthermore, since the work material has changed from cast iron to alloy steel, when changing the grade of the cemented carbide tip (1), prepare only the cemented carbide tip (1) separately as above. , It can be replaced on the machine.

More specifically, in the embodiment of the present invention, the blade width of the cemented carbide tip (1) is 22 mm and the blade height is 16.
mm, the length of the blade is 30 mm, the width of the collar (12) is 10 m
m, the height of the collar (12) is 4 mm, the radius of the collar (13) is 5 m
The cemented carbide chip (1) is fastened and fixed to the chip pedestal (9) by screwing a screw (15) having a diameter of 6 mm and a diameter of 6 mm into the screw hole (11).

Although not shown, the cemented carbide chip (1) is fixed to the chevron projection (8) and then removed once, and the PVD method, the CVD method or the IVD method is applied to the surface of the cemented carbide chip (1). It is possible to form a hard reinforcing coating layer of TiN, TiC, diamond or the like by the method and attach it again to the chevron projection (8) to form a milling cutter. In this way cemented carbide chips (1)
A milling cutter with a reinforced coating layer on the surface of
The wear resistance and chipping resistance of the blade are further improved, and the cutting property becomes better.

In this way, since it is not necessary to load the entire milling cutter into the coating furnace for forming the reinforcing coating layer, the volumetric efficiency during coating can be increased and the cost required for coating can be reduced. .

[0029]

As described above, since the cemented carbide tip (1) of the present invention can be freely attached and detached by the slow away type, it can be combined with the quenched steel body to cut a high hardness work material. A strong milling cutter capable of

Further, since the steel body of the cemented carbide chip (1) of the present invention can be reused, the width of the cemented carbide chip (1) can be changed to change the processing size, or the cemented carbide chip. Applications such as checking the machinability of different work materials using different materials in (1) are possible, eliminating the need to manufacture a new milling cutter.
The cost required for cutting can be greatly reduced and the industrial effect is great.

[Brief description of drawings]

FIG. 1 is a front view of one embodiment showing a mode in which a cemented carbide chip of the present invention is attached to a steel body.

FIG. 2 is a plan view of the cemented carbide chip of FIG.

FIG. 3 is a side view of the cemented carbide tip of FIG. 1 seen from a rake face.

FIG. 4 is a front view of a conventional milling cutter.

[Explanation of symbols]

1. Cemented carbide tip, 2. Flank, 3. Outer peripheral cutting edge, 4. Rake face, 5. Side blade, 6. Side polishing,
7. Screw through hole, 8. Yamagata protrusion 9. Chip pedestal, 10. Back, 11. Screw hole, 1
2. Tsuba, 13. Tsuba, 14. Groove, 15. Groove, 16.
Fixing screw

Claims (3)

[Claims] 1. A chip pedestal having an outer peripheral cutting edge and a side blade, which is formed on the outer periphery of a steel body, and is provided with a screw through hole for fixing from an outer peripheral flank with a screw means. Carbide chips for cutting tools. 2. The cemented carbide chip has a flange for fitting into a fitting groove formed in the chip pedestal, on the bottom surface and the back surface which come into contact with the chip pedestal, or one of these surfaces. A cemented carbide tip for a cutting tool according to claim 1, characterized in that 3. Titanium on the blade surface of the cemented carbide chip,
The cemented carbide tip for a cutting tool according to claim 1, wherein a strengthening coating layer of boron or diamond is formed.