JPH0760525A - Milling cutter - Google Patents

Abstract

PURPOSE:To change a cemented carbide tip separately for partial abrasion by installing the cemented carbide tip on a body of a milling cutter to enable regenerative usage, and use the body commonly for a straight tooth and a staggered tooth. CONSTITUTION:A chevron-shape protruding part 3 is provided at an outer circumference of a steel body 2 to form a tip base seat 10. A cemented carbide tip 4 having an outer circumferential cutting edge 7 and a side edge is fixed on the chevron-shape protruding part 3 by a fixing screw 15 through a screw through-hole 13. Flanges 16 are formed at a bottom surface and a back surface in the tip 4 to be engaged with grooves 18, 19 of the tip base seat 10, and it is constituted 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 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 are brazing and milling cutters in which cemented carbide tips are fixed with silver braze to machine alloy steels with high hardness and hardened hardened work materials.

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 a mountain-shaped protrusion (32), and a surface of the mountain-shaped protrusion (32) facing the rotational direction,
A stepped chip pedestal (33) for fixing a flat-plate chip (34) made of cemented carbide is cut out, and the cemented carbide chip (34) is silver brazed on the chip pedestal (33). It is fixed by brazing such as to form an integrated cutter. Cemented carbide tips for this milling cutter (34)
Using a tool grinder, rake face grinding on the front side and outer flank surface grinding on the outer circumference to form outer peripheral cutting edge (35), and side surface polishing to form side edge (36), It is used for processing.

In the case of the above-mentioned brazing type, a special skill of oxyacetylene welding is required for brazing the cemented carbide tip, and it is also called a bad environment because the workpiece becomes a high temperature exceeding 700 ° C. There is a work problem. In the process of cooling from this high temperature to normal temperature, the steel body (31)
Due to the difference in coefficient of linear expansion between the cemented carbide chip (34) and the cemented carbide chip (34), stress is generated in the cemented carbide chip (34), which causes manufacturing difficulties such as cracking of the cemented carbide chip (34).

Generally, the brazing type steel body (31) is hardened prior to the brazing operation.
Due to the brazing temperature exceeding 700 ° C, the hardened steel is annealed and the pedestal (33) supporting the cemented carbide tip (34) is softened and cannot be used for cutting of high hardness work material. 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. Even so, 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. , Clearance angle is 7-1
A large value of 0 degrees is used to sharpen the cutting edge. Therefore, even if one milling cutter is used to cut both types of work materials, it is difficult to combine them.

Further, the cemented carbide tip (34) protrudes outwardly in the radial direction from the chevron projection (32) by only about 1 mm, and the clearance angle (the inclination angle from the cutting edge to the center of the body).
Even if the tip (34) is worn or damaged, it cannot be re-polished, and once the outer peripheral cutting edge (35)
Once worn, it was necessary to discard the entire milling cutter, including the body (31). Furthermore, cemented carbide chips (3
When 4) is brazed, the body (31) is distorted by a high temperature of about 700 ° C. when the cemented carbide tip (34) is heated to melt the silver solder in order to be replaced, 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, since the cemented carbide tip is fixed in the pocket (groove) drilled in the body from the rake face with a screw, it is different from the present invention.

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 disadvantage that the furnace is not volumetrically efficient and the coating cost is high.

[0011]

The above-mentioned conventional milling cutters have problems of brazing work and destruction of cemented carbide chips due to thermal stress, and even if an attempt is made to obtain a rake angle suitable for a work material. It is not possible to change, it is difficult to form a large peripheral clearance angle, and it is uneconomical to discard the entire milling cutter because the tips cannot be partially replaced when the tips are worn. When forming a reinforcing coating layer of titanium, alumina, diamond or the like on the chip, the coating cost is high.

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 object of the present invention is to provide an economical slow-away type milling cutter which can be applied to a high hardness work material, in which only the chip can be used 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 problem is solved by an assembled structure in which the above is screwed.

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 cutting resistance or an external force in the lateral direction acts on the cemented carbide tip during cutting, the cemented carbide tip is held more firmly and does not move.

As described above, since the cemented carbide tip used in the milling cutter of the present invention is an assembling type slow-away tip, no special skill is required for brazing work, and high temperature and thermal stress are not required. There is no problem such as cracks caused by. 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 there is no waste of discarding the entire milling cutter.

Since the milling cutter 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 machined at an arbitrary angle, By alternately assembling the blades after polishing, a large peripheral clearance angle and rake face angle can be easily obtained, so even with a multi-blade structure, it is easy to create a milling cutter with a large peripheral clearance angle for aluminum. It has the characteristic of being able to

Since the milling cutter of the present invention has the above-mentioned structure, when the necessity of slightly widening the blade width arises, the entire milling cutter is not replaced with a new one, but a wide tip is used. Since it suffices to prepare and replace only the tip, it becomes possible to easily perform applied work such as exchanging the cemented carbide tip on the machine and cutting a groove having a different groove width. 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 applied to the cemented carbide tip of the milling cutter of the present invention is not particularly limited, and it is prepared by appropriately mixing widely used metal carbide powder and metal powder and sintering. Alloys, for example, WC-Co type, WC-TiC-C containing 70% or more of W (tungsten)
Examples thereof include o type and WC-TiC-TaC-Co type. 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 nitride) 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 plating, or the like. Ride), TiC (titanium carbide), SiC (silicon carbide), CBN (cubic boron nitride), TiCN (titanium carbonitride), TiA
By forming a reinforced coating layer of IN (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, in the milling cutter of the present invention, the cemented carbide tip is attached and detachable. Therefore, even if the cemented carbide tip is worn during cutting, it is recovered and the milling cutter with a small step width is used. It is possible to attach it to the body of the cutter, perform flank surface polishing and rake surface polishing again, and reuse it. In this way, the blades are successively reclaimed to have a smaller blade width, and conventionally, once used, the entire milling cutter was discarded, but by applying the structure of the present invention, the cost required for cutting can be significantly reduced. it can.

When forming a zigzag twisting blade using a conventional thin plate tip, it is necessary to form the groove of the body obliquely in correspondence with the helix angle and make the groove surface of the chevron projection oblique. However, since the milling cutter of the present invention can appropriately increase the thickness of the cemented carbide tip in the outer peripheral direction, twisting the rake face of the cemented carbide tip with the chevron protrusions formed linearly It is also possible to form a twisting blade of 1 to 20 degrees. Therefore, it becomes possible to share the body for the staggered blade and the body for the straight blade.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings showing the embodiments of the present invention, FIG. 1 shows cemented carbide on the chevron (3) of the steel body (2) of the milling cutter (1) of the present invention. FIG. 2 is a front view showing a mode in which the tip (4) is attached, FIG. 2 is a plan view of the same, and FIG. 3 is a side view of the cemented carbide tip (4) attached to the milling cutter (1) seen from the rake face.

The milling cutter (1) of the present invention is shown in FIG.
As shown in 2 and 3, the outer peripheral flank surface (5) is ground and the rake surface (6) is ground to form the outer peripheral cutting edge (7), and the side surface grinding (8) is formed to form the side blade (9). Is formed,
Chevron projections (3) provided on the outer circumference of the steel body (2)
The bottom surface (11) and the back surface (12) are brought into contact with the chip pedestal (10) formed on the above, and the peripheral flank (5) to the chip pedestal (10) near the center of the cemented carbide chip (4). Through a screw through hole (13) drilled in the direction of (3), and a fixing screw (15) is screwed into a screw hole (14) provided in the chevron protrusion (3) to mechanically fix the screw. ing. The flange (16) on the bottom surface and the semi-circular flange (17) on the rear surface of the cemented carbide chip (4) are fitted to the chip pedestal (10), so that these flanges (16) and (17) are matched. Shaped grooves (18) and (19) are drilled. By fitting the flanges (16) and (17) with the grooves (18) and (19), the cemented carbide chip (4) is prevented from moving rearward or leftward or rightward even if a resistance force is exerted during cutting. It is firmly fixed.

The angles of the peripheral flank surface (5) and the rake surface (6) are fixed to every other cemented carbide tip (4) and polished, and then the cemented carbide tips (4) adjacent to each other are tooled. Since the obstacle such as the diamond grindstone of the grinder 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 (4) and finally assembling all the blades integrally with the steel body.

Since the milling cutter (1) of the present invention has the above-mentioned structure, it is attached to the chip pedestal (10),
It can be removed at any time, and even if the cemented carbide tip (4) is partially damaged or worn by cutting, only the cemented carbide tip (4) can be replaced and brazing can be performed. It is possible to prevent the situation where the entire milling cutter is discarded like the type, and it is possible to reduce the cost required for cutting.

The cemented carbide tip (4) is subjected to flank and rake surface polishing with a dedicated steel body to form the outer peripheral cutting edge (7) and side edge (9), and then attached to 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 the milling cutter (1), and a cemented carbide tip (4) having a different width can be prepared. On the machine, the cemented carbide tips (4) can be exchanged to machine grooves of different widths. Furthermore, because the work material has changed from cast iron to alloy steel,
When changing the material type of the cemented carbide chip (4), only the cemented carbide alloy chip (4) may be separately prepared and replaced on the machine as in the above case.

More specifically, in the embodiment of the present invention, the blade width of the cemented carbide tip (4) of the milling cutter (1) is 22 mm, the blade height is 16 mm, and the blade length is 30 mm.
The width of the collar (16) is 10 mm, and the height of the collar (16) is 4 m.
m, tsuba (17) is a semicircular shape with a radius of 5 mm, diameter 6 m
The cemented carbide alloy chip (4) is fastened and fixed to the chip pedestal (10) by screwing a screw (15) of m into the screw hole (14).

Although not shown, the cemented carbide tip (4) is fixed to the chevron projection (3) and then once removed, and the PVD method, CVD method or IVD method is applied to the surface of the cemented carbide tip (4). It is possible to form a hard reinforced coating layer of TiN, TiC, diamond or the like by the method and attach it again to the chevron projection (3) to form a milling cutter. In this way, the milling cutter (1) in which the reinforcing coating layer is formed on the surface of the cemented carbide tip (4)
Has further improved wear resistance and chipping resistance of its blade,
It has better machinability.

In this way, it is not necessary to load the entire milling cutter (1) in the coating furnace to form the reinforcing coating layer, so that the volumetric efficiency in coating can be increased and the cost required for coating can be reduced. be able to.

[0030]

As described above, in the milling cutter (1) of the present invention, the cemented carbide tip (4) can be freely attached and detached in the slow away type, so that it can be combined with a hardened steel body to have a high hardness. A strong milling cutter capable of cutting a work material can be manufactured.

Further, since the steel body of the milling cutter (1) of the present invention can be reused, the width of the cemented carbide tip (4) can be changed to change the processing size, or the cemented carbide tip (4). ) It is possible to apply such as confirming the machinability of different work materials by using different materials, and there is no 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 an embodiment showing a mode in which a cemented carbide tip is attached to a milling cutter of the present invention.

FIG. 2 is a plan view showing a cemented carbide tip portion 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. Milling cutter, 2. Tsuna body, 3. Chevron protrusions, 4. Cemented carbide tip, 5. Outer flank,
6. Rake face, 7. Outer peripheral cutting edge 8. Side polishing, 9. Side blade, 10. Chip pedestal, 1
1. Bottom surface, 12. Back side 13. Screw through hole, 14. Screw holes, 15. Screw, one
6. Tsuba, 17. Tsuba, 18. Groove, 19. groove

Claims (3)

[Claims] 1. A chip pedestal in which a cemented carbide chip having an outer peripheral cutting edge and a side edge and having a screw through hole for fixing with a screw means from the outer peripheral flank is provided on the outer periphery of a steel body. A milling cutter characterized in that it is fixed to the above with screw means. 2. The milling cutter according to claim 1, wherein a fitting pedestal for fitting the brim of the cemented carbide chip is formed in the tip pedestal of the steel body. 3. Titanium on the blade surface of the cemented carbide chip,
The milling cutter according to claim 1, wherein a reinforcing coating layer such as boron or diamond is formed.