JPH04275818A - V-groove cutting tool - Google Patents

Abstract

PURPOSE:To provide a V-groove cutting tool which can obtain a suitable strength at the time of machining a narrow V-groove on a work piece by milling. CONSTITUTION:An edge portion 14 provided on one end portion side of a shank portion is formed like a quadrangular pyramid, the ridge line between adjacent sides 16 of the quadrangular pyramid is taken as the outer peripheral cutting edge 18, a part of the tip portion of the cutting edge portion 14 is cut away counting on an end cutting edge angle beta and a back clearance angle theta to provide a back clearance surface 20, and the ridge line between the back clearance surface 20 and one side 16 is taken as a bottom cutting edge 22. There is no large tip pocket like an ordinary end mill in the cutting edge portion 14 so as to ensure the sectional area of the knife edge portion, and the bottom cutting edge 22 is inclined to the axis of a tool, so that at the time of cutting work, instantaneously large load is not applied.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a V-groove cutting tool for forming a narrow V-groove in a workpiece by cutting.

0002

[Prior Art] When machining a narrow V-groove on a workpiece,
For example, when forming a narrow suction groove (V groove) on the inner surface of a casting mold to lower the internal pressure of the casting mold for casting aluminum parts with a complex shape at low pressure, Machining of the narrow V-groove is usually performed by electrical discharge machining using an electrode having a V-shaped tip shaped like the V-groove, or
This is done manually by rotating a disc-shaped cutting tool with a letter-shaped cutting tool on the outer periphery.

0003

[Problem to be Solved by the Invention] However, when machining a narrow V-groove by electrical discharge machining as described above,
During electrical discharge machining, the V-shaped tip of the electrode is sometimes worn out, making it impossible to obtain a suitable V-groove shape. Another drawback is that various electrodes must be prepared to suit the shape of the V-groove machined part of the workpiece, which increases the manufacturing cost of the electrodes, and because it is electrical discharge machining, it takes a relatively long time to machine the V-groove. was there.

On the other hand, when machining a narrow V-groove by hand while rotating a disc-shaped cutting tool as described above, it is difficult to machine the V-groove in a suitable shape because it is done by hand. There was a drawback.

[0005] On the other hand, as shown in Fig. 1 of Japanese Utility Model Application Publication No. 57-193319, milling is performed using an ordinary end mill having a spiral cutting edge at the tip of the blade. It is believed that all of the above problems can be solved suitably by machining a V-groove. However, in this case, in order to machine a narrow V-groove, the tip of the end mill blade must be made thinner.
Since a relatively large chip pocket is formed in the blade, the cross-sectional area of the tip of the blade becomes significantly small, making it impossible to ensure strength. For this reason, it is extremely difficult to machine a narrow V-groove using a normal end mill.

The present invention was made against the background of the above circumstances, and its object is to suitably obtain strength when milling a narrow V-groove in a workpiece by milling. An object of the present invention is to provide a V-groove cutting tool.

[0007]

[Means for Solving the Problems] The gist of the present invention to achieve the above object is to provide a shank portion and a blade portion provided on one end side of the shank portion, and a blade portion provided around the axis of the shank portion. A narrow V is created in the workpiece by rotating the
This is a V-groove cutting tool for cutting grooves, and the blade part is formed in a polygonal pyramid shape that becomes thinner toward the tip, and the ridge line between the adjacent side surfaces of the polygonal pyramid is used as a peripheral edge, while the blade A front relief surface inclined with respect to the axis is provided at the tip of the section by cutting a part of the tip with a predetermined front cutting angle, and the front relief surface and the side surface of the polygonal pyramid are formed. This is because the ridgeline between them is used as the bottom edge.

[0008]

[Operations and Effects of the Invention] The V-groove cutting tool having such a structure is based on the fact that the V-groove cutting tool is attached to the main shaft of the milling machine at the shank portion and rotated around the axis, similar to a normal end mill. , it is possible to machine a narrow V-groove in a workpiece by the outer circumferential edge and bottom edge of the blade part. In this case, the blade has a polygonal pyramidal shape, the ridge line between the sides of the polygonal pyramid serves as the peripheral edge, and a part of the tip of the blade has a predetermined cutting angle. By cutting, a front flank is provided at the tip of the blade, and the ridge line between the front flank and the side surface of the polygonal pyramid is the bottom edge, so the blade can be cut like a normal end mill. There are no large chip pockets in the part, so even if the tip of the blade is made thinner to cut a narrow V-groove, the cross-sectional area can be secured appropriately. Because it is formed at an angle to the axis of the tool,
The bottom of the V-groove can be cut by gradually increasing the cutting portion of the bottom blade from one end to the other, thereby preventing a large load from being applied momentarily to the blade from the bottom blade. be able to. As a result, a V-groove cutting tool that can suitably obtain strength when machining a narrow V-groove in a workpiece by milling is provided.

[0009] The front clearance surface is preferably provided with a predetermined front clearance angle relative to the bottom blade. In this way, the bottom of the V-groove can be more effectively cut by the bottom blade.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings.

The V-groove cutting tool 10 shown in FIGS. 3 and 4 includes a longitudinal cylindrical shank portion 12 and a blade portion 14 integrally provided at one end of the shank portion 12. , for example, is made of carbide material, and the blade portion 14 is formed into a quadrangular pyramid shape that becomes thinner toward the tip. The four ridgelines located between the adjacent side surfaces 16 of the quadrangular pyramid-shaped blade part 14 are respectively used as outer peripheral edges 18, and a pair of outer peripheries facing each other with the axis of the V-groove cutting tool 10 in between. The angle α formed by the blade 18 is the same as the angle formed by both side walls of the V-groove to be machined, and is determined to be, for example, 45°. Note that the angle γ (not shown) formed between the axis of the V-groove cutting tool 10 and each side surface 16 is

[Math 1] It is required according to the following.

[Math 1]

1 and 2 are shown at the tip of the blade portion 14.
As shown in FIG.
By cutting out a surface that is inclined at (90-β) degrees with respect to the axis of A flank 20 and a bottom blade 22 are provided. This bottom blade 22 is formed by a ridgeline between the front flank surface 20 and one side surface 16. Note that FIG. 2 is a view taken in the direction of arrow A in FIG. 1, and d indicates the diameter of the cutting edge. Here, an example of the setting criteria for the cutting edge diameter d, front cutting angle β, and front relief angle θ is shown below.The cutting edge diameter d is
If the angle α formed by 8 is 45°, it should be 0.3 mm or less, and the front cutting angle β should be t if the depth of cut is t.

As shown in Equation 2, the front clearance angle θ is set to 5° or less.

[Math 2]

V-groove cutting tool 10 configured as described above
A narrow V-groove 26 is formed on the surface 28 (see FIG. 7) of a casting die 24 for casting a workpiece, such as an aluminum part, at low pressure using
When machining, for example, the V-groove cutting tool 10 is attached to the main shaft of a vertical milling machine (not shown) at the shank portion 12, and the casting mold 24 is placed to the side of the casting mold 24 fixed on the table of the milling machine. After lowering the mold 24 from the surface 28 by the depth of cut t, the V-groove cutting tool 10 is rotated clockwise around the axis at a rotation speed of, for example, about 30,000 RPM, and the casting mold 2 is placed on the table.
4 at a feed rate of about 300 mm/min, for example, V
By sending it to the groove cutting tool 10 side, cutting of the V-groove 26 is started as shown in FIG. Then, as shown in FIG. 7, the angle α is 45° and the width W is 1.0
mm, and a V-groove 26 with a depth D of, for example, 1.0 mm.
is processed. FIG. 6 is a diagram showing the depth of cut t during such a stepwise cutting process, and the diagonally shaded area surrounded by the one-dot chain line and the two-dot chain line indicates the cutting area to be cut during the current cutting process. There is. During such cutting, since the bottom blade 22 is inclined with respect to the axis of the V-groove cutting tool 10, the bottom blade 22 hits the casting mold 24 from its upper part (the part located on the shank portion 12 side). As the V-groove cutting tool 10 rotates and the casting mold 24 is fed, the bottom of the V-groove 26 is cut while gradually increasing the cutting portion of the bottom blade 22 from the top to the bottom. This prevents a momentary large load from being applied to the blade portion 14 of the bottom blade 22. In addition, the above casting mold 2
4 is made of SKD61, for example, and the cutting edge diameter d of the V-groove cutting tool 10 is equal to 2 of the radius of curvature R of the molten metal 30, which will be described later.
The dimension is sufficiently smaller than 0.2 mm, for example, and the depth of cut t is determined to be 0.03 mm, for example.
determined.

As shown in FIG. 7, for example, molten aluminum 30 enters the V-groove 26 processed in this manner during casting, and a molten metal 30 is formed at the tip of the molten metal 30 due to surface tension. Curved surface 32 with radius of curvature R and V
A suction hole 34 is formed between the groove 26 and the bottom of the groove 26, and the internal pressure of the casting mold 24 is lowered through the suction hole 34, thereby improving the quality of the molded product.

As described above, according to this embodiment, the blade part 14 has a quadrangular pyramid shape, and the ridge line between the side surfaces 16 of the quadrangular pyramid serves as the peripheral edge 18, and the tip of the blade part 14 A part of the part is cut in anticipation of the front cutting angle β, so that a rare clearance surface 20 is provided at the tip of the blade part 14, and the front clearance surface 20 and the four side surfaces 16 of the blade part 14 are Since the ridge line between the end mill and one of the end mills is the bottom blade 22, the blade part 14 does not have a large chip pocket like a normal end mill, and this makes it possible to machine a narrow V-groove 26. Even if the tip of the blade part 14 is made thinner, a suitable cross-sectional area can be ensured. On the other hand, since the bottom blade 22 is formed to be inclined with respect to the axis of the V-groove cutting tool 10, it is possible to reduce the cross-sectional area during cutting. In this case, a momentary large load is prevented from being applied from the bottom blade 22 to the blade portion 14. As a result, the strength of the tip portion of the blade portion 14 can be suitably secured, so that a narrow V shape can be formed on a workpiece such as a casting mold 24 by milling.
A V-groove cutting tool 10 is provided that can suitably provide strength when machining a groove.

Further, according to this embodiment, since the front clearance surface 20 is provided with a front clearance angle θ relative to the bottom blade 22 in mind, cutting of the bottom of the V-groove 26 by the bottom blade 22 is made more suitable. There are possible advantages.

Furthermore, in this embodiment, the V-groove cutting tool 1
When using a milling machine that can control the zero orientation, it is possible to suitably machine a V-groove from a suitable angle even on a curved surface of a workpiece.

In the above embodiment, the blade portion 14 is formed in the shape of a square pyramid, but it can also be formed in other polygonal pyramid shapes such as a triangular pyramid or a pentagonal pyramid.

Further, in the above-described embodiment, the front clearance surface 20 is provided with the front clearance angle θ taken into consideration, but even if such a front clearance angle θ is not provided, the effects of the present invention can still be obtained. Obtainable.

Although no other examples are given, the present invention can be implemented with various modifications and improvements based on the knowledge of those skilled in the art.

[Brief explanation of the drawing]

FIG. 1 is a diagram illustrating the tip shape of the blade portion of the V-groove cutting tool shown in FIG. 3;

FIG. 2 is a view taken along arrow A in FIG. 1, showing main parts.

FIG. 3 is a front view of a V-groove cutting tool that is an embodiment of the present invention.

FIG. 4 is a view of the V-groove cutting tool of FIG. 3 viewed from the tip side.

5 is a diagram illustrating a state in the initial stage of machining a V-groove using the V-groove cutting tool of FIG. 3;
FIG. 3 is a view seen from a direction perpendicular to the axis of the groove cutting tool.

FIG. 6 is a diagram showing the depth of cut t when a V-groove is dug in stages by the V-groove cutting tool of FIG. 3;

7 is a diagram showing an example of a V-groove machined in a casting mold by the V-groove cutting tool of FIG. 3, and is a diagram illustrating an example of a state in which molten metal has entered the V-groove; FIG.

[Explanation of symbols]

10 V groove cutting tool 12 Shank part 14 Blade part 16 Side 18 Peripheral blade 20 Front flank 22 Bottom blade 24 Casting mold (workpiece) 26 V groove β Front cutting angle θ Front relief angle

Claims (2)

[Claims] Claim 1: A V-shaped blade comprising a shank part and a blade part provided at one end of the shank part, which cuts a narrow V-groove in a workpiece by being rotated around the axis of the shank part. The groove cutting tool is a groove cutting tool in which the blade part is formed in a polygonal pyramid shape that becomes thinner toward the tip, and the ridge line between the mutually adjacent side surfaces of the polygonal pyramid is used as an outer peripheral edge, while the tip part of the blade part has:
Providing a front clearance surface inclined with respect to the axis by cutting a part of the tip portion in anticipation of a predetermined front cutting angle,
A V-groove cutting tool characterized in that a ridge line between the front flank face and the side surface of the polygonal pyramid serves as a bottom edge. 2. Claim 1, wherein the front clearance surface is provided with a predetermined front clearance angle with respect to the bottom blade.
V-groove cutting tool described in .