JPH01228705A - Cutting tool - Google Patents

Abstract

PURPOSE:To make a finished surface satisfactory by providing a forward cutting blade which has a predetermined length and which is parallel to a surface to be cut, and a crosswise cutting blade substantially orthogonal to the former cutting blade, and by providing common rake surfaces which have rake angles substantially equal to each other on both cutting blades so that the depth to the bottom is gradually increased from the forward cutting blade to the crosswise cutting blade. CONSTITUTION:A forward cutting blade 4 of a cutting chip 1 having a substantially triangular shape in a plan view is linear, parallel to a surface 18 to be cut, having a predetermined length W, and a crosswise cutting blade 5 is provided substantially orthogonal to the forward cutting blade through the intermediary of a corner part having a radius (r). The forward and crosswise cutting blades 4, 5 have rake angles substantially equal to the respective angles of the cutting blades, and the trailing edges thereof form triangular rake surfaces 7 whose depth is increased gradually from the forward cutting blade 4 to the crosswise cutting blade. With this arrangement, it is possible to make the surface roughness of a finished surface satisfactory, and chips may be satisfactorily discharged toward the feed side along the trailing edges of the rake surfaces 7.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a cutting tool, and in particular, the present invention relates to a cutting tool, in particular, a triangular flat tip with a planar shape is attached to the tip of the shank, and the cutting edge length of the front cutting edge is increased. The present invention relates to a cutting tool equipped with a cutting tip that can obtain a good finished surface even when the feed rate is increased, and has an improved rake face to improve chip evacuation.

(Prior Art) Generally, a cutting tool is used when cutting the outer periphery of a cylindrical workpiece using a lathe. Among these cutting tools, a throw-away cutting tool is known as one in which a disposable carbide tip is firmly tightened to a cutting tool shank. Various types of tips are available, and triangular tips are usually used when cutting the outer periphery (see, for example, Japanese Utility Model Application Publication No. 17878/1987).

[Problem to be solved by the invention]

However, in the above-described conventional throw-away cutting tool, in order to maintain a good finished surface roughness, the feed amount must be set small depending on the nose radius, resulting in a decrease in machining efficiency.

Additionally, there is a method that cuts the outer periphery with an oblique cutting edge, but there is a problem in that it is difficult to process right-angled corners.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to solve the problems of the cutting tools according to the prior art described above, to be able to obtain a good finished surface with a large feed rate, and to avoid interference with the finished surface.
An object of the present invention is to provide a cutting tool that allows easy disposal of chips.

(Means for Solving the Problems) In order to solve the above problems, the cutting tip according to the present invention has the following conditions.

a) The cutting tip must be a planar or triangular flat cutting tip.

b) The front cutting edge must be a straight line or a convex curve parallel to the work surface.

C) The transverse cutting edge shall extend perpendicular to the front cutting edge.

d) The height of the corner where the front cutting edge and the side cutting edge intersect must match the top surface of the chip.

e) The front cutting edge and the lateral cutting edge are given an equal rake angle to each cutting edge, and the trailing edge of the rake face cooperates with the front cutting edge and the lateral cutting edge to form a triangular shape. To be there.

f) The depth of the bottom of the rake face from the top surface of the chip should gradually increase from the front cutting edge to the lateral cutting edge.

(Function) According to the cutting tip of the present invention having the above-mentioned structural features, it is possible to obtain a good finished surface roughness even under a large feed rate, and the chips are fed along the trailing edge of the rake face. Chips can be discharged to the side.

(Example) Examples of the cutting tool according to the present invention will be described below with reference to the drawings.

1 to 5 illustrate an indexable tip according to one embodiment of the present invention.

The cutting tip 1 in this embodiment is made of cermet, and as shown in FIG. It is a flat cutting tip with t. This chip has two mounting holes in the center for mounting on the shank.
It has three cutting edges 3A, 3B, and 3C rotationally symmetrical with respect to the center 0 of this mounting hole 2. Taking cutting blade 3A as an example, the configuration of the cutting blade will be explained in detail.
Each cutting edge 3 is placed parallel to the axis of the workpiece,
It also has a front cutting edge 4 having a predetermined cutting edge length W and a transverse cutting edge 5 that is substantially orthogonal to the front cutting edge 4, and a corner portion 6 is formed at the part where both cutting edges intersect. The corner portion 6 is given a nose radius of radius r. Also,
As is clear from FIGS. 2 to 5, the height of this corner portion 6 is located in the same plane as the chip upper surface 1a of the chip 1.

Further, a common rake face 7 is provided to the front cutting edge 4 and the lateral cutting edge 5, and a trailing edge 8 corresponding to a ridge line where the rake face 7 intersects with the upper surface 1a of the chip is attached to the front cutting edge 4. On the other hand, it is a line segment inclined at an angle θ, and the rear edge 8, front cutting edge 4, and transverse cutting edge 5 cooperate with each other to form a rectangular triangle in plan view.

The depth of the bottom of the rake face 7 from the top surface 1a of the chip is:
It is set so that it gradually increases from the front cutting edge 4 toward the lateral cutting edge 5.

Note that when these cutting tips 1 are attached to a predetermined position on the tip of the shank, a front clearance surface 9 is formed below the front cutting edge 4, while a side clearance surface 1 is formed below the transverse cutting edge 5.
0 is formed.

Further, to describe the planar shape of the cutting tip 1 in geometric detail with reference to FIG. Draw a perpendicular line d at a point P closer to the inside, and let the intersection with the other side be i.

A corner portion 6 with a nose radius r is provided at a portion where the side a and the perpendicular line d intersect. Next, if a perpendicular line e of the side is drawn from a point j on the side to the side a and the intersection thereof is defined as k, this perpendicular line e corresponds to the trailing edge 8.

Note that the position of the point j is selected to be closer to the center 0 than the point i, and a position where the perpendicular line e does not touch the center hole 2.

In this way, the straight line d becomes the front cutting edge 4, the side a becomes the transverse cutting edge 5, and the straight line e becomes the trailing edge 8 of the rake face 7.

As shown in FIG. 5, the transverse cutting edge 5 is provided with a positive rake angle α, and the value of α is approximately V10 to 15″. , as is clear from Fig. 2, a positive rake angle β is given.The value of this β is approximately 10 to 15°, and usually the rake angles α and β are
are set to the same value.

Further, the rear edge 8 of the rake 7 intersects the front cutting edge 4 at an angle θ, and the value of θ is set to about 60 degrees. Further, the rake face 7 near the trailing edge 8 is rounded to form a chip former.

In this way, when the values of the rake angles α and β are set to be the same, the depth m of the deepest part of the rake face of the transverse cutting edge 5 becomes the same as that of the front cutting edge 4.
The rake face 7 is deeper than the depth n of the deepest part of the rake face (see Fig. 5), and the rake face 7 as a whole is configured as an inclined surface that deepens from the front cutting edge 4 side toward the rear edge of the transverse cutting edge 5. be done. That is, the rake face 7 is created so as to become deeper toward the feeding side. The relationship between the angle and dimensions of a single chip is α
Direction β〉01m≧n, θ is a value larger than 45°,
It is usually set at an appropriate angle between 50° and 60°.

The state in which the above-mentioned cutting tip 1 is mounted on the shank 12 will be explained with reference to FIGS. 6 to 8.

The triangular tip 1 is clamped to the tip of the shank 12 by a known and conventional means. That is, when the bolt 13 is rotated in the tightening direction with a wrench, the clamp pin 14 in the mounting hole 2 moves in the tightening direction, and the tip 1 is moved to the shank 1.
2, the tightening is fixed. When actually cutting, the cutting angle k in Fig. 6 ranges from V2O'' to 1006
It is set so that At this position, the front cutting edge 4 is located parallel to the axis of the workpiece, and the cutting edge length is indicated by W. Note that S indicates the direction of feeding.

In FIG. 7, the front surface of the shank 12 is ground down to match the front flank surface 9 of the insert 1, so that only the front cutting edge 4 comes into contact with the workpiece, and the tip of the corner portion 6 is cut into the workpiece. It is located at the center of things. Further, the tip mounting seat 15 formed on the shank 12 is formed in advance so that a front relief angle γ1 and a side relief angle γ2 are given when the tip 1 is attached.

Due to the existence of the inclination of the mounting seat 15 itself and the inclination of the tip 1, the angle actually involved in cutting will be a combination of both. That is, in FIG. 8, the top rake angle α is α+71, and in FIG. 7, the side rake angle θ is β+72.
becomes. γ1. The value of γ2 is usually about γ1−72−−6°, and it is necessary to determine α and β in consideration of these angles.

Further, the slope η of the bottom of the rake face is given by combining the slopes of the tip mounting seat 15 of the shank 12 so that it becomes deeper on the feeding side, as shown in FIG. The angles η and η′ are not true values but angles represented in the plan view.

FIG. 9 is a perspective view of one of the cutting edges of the cutting tool according to the present invention, seen diagonally from the front, showing the state of inclination of the front cutting edge 4 and the lateral cutting edge 5, the rake face 7 common to both, and the front cutting edge. The cutting edge length W1 of the blade 4 and the state of the shank 12 and shim 16 are shown.

FIG. 10 shows a state in which the cutting tool according to the present invention is actually used to turn the machined part of the workpiece 17. In the figure, the tip 1 has reached the end of the step 18 and the nose radius is " The corner portion 6 of the insert 1 has reached the barrel mounting surface 19.As is clear from this figure, the front cutting edge of the insert 1 is parallel to the axis X-X of the workpiece 17; The roughness of the machined surface is better than that of conventional tools that cut with a nose radius.

In this example, the feed S can be increased to about 0.8 times the cutting edge length W of the front cutting edge 4.

FIG. 11 shows the state of discharge of chips during cutting, and as shown, the chips 20 are discharged to the feed side while being wound into a coil along the groove of the chip former.

This is because the groove bottom of the groove-shaped rake surface 7 of the diagonal groove, which is the common rake surface 7 of the transverse cutting edge 5 and the front cutting edge 4, is closer to the feed side.
This is because the chips 20 that touch the trailing edge of the diagonal groove and curl up will flow out along the groove since it is configured to descend.

In this way, in the case of this tool, the shape and flow direction of the chips are constant, so the processing properties are also excellent.

Fig. 12 is a perspective view of the state during cutting as seen from the direction opposite to the feed direction, and the upper rake angle α is in the direction of the depth of cut, and the side rake angle β is in the feed direction, as described above. Since it is applied with a value of , it has good sharpness and low cutting resistance.

Therefore, chatter vibration during cutting is less likely to occur, and finished surface roughness and dimensional accuracy can be improved.

Furthermore, since the cutting resistance is small, the strength of the cutting edge is improved even when the depth of cut is increased, and there is no need to put a strain on the power of the machine tool.

Next, other embodiments of the cutting tool according to the present invention will be described with reference to FIGS. 13 to 27.

In the embodiment shown in FIGS. 13 to 15, the cutting tip 1
An example is shown in which cutting edges with a similar structure are created on both sides of the
According to this embodiment, six cutting edges are formed, which is twice the number of cutting edges when using one side, which is economical. In addition, the cutting edge formed on the front side of the cutting tip is used for right-handed tools, whereas the cutting edge created on the back side of the insert can be used for left-handed tools. The insert allows feed cutting in both directions.

Further, the embodiment shown in FIG. 16 is an example in which the front cutting edge 4 is formed by a part of a circular arc having a radius of curvature R. In this case, the center C of the radius of curvature R is set on the imaginary line q that extends from the transverse cutting edge 5 to the inside of the chip by the nose radius of the corner portion 6. In this way, if the center C of the arc is taken, Since the nose end of the front cutting edge 4 enters the workpiece most deeply, corner machining can be performed accurately.

Further, the embodiment shown in FIGS. 17 to 19 is an example in which the rake face 7 is formed into a convex curved surface, and the front cutting edge 4 and the transverse cutting edge 5 have a curved shape. According to such an embodiment, since the front cutting edge 4 protrudes in the cutting direction as a curved cutting edge with a very large radius of curvature, it is possible to obtain a good finished surface roughness even when machining a flat surface or an inner diameter. . Also, rake face 7
Since it is a convex curved surface, the cutting edge strength is increased, chipping resistance is improved, and there is less welding of chips, which increases the life of the blade.

Furthermore, the embodiment shown in FIGS. 20 to 22 is an example in which cutting edges are provided near three vertices of a chip having a V-triangular planar shape, and a straight line passing through each vertex and the center 0 of the chip. It is symmetrical with respect to YY. In this example as well, the rake angles α and β are equal and can be used for either the left or right hand. Also, large chamfers are formed around the center of each side of the chip to avoid interference with the workpiece. FIGS. 23 and 24 show the state in which the tip 1 of this embodiment is actually mounted on the shank of a cutting tool.

In this example as well, the front cutting edge 4 is y-parallel to the axis of the workpiece, and the cutting angle is set to about 100°.

Figures 25 to 27 show still another embodiment of the present invention, in which the rake face 7 is configured in a convex curved shape, which can improve the cutting edge strength and suppress chatter vibration. You can also.

In addition, in the above-mentioned embodiment, an example was explained in which the mounting hole was opened in the center of the chip, but such a mounting hole may not be provided. Further, as the material of the tip, high speed steel, carbide, cermet bit, ceramic bit, diamond, etc. are appropriately selected. Further, a cutting tool using the tip of the present invention can be applied not only to turning but also to milling and boring tools.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, a front cutting edge having a predetermined cutting edge length and parallel to the workpiece surface and a transverse cutting edge that is orthogonal to this are provided, and these cutting edges A common rake face with a rake angle equal to V is provided, and the depth to the bottom of this rake face gradually increases from the front cutting edge to the lateral cutting edge, resulting in a good surface finish with a large feed rate. It is possible to obtain roughness and also prevent damage to the finished surface by chips that can be ejected along the trailing edge of the rake face to the feed side.

[Brief explanation of the drawing]

Fig. 1 is a plan view showing a cutting tip according to an embodiment of the present invention, Fig. 2 is a front view thereof, Fig. 3 is a rear view thereof, Fig. 4 is a right side view thereof, and Fig. 5 is a left side view thereof. 6 is a front view showing the cutting tip according to the present invention attached to the shank, FIG. 7 is a plan view of the same, FIG. 8 is a left side view of the same, and FIG. 9 is a cutting tool according to the present invention. FIG. 10 is a plan view showing a state in which a step part of a workpiece is being machined using the cutting tool according to the present invention, and FIG. 11 is a perspective view showing a state in which chips are discharged. , FIG. 12 is a perspective view of the cutting tool in a cutting state seen from another angle, FIG. 13 is a plan view showing a cutting tip according to another embodiment of the present invention, FIG. 14 is a front view of the same, and FIG. 16 is a plan view of a cutting tip according to another embodiment, FIG. 17 is a plan view showing a cutting tip according to another embodiment, FIG. 18 is a front view of the same tip, and FIG. The figure is a left side view of the same chip, FIG. 20 is a plan view of a cutting chip according to another embodiment, FIG. 21 is a front view of the same chip, FIG. 22 is a left side view of the same chip, and FIG.
The figure is a plan view showing the state in which the tip is attached to the shank.
24 is a side view of the same, FIG. 25 is a plan view showing another embodiment of the chip, FIG. 26 is a front view of the same chip, and FIG. 27 is a left side view of the chip. DESCRIPTION OF SYMBOLS 1... Cutting tip, 3... Cutting edge, 4... Front cutting edge, 5... Transverse cutting edge, 6... Corner part, 7... Rake face, 8... Trailing edge. Applicant's agent Yuru Sato θ Figure 10 Figure 11 Figure 13 Figure 12 Figure 19 Figure 24 Figure 25 Figure 22 Commissioner of the Patent Office Yoshi 1) Tsuyoshi Moon 1 Display of case 1986 Patent Application No. 50534 2 Name of the invention Cutting tool 3 Relationship with the case of the person making the amendment Patent applicant (30?) Toshiba Corporation Contents of the amendment (1) The "Claims" of the specification are amended as follows. [Claim 1: A cutting tool in which a flat cutting tip having a substantially triangular planar shape is attached to the tip of the shank, wherein the cutting tip is parallel to the workpiece surface and has a predetermined cutting edge length. A front cutting edge having a front cutting edge, a transverse cutting edge that is continuous with the front cutting edge through the nose corner portion and extending in a direction perpendicular to the front cutting edge, and a transverse cutting edge that is approximately equal to the front cutting edge and the transverse cutting edge. a rake face that provides a rake angle and whose trailing edge forms a triangle between the front cutting edge and the lateral cutting edge, -
A cutting tool characterized in that the depth of the bottom surface of the cutting surface, the top surface of the top surface, and the surface of the cutting surface rotate from the front cutting edge to the lateral cutting edge so that r11i1=. 2. The cutting tool according to claim 1, wherein the rake face is constituted by a convex curved surface projecting upward. 3. The front cutting edge is a part of a curve with a radius of curvature R whose center is placed outside the contour of the chip, and the center is located at a point where the curve with a radius r of the nose portion is parallel to the axis of the workpiece. The cutting tool according to claim 1, wherein the cutting tool is located on a straight line that passes through a point in contact with the virtual line and is perpendicular to the virtual line. (2) The following sentence is added before "[Problem to be solved by the invention]" on page 3, line 8 of the specification. "Also, the Kolesoff tool bit is known as a tool that can be fed directly at high speed. This tool is a combination of a rough cutting tool and a finishing tool, and a portion of the cross-cutting edge is chamfered." (3) Add the following sentence after "It was." in line 15 of the same page. ``Furthermore, because the Kolesov tool is rough-cut by chamfering the cross-cutting edge, the cutting resistance of the cross-cutting edge is large, and the front cutting edge and corner part recede from the surface of the workpiece, making corner machining impossible. Therefore, there was a problem that the resistance at the tip of the front cutting edge was large and it was impossible to obtain a good finished surface.'' (4) Specification Section 4 Purchase No. 10 and 11
Row rd) Front cutting edge... Must match. ” to be deleted. (5) Correct “e)” in line 12 of the same page to “d)”. (6) Correct “[)” in line 16 of the same page to “e)”.

Claims (1)

[Claims] 1. A cutting tool in which a flat cutting tip having a substantially triangular planar shape is attached to the tip of the shank, wherein the cutting tip is substantially parallel to the workpiece surface and has a predetermined cutting edge length. A front cutting edge having a front cutting edge, a transverse cutting edge that is continuous with the front cutting edge through the corner portion and extending in a direction substantially perpendicular to the front cutting edge, and a transverse cutting edge that is approximately perpendicular to the front cutting edge and the transverse cutting edge. It has a rake face that gives an equal rake angle and whose trailing edge forms a triangle between the front cutting edge and the lateral cutting edge, and the depth of the bottom of this rake face from the top surface of the chip is from the front cutting edge. A cutting tool characterized in that the height of the corner part of the cutting edge increases gradually toward the transverse cutting edge and where the front cutting edge and the transverse cutting edge intersect, and the height coincides with the upper surface of the chip. 2. The cutting tool according to claim 1, wherein the rake face is constituted by a convex curved surface projecting upward. 3. The front cutting edge is a part of a curve with a radius of curvature R whose center is placed outside the contour of the chip, and the center is located at a point where the curve of radius r of the nose portion is parallel to the axis of the workpiece. The cutting tool according to claim 1, wherein the cutting tool is located on a straight line that passes through a point in contact with the virtual line and is perpendicular to the virtual line.