JP2001287112A - High-feed throwaway type rotary tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tool capable of preventing a defect and abnormal abrasion for controlling chattering vibration when cutting a corner part or a groove to perform a stable process with high efficiency by optimizing a cutting edge shape in a contour process along a wall. SOLUTION: This high-feed throwaway type rotary tool has several throwaway chips. The throwaway chip comprises a main cutting edge and a peripheral cutting edge. The main cutting edge has a cutting edge angle of between 3 and 35 degrees and is formed in an arc or arc-shaped form. The peripheral cutting edge is formed in a straight line, arc or arc-shaped form such that a back taper is formed on a tool center axis. Round parts are formed on both ends of the main cutting edge. At least one of the round parts has a radius of curvature with a lower limit of 1 mm and between 0.05 and 0.5 time of a radius of curvature of the main cutting edge.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a throw-away (tip changeable) rotary tool, and more particularly to a tool suitable for high feed.

[0002]

2. Description of the Related Art Conventionally, a throw-away type rotary tool using a throw-away tip having a triangular, quadrangular, rhombic or other shape has been mainly used. In these tools, the main cutting edge is a linear cutting edge, and the feed amount per blade as general cutting conditions varies depending on the cutting depth and width, but is 0.1 to 0.5 mm in casting cutting. /blade. 0.1 ~ for steel cutting
It is used at about 0.3 mm / blade. However, recently, by using a throw-away type rotary tool using a round insert, it is possible to process with a feed more than about twice the straight cutting edge,
Processing efficiency has begun with improved cases. This indexable rotary tool uses a round positive type insert, and various types of inserts with a size of φ8 to φ20 are used. The clamp mechanism is a type that fixes the tip with wedge and supporter parts. There are holes, and there are roughly two types of methods: inserting a fastening screw into this pin hole and fixing it. Furthermore, due to the shape characteristics of the round insert, the cutting resistance is somewhat large, but the cutting edge length is longer than the straight cutting edge,
It has many advantages such as high cutting edge strength, high feed rate, high hardness material cutting, and long tool life. Japanese Patent Application Laid-open No.
Japanese Unexamined Patent Application Publication No. 225724/1998 and Japanese Unexamined Patent Application Publication No. 10-118901 discloses a tool. Also, Japanese Patent Application Laid-Open No. 2000-5921
There is known a high feed indexable tool suitable for contour line processing described in Japanese Patent Application Laid-Open No. H10-209,036.

[0003]

Although the above-mentioned prior art tool exhibits an excellent effect in contouring along a vertical wall, it has been found that chipping or abnormal wear is liable to occur depending on the shape of the cutting edge. Therefore, an object of the present invention is to provide means for designing an optimal cutting edge shape.

[0004]

SUMMARY OF THE INVENTION The present invention is a high feed indexable rotary tool having a plurality of indexable inserts, the indexable insert having a main cutting edge and an outer peripheral cutting edge. The cutting angle of the blade is not less than 3 degrees and not more than 35 degrees, and the main cutting edge has an arc shape or an arc shape, and the outer peripheral cutting edge has a straight line, an arc shape, or an arc shape so as to have a back taper with respect to a tool center axis. In the high-feed throw-away rotary tool described above, a radius is provided at both ends of the main cutting edge, the radius of curvature of at least one of the radius is 1 mm as a lower limit, and the radius of curvature of the main cutting edge is 0.05. More than double, 0.5
The gist is to make it less than twice.

[0005] In the present invention, the main cutting edge is connected to the next ridge through the round portions at both ends. It is common practice to provide a rounded portion to ensure fracture resistance, but in the present invention, the main cutting edge is an arc or an arc having a radius of curvature of about 8 to 20 mm, so that the smoothness of ridge connection is considered. There is a need to. If the smoothness is lacking, the portion may cause a new defect or abnormal wear. As a result of the examination in view of this special situation, it was found that if the ratio of the radius of curvature of the main cutting edge and the radius portion was within a certain range as described above, it was found that breakage and abnormal wear were less likely to occur, and the present invention was completed. It is a thing. Here, in addition to a normal arc, an arc shape is a combination of a plurality of short straight lines arranged in multiple stages arranged in a substantially arc shape, a shape having a continuously changing radius of curvature, a combination of a plurality of straight lines and curves. And those arranged in a substantially arc shape.

[0006]

In the present invention, by setting the radius of curvature of the radius portion to be 0.05 times or more and 0.5 times or less the radius of curvature of the main cutting edge, occurrence of chipping and abnormal wear can be minimized. The reason why the radius of curvature of the radius portion is set to 0.05 times or more of the radius of curvature of the main cutting edge is that if the radius is less than 0.05 times, the boundary between the main cutting edge and the radius portion is likely to be broken. , Preferably 0.1 times or more. In addition, the reason for setting it to 0.5 times or less is that if it exceeds 0.5 times, the chip shape becomes large, or unless there is a drastic design change such as limiting the length of the main cutting edge, the radius and the main cutting This is because a smooth connection between the blades cannot be realized, and the loss and abnormal wear also increase. More preferably, it is set to 0.3 times or less. The reason why the radius of curvature of the radius portion is 1 mm or more is that if the radius is less than 1 mm, the fracture resistance is insufficient. Preferably, it is good to be 1.6 mm or more.

In the indexable tool of the present invention, the bottom edge is the main cutting edge, and the main cutting edge cutting angle is 3 degrees or more and 35 degrees or more.
It has a radius R-shape at below temperature. This tool cuts only the R part near the tip, so the cutting edge length is shorter than the round insert, the shape of the die with a small draft angle, the corner part with many cutting margins and the groove cutting, etc. Since the cutting edge length is short, chatter vibration does not occur, so that it can be used stably without any trouble. The smaller the cutting angle of the main cutting edge, the smoother the work surface can be obtained. If the angle is more than 35 degrees, the main cutting edge becomes short, so that the chip life is shortened, and it is not suitable for high feed. More preferably, it is 10 degrees to 30 degrees.

The length of the main cutting edge is preferably 3 mm or more and 7 mm or less, for example, when a work material equivalent to carbon steel S50C is cut at fz = 1 to 1.2 mm / tooth, 3 mm
In the following, the chip is apt to be broken and the life is short. Also 7m
If it is longer than m, the cutting resistance becomes excessive. For this reason,
It is preferable that R is increased to 3 to 7 mm. Generally, a main cutting edge length of 20 to 60% of the inscribed circle diameter of the tip is recommended. The main cutting edge has substantially the same performance as the main cutting edge, provided that R-shaped portions are provided at both ends, so that the main cutting edge has a linear shape, and an appropriate amount of R-shaped shape is provided at both ends of the main cutting edge. Is adopted, it is possible to produce a low-cost chip, although the life is slightly inferior. In the indexable insert used in this tool, the line segment from the arc center of the main cutting edge to the contact point between the main cutting edge and the inner peripheral cutting edge is at an angle of less than 90 degrees with the inner peripheral cutting edge (see FIGS. It is preferable to make α) of 4. If the angle is 90 degrees or more, it is difficult to set the main cutting edge cutting angle to 3 degrees to 35 degrees when the chip is mounted on the holder, and to provide the inner peripheral blade at a normal angle.

[0009]

Next, examples of the present invention will be described along cutting tests. A test was conducted using the tool of the present invention shown in FIG. 2 and 3 are schematic views of a chip used in the present invention. The cutting parameters were set to a tool diameter φ80 mm, and the tool protrusion amount L from the gauge line was set as long as 240 mm so that chatter vibration was easily generated, and the tool was attached to the arbor. Further, the processing shape was set to shoulder cutting → groove cutting → shoulder cutting as shown in FIG. The work material was also S50C, and the cutting speed V = 200 m / min (rotational speed N = 800 min)
^-1 ), feed amount per blade fz = 1.0 mm, cutting width Rd = 40 (shoulder cutting) to 80 (groove cutting) mm, and dry cutting. After digging down five times with the cutting depth Ad = 1.5 mm, the state of the cutting edge was evaluated. The results are shown in Table 1.

[0010]

[Table 1]

[0011] In chip number 1, the radius of curvature of the radius portion was too small, but the radius of curvature with the main cutting edge was good, and the chip radius was broken. Chip No. 7 had a large radius of curvature, but the connection with the main cutting edge was not smooth due to the size limitation of the chip, resulting in chipping or large wear. In chip No. 8, a defect occurred at the boundary between the main cutting edge and the radius. In contrast, when the present invention was adopted, good results were obtained.

[0012]

According to the present invention as described above, wear,
There are few defects and the features of high feed tools can be used to the maximum.

[Brief description of the drawings]

FIG. 1 shows a front view of an example of the present invention.

FIG. 2 shows a front view of the throw-away tip used in FIG.

FIG. 3 shows a side view of FIG. 2;

FIG. 4 shows a schematic diagram of contouring such as shoulder milling → grooving → shoulder milling.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Tool main body 2 Tip part 3 Tip used in the example of the present invention 4 Set screw 5 Conventional round tip 6 Tip used in another embodiment of the present invention 7 Main cutting edge 8 Inner peripheral cutting edge 9 Outer peripheral cutting edge R Main cutting edge Arc radius r1 Arc radius on the outer cutting edge side of the main cutting edge r2 Arc radius on the inner cutting edge side of the main cutting edge α Line segment from the arc center of the main cutting edge to the contact point between the main cutting edge and the inner cutting edge Angle between the inner cutting edge and the inner edge κ Cutting angle of the main cutting edge θ Back taper angle D Outer diameter Ad Depth of cut

Claims (1)

[Claims] 1. A high feed indexable rotary tool having a plurality of indexable inserts, the indexable insert having a main cutting edge and an outer peripheral cutting edge, wherein a cutting angle of the main cutting edge is 3 degrees or more. , 35 ° or less, and the main cutting edge is in the shape of an arc or an arc, and the outer peripheral cutting edge is a high feed throw-away type rotation that is linear, arc, or arc shaped so as to have a back taper with respect to the tool center axis. In the tool, a radius is provided at both ends of the main cutting edge, the radius of curvature of at least one of the radius is 1 mm or more, and 0.05 times or more and 0.5 times or less of the radius of curvature of the main cutting edge. A high-feed indexable rotary tool, characterized in that it is provided.