JP5294648B2 - Rotating tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotary tool having high and stable resistance to chipping and wear irrespective of its complicated shape. <P>SOLUTION: This rotary tool 1 is provided with: an inner blade 5 constituted by mounting a throw-away insert 3 on a tool body 2 having a rotary shaft at the center, mounting the inner blade 5 on a tip of the tool body 2 to protrude, forming a positive relief angle, and forming vertical straight 19 for a seating face 14 on an inner blade flank 23 side being continuous with a ridge line part 18 where an inner blade cutting face 22 crosses an inner blade flank 23; and an outer blade 6 constituted by mounting it to protrude on an outer side in the radial direction more than the inner blade 5 on the tip of the tool body 2 and over the tip from the direction of the outer periphery of the tool body 2, forming a positive relief angle, and forming no vertical straight for the seating face 14 on an outer blade flank 29 side being continuous with a ridge line part where an outer blade cutting face 28 crosses an outer blade flank 29 or forming shorter straight 19 than that of the inner blade 5. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a rotary tool having a tool body as a center of rotation and a throwaway insert attached to form an inner blade and an outer blade.

  In tools such as drills and end mills that perform cutting by rotating the tool around the rotation axis, cutting of difficult-to-cut materials such as high-hardness materials and materials with poor thermal conductivity is possible. There is a need for higher wear and fracture resistance of tools.

  In such a rotary tool, the cutting speed is low near the center of rotation during cutting, and the cutting speed is high near the outer edge. Then, there was a problem that wear progressed quickly.

  Therefore, Patent Document 1 describes that a chamfered portion is formed on the inner blade (bottom blade) to ensure the strength of the bottom blade and prevent breakage.

Moreover, in patent document 2, the chip | tip discharge property and cutting-blade stability are ensured by making R honing of an inner blade small 0.03 mm or less, and suppressing that a constituent blade edge | tip is formed in an inner blade. Is described.
JP 2005-271167 A JP 2002-326112 A

  However, in the method of forming the honing on the inner blade as in Patent Document 1 and Patent Document 2, honing can be performed only on a part of the insert with a complicated shape or the cutting edge of the end mill, and the honing is protruded. Since the portion also tends to be honed preferentially, there has been a problem that the amount of honing becomes partially non-uniform depending on the shape of the insert or end mill.

  An object of this invention is to provide the rotary tool which has the stable high fracture resistance also in the complicated tool shape, and is hard to wear.

The rotary tool of the present invention has a throwaway insert attached to a tool body whose center is a rotation axis,
It is mounted so as to protrude from the tip of the tool body, a straight angle perpendicular to the seating surface is formed on the flank side that has a positive flank angle and follows the ridge line portion between the rake face and the flank face , An inner blade with a straight length Li = 0.01 mm to 0.095 mm ;
Is mounted so as to protrude from the tool body from the outer peripheral direction to the tip of the tool body from the radial direction outside the inner blade, the clearance angle is positive, and the straight is not formed,
Alternatively, an outer blade on which the straight shorter than the inner blade is formed is disposed.

Here, in the above configuration, before the length of Kigaiha straight when the Lo, the ratio (Li / (Lo + Li) ) it is desirable that 0.8 to 1.

In the above configuration, the difference in straight length Li over the entire circumference of the cutting edge ridge portion of the inner blade is 0 . It is desirable that 005mm inside than.

  Further, in the above configuration, using two or more throwaway inserts having both the inner blade and the outer blade, one is mounted so that the inner blade protrudes from the tip of the tool body, and the other is It is desirable that the outer blade is mounted so as to protrude from the tool body from the outer periphery to the tip of the tool body.

According to the rotary tool of the present invention, in the inner blade, a straight having a length Li = 0.01 mm to 0.095 mm, which is perpendicular to the seating surface, is formed on the flank side following the cutting edge ridge line portion, and the outer blade Since a straight shorter than the inner blade is formed or not formed, the inner blade having a low cutting speed and a high frictional resistance is not damaged during cutting, and the cutting speed is greatly worn. With an outer blade that progresses quickly, the sharpness can be increased and the progress of wear can be delayed.

Here, in the above configuration, the length of the straight front Kigaiha when the Lo, both that the ratio (Li / (Lo + Li) ) is 0.8 to 1 is, the inner cutter and outer cutter It is desirable to achieve both fracture resistance and wear resistance.

Moreover, in the said structure, length Li of the straight over the perimeter of the cutting edge ridgeline part of the said inner blade
Difference of 0 . It is desirable in that it can reliably prevent an increase in defective cutting edge strength of the inner cutter even complex tool shape is 005mm in following.

  Furthermore, using two or more throwaway inserts having both the inner blade and the outer blade, one is mounted such that the inner blade protrudes from the tip of the tool body, and the other is the outer blade. Even in a configuration in which the tool body is mounted so as to protrude from the outer periphery to the tip of the tool body, the straight configuration of the inner blade and the outer blade can be realized by modifying the mold.

  The rotary tool of the present invention will be described based on an example of a throw-away drill which is a preferred example thereof. FIG. 1 is a schematic side view showing a drill according to the present embodiment. FIG. 2 is a schematic front view of the drill of FIG. 1 as viewed from the tip. FIG. 3 is a schematic diagram for explaining the arrangement of the outer cutter and the inner cutter when the drill of FIG. 1 is used for cutting. In FIG. 3, an insert indicated by a broken line indicates a position when the insert indicated by a solid line rotates 180 degrees.

  As shown in FIG. 1, the drill 1 according to the present embodiment has two throwaway inserts (hereinafter simply referred to as “inserts”) 3 to be described later attached to the tip of the tool body 2 whose center is the rotation axis O. It is a thing. One insert 3a is mounted by a screw 4 so that the inner blade 5 protrudes from the tip of the tool body 2, and the other insert 3b is radially outside the insert 3a at the tip of the tool body 2 and is the tool body 2. The outer blade 6 is mounted with screws 4 so as to protrude from the outer peripheral direction of the tool body 2 to the tip of the tool body 2. That is, the insert 3 a from which the inner blade 5 projects from the tool body 2 is provided on the radially inner side of the insert 3 b from which the outer blade 6 projects from the tool body 2.

  In the drill 1, the inner blade 5 cuts the hole bottom inner peripheral side of the work material (not shown), and the outer blade 6 cuts the hole bottom outer side and outer peripheral surface of the work material (not shown). Although it cuts, as shown in FIG. 2, FIG. 3, the rotation locus | trajectory of the inner blade 5 and the outer blade 6 cross | intersects each other, and it arrange | positions so that it may cover from the front-end | tip to the outer periphery of the drill 1 with both cutting blades. .

Further, using the drill 1, the work material is cut by the following steps (i) to (iii).
(I) The step of rotating at least one of the drill 1 and the work material to bring the inner blade 5 and the outer blade 6 of the drill 1 close to the work material (ii) At least one of the inner blade 5 and the outer blade 6 of the drill 1 A step of bringing the portion into contact with the surface of the work material and cutting the work material (iii) a step of separating the inner blade 5 and the outer blade 6 from the work material. Therefore, in the step (ii), the cutting force is not excessively increased by the cutting blades of the inner blade 5 and the outer blade 6, and the cutting edge is prevented from being broken, thereby enabling good cutting. . As a result, excellent machining accuracy can be exhibited, and a good finished surface can be obtained even for more severe cutting conditions and work materials with high difficulty.

  The tool body 2 has a substantially cylindrical shape, has a rotating shaft of the drill 1 (line O in FIG. 3), has a shank portion 8 for fixing itself to the machine tool on the rear end side, and a shank. A chip discharge groove 9 for discharging chips from the front end to the rear end of the tool body 2 is formed in a spiral shape on the front end side of the portion 8. In addition, an insert pocket 10 for attaching the insert 3 is provided at two positions at the distal end of the tool body 2, and the inner insert pocket 10a is opened to the distal end side in the axial direction of the tool body 2 so that the insert 3a is mounted. The outer insert pocket 10b is opened from the front end side in the axial direction of the tool body 2 to the outer blade, and the insert 3b is mounted.

  The details of the insert 3 attached to the drill 1 will be described. FIG. 4 is a plan view showing the insert of this embodiment. 5 is a side view of the insert of FIG. 4 as viewed from the arrow A side, and (b) is a side view as viewed from the arrow B side. FIG. 6: is an enlarged view which shows the cross section of the (a) II line about the insert of FIG. 4, (b) is an enlarged view which shows the cross section of the II-II line.

  The insert 3 according to the embodiment shown in FIG. 4 has a plate shape that is substantially polygonal when viewed from above, and a through hole 14 is formed at the center of the upper surface 11. Further, an inner blade 5 and an outer blade 6 are formed adjacent to each other on the intersecting ridge side portion 18 of the upper surface 11 of the insert 3.

According to the present invention, the inner blade 5 has a positive inner blade clearance angle β1 (an angle formed by the inner blade clearance surface 23 (side surface 12) and the line L1 perpendicular to the lower surface 17), and the upper surface 11 and the side surface 12 A straight 19 having a length Li = 0.01 mm to 0.095 mm perpendicular to the lower surface (sitting surface) 17 is formed on the side surface 13 side following the intersecting ridge line portion 18. The outer blade 6 has a positive outer blade clearance angle β2 (an angle formed by the outer blade clearance surface 29 (side surface 12) and the line L1 perpendicular to the lower surface 17), and the straight 20 is not formed, or the straight 20 Has a shape shorter than the inner blade 5. As a result, the inner blade 5 close to the rotation axis center (line O) at the time of cutting has a small cutting speed and the outer blade 6 far from the rotation center has a large frictional resistance even if the cutting speed increases. Even the outer blade 6 which is high in strength, is not broken, and is fast in wear can be sharp and slow in wear.

Here, when the length of the straight 20 of the outer blade 6 is Lo, the ratio (Li / (Lo + Li)) is 0.8 to 1 so that both the inner blade 5 and the outer blade 6 have resistance to resistance. It is desirable to achieve both fracture and wear resistance.

Even the insert 3 is a complicated shape, the difference of the straight 19 length Li over the entire circumference ridge of the cutting edge 18 of the inner cutter 5 is 0.005mm inside than is the cutting edge of the inner blade 5 This is desirable because the strength can be reliably increased to prevent defects.

  Furthermore, two or more inserts 3 having both the inner blade 5 and the outer blade 6 are used, one of which is mounted so that the inner blade 5 protrudes from the tip of the tool body 2, and the other is the outer blade 6 that is a tool. Even in a configuration in which the outer periphery of the main body 2 is projected from the tool main body 2 so as to protrude from the tool main body 2, that is, in an insert shape in which both the inner blade 5 and the outer blade 6 are formed in one insert 3, By adding a contrivance, the configuration of the straight 19 of the inner blade 5 and the straight 20 of the outer blade 6 can be realized in the insert 3.

  As shown in FIG. 5A, the inner blade 5 is formed at the intersecting ridge line portion 18 between the upper surface 11 (the inner blade scooping surface 23) and the side surface 12 (the inner blade flank 23) of the insert 3. 6 (a), an inner blade land 21 of 0.05 to 0.15 mm in order from the inner blade 5 and an inner blade rake angle α1 (virtual extension line L2 of the inner blade rake surface 22; An inner blade scooping surface 22 that is inclined downward at an angle formed by a line L3 parallel to the lower surface 17 of 5 ° to 25 ° is subsequently formed. Further, an inner blade relief surface 23 is formed on the side surface 12 of the inner blade 5.

  On the other hand, as shown in FIG. 5 (b), the outer blade 6 is formed at the intersecting ridge line portion 18 of the upper surface 11 (outer blade rake surface 28) and the side surface 12 (outer blade flank 29). As shown in FIG. 1, a projecting portion 25 projecting outward from the insert 3 in a top view is provided on one end side thereof. Then, as shown in FIG. 6 (b), in order from the outer blade 6, an outer blade land 26 of 0.05 to 0.15 mm, a width of 1.2 to 2 mm, and a depth of 0.03 to 0.15 mm. The outer blade breaker groove 27 and the outer blade land portion 24 are formed successively. An outer blade flank 29 is formed on the side surface 12 of the outer blade 6.

  The outer blade breaker groove 27 has a rake angle α2 (an angle formed by a virtual extension line L4 of the outer blade rake surface 28 and a line L3 parallel to the lower surface 17) inclined downward by 5 ° to 25 °. 28 and a rising angle γ (a virtual extension line L5 of the outer blade rising surface 30 and a line L3 parallel to the lower surface 17) from the outer blade rake surface 28 toward the center side of the insert 3 (through hole 14 side). Angle) It consists of an outer blade rising surface 30 rising from 20 ° to 45 °.

  Next, a method for manufacturing the above-described insert 3 will be described.

  The insert 3 is made of, for example, a hard sintered body such as cemented carbide, cermet, ceramics, diamond, cBN, or the like, and its surface is coated with a coating film as desired. The hard sintered body is manufactured by press-molding a mixed powder obtained by mixing a predetermined raw material powder together with an organic binder to produce a molded body, and then firing the molded body.

  The 1st method for implement | achieving the said structure of the inner blade 5 and the outer blade 6 of this invention is devising the shape of the metal mold | die used for press molding. FIG. 7 is a view for explaining an example of the manufacturing method of the insert of FIG. 4, and (a) a schematic plan view of an example of a die in a press-molding die for producing a molded article for insert; b) The principal part expanded sectional view of the AA cross section of (a) is shown. FIG. 8 is a schematic diagram showing (a) a state in which the compact is pressed using the press molding die in FIG. 7 and (b) a state in which the press compact is taken out.

As shown in FIGS. 7 and 8, the press-molding die 38 has a molded body portion in which the shape of the inner cavity 34 is widened toward the top in order to mold the insert 3 having a clearance angle β2 (> 0). 31 and the ratio t ₂ between the height t ₂ of the vertical wall surface portion 32 located immediately above the upper end surface X of the outer blade 6 of the molded body portion 31 / the height t ₁ of the molded body portion 31 = 0.03. A die 35 including a 0.35 vertical wall surface portion 32 and a relief portion 33 which is located immediately above the vertical wall surface portion 32 and has a width (w) wider than the vertical wall surface portion 32 at an angle θ (θ> β). The upper punch 36 and the lower punch 37 are a pair of punches.

  When the press-molding die 38 is used for molding, as shown in FIG. 8, when the molded body 39 is taken out from the die 35, a vertical wall surface is formed on the outer blade 6 side even if the molded body 39 expands due to a springback. Since the upper surface side surface end portion 40 of the molded body 39 interferes only by the length of the portion 32, the shape of the upper surface side surface edge portion 40 of the molded body 39 is not crushed and almost no frictional wear portion is formed. In addition, when pressed by the pair of punches 36 and 37, the powder pushed out from the upper surface of the molded body 31 to the upper horizontal part is usually sandwiched between the upper punch 36 and the die 35 to cause burrs. However, according to the present invention, since the extruded powder is discharged to the escape portion 33, the burrs generated without being pressurized at a very high pressure are made extremely thin and have a low density. be able to. Therefore, deburring can be easily performed with a slight force such as blowing air after molding. As a result, the straight 20 on the outer blade 6 side of the molded body 39 can be made small to form a sharp edge. It should be noted that the vertical wall surface portion 32 is higher than the height t2 or continues to the upper surface of the die 38 without providing the relief portion 33 on the side where the inner blade 5 of the die 38 is formed. Accordingly, when the molded body 39 is pushed up to the upper portion of the die 35 and taken out, the portion of the inner blade 5 interferes with the inner wall surface of the die 35 and is rubbed directly under the intersecting ridge line portion 18 of the side surface 12 of the molded body 39 to cause the straight 19 Form.

  That is, a relief portion 32 and, if desired, a vertical wall surface portion 32 are formed above the upper surface side surface end portion 40 on the outer blade 6 side, and an escape portion is formed above the upper surface side surface end portion 40 on the inner blade 5 side. By the method in which 32 is not formed, the large straight 19 is formed on the inner blade 5 and the straight 20 of the outer blade 6 can be made smaller. This method can also be applied to the case where the inner blade 5 and the outer blade 6 are formed on one insert 3.

  Moreover, although the 2nd method for implement | achieving the said structure of the inner blade 5 and the outer blade 6 of this invention is a method applicable when producing the inner blade 5 and the outer blade 6 as another insert. This is a method of changing the type of organic binder added to the raw material. Specifically, the organic binder added to the raw material for the inner blade insert uses a highly elastic material, and the molded body recovers elastically after molding, and a large straight is formed immediately below the intersecting ridge line portion of the molded body. The organic binder added to the raw material for the insert is small in elasticity, so that the elastic recovery amount of the molded body after molding is small, and the straight formed directly under the intersecting ridge line portion of the molded body can be reduced.

  Further, the third method for realizing the above-described configuration of the inner blade and the outer blade of the present invention is also a method applicable when the inner blade and the outer blade are produced as separate inserts. This is a method of changing the molding pressure. Specifically, the molded body for the inner blade insert is molded at a high molding pressure, and after the molding, the molded body recovers greatly and a large straight is formed immediately below the cutting edge ridge line portion of the molded body. The molded product for molding can be molded with a high molding pressure, and the amount of elastic recovery of the molded product after molding is small, and the straight formed directly under the cutting edge ridge line portion of the molded product can be reduced.

WC powder, Co powder, Cr ₃ C ₂ powder and TaC powder were mixed, and paraffin was added as a binder and granulated to prepare a granulated powder having an average particle size of 100 μm. Next, the predetermined portion has the cross-sectional shape shown in FIG. 7, model number SOMT06T204-5, insert thickness (molded body height) t ₁ = 3.79 mm, inner blade clearance angle β1 = 7 °, outer blade clearance. Prepare a die that can form an insert with an angle β2 = 13 ° and a pair of punches to be inserted into this, fill it with the granulated powder, press mold it, deburr it with an air brush, and make sure the clearance angle is correct. A positive chip-shaped compact was obtained. The molded body was debindered and vacuum fired to perform grinding and honing, and then a 3 μm thick TiAlN film was formed by PVD to produce an insert.

  The cutting edge portion of the obtained insert was observed with a projector, and whether or not a straight was formed immediately below the cutting edges of the flank surfaces of the inner blade and the outer blade and the length thereof were measured. The results are shown in Table 1. Further, no burrs remained on the inner blade and the outer blade. Here, the measurement of the straight length was performed using a shape measuring instrument. Specifically, the side of the insert was observed with a shape measuring instrument, and the straight length was measured from the contrast of the photograph. When the honing was formed on the cutting edge at the time of measurement, the straight length extending toward the flank face was measured with the lower limit of the honed portion as the reference point. Further, when the straight length was not known by this method, the insert was cut along a cross section including the intersecting ridge line portion, and the cross section was observed with a microscope to measure the straight length.

Then, this insert was mounted on the tool body of FIG. 1 and the following cutting test was performed to evaluate the cutting performance.
Cutting method: Drilling
Work material: SCM440H
Cutting speed: 150 m / minute feed: 0.1 mm / blade cutting: hole diameter 20 mm, hole depth 20 mm
Cutting state: wet evaluation method: Cutting was performed with an upper limit of 800 hole machining, and the number of machining until the inner blade (or outer blade) was damaged was recorded. Further, for the outer cutter, the amount of flank wear after 400 holes was machined was measured to compare the wear resistance. In measuring the wear amount, the honing length was not included in the wear amount.

  As is clear from the results of Table 1, no straight is formed on the inner blade, or the sample No. whose length is less than 0.01 mm. In 6 and 7, the inner blade was lost early. In addition, sample No. in which the straightness of the inner blade is larger than 0.095 mm. In No. 8, the cutting resistance in the inner blade increased and the fracture resistance was poor. In addition, the sample No. with the same straight length of the inner cutter and the outer cutter is the same. In No. 9, the wear on the outer blade progressed rapidly and the wear life was fast.

  On the other hand, in accordance with the present invention, the sample No. 1 in which a straight longer than the straight of the outer blade was formed on the inner blade. In Nos. 1 to 5, all were excellent in fracture resistance and wear resistance.

It is a schematic side view which shows the drill concerning one Embodiment of the rotary tool of this invention. It is the schematic front view which looked at the drill of FIG. 1 from the front-end | tip. It is a schematic diagram for demonstrating arrangement | positioning of the outer blade and the inner blade at the time of cutting with the drill of FIG. It is a top view which shows the throw away insert (insert) with which the drill of FIG. 1 is mounted | worn. It is the side view which looked at the insert of FIG. 4 from the (A) arrow A side, (b) It is the side view seen from the arrow B side. It is an enlarged view which shows the cross section of the (a) II line about the insert of FIG. 4, (b) It is an enlarged view which shows the cross section of the II-II line. It is a figure for demonstrating the manufacturing method of the insert of FIG. 4, and shows an example of the die | dye in the press molding die for producing the molded object for insert, (a) Schematic top view, (b) (a It is a principal part expanded sectional view of the AA cross section of). It is a schematic diagram which shows the state which has pressed the molded object using the metal mold | die for press molding of FIG. 7, (b) the state which takes out a press molded object.

Explanation of symbols

1 Drill 2 Tool body 3 Throw away insert (insert)
3a One insert 3b The other insert 4 Screw 5 Inner blade 6 Outer blade 8 Shank portion 9 Chip discharge groove 10 Insert pocket 10a Inner insert pocket 10b Outer insert pocket 11 Upper surface 12 Side surface 14 Through hole 17 Lower surface (sitting surface)
18 Crossed ridges 19 and 20 Straight 21 Inner blade land 22 Inner blade rake surface 23 Inner blade flank surface 24 Outer blade land portion 25 Projection portion 26 Outer blade land 27 Outer blade breaker groove 28 Outer blade rake surface 29 Outer blade flank surface 30 Outer blade rising surface 31 Molded body portion 32 Vertical wall surface portion 33 Relief portion 34 Inner cavity 35 Die 36 Upper punch 37 Lower punch 38 Press molding die 39 Molded body 40 Upper surface side surface end O Drill rotation axis Li Inner blade Straight length Lo Outer blade straight length L1 Line perpendicular to the lower surface (sitting surface) L2 Virtual cutting line L3 of the inner blade rake surface L3 Parallel line to the lower surface (sitting surface) L4 Virtual extension line of the outer blade rake surface L5 Virtual extension line α1 of outer blade rising surface Inner blade rake angle α2 Outer blade rake angle β1 Inner blade clearance angle β2 Outer blade clearance angle γ Rising angle t ₁ Height of molded part t ₂ Height of vertical wall surface

Claims (4)

Attach a throw-away insert to the tool body whose center is the rotation axis,
It is mounted so as to protrude from the tip of the tool body, a straight angle perpendicular to the seating surface is formed on the flank side that has a positive flank angle and follows the ridge line portion between the rake face and the flank face , An inner blade with a straight length Li = 0.01 mm to 0.095 mm ;
It is mounted on the outer side of the tool body so as to protrude from the outer periphery to the tip of the tool body so as to protrude from the tool body, and the clearance angle is positive and a straight is not formed or shorter than the inner blade. An outer blade formed with a straight,
A rotating tool characterized by comprising: The length of the straight front Kigaiha when the Lo, the ratio (Li / (Lo + Li) ) is rotary tool of claim 1, wherein it is 0.8 to 1. The difference in straight length Li over the entire circumference of the cutting edge ridge portion of the inner blade is 0 . Claim 1 or 2 rotary tool, wherein it is a 005mm inside than.   Using two or more throwaway inserts having both the inner blade and the outer blade, one is mounted so that the inner blade protrudes from the tip of the tool body, and the other is the outer blade is the tool. The rotary tool according to any one of claims 1 to 3, wherein the rotary tool is mounted so as to protrude from the tool main body from an outer periphery to a tip of the main body.

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