JP5243396B2 - Interchangeable cutting edge insert and milling cutter - Google Patents

Description

  The present invention relates to a corner cutting edge replaceable tip used for machining a right-angle corner and a milling cutter (milling cutter or end mill) for corner cutting using the tip.

  As a corner cutting edge replaceable tip (hereinafter referred to as a corner cutting tip), for example, those disclosed in the following Patent Documents 1 to 3 and those having a cutting edge having a shape approximate to a convex arc are known. .

  The corner cutting tip disclosed in Patent Document 1 has a shape in which a cutting edge formed by an intersection ridge of a side surface and a rake surface reaches the vicinity of the other end while gradually lowering the position from one end, and then the position gradually increases. It has become.

  Further, the corner cutting tips disclosed in Patent Document 2 and Patent Document 3 are temporarily raised so that the cutting edge forms a convex arc from one end, then the position gradually decreases toward the other end side, and then The shape is such that the position gradually increases.

JP 7-246505 A JP 2002-178210 A JP-A-6-190624

  For example, when a groove is formed in a workpiece by cornering, for example, a step processing method is often employed in which after the first pass processing is completed, the second pass processing is performed and the operation is repeated to deepen the groove. In that case, there is a step in the Z-axis direction connecting portion of the side surface (surface standing in the Z-axis direction) of the groove formed in the workpiece in the preceding process and the subsequent process. The step is caused by the locus of the cutting edge in the preceding process and the subsequent process being shifted in the Y-axis direction (perpendicular to both the Z-axis and the X-axis that is the cutter feed direction). is there.

  The model of the step is shown in FIGS. FIG. 18 shows a step s formed on the side surface 21a of the workpiece 20 when using the corner cutting tip disclosed in the above-mentioned Patent Documents 1 to 3, and FIG. 19 has a convex arc cutting edge. The steps s formed on the side surface 21a of the workpiece 20 when using a chip are exaggerated.

  The conventional corner cutting tip has a large step s, and the accuracy of the side surface processed into the workpiece is not sufficient. The step appears clearly on the processed side surface, the surface roughness of the side surface becomes rough, and the side surface becomes a surface with poor appearance and touch.

  It is an object of the present invention to improve a cornering insert and a milling cutter so that the step in the Z-axis joint portion of the side surface formed on the workpiece by step machining is reduced and the processing accuracy of the side surface is increased. It is said.

In order to solve the above problems, in the present invention, a rake face and a flat bottom face, a side face that intersects with the rake face at an acute angle and an obtuse angle with respect to the bottom face, and a cross ridge between the rake face and the side face. A positive-type corner cutting tip having a cutting edge constituted by:
That is, a first part having an L1 region length from which the cutting edge extends from one end to the other end, a second part having an L2 region length connected to the end of the first part, and a second part thereof A third part having an L3 region length connected to the terminal end of the second part on the other end side of the part,
The first, second and third parts are distributed in a right / left asymmetric ratio in a side view of the chip, and both the first part and the second part occupy most of the cutting edge,
Further, the second part is formed at a position biased toward the other end side of the cutting edge so as to be parallel to the bottom surface in a side view, and the chip thickness is T2 which is the maximum in the installation area of the second part. And
The first part and the third part are configured by straight lines, curved lines, or lines combining straight lines and curved lines, and the first part is the second part side from one end of the cutting edge set at the position of T1 where the chip thickness is minimum. The position of the third part gradually increased from the second part side toward the other end of the cutting edge.

  The tip is preferably set so that the total area of the first part and the second part occupies 70 to 80% of the entire installation area of the cutting edge. It is also preferable that the region length L1 of the first part is larger than the region length L3 of the third part.

  In addition, the first part is formed by a convex curve having a radius R1 in a side view of the chip, the third part is formed by a plurality of curves including a convex curve having a radius R2 in a side view of the chip, and the radius R2 is a radius R1. It is also preferable that the convex curve having a radius R2 is continuous with the second portion.

  In addition, the difference between the thicknesses T1 and T2 (T2−T1) is suitably in the range of 0.05 mm to 0.5 mm. The rake face is preferably a face provided with a positive rake angle. More preferably, the rake angle of each part of the cutting edge in the cross section perpendicular to the longitudinal direction is slightly changed so that the rake angle of each part of the cutting edge is substantially uniform in the usage state of the chip.

  The tip of the present invention has a square shape as a basic shape, and the cutting edge formed on the four sides of the rake face is excellent in economy. The cutting edge may be formed on one long side, and the cutting edge may be formed on three sides using a regular triangle as a basic shape.

  The corner cutting tip of the present invention described above has a state in which the axial rake is positive and the radial rake is negative on the tip seat provided on the outer periphery of the tip of the cutter body, and the first part is the tip side of the cutter, The second part is arranged in parallel with the axis of the cutter and is arranged on the rear side of the cutter so that the cutting blade is mounted on the outermost periphery of the cutter. The present invention also provides a corner milling cutter configured in this manner.

  In the corner cutting tip according to the present invention, most of the cutting edge is occupied by the first part and the second part, and with respect to the locus of the second part formed on the workpiece by the preceding machining in the above-described step machining. Processing can be performed in which the depth of cut in the subsequent processing is set so that the trajectories of the first part formed on the workpiece in the subsequent processing intersect.

  The step at the Z-axis direction connecting portion of the side surface formed on the workpiece by this method is such that the locus of the first portion from the radially outer end of the first portion (connection point with the second portion) is the locus of the second portion. It is represented by the amount of radial displacement of the first part in the range up to the position where it intersects.

  When a conventional tip is used, as shown in FIG. 18, most of the radial displacement of the cutting edge appears as a step s at the joint. Alternatively, as can be seen from FIG. 19, the locus of the cutting edge in the preceding machining and the subsequent machining intersects at a position displaced from the radial outer end of the cutting edge to the cutter center side, and from the radial outer end of the cutting edge. The amount of radial displacement up to the intersection is the step s.

  On the other hand, the corner cutting tip according to the present invention does not have a bulge that protrudes radially outward in the second portion of the cutting edge in use. In addition, since the first part and the second part occupy most of the cutting edge, the area length of the second part is made sufficiently long or the installation area of the first part is set to the longitudinal center of the cutting edge. It is possible to make the inclination of the first part gentler by extending it to a position exceeding. As a result, the radial distance from the intersecting portion to the radially outer end of the cutting edge becomes shorter, and the step s becomes smaller than the conventional chip. Therefore, the surface roughness of the side surface processed into the workpiece is improved.

  In addition, the area | region length of a 2nd part can fully be lengthened by setting so that the area | region which added the 1st part and the 2nd part may occupy 70 to 80% of all the installation area | regions of a cutting blade. Alternatively, the step s can be made smaller by making the slope of the first part gentler. Also, by doing so, it becomes possible to increase the cutting amount per pass.

  The operations and effects of the other configurations that are preferable in the above will be described in the following sections.

The perspective view which shows one form of the chip | tip for corner cutting of this invention Plan view of the chip for corner cutting in FIG. Side view of the corner cutting tip of FIG. The side view which looked at the chip | tip for corner cutting of FIG. 1 from the direction where a corner is placed in the center The figure which expanded the plane of a chip same as the above An enlarged view of the side of the chip The figure which expanded a part of side of Drawing 6 further Sectional drawing along the II line of FIG. Sectional view along the line II-II in FIG. Sectional view along line III-III in FIG. Sectional view along line IV-IV in FIG. The perspective view of the milling cutter of this invention Side view of the milling cutter of FIG. Front view of the milling cutter of FIG. Perspective view showing an example of corner cutting using a milling cutter The figure which shows the overlapping state of the locus | trajectory of the cutting edge in the step process using the chip | tip for corner cutting of this invention Sectional drawing which shows the level | step difference of the junction part of the side obtained by performing step processing with the chip | tip for cutting corners of this invention The figure which shows the outline | summary of the chip | tip for corner cutting of patent documents 1-3, and the level | step difference of the joint part of the side surface in the step processing using it A figure showing an example of a conventional corner cutting tip and a step at a joint portion of a side surface in step processing using the chip

  DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a corner cutting tip and a corner milling cutter using the same according to the present invention will be described below with reference to FIGS.

  FIG. 1 to FIG. 11 show an example in which the present invention is applied to a four-corner cutting edge replaceable tip whose basic shape is a square. The illustrated corner cutting tip 1 has a rake face 2 shown in FIGS. 1 and 2, a flat land 3 (upper surface) surrounded by the rake face 2, and a back face with respect to the land 3 and the rake face 2. A flat bottom surface 4 (see FIGS. 3, 4, 6, and 8 to 11), four side surfaces 5, and a mounting hole 6 disposed in the center of the land 3. A cutting edge 7 is formed by a ridge line generated at the intersection with the surface 2.

  As shown in FIGS. 8 to 11, the rake face 2 is inclined with respect to the direction in which a positive rake angle is generated in the cutting edge 7, the land 3 is parallel to the bottom face 4, and the side face 5 is relative to the rake face 2. Thus, the surfaces intersect each other at an acute angle and an obtuse angle with respect to the bottom surface 4.

Cutting edge 7, Part 1 _7-1 shown in FIGS. 5 to 7, Part 2 _{7 -2,} it consists of three regions of the third part _{7 -3.} The first part 7 _-1 and the second part 7 _-2 constitute the main cutting edge. Exemplary chip is provided with a third part _{7 -3} constituting the first part _{7 -1,} immediately next to Sarae edge of the second portion _{7 -2.}

The third portion _7-3 is inclined in a direction in which the side close to the corner portion approaches the bottom surface 4. Step is not generated in the cutting edge and the third part 7 _-3 such a shape. In addition, a third part 7 _-3 to function as Sarae blade when cutting the bottom side of the grooves, etc. to improve the surface roughness of the bottom surface, the side surface to be processed by the other hand main edge, the first You can escape 3 _{7 -3} from the workpiece. Further, since Part 3 7 _-3 first part _7-1 and the second part 7 there is no jumping out than _-2, there is no need to provide a special Sarae surface, the mounting surface of the tool body It is also possible to configure the side surface 5 (a surface formed between two corners; only the second surface 5b) may be a single plane.

Part 1 _7-1 is out extends from one end side to the other end of the cutting edge beyond the longitudinal center, has a region length of L1.

The second part _{7 -2} and continues to the end of the first part _{7 -1,} has a region length of L2. Part 3 7 _-3, at the other end of the cutting edge than the second part 7 _-2 and continues to the end of the second part 7 _-2, has a region length of L3.

The cutting edge 7 formed in the three regions of the first part _7-1 to the third part _7-3 has the first part _7-1 , the second part _7-2 , and the third part _7-3 as chips. Both the first part _7-1 and the second part _7-2 are blades that occupy most of the entire area of the cutting blades, which are distributed in a left-right asymmetric ratio in a side view.

The first part _7-1, includes cutting edge corner portion of the chip. Illustration of the chip, the nose R have been subjected to corner, edge of the arc of the cutting edge of the nose R portion is a starting end a of the first part 7 _-1. The cutting edge of the corner portion may not be arcuate.

As can be seen from FIGS. 5, 6, and 7, the second part _7-2 is in a position biased toward the other end side of the cutting edge 7. The second part _7-2 is formed so as to be parallel to the bottom surface 4 in a side view of the chip, and the chip thickness is T2 in the installation region of the second part _7-2 .

The 1st part _7-1 and the 3rd part _7-3 are comprised by the line which combined the straight line, the curve, or the straight line and the curve. Figure chip, first part _7-1 is formed in a convex arc of a curve of radius R1, Part 3 7 _-3 convex arc curve having a radius R2 having one end connected to an end of the second part 7 _-2 And a curved line of a concave arc having a radius R3, followed by a curved line of a convex arc having a radius R4 reaching the other end of the cutting edge 7.

Exemplary chip is the length of one side 12.7 mm, in this case, the radius R1 = 130 mm of the first part _{7 -1,} the radius R2 = 5 mm of the 3 _{7 -3,} radius R3 = 8 mm, the radius Although R4 = 3 mm, this value is only an example. About these R radii, the optimal value according to chip size etc. can be selected.

Also, the first part 7 _-1 Part 3 7 _-3, the angle between the extended straight line of the second part 7 _-2 as If it is the cutting edge of the convex curve closer to the second portion 7 _-2 gradually For this reason, it is preferable that the step in the Z-axis direction connecting portion of the side surface formed on the workpiece is smaller when it is considered that the cutting amount is the same, but this first part _7-1 and third part _7-3 can also be configured with a straight line. In the case of forming a straight blade, both may be connected to the second part _7-2 via a convex curve.

The length obtained by summing the area length L2 between the region length L1 of the first portion _{7 -1} second part _{7 -2,} for the reasons mentioned above, about 70-80% of the total installation area of the cutting edge 7 It is preferable to set the remaining 30 to 20% to the region length L3 of the third part.

Illustration of the chip length of one side 12.7mm is, (L1 + L2) was set at 70% of the total installation area of the blade 7 cut the chip thickness at the minimum value T1 (beginning of the first part _{7 -1} chips thickness ) And the maximum value T2 of the chip thickness (the chip thickness of the second portion formation region) t (= T2−T1) is set to 0.20 mm.

A value of t is suitably about 0.05 mm to 0.5 mm. Its A value of less than 0.5mm not tilt angle of the first portion 7 _-1 so large an increase in the level difference in the Z axis direction connecting portion with respect to the increase in the depth of cut is kept small.

Further, by the value or more 0.05 mm, to prevent the trajectory of the first part 7 _-1 while setting axial rake positively protrudes radially outward from the locus of the second part 7 _-2 be able to.

As shown in FIGS. 8 to 11, the rake surface 2 is a surface in which the rake angle θ of each part of the cutting edge is made different. In the illustrated chip rake angle θ2 of 13 ° strength at the position of the third part _{7 -3} shown in Fig. 9 (II-II in FIG. 2), the second part _{7 -2} shown in FIG. 10 (FIG. 2 setting θ3 of 17 ° little rake angle at the position of the III-III), the 20 ° little rake angle θ4 at the position of the first part 7 _-1 shown in Fig. 11 _(IV-IV in FIG. 2), respectively doing.

  In this way, by gradually changing the rake angle of each part of the cutting edge 7, the rake angle in the state of use of each part of the cutting edge involved in side cutting (when the chip is mounted on the cutter body) is made uniform. Therefore, the cutting performance of each part of the cutting edge and the chip discharge performance can be made uniform.

  Since the cutting edge of the corner portion of the chip is not a blade involved in the side cutting of the workpiece, the rake angle θ1 of the cutting edge of the corner portion (II in FIG. 2) shown in FIG. It may be set to an angle not related to the rake angle of the cutting edge involved. In the illustrated chip, the rake angle θ1 is set to be slightly over 6 °.

  The side surface 5 is composed of two curved surfaces: a first surface 5a having a predetermined radius of curvature and a second surface 5b having a smaller radius of curvature than the first surface 5a, and the first surface 5a is on the rake face side. In this example, the first escape is shown when the chip is used, but a side surface in which the first surface and the second surface are both flat may be used.

  In addition, the first surface 5a serving as the first clearance is effective for increasing the strength of the blade edge, but is not essential. In addition, the cutting edge 7 can be provided with a negative land for reinforcing the cutting edge as required.

The present invention can also be applied to a chip having a basic shape of a rectangle or a parallelogram or a chip having a regular shape of a regular triangle. In the former, the cutting edge 7 formed by the first part _7-1 to the third part _7-3 is formed on two long sides of the rake face, and in the latter, the cutting edge 7 is formed on three sides. That's fine.

  Next, an example of the milling cutter for corner cutting according to the present invention will be described with reference to FIGS. In the illustrated milling cutter 10, the tip rake 12 of the present invention is placed on the tip seat 12 provided on the outer periphery of the tip of the cutter body 11, the axial rake γp (see FIG. 13) is positive, and the radial rake γf (see FIG. 14). ) Is mounted in a negative state. In the illustrated chip 1, the axial rake γp is set to 10 ° and the radial rake γf is set to −8 °, but the numerical values are not limited thereto.

Corner cutting chip 1, first part _7-1 of the cutter tip side of the cutting edge 7, the second part 7 _-2 parallel to the axis of the cutter is arranged on the rear side of the cutter, the cutting edge The portion excluding the corner portion 7 is positioned on the outermost periphery of the cutter, and is seated on the chip seat 12 so that this situation is maintained. And it clamps with the clamp screw 13 which let the attachment hole 6 pass, and is fixed to the cutter body 11 so that attachment or detachment is possible. Reference numeral 14 denotes a chip pocket formed on the outer periphery of the cutter body 11 so as to correspond to the cutting edge of each chip.

As described above, the radial rake γf in the front view of the cutter is set to a negative value, but the rake face 2 is inclined so that the cutting edge involved in the cutting of the side face of the workpiece, that is, the first portion excluding the corner parts _7-1 and the second part 7 _-2 various parts of the third part 7 _-3, positive rake angle is imparted. The rake angle is an angle approximated to each part of the cutting edge when a radial straight line connecting the center (rotation center) of the cutter body and each part of the cutting edge is used as a reference. This is because the rake angle at each part of the cutting edge 7 is gradually changed, which leads to stabilization of sharpness of each part of the cutting edge and stabilization of chip discharge.

  FIG. 15 shows an example of step machining using a milling cutter for corner cutting. In this step machining, the milling cutter 10 for corner cutting is cut into the workpiece 20 at a predetermined cutting depth, the cutter is fed in one direction, and the operation is repeated several times to form the groove 21 formed in the workpiece 20. I will dig deeper.

Part 3 in the vicinity of the boundary between the second part 7 _-2 locus or second part 7 _-2 formed in the workpiece in a subsequent processing with respect to the first part 7 _-1 trajectory formed workpiece in the preceding process 7 locus of _-3 to implement stage process by setting the cutting depth in the subsequent processing so as to intersect.

21a is the side surface of the groove 21 formed in the workpiece 20 by the processing, and the side surface formed by the first pass processing in FIGS. 16 and 17 is the side surface formed by 21a _-1 and the second pass processing. Was displayed as 21a- ₂ . A step in the Y-axis direction is formed at the connecting portion in the Z-axis direction of the side surfaces 21a _-1 and 21a _-2 , and the step becomes smaller than the conventional one by using the tip and the milling cutter of the present invention.

  The step machining was performed using the corner cutting tip having the dimensions described above and the milling cutter using the same. As a result, the step generated at the side Z-axis connecting portion is extremely small, 0.008 mm in the present invention, compared to 0.026 mm when the conventional chip is used. This test confirmed the effectiveness of the present invention.

DESCRIPTION OF SYMBOLS 1 Corner-cutting tip 2 Rake face 3 Land 4 Bottom face 5 Side face 5a First face 5b Second face 6 Mounting hole 7 Cutting edge 10 Milling cutter 11 Cutter body 12 Chip seat 13 Clamp screw 14 Chip pocket 20 Work piece 21 Slot 21a Side surface 21a _- 1 Side surface 21a _- 2 of the first pass Side surface θ, θ1-θ4 of the second pass Rake angle γp Axial rake γf Radial rake T1 Minimum chip thickness T2 Maximum chip thickness s Step

Claims (8)

A rake face (2), a flat bottom face (4), a side face (5) that intersects the rake face (2) at an acute angle and an obtuse angle with respect to the bottom face (4), and the rake face (2) A corner cutting edge replaceable tip having a cutting edge (7) composed of a crossed ridge with the side surface (5),
The first portion (7 ₋₁ ) having the region length L1 that the cutting edge (7) extends from one end to the other end side, and the region length of L2 connected to the end of the first portion (7 ₋₁ ) A second part ( _7-2 ) having a length L3 and a third part having a region length L3 connected to the end of the second part ( _7-2 ) on the other end side of the second part ( _7-2 ). Part ( _7-3 ),
The first, second, and third parts (7 _{-1 to} 7 _-3 ) are distributed at an asymmetric ratio in a side view of the chip, and the first part (7 _-1 ) and the second part (7 _-2 ) Both occupy most of the cutting edge (7),
Furthermore, second parts _{(7 -2)} is formed so as to be parallel to the bottom surface (4) in side view, to a maximum (T2) chip thickness in the installation region of the second part _{(7 -2)} And
The first part (7 _-1 ) and the third part (7 _-3 ) are composed of a straight line, a curve, or a line combining a straight line and a curve, and the first part (7 _-1 ) has a minimum chip thickness (T1). ), The position gradually increases from one end of the cutting edge (7) set to the position of the second part ( _7-2 ) to the third part ( _7-3 ). _-2 ) A corner cutting edge replaceable tip whose position gradually decreases from the side toward the other end of the cutting edge (7). The region obtained by adding the first part (7 _-1 ) and the second part (7 _-2 ) is set so as to occupy 70 to 80% of the entire installation area of the cutting edge (7). Cutting edge replaceable tip for corner cutting. The first part (7 ₋₁ ) is formed with a convex curve with a radius R1 in a side view of the chip, and the third part (7 ₋₃ ) is a plurality of curves including a convex curve with a radius R2 in a side view of the chip. The cutting edge-replaceable tip for corner cutting according to claim 1 or 2, wherein the radius R2 is smaller than the radius R1, and the convex curve of the radius R2 is continuous with the second part ( _7-2 ).   The cutting edge replaceable tip for corner cutting according to any one of claims 1 to 3, wherein a difference (T2-T1) between the thicknesses T1 and T2 is set in a range of 0.05 mm to 0.5 mm.   The cutting edge replaceable tip for corner cutting according to any one of claims 1 to 4, wherein a positive rake angle is imparted to the rake face (2).   6. A cutting edge replaceable tip for corner cutting according to any one of claims 1 to 5, wherein a square is a basic shape, and the cutting edge (7) is formed on four sides of the rake face.   The cutting edge exchanging tip for corner cutting according to any one of claims 1 to 5, wherein the cutting edge (7) is formed on two long sides opposite to the rake face, the basic shape being a rectangle or a parallelogram. The blade tip replaceable tip according to any one of claims 1 to 7, wherein the axial rake (γp) is positive and the radial rake (γf) is on the tip seat (12) provided on the outer periphery of the tip of the cutter body (11). In a negative state, the first part (7 _-1 ) is arranged on the front end side of the cutter, and the second part (7 _-2 ) is arranged on the rear side of the cutter in parallel with the axis of the cutter. A milling cutter for corner cutting configured to be mounted in a state in which a portion excluding the corner portion of the cutting edge (7) is located on the outermost periphery of the cutter.

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