JP2014184552A - Metal saw, and processing method using the metal saw - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that a metal saw is liable to get clogging of cut chips between itself and a cutting object workpiece and a thin-walled part is deformable upon strike of a cut chip when a thin-walled multistage shape is formed in the metal saw.SOLUTION: A metal saw, which includes a disk-like body 1 provided at the center with a mount hole 3 used to mount the body 1 on a rotary shaft and a plurality of cutting parts 2 provided outside in the radial direction of the body 1, is characterized in that each cutting part 2 includes: a bottom blade 4 provided on a bottom surface side to cut a cutting object workpiece 51 coming in contact with the cutting part 2; a peripheral cutting blade 5 provided on the outer peripheral surface side to cut the cutting object workpiece 51 coming in contact with the cutting blade 5; a rake surface 19 with the bottom blade 4 and the peripheral cutting blade 5 as its sides; and a blade bottom dent part 14 where a thickness of the cutting part 2 provided behind flank surfaces 8, 9 of the bottom blade 4 in a direction of rotation.

Description

  The present invention relates to a metal saw and a processing method using the metal saw.

  In a conventional processing method for performing multi-stage cutting with a stepped cross section on a thin metal plate having a thickness of 10 mm or less, an end mill with less tool runout and cutting resistance is used to cut the thin metal plate. Normally used end mills have a diameter of 10 mm or less, the number of blades is 2 to 4, and the tool diameter is small and the number of blades is small. Therefore, in order to ensure a certain processing speed and processing accuracy, the spindle of the processing machine must be rotated. A low-vibration facility with a high speed of 20000 [rotation / min] or more and a small shaft runout was required (see Patent Document 1).

  As another multistage processing method, there is a method using a metal saw having 24 to 28 blades. By using a metal saw with a large tool diameter and a large number of blades in this way, it is possible to use a processing machine with a spindle rotation speed of less than 10000 [rotation / minute], and even if it is not a high-speed and low vibration equipment Time can be shortened and variations in processing accuracy can be reduced (see Patent Document 2).

JP-A-9-131610 JP 2011-178138 A

  As described above, in the multi-stage machining method using the conventional end mill, equipment for rotating the spindle of the machining machine at a high speed and with low vibration is necessary to ensure the machining speed and suppress the tool runout. In addition, since the number of blades of the tool is small from 2 to 4, the tool wears quickly, which causes the processing accuracy to vary.

  On the other hand, using a metal saw instead of an end mill can improve the problems associated with fast tool wear. There was a problem that the thin-walled portion was easily deformed by hitting with chips.

  The present invention is for solving the above-described problems, and provides a metal saw capable of easily discharging cut chips and preventing deformation of a workpiece to be processed with high accuracy, and a processing method using the metal saw. Objective.

  A metal saw according to the present invention is a metal saw having a disk-like body provided with a mounting hole at the center for mounting on a rotating shaft, and a plurality of blade portions provided on the outer side in the radial direction of the body. Each of the blade portions is provided on the bottom surface side to cut the workpiece, an outer peripheral blade provided on the outer peripheral surface side to cut the workpiece, the bottom blade and the outer cutter as a side. The rake face has a dent portion having a rake face which is smaller than the thickness of the body, the thickness of the blade portion provided behind the flank face of the bottom blade with respect to the rotation direction.

  According to the metal saw according to the present invention, it is difficult to cause deformation of the material to be cut and processing can be performed with high accuracy.

It is the top view seen from the bottom face side of the metal saw which concerns on Embodiment 1 of this invention. It is sectional drawing in the AA cross section shown in FIG. 1 of the metal saw which concerns on Embodiment 1 of this invention. It is sectional drawing which looked at the blade part which the metal saw which concerns on Embodiment 1 of this invention has from the front of the rotation direction, and the side view which looked at the blade part from the radial direction outer side. It is the top view seen from the bottom face side of the metal saw explaining the length relevant to the magnitude | size of the blade part of a metal saw. It is a figure explaining the positional relationship of the part and the blade part of the to-be-cut material cut by the metal saw which concerns on Embodiment 1 of this invention. It is an expanded sectional view at the time of the cutting process of the bottom blade which the metal saw which concerns on Embodiment 1 of this invention has. It is the side view seen from the thickness direction of the to-be-cut material processed into the thin multistage shape by the metal saw which concerns on Embodiment 1 of this invention, and the side view seen from the side. It is the top view seen from the upper side of the to-be-cut material explaining the processing method of the metal saw by the to-be-cut material which concerns on Embodiment 1 of this invention. It is the side view seen from the thickness direction of the to-be-cut material explaining the processing method of the metal saw by the to-be-cut material which concerns on Embodiment 1 of this invention. It is the side view which looked at the blade part of the metal saw which concerns on Embodiment 2 of this invention from the outer side of radial direction. It is the side view which looked at the blade part of the metal saw which concerns on Embodiment 3 of this invention from the outer side of radial direction. It is the side view which looked at the blade part of the metal saw which concerns on Embodiment 4 of this invention from the front of the rotation direction, and the side view which looked at the blade part from the outer side of radial direction.

Embodiment 1 FIG.
1 to 3 are views showing the shape of a metal saw according to Embodiment 1 of the present invention. 1 is a plan view seen from the bottom side of a metal saw according to Embodiment 1 of the present invention. 2 is a cross-sectional view of the metal saw according to Embodiment 1 of the present invention, taken along the line AA shown in FIG. 3 is a cross-sectional view of the blade portion of the metal saw according to Embodiment 1 of the present invention as viewed from the front in the rotational direction, and a side view of the blade portion as viewed from the outside in the radial direction. FIG. 3A is a cross-sectional view of the blade portion viewed from the front in the rotation direction, and is a cross-sectional view taken along the line BB shown in FIG. FIG. 3B is a side view of the blade portion as viewed from the outside in the radial direction, and is a side view of the portion of the blade portion surrounded by the dashed ellipse C in FIG. 1 as viewed from the D direction.

  In the present specification, the surface of the metal saw on the side where the workpiece is present during cutting is defined as the bottom surface, and the opposite surface is defined as the top surface. The direction from the top surface to the bottom surface is referred to as the bottom surface side or the bottom side, and the direction from the bottom surface to the top surface is referred to as the top surface side or the top side. The front means the front in the rotation direction of the metal saw at the time of cutting, and the rear means the rear in the rotation direction.

  As shown in FIGS. 1 to 3, the metal saw according to the first embodiment of the present invention has a disc-shaped body 1. A large number of blade portions 2 are provided on the outer side of the body 1 in the radial direction, and a key grooved hole 3 that is an attachment hole for attaching to the rotating shaft is provided at the center. A tooling part for attaching to an automatic machine such as a machining center is mounted on the key grooved hole 3 and attached to the rotary shaft of the automatic machine. As the material of the metal saw, for example, a cemented carbide obtained by mixing and sintering tungsten carbide and a binder is mainly used.

  The metal saw is used at a rotational speed of 10,000 [rotations / minute] or less, preferably 5000 [rotations / minute] to 8000 [rotations / minute]. Since the rotation speed is small, the centrifugal force acting on the metal saw is also reduced, and shaft runout can be suppressed.

  The blade portion 2 includes a bottom blade 4 that cuts the workpiece 51 (shown in FIG. 5) on the bottom surface side of the metal saw, and an outer peripheral blade 5 that cuts the workpiece 51 on the outer peripheral surface side. The number of blade portions 2 is about 15 to 20 when the outer diameter of the metal saw is, for example, 70 mm in diameter. The number of chip pockets 6 that are spaces between the blade portion 2 and the front blade portion 2 can be increased so that the cut chips can be effectively stored and discharged. In the first embodiment, the number of blade portions 2 is 16. The number of blades and the rotation speed are determined by comprehensively considering the chip discharge, machining accuracy, and machining speed.

  The upper surface of the body 1 is a plane. On the bottom surface of the body 1, a metal saw fixing portion 7 is provided around the key grooved hole 3. The metal saw fixing part 7 is for attaching a metal saw to a rotating shaft. On the outer side in the radial direction of the metal saw fixing portion 7, there is a main body bottom surface portion 8. The metal saw fixing portion 7 is formed with a height difference that protrudes toward the bottom surface side with respect to the body main bottom surface portion 8. The blade portion 2 also has a portion that protrudes further to the bottom surface side than the main body bottom surface portion 8.

  The thicknesses of the blade part 2 and the metal saw fixing part 7 are approximately the same at about 1 mm to 3 mm. On the other hand, the thickness of the body main bottom surface portion 8 is smaller than the thickness of the metal saw fixing portion 7. For example, when the thickness of the blade portion 2 is 3 mm, a difference in height that the body main bottom surface portion 8 is about 0.5 mm higher than the lowermost position of the blade portion 2 is different from the body main bottom surface portion 8 and the metal saw. Provided between the fixed portion 7. Since the body main bottom surface portion 8 is higher than the metal saw fixing portion 7, a space is formed between the body main bottom surface portion 8 and the workpiece 51. Even if the chips cut by the bottom blade 4 move to the bottom surface side of the body 1, the chips are accommodated in this space. Thus, clogging of chips between the bottom surface of the body 1 and the workpiece 51 can be prevented.

  As shown in FIGS. 1 and 3 (b), on the bottom surface of the blade portion 2, a bottom blade 4, a first bottom blade relief surface 9, a second bottom blade relief surface 10, a blade thickness reducing surface 11 and The blade thickness recovery surface 12 is formed continuously. As can be seen from FIG. 1, the first bottom blade clearance surface 9 and the second bottom blade clearance surface 10 have a quadrangular shape when viewed from the bottom surface side. On the other hand, the blade thickness reduction surface 11 and the blade thickness recovery surface 12 have a triangular shape when viewed from the bottom surface side. The blade thickness reducing surface 11 and the blade thickness recovery surface 12 have a radial inclination such that the apex of the triangle comes to the boundary between the body main bottom surface portion 8 and the blade thickness on the outer peripheral side becomes thin.

  The bottom blade 4, the first bottom blade flank 9, and the second bottom blade flank 10 protrude from the main body bottom surface 8 toward the bottom surface. On the radially inner side of the first bottom blade flank 9 and the second bottom blade flank 10, a bottom blade inclined surface 13 that is inclined between the body main bottom surface portion 8 is provided. The blade thickness reducing surface 11 and the blade thickness recovery surface 12 are provided on the upper surface side of the body main bottom surface portion 8. Therefore, the blade bottom reducing surface 11 and the blade thickness recovery surface 12 dent into the bottom of the blade, which is the space of the recessed portion of the triangular pyramid shape so as to be thinner than the thickness of the main body bottom surface 8 on the bottom surface side. Part 14 is formed.

  The first bottom blade clearance surface 9 is a clearance angle that is an angle with respect to a bottom blade cutting surface 52 (shown in FIG. 6) that is parallel to the main body bottom surface portion 8 at the lowest position of the bottom blade 4. A first bottom blade clearance angle θs1 is provided in the circumferential direction. The second bottom blade clearance surface 10 has a second bottom blade clearance angle θs2 that is larger than the first bottom blade clearance angle θs1 in the circumferential direction. The blade thickness reduction surface 11 has a blade thickness reduction angle θs3 that is an angle larger than the second bottom blade clearance angle θs2. That is, there is a relationship of θs1 <θs2 <θs3 between the two bottom blade clearance angles and the blade thickness reduction angles.

  The first bottom blade clearance angle θs1 is set to a value at which the first bottom blade clearance surface 9 immediately after the bottom blade 4 can avoid contact with the bottom blade cutting surface 52. The second bottom blade clearance angle θs2 and the blade thickness reduction angle θs3 are determined so that the volume of the blade bottom recess 14 is sufficiently increased while maintaining the strength of the blade portion. The first bottom blade clearance angle θs1 is, for example, 3 degrees, the second bottom blade clearance angle θs2 is, for example, 8 degrees, and the blade thickness reduction angle θs3 is, for example, 30 degrees.

  As shown in FIG. 2, the first bottom blade clearance surface 9 has a radial bottom blade clearance angle θsd in which the outer peripheral side slightly protrudes in the radial direction with respect to a plane parallel to the main body bottom surface portion 8. Similarly to the first bottom blade clearance surface 9, the second bottom blade clearance surface 10 has a slight clearance angle with respect to the bottom surface in the radial direction. By providing a clearance angle in the radial direction on the bottom surface of the blade portion 2, the contact surface of the bottom surface can be reduced and friction can be suppressed. The radial bottom blade clearance angle θsd is, for example, 1 degree.

  As shown in FIG. 1 and FIG. 3 (b), the blade portion 2 has a peripheral blade 5, a first peripheral blade clearance surface 15, a second peripheral blade clearance surface 16, and a blade diameter reduction surface 17 on the side surface. Between the adjacent blade portions 2, a chip pocket 6 which is a space for entering chips is formed. The outer peripheral blade 5 on the outer peripheral side of the blade portion 2 and the bottom blade 4 on the bottom surface side are collectively referred to as a cutting blade 18 (not shown). The cutting edge 18 is positioned in front of the blade part 2. Here, the blade diameter is the distance between the outer peripheral surface of the blade portion and the rotation center.

  The rake face 19 is a face having the outer peripheral edge 5 and the bottom edge 4 as sides. The rake face 19 has a bottom edge rake angle φs. The bottom edge rake angle φs is an inclination angle of the rake face 19 with respect to a bottom edge reference surface 53 (shown in FIG. 6) which is a plane perpendicular to the upper surface of the metal saw and parallel to the bottom edge 4. In addition, an outer peripheral edge rake angle φg is provided with respect to an outer peripheral edge reference surface 54 (not shown) which is a surface perpendicular to the bottom surface of the metal saw and parallel to the outer peripheral edge 5.

  The second outer peripheral blade flank 16 and the second bottom flank 10 are provided from the same circumferential position on the ridge line on the bottom surface side of the blade portion 2, and the blade bottom dent portion 14 and the blade diameter reducing surface 17 are the blade portion 2. Are provided from the same circumferential position on the ridge line on the bottom surface side. By doing so, the number of vertices of the blade portion having a polyhedral shape is minimized.

  The bottom edge rake angle φs and the outer edge rake angle φg of the rake face 19 are set to 8 to 10 degrees to achieve both reduction in resistance during cutting and edge strength. If the rake angle is increased, the cutting edge becomes sharper and the cutting resistance decreases, but the strength of the cutting edge decreases. The same applies to the peripheral edge rake angle φg. The bottom edge rake angle φs and the outer edge rake angle φg are appropriately determined in consideration of the strength and cutting performance of the edge.

  As shown in FIG. 3B, the outer peripheral blade 5 has a twisted shape having a twist angle δ. The twist angle δ is an inclination angle of the outer peripheral blade 5 with respect to the rotation axis of the metal saw. Moreover, the 1st outer periphery blade flank 15, the 2nd outer periphery flank flank 16 and the blade diameter reduction | decrease surface 17 which are continuously provided in order behind the outer periphery blade 5 have the same helix angle (delta). Each of the first outer peripheral blade clearance surface 15, the second outer peripheral blade clearance surface 16, and the blade diameter reduction surface 17 has a first outer peripheral clearance angle θg1, a second outer peripheral clearance angle θg2, and a blade diameter reduction angle θg3. Each of the first outer clearance angle θg1, the second outer clearance angle θg2, and the blade diameter reduction angle θg3 is parallel to the tangent to the outer circumference of the metal saw at the outermost radial position of the outer peripheral blade 5 and is the main body bottom surface portion 8. It is an angle with respect to the outer peripheral cutting surface 55 (shown in FIG. 5) which is a surface perpendicular to. The peripheral blade clearance angle and the blade diameter reduction angle have a relationship of θg1 <θg2 <θg3 so that the flank surface and the blade diameter reduction surface have a larger angle with respect to the peripheral blade cutting surface 55 as the distance from the peripheral blade 5 increases. .

  One of the points of the present invention is to reduce the number of blades from 15 to 20 in the case of a diameter of 70 mm, for example, as a metal saw for processing a thin multistage shape, in the case of a diameter of 70 mm. . A configuration for reducing the number of blade portions will be described. In addition, in the JIS standard (JIS-B4115) regarding the solid carbide metal saw to which the present invention applies, the number of blade portions is defined as 34 or more when the diameter is 63 mm. Thus, reducing the number of blades is contrary to conventional technical common sense, and has been devised by the inventors to improve processing accuracy.

  In FIG. 4, the top view seen from the bottom face side of the metal saw explaining the length relevant to the magnitude | size of the blade part of a metal saw is shown. FIG. 4A is a plan view of the entire metal saw viewed from below, and FIG. 4B is an enlarged view of the blade portion. Here, the following three circles are defined for the rotating metal saw. The blade circumscribed circle C1 is a circle drawn by the tip of the blade portion 2 when the metal saw rotates. The blade inscribed circle C2 is a circle drawn by the most radially inner point in front of the rake face of the blade portion 2. The interference limit circle C3 is a circle having a radius smaller than the radius of the blade circumscribed circle C1 by the interference consideration distance D. The interference consideration distance D is a distance from the contacted material that should be considered that the outer peripheral blade interferes (contacts) with the contacted material.

  The diameter L of the blade circumscribed circle C1 is the diameter of the metal saw. The height H of the blade portion is a difference in radius between the blade circumscribed circle C1 and the blade inscribed circle C2, that is, a radial distance. The length E of the blade edge is the distance between the point where the blade part contacts the blade circumscribed circle C1 and the point where the interference limit circle C3 intersects the blade part behind the outer peripheral blade. The distance P between the blade edges is a distance between the points in contact with the blade circumscribed circle C1 of the adjacent blade portion.

  The cross-sectional area of the chip pocket in a plane parallel to the upper surface of the metal saw changes substantially in proportion to the interval P between the cutting edges and the height H of the cutting edges, as shown in FIG. Therefore, in order to enlarge the chip pocket, it is necessary to increase the interval P between the blade edges and the height H of the blade portion. The inventors have examined in the case of a metal saw having a diameter of 70 mm, and determined that the number N of blade portions is 20 to 15 is appropriate. Note that the smaller the number N of blades, the larger the chip pocket and the better the chip discharge, but the lower the machining speed. Accordingly, there is an appropriate range for the number N of blade portions.

  In the case of a metal saw with a diameter of 70 mm, the number N of blades is 20 to 15 because the distance P between the blade edges falls within the range of about 15% to about 21% with respect to the diameter L of the metal saw. It means that there is. Even when the diameter L of the metal saw is not 70 mm, if the distance P between the cutting edges is within a range from about 15% to about 21% with respect to the diameter L of the metal saw, the cutting speed is maintained while maintaining the processing speed. The chip pocket can be enlarged so that it can be discharged efficiently.

  Regarding the height H of the blade portion, the chip pocket becomes larger as the height H of the blade portion is larger. However, if it is too large, the body becomes smaller and the strength of the metal saw is lowered. The height H of the blade portion needs to be about 5% or more of the diameter L of the metal saw, and is desirably a length that falls within the range of about 8% to about 10%. The upper limit determined from the point of strength is also taken into consideration.

  In order to enlarge the chip pocket, the shape of the blade is also important. The shape of the blade portion that ensures the strength of the blade edge and enlarges the chip pocket will be described. In order to ensure the strength of the blade part, the length E of the blade edge is made sufficiently large, and the flank face of the outer peripheral blade is moved away from the outer peripheral blade at an angle smaller than 15 degrees outside the interference limit circle C3. It is formed by changing discretely or continuously in two or more stages so as to increase. Inside the interference limit circle C3, the blade diameter (between the outer peripheral surface of the blade portion and the rotation center) is a straight line, a broken line, or a curve up to a position that contacts the blade inscribed circle C2 at an angle of 15 degrees or more, preferably 30 degrees or more. Provide a blade diameter reduction surface that reduces the distance. In the first embodiment, there are provided two flank surfaces, a first outer flank flank 15 and a second outer flank flank 16. By doing so, the cutting edge strength can be ensured and the chip pocket can be enlarged.

  Although it is possible not to provide the second outer peripheral blade flank 16, by providing the second outer peripheral blade flank 16 having the second outer peripheral blade flank angle θg2 having the relationship θg1 <θg2 <θg3, The blade portion is less likely to interfere with the material to be cut than when the blade diameter reducing surface 17 is provided immediately after the first outer peripheral blade clearance surface 15 while maintaining the strength.

  The clearance angles and circumferential lengths of the first outer peripheral blade clearance surface 15 and the second outer peripheral blade clearance surface 16 are appropriately determined in consideration of cutting resistance, blade edge strength, and the size of the tip pocket. When the lengths of the first outer peripheral blade flank 15 and the second outer peripheral flank 16 are increased, the blade edge strength is increased, but it is difficult to increase the chip pocket.

  The first outer peripheral blade flank 15 and the second outer peripheral flank 16 need to have a sufficient length so that the blade portion 2 has sufficient strength. For example, when the diameter of the metal saw is 70 mm, the first outer peripheral blade flank 15 has a length of about 2 mm or more in the circumferential direction, and the second outer peripheral blade flank 16 has a length of about 3 mm or more. . The length E of the blade edge must be about 5 mm or more. The first outer clearance angle θg1 is, for example, 1 degree, the second outer periphery clearance angle θg2 is, for example, 10 degrees, and the blade diameter reduction angle θg3 is, for example, 45 degrees.

  Subsequently, the function of each part constituting the metal saw will be described. FIG. 5 is a diagram for explaining the positional relationship between a portion of a workpiece to be cut by the metal saw according to Embodiment 1 of the present invention and a blade portion. FIG. 5A is a plan view seen from the upper surface side, FIG. 5B is a side view seen from the direction in which the metal saw exists, and FIG. 5C is seen from the rear in the moving direction of the metal saw. It is a side view. In FIG. 5, for easy understanding of the drawing, the metal saw shows only one blade portion 2 to be cut, and in FIG. 5B and FIG. 5C, the blade portion 2 is indicated by a dotted line. 6 is an enlarged cross-sectional view of the bottom blade of the metal saw according to Embodiment 1 of the present invention when it is cut. FIG. 6 is a cross-sectional view taken along the line EE shown in FIG.

  In FIG. 5, the workpiece 51 has been cut to the portion indicated by the solid line, and the metal saw is moved from the left to the right in FIG. 5A in order to cut to the portion indicated by the broken line. The tip of the blade 2 shown in FIG. 5A moves as indicated by a dotted line, and a hatched portion 56 surrounded by the solid line and the dotted line is cut by the illustrated blade 2.

The cut chips are mainly generated on the upper side of the rake face 19 and are discharged to the outside through the chip pocket 6. A small amount of chips moving below the bottom blade 4 are also generated. The following five factors can be considered.
(1) When the workpiece 51 is torn by applying a shearing force by the bottom blade 4, large chips are formed on the upper side of the rake face 19 and small chips are also formed on the lower side of the bottom blade 4.
(2) The bottom blade cutting surface 52 cut by the bottom blade 52 is raised, and the protruding portion is cut by the subsequent blade portion 2 to generate chips that move to the lower side of the bottom blade 4. .
(3) When the workpiece 51 is torn by the shearing force applied by the outer peripheral blade 5, large chips are formed inside the rake face 19 in the radial direction, and small chips are also formed outside the outer peripheral blade 5 in the radial direction. Occur. Part of the chips generated on the outer side in the radial direction of the outer peripheral blade 5 falls on the bottom blade cutting surface 52 and moves below the bottom blade 4.
(4) The outer peripheral blade cutting surface 55 cut by the outer peripheral blade 5 is in a raised state, and the protruding portion is cut by the subsequent blade portion 2 to generate small chips on the outer side of the outer peripheral blade 5 in the radial direction. To do. Part of the chips generated on the outer side in the radial direction of the outer peripheral blade 5 falls on the bottom blade cutting surface 52 and moves below the bottom blade 4.
(5) A part of the chips generated on the upper side of the rake face 19 falls on the bottom blade cutting surface 52 by hitting the side surface of the metal saw surrounding the chip pocket 6. Large chips are spattered by the rake face 19 of the subsequent blade 2, while small chips move below the bottom blade 4.

  A blade that is a space in a recessed portion of a triangular pyramid shape in which the thickness of the blade portion 2 is smaller than the thickness of the main body bottom surface portion 8 on the bottom surface side of the blade portion 2 by the blade thickness reducing surface 11 and the blade thickness recovery surface 12 A bottom recess 14 is formed. By providing the indented portion 14 on the bottom of the blade, chips moving below the bottom blade 4 can be discharged to the outside without hitting the bottom surface of the blade portion 2, or hit the blade thickness reducing surface 11 or the blade thickness recovery surface 12. After that, the traveling direction is bent outward in the radial direction and discharged to the outside. Moreover, since the space on the bottom surface side of the blade portion 2 can be increased, chips are not clogged between the blade portion and the bottom blade cutting surface 52.

  In order to efficiently discharge chips, it is desirable that the indented portion of the blade bottom is as large as possible. When the dent portion is enlarged, the strength of the blade portion decreases. The shape and size of the indented portion of the blade bottom are determined so that the strength of the blade portion can be maintained and chips can be efficiently discharged. As one guideline for ensuring the strength, it is desirable that the depth of the indented portion of the bottom of the blade bottom is about ½ or less of the thickness of the body at the main bottom surface of the body. In the first embodiment, the indented portion of the blade bottom has a triangular pyramid shape. However, the shape may be a polygonal pyramid shape such as a quadrangular pyramid shape, a polyhedral shape that is not a pyramid shape, a shape having a curved surface in part or all, and the like. Any shape may be used as long as it has a volume as large as possible to accommodate and discharge chips moving on the bottom surface side of the blade, opens to the outer peripheral side, and maintains the strength of the blade portion.

  As shown in FIG. 6, irregularities of about 20 μm to 30 μm are generated on the bottom blade cutting surface 52. The length of the first bottom blade clearance surface 9 and the first bottom blade clearance angle θs1 are such that the distance between the bottommost portion of the second bottom blade clearance surface 10 and the bottom blade cutting surface 52 is equal to the bottom blade cutting surface 52. Determine to be larger than the height of the unevenness. Although it is possible not to provide the second bottom blade flank 10, it is possible to increase the strength of the blade edge by providing the second bottom blade flank 10 having the second bottom blade flank angle θs2 having the relationship θs1 <θs2 <θs3. As compared with the case where the blade thickness reducing surface 11 is provided immediately after the first bottom blade flank 9, the volume of the blade portion that protrudes to the bottom surface side of the main body bottom surface portion can be reduced, and the bottom surface side of the blade portion is maintained. The chips will be able to move easily. Note that the clearance angle may be changed discretely or continuously between the first bottom blade clearance surface 9 and the blade thickness reduction surface 11 in two or more steps.

  Since the outer peripheral blade 5 has a twist angle δ, the outer peripheral blade 5 starts to cut the workpiece 51 from the bottom side. Therefore, chips are cut from the bottom surface side to the top surface side by the outer peripheral blade 5, chips are generated on the top surface side, and chips can be efficiently discharged to the top surface side of the metal saw. Thereby, even when the chip dischargeability is improved and cutting is performed at a higher processing speed, chips on the outer peripheral surface side of the blade portion 2 are quickly discharged to the outside, and deformation of the workpiece 51 due to chip collision can be suppressed.

  Furthermore, in the metal saw according to the first embodiment, 34 or more pieces with a diameter of 63 mm, which is a general number of blades of a metal saw, are reduced from 15 pieces to 15 pieces with a diameter of 70 mm. By reducing the number of blades, the chip pocket can be enlarged and the cut chips can be effectively discharged. The cut chips are discharged from the chip pocket mainly from the upper side to the outside. If the chip pocket capacity is small, some of the chips overflow and move toward the workpiece or bottom, and may hit the workpiece or be damaged, or clog between the bottom of the blade and the workpiece. . When chips are clogged between the workpiece and the blade, the workpiece is scraped or rubbed with the chips, and the surface roughness and dimensional accuracy deteriorate.

  Next, a processing method for processing a material to be cut into a thin multistage shape when using the metal saw of the first embodiment will be described.

  FIG. 7 is a side view seen from the thickness direction and a side view seen from the side of a workpiece to be cut into a thin multistage shape by the metal saw according to Embodiment 1 of the present invention. Fig.7 (a) is the side view seen from the thickness direction of the to-be-cut material, FIG.7 (b) is the side view seen from the side.

  The machined material 51 after processing has a thinnest portion 57 at the tip, and the thickness increases as it goes down. Since the thickness of the minimum thin portion 57 at the tip is very thin, 0.1 mm or less, and the chips at the time of cutting are deformed when colliding with the thin portions, the chips are more efficiently released, so that the workpiece 51 It is necessary to suppress deformation.

  8 and 9 show a method for processing a thin multi-stage shape using the metal saw of the present invention. FIG. 8 is a plan view seen from the upper side of the material to be cut, for explaining the method of processing the material to be cut by the metal saw according to Embodiment 1 of the present invention. FIG. 9 is a side view seen from the thickness direction of the workpiece for explaining the machining method of the workpiece by the metal saw according to Embodiment 1 of the present invention.

  As can be seen from FIG. 8, the metal saw rotates while the bottom blade 4 and the outer peripheral blade 5 are pressed against the workpiece 51, and moves around the workpiece 51 to cut the side surface of the workpiece. . By cutting by changing the cutting width stepwise depending on the height, the workpiece 51 can be processed into a multi-stage shape in which the cross section viewed from the thickness direction is stepped. In FIG. 8, the metal saw that rotates clockwise as viewed from above is moved counterclockwise as viewed from above around the workpiece 51 in order to cut by up-cutting. In addition, the side surface of the workpiece is cut with the outer peripheral blade, and the horizontal surface of the workpiece is cut with the bottom blade for processing. By cutting by up-cutting, the collision force of the cutting edge to the workpiece 51 during cutting is suppressed, and deformation of the thin portion is suppressed. The metal saw rotates around the workpiece 51 as many times as necessary to cut the cutting material to the required cutting width. If it can cut to the required cutting width, the workpiece or metal saw is moved in the thickness direction, and then moved in the height direction to cut the lower side of the cut portion of the workpiece. The cutting width is changed discretely according to the height.

FIG. 9 shows the cutting sequence in the height direction of the workpiece 51 when the workpiece 51 is processed into a thin multi-stage shape. FIG. 9 is a view of the workpiece 51 as viewed from the side, and the cutting sequence in the height direction when forming the thin multi-stage shape is 1 from the top to the bottom so as to form from the thinnest portion 57 side of the tip. Cutting is performed step by step or by changing the cutting height per step to two or more times. Since machining is performed from the thinnest wall portion 57 at the uppermost stage, the material to be cut below the thinnest wall portion 57 can secure a sufficient thickness, and can secure rigidity at the time of cutting, thereby suppressing deformation of the thin wall portion due to cutting. Can do.
The above also applies to other embodiments.

Embodiment 2. FIG.
The metal saw of the second embodiment is characterized in that a sintered diamond material is provided at the tip of at least one of the bottom blade and the outer peripheral blade. FIG. 10 is a side view of the blade portion of the metal saw according to Embodiment 2 of the present invention as viewed from the outside in the radial direction. Here, a super hard material is used as the base material of the metal saw, and a portion of the sintered diamond material 20 that is a material harder than the base material is provided at the tip of the cutting edge 18A (not shown). The size of the sintered diamond material 20 is such that the vertical length is cut by the outer peripheral blade 5A, the horizontal length is cut by the bottom blade 4A, and the thickness is about 1 mm. After being attached to the tip of the cutting edge 18A by brazing or the like, it is polished so as to have the shape of the cutting edge 18A. The vertical length of the sintered diamond material 20 may be shorter than the length cut by the outer peripheral blade 5A. The horizontal length of the sintered diamond material 20 may be shorter than the length cut by the bottom blade 4A.

  When the number of steps of the thin multi-stage shape is large or the overall size is large, the total length that the metal saw cuts becomes long, and the tip of the cutting edge 18A is easily worn, resulting in a problem that the tool life is shortened. In Embodiment 2, the tool life of the metal saw can be improved by providing the hard sintered diamond material 20 at the tip of the cutting edge 18A.

  After processing into a thin wall, bending may occur if a force in the lateral direction (direction perpendicular to the thin wall) is applied to the thin wall portion. When the outer peripheral blade is worn, the cutting force in the lateral direction increases, and bending tends to occur. The outer peripheral blade has a lower tolerance for wear, and the tool life is often determined by the wear of the outer peripheral blade. In the case of thin wall processing, it is more important not to wear the outer peripheral blade.

Embodiment 3 FIG.
The metal saw according to the third embodiment is characterized in that the cutting edge (bottom edge and outer peripheral edge) is rounded. FIG. 11: is the side view which looked at the blade part of the metal saw which concerns on Embodiment 3 of this invention from the radial direction outer side.

  In the metal saw of the third embodiment, in order to increase the strength of the cutting edge 18B (not shown), the tip of the cutting edge 18B which is the position on the outermost peripheral side of the bottom blade 4B and the position on the bottommost side of the outer peripheral blade, A cutting edge corner 21 that is a minute rounding with a radius of curvature of 0.1 mm to 0.3 mm is provided. That is, the cutting edge corner 21 is a curved portion such as a part of a spherical surface provided at the tip of the cutting edge 18B.

  When the number of thin multi-stage shapes is large or the overall size is large, the total length of cutting with a metal saw becomes long, and the tip of the cutting edge that first collides with the work material in the blade part tends to wear out. The problem is that the tool life is short. Therefore, in the third embodiment, in order to improve the tool life of the metal saw, by providing the cutting edge corner 21 at the tip of the cutting edge 18B, it is possible to avoid the concentration of force on the tip of the cutting edge 18B. It is possible to suppress only 18 chips and tips from wearing out quickly, and the tool life can be improved.

Embodiment 4 FIG.
The metal saw of the fourth embodiment is a case where the length of the outer peripheral blade is made smaller than the thickness of the body portion. By doing so, the thickness of the body part necessary for maintaining the strength of the metal saw can be ensured even if the length of the outer peripheral blade is reduced so that fine processing can be performed in the height direction. FIG. 12: is the side view which looked at the blade part of the metal saw which concerns on Embodiment 4 of this invention from the front of the rotation direction, and the side view which looked at the blade part from the radial direction outer side. FIG. 12A is a side view of the blade portion viewed from the front in the rotational direction, and FIG. 12B is a side view of the blade portion viewed from the outside in the radial direction. As shown in FIG. 12, the metal saw of the fourth embodiment is provided with a notch 22 that is a space where the outer peripheral blade 5C does not exist above the outer peripheral blade 5C and below the upper surface of the metal saw.

  When the height of one step cut by the outer peripheral blade is about 2 mm, for example, and the thickness of the body part necessary for securing the strength of the metal saw is smaller than, for example, 3 mm, the height of the outer peripheral blade 5C of the metal saw is A cutout 22 that is a space on the upper surface side of the outer peripheral blade 2C is provided so as to be the same as the height of one step to be cut. Providing the notches 22 enables fine processing in the height direction while maintaining the strength of the metal saw. Further, since a space is formed above the outer peripheral blade 5C, chips cut by the outer peripheral blade can be quickly discharged to the outside, and chips can be prevented from clogging between the outer peripheral blade and the workpiece.

1 Body 2, 2A, 2B, 2C Blade 3 Hole with keyway (Mounting hole)
4, 4A, 4B Bottom blade 5, 5A, 5B, 5C Peripheral blade 6 Tip pocket 7 Metal saw fixing portion 8 Body main bottom surface portion 9 First bottom blade clearance surface 10 Second bottom blade clearance surface 11 Blade thickness reduction surface 12 Blade thickness Recovery surface 13 Bottom blade inclined surface 14 Bottom bottom recess 15 First outer peripheral blade clearance surface 16 Second outer peripheral blade clearance surface 17 Blade diameter reduction surface 18 Cutting edge 19, 19C Rake surface 20 Sintered diamond material 21 Cutting edge corner 22 Notch 51 Workpiece material 52 Bottom blade cutting surface 53 Bottom blade reference surface 54 Peripheral blade reference surface 55 Peripheral blade cutting surface 56 Part to be cut 57 Thinnest portion θs1 of the cutting material First bottom blade clearance angle θs2 Second bottom blade clearance Angle θs3 Blade thickness reduction angle θsd Radial bottom blade relief angle φs Bottom blade rake angle φg Peripheral blade rake angle δ Torsion angle θg1 First outer circumference relief angle θg2 Second outer circumference relief angle θg3 Blade diameter reduction angle C1 Blade circumscribed circle C2 Inside the blade Contact circle C3 Interference limit circle D Interference consideration distance L Blade circumscribing Number of intervals N blade portion of the height E tip diameter H blade portion (metal saw)

Claims (15)

A disc-shaped body provided with a mounting hole at the center for mounting on the rotary shaft;
A metal saw having a plurality of blade portions provided on the outer side in the radial direction of the body,
Each of the blade portions has a bottom blade that is provided on the bottom surface side to cut the workpiece, an outer peripheral blade that is provided on the outer peripheral surface side to cut the workpiece, the bottom blade, and the outer peripheral blade as sides. A metal saw, characterized in that it has a rake face and a dent part on the bottom of the blade provided behind the flank face of the bottom blade with respect to the direction of rotation, which is smaller than the thickness of the body.   The metal saw according to claim 1, wherein a metal saw fixing portion provided around the attachment hole and a body main bottom surface portion having a thickness smaller than that of the metal saw fixing portion are provided on the bottom surface of the body.   3. The metal saw according to claim 1, wherein the indented portion of the blade bottom is provided as a triangular pyramid-shaped space above the main body bottom surface portion.   The metal saw according to any one of claims 1 to 3, wherein the blade portion is provided with a portion that protrudes below the main body bottom surface portion.   A blade diameter reducing surface having an angle larger than an angle of the flank with respect to the outer peripheral blade cutting surface cut by the outer peripheral blade between the flank of the outer peripheral blade and the rake face of the blade portion at the rear. The metal saw according to any one of claims 1 to 4, wherein the metal saw is provided.   The metal saw according to claim 5, wherein the blade bottom dent portion and the blade diameter reducing surface are provided from the same position in the circumferential direction on a ridge line on the bottom surface side of the blade portion. A first outer peripheral flank provided immediately after the outer peripheral blade, which is a flat surface having a first outer peripheral blade clearance angle with respect to the outer peripheral blade cutting surface cut by the outer peripheral blade, and provided behind the first outer peripheral flank. A second outer peripheral flank that is a flat surface having a second outer peripheral blade escaping angle larger than the first outer peripheral flank clearance angle,
A first outer peripheral flank provided immediately after the bottom blade, which is a flat surface having a first bottom blade clearance angle with respect to a bottom blade cutting surface cut by the bottom blade, and provided behind the first outer peripheral flank. A second outer peripheral flank that is a flat surface having a second bottom blade clearance angle larger than the first bottom blade clearance angle
The said 2nd outer peripheral blade flank and the said 2nd bottom flank are provided from the same position of the circumferential direction in the ridgeline by the side of the bottom face of the said blade part, The any one of Claim 1-6 Metal saw according to item.   The metal saw according to any one of claims 1 to 7, wherein the outer peripheral blade is a twist blade having a twist angle.   When the metal saw rotates, the distance between the blade tip, which is the distance between the tip of the blade part farthest from the rotation center and the tip of the adjacent blade part, is 15 of the diameter of the blade circumscribed circle that is a circle drawn by the tip. The metal saw according to any one of claims 1 to 8, wherein the length is in a range from% to 21%.   The radius of the blade circumscribed circle that is the circle drawn by the tip of the blade portion farthest from the rotation center when the metal saw rotates, and the blade inscribed circle that is drawn by the point closest to the rotation center in front of the rake face The metal saw according to any one of claims 1 to 9, wherein a height of the blade portion which is a difference in radius of a circle is set to a length of 5% or more of a diameter of the circumscribed circle of the blade. .   The metal saw according to any one of claims 1 to 10, wherein a sintered diamond material is provided on the bottom blade or the outer peripheral blade.   The rounding process is performed on the tip of the blade portion which is the position on the outermost peripheral side of the bottom blade and the position on the most bottom surface side of the outer peripheral blade. Metal saw.   The metal saw according to any one of claims 1 to 12, wherein a notch, which is a space without the outer peripheral blade, is provided above the outer peripheral blade and below the upper surface of the body. .   Using the metal saw according to any one of claims 1 to 13, by cutting the side surface of the workpiece with the outer peripheral blade and cutting the bottom surface of the workpiece with the bottom blade. A processing method using a metal saw, wherein the material to be cut is processed into a multi-stage shape with a thickness increasing toward the lower side.   The processing method using a metal saw according to claim 14, wherein the metal saw is used to cut from the uppermost stage having the smallest thickness of the multistage shape.

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