JP4211655B2 - Roughing end mill manufacturing method - Google Patents

Description

  The present invention relates to a method for manufacturing a roughing end mill in which a corrugated cutting edge is used exclusively for roughing a workpiece.

For example, as shown in Patent Documents 1 to 3, the luffing end mill has a cutting edge 2 that is uneven in a waveform such as an arc shape or a sine wave shape on the outer periphery of the end portion of the end mill body 1 rotated around the axis O as shown in FIG. In general, the end mill main body 1 is formed with such cutting edges 2 at intervals in the circumferential direction, and the cutting edges 2 adjacent to each other in the circumferential direction are not The resulting waveform is out of phase. According to such a luffing end mill, the cutting blade 2 is cut into the workpiece while rotating the end mill main body 1 so that the convex portion of the waveform of the cutting blade 2 is shifted as shown in FIG. Since the cross-sectional chips are generated by being divided, it is used to increase machining efficiency for roughing in the machining of a workpiece made of a metal material exclusively.
Japanese Patent No. 3356823 JP-A-8-13211 JP 2001-121340 A

  By the way, in the roughing end mill having the corrugated cutting edge 2, a groove portion is first formed on the outer periphery of the end portion of the end mill body 1 by a known means, and the outer peripheral side of the wall surface facing the end mill rotation direction of the groove portion. Grinding is performed by the grindstone 4 provided with the grinding surface 3 having a cross-sectional shape corresponding to the waveform formed by the cutting edge 2 on the outer peripheral surface of the end mill main body 1 continuous from the side ridge to the side ridge as shown in FIGS. By applying, the cutting edge 2 is formed in the outer peripheral side ridge part of the said wall surface, and it manufactures. In addition, it is also possible to manufacture by manufacturing a normal end mill in which the cutting edge is not uneven, and grinding the cutting edge with the grindstone 4 having the grinding surface 3 as described above. Here, in FIG. 6, one convex portion having a cross-sectional shape corresponding to the corrugated concave portion formed by the cutting edge 2 is formed on the grinding surface 3 of the grinding wheel 4, and both ends of the grinding surface 3 on both sides of this convex portion are formed. The part is formed with a semi-recess having a cross-sectional shape corresponding to substantially half of the convex part of the cutting edge 2, and this grinding wheel 4 is moved along the cutting edge 2 by one pitch of the waveform formed by the cutting edge 2. In this way, the corrugated irregularities are sequentially connected to form the entire length of the cutting blade 2 in a corrugated shape.

  In FIG. 7, two convex portions corresponding to the corrugated concave portion formed by the cutting blade 2 are formed on the grinding surface 3, and a concave portion corresponding to the convex portion of the cutting blade 2 is formed between them. Both end portions are inclined surfaces extending in the tangential direction from the middle of the two convex portions, and grinding is also performed by moving the grindstone 4 along the cutting blade 2 by one pitch of the waveform of the cutting blade 2. The corrugated irregularities are sequentially connected, and the periphery of the convex portion of the cutting blade 2 left uncut by the inclined surface is ground by the concave portion at the center of the grinding surface 4. The corrugated cutting edge 2 ground in this way is on the rear end side of the end mill body 1 (right side in FIGS. 6 and 7), and in the example of FIG. 1 is connected to the outer peripheral surface of the shank portion 5 at the rear end portion, and in the example of FIG. 7, the inclined surface intersects the outer peripheral surface of the shank portion 5 at an obtuse angle.

  However, in the example shown in FIG. 6, when the grindstone 4 is shifted and moved along the cutting edge 2, the interval of each movement is precisely matched to one pitch of the waveform formed by the cutting edge 2. Otherwise, the position of the end portion of the grinding surface 3 before and after the movement is shifted, and a corner portion or a step portion is formed at the joint C of the corrugated cutting blade 2 formed by the end portions of the grinding surface 3 before and after the movement. Will be formed. However, in FIG. 6, both end portions of the grinding surface 3 of the grindstone 4 are half-recessed portions corresponding to substantially half of the projecting portions of the cutting edge 2 as described above, and thus the corner portions and the stepped portions are formed in this way. The joint C to be formed is located at the apex of the corrugated convex portion formed by the cutting blade 2, but since this portion is a portion that is cut into the workpiece during cutting, an impact load is applied. Therefore, if corners or stepped portions are formed in such a portion, there is a possibility that the cutting edge 2 may be lost during cutting due to the occurrence of cracks.

  On the other hand, in the example shown in FIG. 7, both end portions of the grinding surface 3 of the grindstone 4 are inclined surfaces as described above, and a portion left uncut by the inclined surface is ground by a recess at the center of the grinding surface 3. In order to form the convex part of the cutting edge 2, the joint C when the grindstone 4 is moved is located at the portion where the concave part at the center of the grinding surface 3 and the inclined surfaces at both ends overlap. The position is slightly shifted from the top of the convex portion toward the concave portion. Therefore, even if the interval at the time of movement of the grindstone 4 is deviated from one pitch of the waveform in the direction along the cutting edge 2, the corner or stepped portion is not positioned at the top of the convex portion of the cutting edge 2. Although there is little influence on the fracture resistance compared to the example of FIG. 6, there is a possibility that the cutting edge 2 may crack due to cracks from such corners or stepped portions while being used for long-term cutting. In addition, in this example, when the grinding surface 3 of the grindstone 4 is slightly inclined with respect to the cutting edge 2 as shown in FIG. 8, the cutting edge is ground by the recess at the center of the grinding surface 3 at the joint C portion. The two convex portions may be cut out by the inclined surface, and a corner portion that causes a defect may be formed in the vicinity of the apex of the convex portion.

  The present invention has been made under such a background, and a roughing end mill having a cutting edge that has a corrugated shape is arranged along the cutting edge by a grindstone having a grinding surface having a cross-sectional shape corresponding to the corrugation. When manufacturing while moving in the direction, even if there is an error in the amount of movement of this grinding wheel or the grinding surface of the grinding wheel is tilted, It aims at providing the manufacturing method of the roughing end mill which can be manufactured.

  In order to solve the above-mentioned problems and achieve such an object, the present invention provides a roughing end mill in which an end mill body is provided with a corrugated cutting edge, and has a cross-sectional shape corresponding to the corrugation formed by the cutting edge. A method for manufacturing a luffing end mill, wherein a grinding wheel having a grinding surface having a grinding surface is used to grind the cutting blade while moving the grinding wheel along the cutting blade at intervals based on the pitch of the waveform. Of the grinding surfaces of the grindstone, both end portions in the direction along the cutting edge have a cross-sectional shape corresponding to the corrugated concave portion formed by the cutting blade, and the grinding surfaces are joined when the grindstone is moved. The eye is positioned in a range within 1/2 of the depth of the waveform from the wave bottom of the waveform formed by the cutting blade.

  However, in the luffing end mill manufactured by such a manufacturing method, both end portions of the grinding surface of the grindstone have a cross-sectional shape corresponding to the corrugated recess formed by the cutting blade, and the grindstone is disposed along the cutting blade. The joint between the grinding surfaces of the grindstone when grinding while being moved is located within a range within 1/2 of the depth of the waveform from the corrugated wave bottom formed by the uneven cutting edge, that is, the joint is The corrugated concave portion formed by the cutting blade is less likely to be cut into the workpiece during cutting by the luffing end mill, as shown in FIG. If the depth of the corrugation of the cutting edge in a roughing end mill and the depth of cut per tooth are taken into consideration, the cutting edge should be located within a half of the corrugation depth from the corrugated wave bottom. The connection There is no possibility that the eyes of the part are involved in the cutting. Therefore, even if a corner or a step portion is formed at this joint due to an error in the movement distance of the grindstone during grinding or because the grinding surface of the grindstone is inclined, The load at the time of cutting does not act on the stepped portion. Therefore, according to the present invention, there is provided a roughing end mill capable of preventing the cutting edge from being cracked from the corner portion or the stepped portion and missing the cutting edge. Can be manufactured.

  Here, the grinding surface of the grindstone has a cross-sectional shape having a width larger than one pitch of the corrugation formed by the cutting blade, so that the grindstone is moved at intervals based on the corrugated pitch. By doing so, since the edge part of the grindstone before and behind movement overlaps, the joint can be made smoother. Furthermore, by forming a plurality of cross-sectional portions corresponding to the corrugated convex portions formed by the cutting blades on the grinding surface of such a grindstone, the intervals at which the grindstone is moved are set to a plurality of pitches of the corrugated shape. In addition, since the number of joints per se with respect to the cutting edge can be reduced, a roughing end mill capable of more effectively preventing the occurrence of defects can be manufactured. Further, if a grindstone having a plurality of cross-sectional portions corresponding to the corrugated convex portions formed by such cutting blades is moved at intervals of, for example, one pitch of the corrugation, roughing is performed on the grinding surface on the moving direction side. On the other hand, finishing can be simultaneously performed on the grinding surface on the rear side in the moving direction, and a better ground surface and an accurate waveform can be obtained.

  FIGS. 1 and 2 show a first embodiment of the present invention in the case of manufacturing a roughing end mill as shown in FIG. 4, and are common to the examples shown in FIG. 4 and FIGS. The same symbols are assigned to the elements to be performed. The roughing end mill manufactured according to the present embodiment has a corrugated shape in which the cutting edge 2 is made by continuously contacting, for example, concave arcs and convex arcs of equal radius alternately and smoothly. The distance between the apex 2a of the convex part 2A formed by the above and the wave bottom 2b of the concave part 2B formed by the concave arc is the depth D of the waveform formed by the cutting edge 2. However, the radii of the convex arc and the concave arc may be different from each other, and may be smoothly connected by a straight line. Furthermore, the waveform formed by the cutting edge 2 may be another shape such as a sine curve.

  The grindstone 11 of this embodiment for forming such a cutting edge 2 includes a grinding surface 12 having a cross-sectional shape corresponding to the waveform formed by the cutting edge 2 as in the examples of FIGS. However, the ground surface 12 has a cross-sectional shape in which both end portions 12A in the direction along the cutting edge 2 correspond to the corrugated recess 2B formed by the cutting edge 2. That is, when the concave portion 2B has a concave arc shape as described above, both end portions 12A have a convex arc shape in cross section having the same radius as the concave arc, but the concave portion 2B smoothly contacts the adjacent convex portion 2A. In contrast, the side edge portions 12B facing the opposite sides of the both end portions 12A are formed so as to be cut off with a ¼ arc of the cross section with the above-mentioned radius. Further, the central portion 12C of the grinding surface 12 between the both end portions 12A has a concave arc shape in cross section corresponding to the convex portion 2A of the cutting edge 2, and in this embodiment, only one such concave arc is adjacent. It is formed so as to be in smooth contact with the convex arc of the cross section formed by the two end portions 12A in the same manner as the cutting edge 2 and to be continuous. Therefore, the grinding surface 12 of the grindstone 11 of this embodiment has a width corresponding to one pitch of the waveform formed by the cutting edge 2 and one recess 2B.

  Also in this embodiment, a groove portion is formed on the outer periphery of the tip end portion of the end mill body 1 by known means, and the end mill body 1 connected to the edge ridge portion from the outer peripheral side ridge portion of the wall surface facing the end mill rotation direction of the groove portion. The peripheral surface of the end mill body 1 is moved while the outer peripheral surface is sequentially moved along the side ridges at intervals (one pitch in the present embodiment) based on the pitch of the waveform to be formed on the cutting edge 2 of the grindstone 11. The corrugated cutting edge 2 as described above is formed by grinding in the direction. Needless to say, it is also possible to manufacture a normal end mill in which the cutting edge is not uneven, and to grind the cutting edge with the grindstone 11 having the grinding surface 12 as described above. Since the side edge portion 12B of both end portions 12A of the grinding surface 12 has a ¼ arc in cross section as described above, the rear end side of the end mill body 1 of the cutting blade 2 (right side in FIGS. 1 and 2) is It intersects the outer peripheral surface of the shank part 5 substantially perpendicularly. And when moving the grindstone 11 along the cutting edge 2 in this way, since both ends 12A of the grinding surface 12 of the said grindstone 11 are made into the shape corresponding to the recessed part 2B of the cutting edge 2, the grindstone 11 is moved after movement. One end portion 12A located on the opposite side to the moving direction of is located in the concave portion 2B of the cutting blade 2 ground by the other end portion 12B before the movement, and thus the ground surface 12 before and after the movement is connected. The eye C will be located in this recessed part 2B.

  Therefore, in the roughing end mill manufactured by such a manufacturing method, an error occurs in the interval when the grindstone 11 is moved, and a corner portion is formed at the joint C without strictly forming the waveform 1 pitch of the cutting edge 2. 2 or even if the grinding surface 12 of the grindstone 11 is inclined with respect to the cutting edge 2 and a stepped portion is formed at the joint C as shown in FIG. Since it will be formed in the recess 2B that is not cut into the workpiece, cracks may occur from the corners or stepped portions of the joint C due to the load during cutting, or the cutting edge 2 may be lost due to this crack. There is nothing to do. For this reason, according to this embodiment, it is possible to provide a roughing end mill having high fracture resistance and a long tool life.

  Moreover, in the present embodiment, as described above, of the both ends 12A of the grinding surface 12, one end 12A after the movement of the grindstone 11 is the cutting edge 2 ground by the other end 12A before the movement. Since it is located in the recess 2B, the movement interval of the grindstone 11 can be confirmed using this as a guide. For example, every time the grindstone 4 is moved as in the example shown in FIG. It is also possible to prevent the occurrence of an error in this movement interval as compared with the case where two are formed and connected. Further, in the present embodiment, the side edge portion 12B of the both end portions 12A of the grinding surface 12 has a ¼ arc shape in accordance with the radius of the concave portion 2B of the cutting blade 2, so for example in FIGS. Compared to the case where both ends of the grinding surface 3 of the grindstone 4 are inclined surfaces as in the example shown, even if corners or step portions are formed in the joint C, it can be made smaller. It becomes possible to manufacture a roughing end mill in which the fracture resistance of the blade 2 is higher.

  In this embodiment, the joint C is located on the wave bottom 2b of the recess 2B if the movement interval of the grindstone 11 exactly matches the waveform 1 pitch of the cutting edge 2. Even when there is an error in the interval and the waveform 1 pitch of the cutting edge 2 or when the grinding surface 12 is tilted, it is ½ of the depth D of the waveform from the wave bottom 2b of the waveform formed by the cutting edge 2. It is supposed to be located within the range. This is because if the seam C is located at a position closer to the apex 2a of the convex portion 2A having a further waveform, if a corner or a step is formed in the seam C due to an error or inclination, depending on the cutting amount per blade This is because the corners or the stepped portions may be cut into the workpiece.

  Furthermore, the grinding surface 12 of the grindstone 11 of the present embodiment has a width corresponding to one pitch of the corrugation formed by the cutting edge 2 and one recess 2B, that is, a cross section having a width larger than one pitch of the corrugation. It has a shape. For this reason, when grinding is performed by moving the grindstone 11 by one waveform pitch as described above, the trajectory of the grinding surface 12 of the grindstone 11 before and after the movement overlaps. The waveform formed by the ground surface 12 can be continued more smoothly at the joint C, and the effect of making the corners and stepped portions inconspicuous can also be obtained.

  In the present embodiment, as described above, only one portion having a concave arc shape in cross section corresponding to the corrugated convex portion 2A formed by the cutting blade 2 is formed in the central portion 12C of the grinding surface 12 of the grindstone 11, and this grindstone 11 is moved by one pitch of the waveform to form the cutting edge 2 in a waveform. For example, as in the second embodiment of the present invention shown in FIG. 3, both ends of the grinding surface 12 of the grindstone 11 are formed. A plurality of cross-sectional portions corresponding to the convex portions 2A are formed between the portions 12A in accordance with the waveform pitch formed by the cutting blade 2, and the grindstone 11 is moved at intervals corresponding to the pitches of the plurality of portions. You may make it make it. According to the second embodiment as described above, the joint C itself is not formed at a plurality of pitch portions other than the both end portions 12A of the grinding surface 12, so that the chipping end mill to be manufactured is further fracture resistant. In addition to the improvement, the number of times of grinding by the grindstone 11 per one cutting edge 2 is reduced, so that it is possible to promote the production of an efficient luffing end mill.

  On the other hand, in the second embodiment of the present invention using the grindstone 11 in which a plurality of cross-sectional portions corresponding to the convex portions 2A are formed on the grinding surface 12, as described above, the pitch is equal to the plural convex portions 2A. In addition to moving the grindstone 11 at a combined interval, by moving the grindstone 11 at a pitch smaller than this, for example, at intervals of 1 pitch, roughing is performed on the grinding surface 12 on the moving direction side. In addition, the ground surface 12 on the rear side in the moving direction can take a form in which the rough waveform is finished. Therefore, in such a manufacturing method, a better ground surface can be obtained, and accordingly, the cutting edge 2 can be given a more accurate waveform.

It is a figure which shows the 1st Embodiment of this invention. FIG. 2 is a view showing a state where a grinding surface 12 of a grindstone 11 is inclined with respect to a cutting edge 2 in the embodiment shown in FIG. 1. It is a figure which shows the 2nd Embodiment of this invention. It is a side view of a luffing end mill. It is a figure which shows the cutting form by a luffing end mill. It is a figure which shows the conventional manufacturing method of a luffing end mill. It is a figure which shows the other conventional manufacturing method of a luffing end mill. FIG. 8 is a view showing a state in which the grinding surface 3 of the grindstone 4 is inclined with respect to the cutting edge 2 in the example shown in FIG. 7.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 End mill main body 2 Cutting edge 2A Convex part of cutting edge 2 2B Concave part of cutting edge 2 11 Grinding wheel 12 Grinding surface 12A End part of grinding surface 12 C Joint of grinding surface 12 when grindstone 11 is moved D Cutting edge 2 is the depth of the waveform

Claims (3)

  A roughing end mill in which a corrugated cutting edge is formed on an end mill body, and a grindstone having a grinding surface having a cross-sectional shape corresponding to the corrugation formed by the cutting edge is used, and the grindstone is based on the corrugated pitch. A method of manufacturing a luffing end mill that is manufactured by grinding the cutting edge while moving along the cutting edge at intervals, of the grinding surface of the grindstone, both ends in the direction along the cutting edge, A cross-sectional shape corresponding to the corrugated concave portion formed by the cutting edge, and the joint between the grinding surfaces when the grindstone is moved is 1 / of the depth of the corrugation from the corrugated wave bottom formed by the cutting blade. A method for producing a luffing end mill, wherein the method is positioned within a range of 2 or less.   2. The method of manufacturing a roughing end mill according to claim 1, wherein the grinding surface of the grindstone has a cross-sectional shape having a width larger than one pitch of the corrugation formed by the cutting edge. 3. The method of manufacturing a roughing end mill according to claim 1, wherein a plurality of cross-sectional portions corresponding to corrugated convex portions formed by the cutting blade are formed on a grinding surface of the grindstone. .

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