JP2008307621A - Christmas cutter for rough cutting - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a Christmas cutter used to further increase recessed groove width of a total form groove having irregularities on a groove wall surface. <P>SOLUTION: This Christmas cutter on which a plurality of protruded parts and recessed parts are provided to the shank side from a head end is constituted so that a front connecting part is retreated more than a cutting blade making contact with the protruded part on the head end side by providing a rectilinear part in the radial direction of the cutter when the recessed parts of the cutter are made non-cutting parts, the protruded part on the head end side is made the front connecting part and the protruded part on the shank side is made a rear connecting part. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a Christmas cutter used for cutting a groove of a turbine blade connecting portion.

Among the grooves of the turbine blade connecting portion, there are a small total groove having a depth of less than 50 mm and a large total groove having a depth of 50 mm or more. Cutting large large grooves has a large amount of cutting, and the roughing process of the total grooves is divided into a plurality of times. In the cutting method of the roughing process, first, a general-purpose groove having a slight unevenness is formed on a groove wall surface using a general-purpose milling cutter disclosed in Patent Document 1, and then rotated with the same specifications as the milling cutter. There is an apparatus that simultaneously widens the groove width of the concave and convex portions on the groove wall surface using a general-purpose milling cutter whose trajectory is one size larger. There is a type in which a groove whose width is expanded stepwise from the groove bottom to the upper part of the groove is cut, and a recess is formed on the flat wall surface of the groove using the insert type milling machine of Patent Document 2.
JP 2000-107924 A JP-T-2004-507369

  However, in Patent Document 1, since the cutting edge is provided continuously to the cutting edge of the general-purpose milling cutter, there is a cutting groove at the position of the minimum cutting edge diameter of the cutting edge, and the strength thereof is low and it is easy to be a starting point of breakage. . Patent Document 2 is insufficient because it cannot provide a large difference in the unevenness of the groove wall surface. The present invention has been made based on the background as described above, and an object of the present invention is to provide a Christmas cutter that is used to further widen the groove width of a general groove having irregularities on the groove wall surface. .

The present invention relates to a Christmas cutter in which a plurality of convex portions and concave portions are provided from the tip to the shank side. The concave portion of the cutter is defined as a non-cutting portion, and the non-cutting portion is defined as a front convex portion. When the connecting part and the convex part on the shank side are used as the rear connecting part, the front connecting part is provided with a linear part in the radial direction of the cutter, and is retreated from the cutting edge in contact with the convex part on the tip side. This is a rough cutting Christmas cutter. By applying the present invention, it was possible to produce a Christmas cutter with a wide groove.
Furthermore, the length of the straight portion of the front joint portion is the same length as the maximum escape amount of the flank face of the cutting edge that contacts the rear joint portion, and the rear joint portion is provided with a straight portion in the radial direction of the cutter. In addition, when the convex portion is provided with a wavy cutting edge, the length thereof is set to the same length as the maximum clearance amount of the flank face of the cutting edge in contact with the front joint portion. It can be manufactured without the grindstone biting and notching.

  The present invention can provide a Christmas cutter that is used to further widen the groove width of the overall groove having irregularities on the groove wall surface.

In FIG. 1, a plurality of convex portions and concave portions are provided from the tip to the shank side, and the first convex portion 1, the second convex portion 2, the third convex portion 3, and the shank portion 4 are provided from the tip. In the Christmas cutter, the first to third convex portions are provided with wavy cutting edges, the concave portion between the first convex portion 1 and the second convex portion 2, the second convex portion 2 and the third. A non-cutting portion 6 described later is provided in the concave portion between the convex portion 3. FIG. 2 is a cross-sectional view of the groove of the total shape, and the portion cut by the Christmas cutter of FIG. 1 is represented by a cutting allowance 5 and can be processed so that the unevenness difference 7 of the groove wall surface 6 is 10 mm or more. It can be formed in a shape approximate to the final finished shape of the groove.
When the non-cutting part 6 is the concave part of the cutter, the front-side convex part is the front joint part 7 and the shank-side convex part is the rear joint part 8 from FIG. A linear portion is provided in the radial direction of the cutter, and is moved backward toward the center of rotation from the cutting edge that contacts the convex portion on the tip side. The linear portion may be provided in a straight line so as not to contact the work material, and may be retracted at an angle or the like.
From the front joint portion 7 to the rear joint portion 8, no blade groove is provided, and a cross section perpendicular to the rotation axis is provided in a substantially circular shape, thereby improving the strength of the portion that becomes the minimum diameter of the Christmas cutter and suppressing breakage. The distance from the front connecting portion 7 to the rear connecting portion 8 needs to be smaller than the corresponding groove width of the total groove, but generally 75% or more is provided with respect to the corresponding groove width. As an aspect from the front joint portion 7 to the rear joint portion 8, the diameter may be increased by a taper, the diameter may be reduced by one time, and the diameter may be increased.

Next, the length L of the linear portion of the front joint portion 7 is set to the same length as the maximum relief amount 10 of the flank 9 of the cutting edge in contact with the rear joint portion 8 as shown in FIG. When the wave-shaped cutting edge is provided on the convex portion, the grindstone used when machining the flank 9 of the cutting edge can be prevented from biting into the non-cutting portion 6 during the flank machining, and the surface of the non-cutting portion 6 The state is kept good, and breakage due to the notch effect due to the bite mark 11 can be prevented. If the front joint portion 7 is not provided, as shown in FIG. 6, the grindstone bites into the surfaces of the non-cutting portion 6 and the front joint portion 7, and a cutout effect is generated by the bite marks 11, resulting in a decrease in breakage resistance.
Further, the rear joint portion 8 is provided with a linear portion in the radial direction of the cutter, and the length thereof is the same as the maximum escape amount 10 of the flank 9 of the cutting edge in contact with the front joint portion 7. Thus, when the cutter is manufactured, the notch effect can be prevented and the breakage resistance can be improved without causing the bite mark 11 in the rear joint 8.
As an embodiment of the front connecting portion 7, from FIG. 6, it may be provided with a surface perpendicular to the rotation axis or a surface recessed to the cutter tip side, and as an embodiment of the rear connecting portion 8, a surface perpendicular to the rotation axis, You may provide in the surface dented to the shank part side. Hereinafter, the present invention will be specifically described with reference to examples.

Example 1
As Example 1 of the present invention, the maximum blade diameter of the first convex portion is 32 mm, the maximum blade diameter of the second convex portion is 45 mm, the maximum blade diameter of the third convex portion is 60 mm, and each convex has a wavy cutting edge The minimum diameter of the non-cutting part between the first convex part and the second convex part is 10 mm, the minimum diameter of the non-cutting part between the second convex part and the third convex part is 22 mm, A Christmas cutter having a maximum relief 10 of 1.2 mm for the rear end of the first convex part and the front end of the second convex part and the respective relief surfaces 9 is prepared, and the first convex part and the second convex part The front connecting portion 7 and the rear connecting portion 8 are provided on the front end side and the shank portion side of the non-cutting portion in a plane perpendicular to the rotation axis, and the length L of the linear portion is equal to the maximum clearance 10 Provided. As Example 2 of the present invention, a linear portion having a length L of 2.0 mm was prepared, and as Comparative Example 3, a linear portion having a length L of 0.6 mm was also produced.
Inventive Examples 1 and 2 and Comparative Example 3 were visually observed. In the Inventive Examples 1 and 2, the grindstone biting marks 11 were not observed in the non-cut portion, and in the Comparative Example 3, the non-cut portion. The biting mark 11 as shown in FIG.

Inventive Examples 1 and 2 and Comparative Example 3 were processed with a large-sized groove having a groove depth of 80 mm as shown in FIG. 5 parts were processed. At this time, the difference in the unevenness of the groove wall surface is 13 mm. Rotational speed of the cutter 180 min ^-1, the feed speed from 16 mm / min, cutting distance 20mm every 24mm / min, 32mm / min, 40mm / min, increasing the feed rate and 48 mm / min. A water-soluble cutting fluid was used. As an evaluation, the test was stopped when a defect such as chipping, chipping or breakage occurred, and the feed rate was recorded. Moreover, the Christmas cutter which was not broken was used for the magnetic particle flaw detection test, and the presence or absence of the crack of the surface of a Christmas cutter was investigated.
As a result, Examples 1 and 2 of the present invention were able to increase the feed rate to 48 mm / min. No cracks were observed even after cutting, which was good and could be continuously cut. On the other hand, Comparative Example 3 was broken from the front end side of the non-cutting portion when the feed was increased to a feed rate of 32 mm / min.

FIG. 1 shows a front view of the present invention. FIG. 2 shows a cross-sectional view of the overall groove cut with the tool of FIG. FIG. 3 shows an enlarged view of the non-cut portion of FIG. FIG. 4 shows a cross section perpendicular to the axis of FIG. . FIG. 5 shows a bite mark generated in the non-cut portion. FIG. 6 shows another embodiment of the non-cut portion.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st cutting edge part 2 2nd cutting edge part 3 3rd cutting edge part 4 Shank part 5 Cutting allowance 6 Non-cutting part 7 Front joint part 8 Rear joint part 9 Relief surface 10 Maximum escape amount 11 Biting mark L Front joint part Length of linear part

Claims (4)

In a Christmas cutter provided with a plurality of convex portions and concave portions from the tip to the shank side, the concave portion of the cutter is defined as a non-cutting portion, the non-cutting portion is defined as a front-end convex portion, and a shank. When the convex portion on the side is used as the rear joint portion, the front joint portion is provided with a linear portion in the radial direction of the cutter and is made to recede from a cutting edge that contacts the convex portion on the tip side. Christmas cutter for cutting. The rough cutting Christmas cutter according to claim 1, wherein the cutting edge of the convex portion is a wave cutting edge. The rough cutting Christmas cutter according to claim 2, wherein the length of the linear portion of the front joint portion is the same as the maximum relief amount of the flank face of the cutting edge in contact with the rear joint portion. Christmas cutter for cutting. 3. The rough cutting Christmas cutter according to claim 2, wherein the rear joint portion is provided with a linear portion in a radial direction of the cutter, and the length of the rear joint portion is a maximum clearance of a flank face of the cutting edge in contact with the front joint portion. A rough-cutting Christmas cutter characterized by the same length as the amount.

Images