JP5317662B2 - Cutting tips and milling cutters - Google Patents

Description

  The present invention relates to a cutting tip and a milling cutter that can maintain or improve the finished surface roughness even when the feed rate is increased.

Conventionally, as a cutting tool, try to reduce the cutting resistance by using a side cutter (see, for example, Patent Documents 1 and 2) characterized by the method of assembling a chip, a cartridge and a holder, and cutting blades, and try to process with high accuracy. A side cutter (see, for example, Patent Document 3) is used.
JP 2008-18491 A JP 2004-90153 A Japanese Patent Laid-Open No. 11-300505

  However, in the conventional side cutter (side milling), when the feed rate is increased, a scallop height may be formed on the workpiece. Therefore, it is often difficult to maintain or improve the surface roughness of the side surface of the workpiece.

  The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a cutting tip and a milling cutter that can maintain or improve the roughness of the finished surface even when the feed rate is increased, and that enables highly efficient machining. To do.

In order to solve the above-described problems, the present invention provides a cutting tip attached to a milling cutter, wherein the cutting tip body has a substantially hexahedral shape, and when attached to the milling cutter, a part of the outer peripheral surface and side surface of the milling cutter. A surface that faces the outer peripheral surface and contacts the milling surface, a lower surface that contacts the outer peripheral surface, the side surface, the seating surface, and the milling surface, and an upper surface that faces the lower surface. A screw hole for freely attaching, and a cutting edge portion that forms an arcuate cutting edge on the side surface of the milling cutter when attached to the milling cutter, and the cutting edge portion has a curvature radius r of the nose corner portion and The curvature radius r is smaller than the curvature radius R, and the upper surface is cut from the edge of the cutting edge portion at the first angle α and the outer peripheral surface is cut at the second angle β. The true rake angle γ defined by A cutting tip having a rake face formed to be 0 ° to 30 ° is provided. Note that γ = tan ⁻¹ {(sin β) / (cos β · cos α)}.

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Therefore, according to the present invention, by taking the above-described means, a screw hole for detachably attaching the screw from the outer peripheral surface, and an arc-shaped cutting edge on the side surface of the milling cutter when attached to the milling cutter. Since it is a cutting tip provided with the cutting edge part to form, even if it raises feed speed, a scallop height can be suppressed and highly efficient machining will be attained.

  According to the present invention, the finished surface roughness can be maintained or improved even when the feed rate is increased, and highly efficient machining is possible.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic diagram showing a configuration of a milling cutter 1 according to an embodiment of the present invention. FIG. 1A is a front view, and FIG. 1B is a cross-sectional view along A-A ′. Here, as an example of the milling cutter 1, a side cutter having a tool diameter of 800 mm and a width of 35 mm is shown. The side cutter is attached to the drive mechanism around the axis L, and moves to the right in the drawing at a constant speed F while rotating in the S direction. Thereby, a to-be-cut object is cut and a workpiece is manufactured. A plurality of cutting tips 10 are attached to the side cutter.

  When the cutting tip 10 is attached to the milling cutter 10, it forms a cutting edge on the outer peripheral surface 2 and the side surface 3 of the milling cutter 1. As shown in FIG. 2, the cutting tip 10 according to the present embodiment has a cutting edge portion CE that forms an arcuate cutting edge on the side surface 3 of the milling cutter 1 when attached to the milling cutter 1. The cutting tip 10 is made of hardened steel or the like.

  The shape of the cutting tip body is substantially hexahedral as shown in FIG. Specifically, when the cutting tip 10 is attached to the milling cutter 10, the outer circumferential surface 11 and the side surface 12 that are part of the outer circumferential surface 2 and the side surface 3 of the milling cutter 1, It has a seating surface 13 that contacts, a lower surface 14 that is adjacent to the outer peripheral surface 11, the side surface 12, and the seating surface 13 and that contacts the milling cutter 1, and an upper surface 15 that faces the lower surface 14.

  More details are as shown in FIG. 4A and 4B are views of the cutting tip 10 viewed from the outer peripheral surface and the seating surface, respectively, and FIG. 4C is an arrow view viewed from the A direction of FIG. 4A. . The cutting tip 10 cuts the upper surface 15 from the edge of the cutting edge portion CE at the first angle α and the outer peripheral surface 11 at the second angle β, and the true rake angle γ defined by the following equation (1) is a metal. The rake face 15R is formed so as to be 0 ° to 30 ° in the case of cutting.

γ = tan ⁻¹ {(sin β) / (cos β · cos α)} (1)
However, the first angle α is an angle in the range of 0 ° to 90 °, and the second angle β is an angle in the range of 10 ° to 60 °. As a preferred example, the angle (α, β) = (30 °, 10 °). Here, the length D = 20 mm, the thickness T = 10 mm, and the width H = 15 mm. In FIG. 4C, reference numeral 12F represents a flank.

  In the cutting edge portion CE, the radius of curvature r of the nose corner portion is set to be smaller than the radius of curvature R of the central portion that is ½ of the thickness T of the cutting tip 10. Further, the radius of curvature r of the nose corner portion is set to be equal to or smaller than the radius of curvature of the corner of the workpiece. For example, when processing a turbine lid or the like, the curvature radius r is set to 0.4 mm to 1 mm. Moreover, the curvature radius R of a center part shall be 50 mm-300 mm. The curvature radius R is set so that the scallop height Rz is 6/1000 mm or less according to the following equation (2). However, f represents the feed amount per blade.

R = f ² / 8Rz (2)
The cutting tip 10 has a screw hole 16 for detachably attaching a screw from the outer peripheral surface 11, and is screwed at a right angle to the axis L.

  FIG. 5 is a schematic view for explaining the operation of the milling cutter 1 to which the cutting tip 10 according to the present embodiment is attached. The milling cutter 1 rotates in the S direction by the driving mechanism 5 and moves in a direction parallel to or perpendicular to the axis L to cut the workpiece 6. For example, the milling machine 1 cuts a workpiece or the like of the casing.

  FIG. 6 is a schematic diagram geometrically comparing the finished surfaces of the workpiece 6 of the milling machine 1 according to the present embodiment and a general milling machine. A general milling cutter has a linear cutting edge. Therefore, at the position of the cutting edge part CE2 where the feed amount F1 per blade is advanced from the position of the cutting edge part CE1, a scallop height of height S1 is generated as shown in FIG. In contrast, the milling blade 1 according to the present embodiment has a curved cutting edge. Therefore, at the position of the cutting edge part CE4 in which the feed amount F2 per blade is advanced from the position of the cutting edge part CE3, as shown in FIG. Comparing the finished surface roughness of both, in the milling machine 1 according to the present embodiment, the feed amount per blade can be increased with the scallop height of the same height. That is, if S1 = S2, F1> F2. As described above, according to the milling machine 1 according to the present embodiment, even when the feed amount is increased, a good finished surface roughness can be obtained, and thereby high productivity can be obtained.

  When the feed rate of the milling cutter is increased, the scallop height may be increased even if an arcuate cutting edge having a large curvature radius R is formed. This is because when the radius of curvature R of the cutting edge increases, the contact length between the cutting edge and the workpiece 6 during cutting increases, and chatter vibration occurs as a result. On the other hand, in the milling machine 1 according to the present embodiment, the cutting edge portion CE is inclined by the first angle α with respect to the upper surface 15 and is inclined by the second angle β with respect to the outer peripheral surface 11. That is, chatter vibration can be reduced by cutting by a so-called inclined cutting method.

  Further, when the curvature radius R of the cutting edge is increased, uncut portions may be left in the processing of the corner portion 6C of the workpiece 6. On the other hand, in the cutting tip 10 according to the present embodiment, since the curvature radius r of the nose corner portion has the cutting edge portion CE smaller than the curvature radius R of the central portion, the uncut portion at the corner portion 6C is reduced. be able to. Specifically, when the radius of curvature r of the nose corner portion is made smaller than the radius of curvature R of the central portion, the finished surface of the corner portion 6C is represented as shown in FIG. On the other hand, if the radius of curvature r of the nose corner portion is not reduced, a large amount of uncut material is generated at the corner portion 6C as shown in FIG.

  Note that the cutting tip 10 according to the present embodiment may be attached not only to one side surface of the cutting edge of the milling cutter 1 but also to both side surfaces as shown in FIG. Thereby, the milling cutter 1 can be used by moving in the left-right direction on the paper surface.

  In general side cutters, a cutting tip screw is often attached from the side surface 2. For this reason, the work space is small, and it takes time and labor to attach the cutting tip. On the other hand, since the cutting tip 10 according to the present embodiment has the screw hole 16 for removably attaching the screw from the outer peripheral surface 2, maintenance such as replacement work of the cutting tip 10 is easy. According to the study by the present inventors, the attachment time for attaching the screw from the outer peripheral surface 3 is about 2/3 as compared with the attachment time for attaching the screw from the side surface 2. In this respect, since the cutting tip 10 is frequently attached, the cutting tip 10 according to the present embodiment can reduce the influence of maintenance on the delivery date of the workpiece.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, you may combine a component suitably in different embodiment.

It is a mimetic diagram showing composition of milling machine 1 concerning an embodiment of the present invention. It is a figure showing a state when cutting tip 10 concerning the embodiment is attached to milling machine 1. It is a mimetic diagram showing the shape of cutting tip 10 concerning the embodiment. It is a mimetic diagram showing the shape of cutting tip 10 concerning the embodiment. It is a mimetic diagram for explaining operation of milling machine 1 which attached cutting tip 10 concerning the embodiment. It is the schematic diagram which geometrically compared the finishing surface of the workpiece 6 of the milling machine 1 by the same embodiment, and the common milling machine. It is a mimetic diagram for explaining the effect of milling machine 1 concerning the embodiment. It is a mimetic diagram showing the composition of the modification of milling machine 1 concerning the embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Milling, 2 ... Outer peripheral surface of milling, 3 ... Side surface of milling, 5 ... Driving mechanism of milling, 6 ... Workpiece, 6C ... Corner, 10 ... Cutting tip, 11 ... outer peripheral surface, 12 ... side surface, 12F ... flank surface, 13 ... seating surface, 14 ... lower surface, 15 ... upper surface, 15R ... rake surface, 16 ... Screw holes.

Claims (3)

A cutting tip attached to a milling cutter,
The cutting tip body has a substantially hexahedron shape, a surface that is a part of an outer peripheral surface and a side surface of the milling cutter when attached to the milling cutter, and a seating surface that faces the outer peripheral surface and contacts the milling cutter. A lower surface adjacent to the outer peripheral surface, the side surface, and the seating surface and in contact with the milling cutter, and an upper surface facing the lower surface,
A screw hole for detachably attaching a screw from the outer peripheral surface;
A cutting edge portion that, when attached to the milling cutter, forms an arcuate cutting edge on the side surface of the milling cutter;
Equipped with a,
The cutting edge portion has a curvature radius r of the nose corner portion and a curvature radius R of the central portion, and the curvature radius r is smaller than the curvature radius R,
From the edge of the cutting edge portion, the upper surface is cut at the first angle α, and the outer peripheral surface is cut at the second angle β so that the true rake angle γ defined by the following formula is 0 ° to 30 °. A cutting tip characterized by forming a rake face .
γ = tan ⁻¹ {(sin β) / (cos β · cos α)} The cutting tip according to claim 1 ,
The radius of curvature r of the nose corner portion is equal to or less than the radius of curvature of the corner of the workpiece;
A cutting tip having a radius of curvature R of the central portion of 50 mm to 300 mm. A milling machine to which the cutting tip according to claim 1 or 2 is attached.

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