JP2016083725A - Rotary cutting tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotary cutting tool for finishing hole processing, capable of performing processing with high accuracy and high in durability.SOLUTION: The rotary cutting tool includes a columnar base metal made of hard metal, and a cutting blade made of a sintered diamond and a guide pad formed on the outer peripheral surface of at least the tip side of the base metal. A range in which the guide pad is formed is preferably 45° or more to 270° or less in a peripheral direction. A plurality of cutting blades is provided, a guide pad is provided between the cutting blades in the peripheral direction, and the diameter of the cutting blade is set to 20 mm or less. The surface roughness of the guide pad is 2 μm or less at Ra. A hole for supplying cutting oil is provided from the rear end side of the base metal toward the tip.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a rotary cutting tool for processing various metal materials and the like, and more particularly to a rotary cutting tool suitable for performing high-precision finishing such as hole finishing.

  As rotary cutting tools for processing various metal materials, for example, there are those disclosed in Patent Documents 1 to 3.

  In Patent Document 1, a drilling tool having a cutting edge portion at the tip and a guide portion on the outer periphery is disclosed. As a conventional technique, the cutting blade portion is made of an ultra-high pressure sintered body, and the guide pad is made of cemented carbide. A two-blade gun reamer configured as described above is cited, and although the cutting blade portion is still sufficiently usable, the problem is that the guide pad is worn first and the hole accuracy cannot be maintained. For this reason, a tool that can improve the wear resistance of the guide part is provided by providing a guide part made of an ultra-high pressure sintered body of diamond on the outer periphery of the guide pad as an improvement. Both of these guide pads and guide portions are joined to the tool body by brazing.

  In Patent Document 2, a cutting blade body made of a high-hardness sintered body is inserted along the outer diameter of a stepped small-diameter column body formed at the tip of a blade diameter portion extending from a cemented carbide or steel shank, and bonded. A reamer brazed against the part is disclosed. In this reamer, a plurality of continuous blade grooves are formed in the outer peripheral portion of the cutting blade body and the blade diameter portion, an oil hole is formed in the center of the shank, from the rear end portion of the shank to just before the joint portion, and an injection hole is formed. The oil hole is formed so as to reach radially into the blade groove near the joint from the oil hole toward the tip of the shank, and the blade groove is formed in a left-hand thread. With such a reamer, stable cutting performance is maintained for a long time, and chips are discharged forward so that excellent surface accuracy and dimensional accuracy are maintained, and it is easy to bite between the finished inner wall and the cutting blade. Hard cementite in the sintered metal is allowed to flow forward, and the cutting heat in the vicinity of the joint portion of the cutting blade body can be cooled to prevent thermal deterioration of the brazing material.

  In Patent Document 3, an outer peripheral cutting edge portion of a rotary cutting tool is disclosed in which a reinforcing chip made of sintered diamond is embedded integrally at a predetermined interval from a chamfered portion of a cutting edge made of cemented carbide or the like. In addition, the hole or groove can be finished to a high-precision processed surface unique to the sintered diamond tool by a burnishing action that pushes the inner wall portion of the hole or groove by the sintered diamond portion.

JP-A-62-188613 JP 2000-263328 A Japanese Utility Model Publication No. 63-193621

  For rotary cutting tools that perform high-precision finishing such as hole finishing using a reamer, a sintered diamond cutting blade is formed on the outer periphery of the cemented carbide shank to satisfy the requirements. To provide a chip, increase the number of cutting blades, or provide a guide pad as an action part other than the cutting blades, and apply the techniques disclosed in Patent Documents 1 to 3 in order to improve the performance Can be considered.

  However, the following problems remain in the tools disclosed in Patent Documents 1 to 3.

  In Patent Document 1, since a guide portion made of an ultra-high pressure sintered body of diamond is provided, wear of the guide pad can be suppressed, and the occurrence of tool deflection can be prevented. Therefore, it is necessary to perform processing such as providing a recess in the joint portion on the tool body side, and the rigidity of the tool body is reduced. In addition, in a small-diameter tool or a multi-blade tool with many cutting edges, the cutting edge tip and guide pad are close to each other. There is a tendency to cause a problem that the pad is detached or the bonding accuracy is wrong. In particular, the smaller the diameter of the tool, the smaller the cutting edge and the guide pad, so that brazing becomes difficult. Furthermore, when it is desired to increase the circumferential length of the guide pad, the cross section becomes a fan shape, so that it is difficult to process into such a shape.

  Moreover, in patent document 2, the cutting blade body which consists of a high-hardness sintered body is brazed to the shank of a cemented carbide or steel, and cutting oil is injected into the blade groove made into the left-handed thread, and chips are discharged ahead. It is possible to maintain excellent surface accuracy and dimensional accuracy, but only the technology for improving chip discharge performance is disclosed. What is the technology for realizing high-precision machining with a guide pad? Not disclosed.

  Furthermore, Patent Document 3 only discloses that after machining with a cutting edge of a biting portion made of cemented carbide or the like, finishing processing is performed with a sintered diamond reinforcing tip. There is no disclosure of a technique for realizing higher precision machining with a tool using a blade.

  In view of the above, an object of the present invention is to provide a rotary cutting tool that can perform highly accurate machining and has high durability.

  A rotary cutting tool according to the present invention includes a cylindrical base metal made of cemented carbide, and a cutting blade and a guide pad made of sintered diamond formed on an outer peripheral surface of at least the tip side of the base metal. The alloy and the sintered diamond are rotary cutting tools that are sintered together.

  In the rotary cutting tool configured in this way, the cutting blade and the guide pad are made of sintered diamond made of the same material. The cutting performance is stable and high-precision machining can be continued, and the tool life is extended. Moreover, since the friction coefficient of the guide pad is low, generation of frictional heat between the guide pad and the processed surface can be suppressed, seizure can be prevented, and the cutting speed can be increased. Furthermore, since it is not necessary to provide a recess for joining the guide pad to the base metal or the tool body, the rigidity of the base metal or the tool body does not decrease, the tool can be prevented from shaking during cutting, and the joint part can be prevented. High-precision processing is possible without clogging chips.

  Preferably, a range in which the guide pad is formed is 45 ° or more and 270 ° or less in the circumferential direction.

  Preferably, a plurality of the cutting blades are provided, a guide pad is provided between the cutting blades in the circumferential direction, and the diameter of the cutting blade is 20 mm or less.

  Preferably, the surface roughness of the guide pad is Ra 2 μm or less.

  Preferably, a hole for supplying cutting oil is provided from the rear end side to the front end side of the base metal.

  According to the present invention, it is possible to provide a rotary cutting tool with a long life that can be processed with high accuracy over a long period of time.

It is a figure which shows the 1st example of the rotary cutting tool of this invention, (a) is a front view, (b) is a left view. It is a figure which shows the 2nd example of the rotary cutting tool of this invention, (a) is a front view, (b) is a left view. FIG. 3 is an enlarged view of FIG. It is the figure which expanded the A section of Fig.2 (a). It is the elements on larger scale which looked at the A section of Drawing 2 (a) from the diagonal direction containing a front, a left side, and a plane.

  Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1)
1A and 1B are diagrams showing a configuration of a reamer as a rotary cutting tool according to Embodiment 1 of the present invention, in which FIG. 1A is a front view and FIG. 1B is a left side view. With reference to FIG. 1A, the rotary cutting tool 1 has a tool body 10, and the tool body 10 has a shaft portion 11. The shaft portion 11 is a portion for attaching the rotary cutting tool 1 to the machine, and the chuck can hold the shaft portion 11 and rotate the tool body 10.

  With reference to FIG. 1A and FIG. 1B, a cylindrical base metal 2 made of cemented carbide at the tip of the tool body 10 of the rotary cutting tool 1 and an outer periphery on the tip side of the base 2 A diamond 3 is bonded to the surface, and a cutting edge 4 and guide pads 6a and 6b, each of which includes a cutting edge 4a, a cutting edge 4b, and an outer cutting edge 4c, are formed on the diamond 3. The base metal 2 and the diamond 3 made of cemented carbide are materials that are integrally sintered in advance under an ultra-high pressure, and this material is joined to the tip of the tool body 10 by brazing or the like.

  The cutting edge 4 is provided at the boundary portion by forming a rake face 5a and a flank face 5b, and the diamond 3 is removed on the front side in the rotational direction of the rake face 5a so that a notch is formed in the cemented carbide base metal 2. 7 is provided. On the rear side of the flank 5b in the rotational direction, a guide pad 6a is provided over 180 °, and the guide pad 6b is provided with the nosumi portion 8 interposed therebetween.

(Embodiment 2)
2A and 2B are diagrams showing the configuration of a reamer as a rotary cutting tool according to Embodiment 2 of the present invention, where FIG. 2A is a front view and FIG. 2B is a left side view. 3 is an enlarged view of FIG. 2B, FIG. 4 is an enlarged view of portion A of FIG. 2A, and FIG. 5 is a front view, a left side surface, and a plan view of portion A of FIG. It is the expansion perspective view seen from the diagonal direction containing. With reference to FIG. 2A, the rotary cutting tool 101 has a tool main body 110, and the tool main body 110 has a shaft portion 111. The shaft portion 111 is a portion for attaching the rotary cutting tool 101 to the machine, and the chuck can hold the shaft portion 111 and rotate the tool body 110.

  2 to 5, a cylindrical base metal 102 made of cemented carbide is attached to the tip of the tool body 110 of the rotary cutting tool 101, and a diamond 103 is bonded to the outer peripheral surface of the base metal 102 on the tip side. This diamond has a cutting edge 104 consisting of a tip cutting edge 104a, a biting cutting edge 104b and an outer peripheral cutting edge 104c, and a guide pad 106. The material is integrally sintered in advance under ultrahigh pressure, and this material is joined to the tip of the tool body 110 by brazing or the like.

  The cutting edge 104 is provided at the boundary portion by forming a rake face 105a and a flank face 105b, and a part of the diamond 3 is removed and a notch 107 is provided on the front side in the rotation direction of the rake face 105a. Yes. In addition, an oil hole 109 for supplying cutting oil toward the cutting edge 104 is opened in the cutout portion 107, and the cutout portion 107 is for discharging chips cut by the cutting blade 104. . On the rear side in the rotation direction of the flank 105b, a Nusumi portion 108 is provided, and on the further rear side in the rotation direction of the Nusumi portion 108, a guide pad 106 is provided.

  The rotary cutting tool of the present invention and a conventional rotary cutting tool for comparison were manufactured, and a cutting test of a pilot hole in the shape of a blind hole that was previously drilled was performed. As the rotary cutting tool of the present invention, the reamer of FIG. 1 described above (the present invention 1) was manufactured. As a conventional rotary cutting tool, a reamer (Comparative Example 1) is manufactured in which the cutting edge and guide pad are the same size as the reamer shown in FIG. 1, and the cutting edge tip and guide pad are joined to the tool body by brazing. did.

  As a result of performing a cutting test using these rotary cutting tools, the rotary cutting tool according to the first aspect of the present invention does not burn the guide pad and does not damage the processing surface, and processes to the required processing accuracy. On the other hand, in the rotating tool of Comparative Example 1, the rigidity of the tool was lowered and the vibration occurred, and the phenomenon that the vibration occurred compared to the present invention 1 was observed. In addition, since the chips were caught in the joint portion of the guide pad, scratches were seen on the processed surface, and processing could not be performed to the required processing accuracy.

  As the rotary cutting tool of the present invention, a reamer (present invention 2) shown in FIG. 2 described above and having a cutting edge diameter of 20 mm was manufactured. Further, as a conventional rotary cutting tool, a reamer (Comparative Example 2) in which the size of the cutting edge and the guide pad was the same as in the present invention 2 and the cutting edge tip and the guide pad were joined to the tool body by brazing was manufactured.

  As a result, the reamer of the present invention 2 was able to form the cutting blade and the guide pad without any problem and was able to be manufactured with high accuracy. However, the reamer of Comparative Example 2 was already used when the cutting blade and the guide pad were joined by brazing. Adjacent cutting blades and guide pads that were joined by brazing moved and could not be joined with high accuracy.

  The rotary cutting tool of the present invention can be applied to the reamer described in the above embodiment, as well as various rotary cutting tools such as a milling cutter and an end mill, and a rotary tool having a superabrasive layer as a cutting edge instead of a super hard chip. it can.

1,101 Rotary cutting tool (reamer)
2,102 Base metal 3,103 Diamond 4,104 Cutting edge 5a, 105a Rake face 5b, 105b Relief face 6a, 6b, 106 Guide pad 7, 107 Notch 8, 108 Nusumi 109 Coolant supply hole 10, 110 Tool body 11, 111 Shaft

Claims (5)

A cylindrical base metal made of cemented carbide;
A cutting blade and a guide pad made of sintered diamond are formed on the outer peripheral surface of at least the tip side of the base metal,
A rotary cutting tool in which the cemented carbide and sintered diamond are integrally sintered.   The rotary cutting tool according to claim 1, wherein a range in which the guide pad is formed is 45 ° or more and 270 ° or less in the circumferential direction.   2. The rotary cutting tool according to claim 1, wherein a plurality of the cutting blades are provided, a guide pad is provided between the cutting blades in a circumferential direction, and the diameter of the cutting blade is 20 mm or less.   4. The rotary cutting tool according to claim 1, wherein the surface roughness of the guide pad is Ra 2 μm or less. 5.   The rotary cutting tool according to any one of claims 1 to 4, wherein a hole for supplying cutting oil is provided from a rear end side of the base metal toward a front end.

Images