JP2008296326A - Cutting holder and cutware - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cutting holder precisely inhibiting chatter without replacing a cutting insert or a holder, and performing an efficient and accurate cutting operation. <P>SOLUTION: The cutting holder 14 includes: a holder body 15; a head 16 provided at the tip of the holder body 15 and attaching the cutting insert 12; and a center pin 17 provided on a center axis of the holder body 15 for coupling the body 15 with the head 16. The center pin 17 has an external thread 21 at the end 20 of the center pin protruding from the holder body 15, and the end 20 is screwed with a threaded hole 22 provided on the head 16. A slotted set screw 23 is inserted along a radial direction of the holder body 15, and the head 16 is nonrotatably fixed to the holder body 15 with the set screw 23. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a cutting holder to which a cutting insert for performing a cutting process is attached, and a cutting tool.

  In a lathe machine, a cutting tool 46 (see FIG. 7) including a cutting insert 42 for performing cutting and a cutting holder 44 for attaching the cutting insert 42 is used.

  When this type of cutting tool 46 is used to cut an inner diameter of a cylindrical workpiece, for example, the diameter, length, and thickness (particularly in the case of a thin wall) of the workpiece and the mechanical rigidity of the processing machine to be used. In some cases, the cutting tool 46 vibrates during processing, and the surface to be cut becomes rough due to chatter. Therefore, there may be a problem that the inner diameter of the work piece cannot be processed with high accuracy.

  As a countermeasure against this, a technique is considered in which chatter is suppressed by changing the rake angle of the cutting edge of the cutting tool 46 and changing the cutting resistance. However, in order to change the rake angle of the cutting edge, it is necessary to change to a cutting insert 42 having a different cutting edge shape (rake angle) or to change the mounting angle of the cutting insert 42. In this case, it is not an industrial method because many kinds of cutting inserts 42 and cutting holders 44 must be prepared and the cost increases.

  As a specific technique for suppressing chatter by changing the rake angle of the blade edge as described above, for example, Patent Document 1 discloses a head exchangeable cutting holder.

Moreover, in patent document 2, the cutting tool which suppressed chatter using the split type cutting holder is disclosed. Furthermore, Patent Document 3 discloses a cutting tool configured to insert a vibration damping piece into a cutting holder to suppress chatter.
JP-A-6-170615 JP 2005-329509 A JP 2006-102837 A

  By the way, the cutting holder of Patent Document 1 described above does not have a rake angle adjustment function, and when chatter occurs in the cutting tool during processing, it is selected while changing an appropriate head and cutting insert so that chatter does not occur. There is a problem that work efficiency is poor. Moreover, even if the chatter can be suppressed by replacing the head, when a large number of workpieces are continuously processed, chattering occurs because the cutting edge of the insert wears during the cutting and the cutting resistance changes. Sometimes. In this case, it becomes difficult to perform continuous machining of the workpiece, and the machining accuracy is lowered.

  Even when the cutting holders of Patent Document 2 and Patent Document 3 are used, it has been confirmed that chattering occurs when the material and processing conditions of the cutting insert are changed. Even in this case, it is necessary to select an appropriate cutting insert or cutting holder so that chatter does not occur, resulting in a problem that work efficiency deteriorates.

  This invention is made | formed in view of said subject, The objective can suppress a chatter accurately, without replacing | exchanging a cutting insert and a holder, and can perform cutting work efficiently and with high precision. To provide a cutting holder and a cutting tool.

  And as means (means 1) for solving the above-mentioned problems, there are a holder main body, a head portion arranged on the tip end side of the holder main body, to which a cutting insert can be attached, and a central axis in the longitudinal direction of the holder main body. The head unit is selected at a plurality of different rotation positions with reference to a center pin that is disposed and connects the holder body and the head unit and a center pin that is disposed on a central axis in the longitudinal direction of the holder body. There is a cutting holder characterized in that it includes an anti-rotation mechanism for holding it so as to be unrotatable.

  Therefore, according to the cutting holder of the means 1, the center pin is arranged on the central axis in the longitudinal direction of the holder body, and the rigidity of the cutting holder can be increased by the center pin. Further, by dividing the cutting holder into the holder main body and the head portion, vibration at the time of cutting can be mitigated at the divided portion. As a result, the occurrence of chatter during cutting can be suppressed, and the processing accuracy can be improved. Further, the rotation preventing mechanism can hold the head portion selectively in a non-rotatable state at a plurality of different rotation positions with the center pin as a reference in the holder body. Therefore, when the cutting edge of the cutting insert wears and chatter occurs, the angle of the cutting edge of the cutting insert can be adjusted by changing the rotation position of the head while the cutting tool is still mounted on the lathe machine. It can be done easily. As a result, chattering can be prevented and more workpieces can be continuously processed, and work efficiency can be improved.

  The center pin is preferably made of a hard material mainly composed of ceramic particles having a higher elastic modulus than the holder body. Specifically, the center pin is formed of a ceramic sintered body mainly composed of silicon nitride, silicon carbide, aluminum oxide, or the like. The center pin is preferably formed of a material having a higher Young's modulus than the material for forming the holder body, and a center pin made of cemented carbide or cermet may be used in addition to ceramic. . In this case, the rigidity of the cutting holder can be further increased, and chattering during cutting can be reliably suppressed.

  It is preferable that the center pin has a male screw portion at a tip portion of the center pin protruding from the holder main body, and the tip portion of the center pin is screwed into a screw hole provided in the head portion. If comprised in this way, a head part can be easily rotated on the basis of a center pin in a holder main body.

  In addition, a scale may be displayed in the circumferential direction at the connecting portion between the head portion and the holder body. In this case, the rotational position of the head part can be accurately adjusted while checking the scale.

  The center pin has a center pin tip portion having a non-circular cross-section projecting from the holder body, and the center pin tip portion is fitted into a non-cross-section fitting hole provided in the head portion. It is preferable. Specific examples of the non-circular cross section include a spline shape, a polygonal shape, and the like, and a shape having a protrusion protruding in the circumferential direction as long as it is a shape to be rotated about the axis of the center pin as a target axis. It may be. If comprised in this way, a head part can be fixed to a non-rotatable state in the several different rotation position on the basis of the center pin arrange | positioned in the center axis | shaft in a holder main body.

  The anti-rotation mechanism is preferably an anti-rotation pin that is inserted along a radial direction of the holder body so as to fix the head portion and the holder body. With this detent pin, the head portion can be fixed to the holder body in a non-rotatable state.

  As another means (means 2) for solving the above problem, there is a cutting tool including the cutting holder of the means 1 and a cutting insert attached to the cutting holder.

  Therefore, according to the cutting tool of the means 2, the occurrence of chatter during the cutting process can be suppressed, and the machining accuracy can be improved. Moreover, when the cutting edge of the cutting insert is worn and chatter occurs, the rake angle of the cutting insert can be easily adjusted by changing the rotation position of the head portion without replacing the cutting holder. Accordingly, it is possible to continuously process a large number of workpieces without generating chatter, and work efficiency can be improved.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

  As shown in FIG. 1, the cutting tool 10 of the present embodiment includes a cutting insert 12 having a cutting edge 11 for performing a cutting process, and a cutting holder 14 for attaching the cutting insert 12. The cutting holder 14 is disposed on a substantially cylindrical rod-shaped holder main body 15, a head portion 16 that can be attached to the distal end side of the holder main body 15, the cutting insert 12 can be attached, and a central axis in the longitudinal direction of the holder main body 15. A center pin 17 for connecting the holder main body 15 and the head portion 16 is provided. The cutting holder 14 according to the present embodiment has a diameter of 40 mm and a length of 300 mm (the length of the head portion 16 is 60 mm and the length of the holder body 15 is 240 mm). In the cutting holder 14, the holder main body 15 and the head portion 16 are made of, for example, chrome molybdenum steel (specifically, JIS standard SCM440). The center pin 17 is preferably formed using a material having a higher Young's modulus than the material for forming the holder main body 15, and is preferably made of carbide, cermet, ceramic (for example, silicon nitride), or the like.

  The cutting insert 12 is a ceramic chip whose main component is aluminum oxide, and has a shape of CNGA 433 according to ISO standards. Specifically, the cutting insert 12 is a diamond-shaped chip having an inscribed circle on the rake face side of φ12.7 mm and a thickness of 4.76 mm. The cutting insert 12 of the present embodiment has an integrated structure with the head portion 16 of the cutting holder 14.

  A flat surface 18 having a chamfered portion is formed on the outer peripheral surface of the holder body 15 (see FIG. 2). The cutting tool 10 is mounted on the lathe machine by sandwiching the holder body 15 with the lathe machine side fixing member (not shown) in contact with the flat surface 18.

  As shown in FIGS. 1 and 3, the center pin 17 of the present embodiment has a male screw portion 21 at a tip portion 20 (center pin tip portion) protruding from the holder body 15, and the tip portion 20 is The screw hole 22 provided in the head portion 16 is screwed. Further, a set screw 23 (rotating pin) for fixing the holder main body 15 and the head portion 16 is inserted in a plurality of locations on the outer peripheral surface of the holder main body 15 along the radial direction.

  More specifically, a circular recess 25 is formed on the end surface of the holder body 15 at the connection portion between the holder body 15 and the head portion 16, and a protrusion 26 that fits into the recess 25 is formed on the end surface of the head portion 16. Has been. A screw hole 22 is opened at the center of the convex portion 26 in the head portion 16, and the center pin 17 is screwed into the screw hole 22. In addition, a female screw 23 is inserted into the outer peripheral surface of the holder body 15 at a position corresponding to the concave portion 25, and the tip of the female screw 23 protrudes from the inner peripheral surface of the concave portion 25 and contacts the outer peripheral surface of the convex portion 26 in the head portion 16. Be touched. In this way, the tip of the female screw 23 comes into contact with the head portion 16 to prevent the rotation of the head portion 16 in the circumferential direction with respect to the holder body 15.

  Further, as shown in FIG. 1, a scale 28 is displayed in the circumferential direction at a connection portion between the holder main body 15 and the head portion 16. By this scale 28, the rotational position of the head portion 16 with respect to the holder body 15 is adjusted. Specifically, each of the female screws 23 is once loosened so that the head portion 16 can be rotated with respect to the holder main body 15, and the rotational position is adjusted by turning the head portion 16 while checking the scale 28. Thereafter, each grommet screw 23 is tightened so that the head portion 16 cannot be rotated at the rotational position. In this way, the rake angle and clearance angle of the cutting insert 12 can be changed while the cutting holder 14 is mounted on a lathe machine (not shown).

The inventor of the present application installed the cutting tool 10 of the present embodiment on a lathe machine (not shown), and confirmed the effect of suppressing chatter by continuously performing inner diameter cutting of a plurality of workpieces. The results are shown in Table 1. In Table 1, Examples 1 to 4 are cutting tools 10 in which the material of the center pin 17 is changed, and the center pin 17 is made of chromium molybdenum steel (SCM440), which is the same material as the holder body 15. And Example 2 in which the center pin 17 is made of carbide. Further, the center pin 17 is made of cermet as Example 3, and the center pin 17 is made of silicon nitride as Example 4. Furthermore, as shown in FIG. 7, a conventional cutting tool 46 (conventional products 1 and 2) including an integrated cutting holder 44 without the center pin 17 is shown as a comparative example.

  Here, the cutting conditions are a peripheral speed V = 450 m / min, a feed speed f = 0.4 mm / rev, a cut d = 1.5 mm, and dry machining. The workpiece is a cylindrical material having a diameter φ of 100 mm and a length L of 130 mm, and the material is cast iron (specifically, JIS standard FC200). And the internal diameter process whose diameter (phi) is 90 mm was given with respect to the to-be-cut material on said cutting conditions.

  In Example 1, when the cutting edge of the cutting insert 12 is worn and chatter of the cutting tool 10 occurs, the lathe is temporarily stopped and the angle of the cutting insert 12 is adjusted. After the adjustment, the lathe machine was restarted, the inner diameter machining of the workpiece was continued, and the number of workpieces that could be machined without chatter was counted as the number of machining.

  As shown in Table 1, in the cutting tool 10 of Examples 1 to 4, the cutting holder 14 has a two-part structure (structure consisting of a holder main body 15 and a head portion 16), and further has a center pin 17 As a result, the deflection of the cutting tool 10 was relaxed at the divided locations, and more workpieces could be continuously processed without chattering. Specifically, in the cutting tool 10 of the first embodiment, 87 pieces of workpieces that are larger than the cutting tool 46 of the conventional product 1 (the number of processing = 55) and the cutting tool 46 of the conventional product 2 (the number of processing = 37). The work was able to be machined. Furthermore, the surface roughness (Ra) of the processed surface at the initial stage was 16.9 μm, and good processing accuracy was obtained.

  Moreover, in the cutting tool 10 of Example 2-Example 4, since the center pin 17 was formed with a material (super hard, cermet, silicon nitride) harder than the holder main body 15, the bending of the cutting tool 10 is further reduced. Even when 150 or more workpieces were continuously processed, chatter did not occur. Furthermore, the surface roughness of the processed surface was also good, and sufficient processing accuracy was obtained.

  Therefore, according to the present embodiment, the following effects can be obtained.

  (1) In the cutting holder 14 according to the present embodiment, the center pin 17 is disposed on the center axis of the holder body 15, so that the rigidity of the cutting holder 14 can be increased by the center pin 17. Further, by dividing the cutting holder 14 into the holder main body 15 and the head portion 16, vibration at the time of cutting can be mitigated at the divided portions. As a result, the occurrence of chatter during cutting can be suppressed, and the processing accuracy can be improved. Further, the cutting holder 14 can selectively hold the head portion 16 at a plurality of different rotation positions of the holder main body 15 so as to be in a non-rotatable state. Therefore, when the cutting edge of the cutting insert 12 is worn and chatter occurs, the cutting edge of the cutting insert 12 is changed by changing the rotational position of the head portion 16 with the cutting tool 10 mounted on the lathe. The rake angle can be easily adjusted. As a result, chattering can be prevented and more workpieces can be continuously processed, and work efficiency can be improved.

  (2) In the cutting holder 14 of the present embodiment, as in Examples 2 to 4, the center pin 17 is a material having a higher Young's modulus than the material for forming the holder body 15 (carbide, cermet, silicon nitride). By forming by, the rigidity of the cutting holder 14 can be improved more and generation | occurrence | production of the chatter at the time of cutting can be suppressed reliably. In this case, the manufacturing cost can be reduced as compared with the case where the entire holder (the holder main body 15 and the head portion 16) is formed of a material having a high Young's modulus (super hard, cermet, silicon nitride).

  (3) In the cutting holder 14 of the present embodiment, the center pin 17 has a male screw portion 21 at the tip portion 20 protruding from the holder body 15, and the tip portion 20 is screwed into the screw hole 22 of the head portion 16. It is worn. Further, the head portion 16 is fixed in a non-rotatable state by a set screw 23 inserted along the radial direction of the holder main body 15. If the cutting holder 14 is configured in this way, the rotational position of the head portion 16 relative to the holder body 15 can be finely adjusted, which is practically preferable.

  (4) In the cutting holder 14 of the present embodiment, since the scale 28 is displayed at the connection portion between the holder main body 15 and the head part 16, the rotational position of the head part 16 is accurately determined while checking the scale. Can be adjusted.

  In addition, you may change embodiment of this invention as follows.

  In the cutting holder 14 of the above embodiment, the center pin tip 20 protruding from the holder main body 15 has the male screw 21, and the center pin tip 20 is screwed into the screw hole 22 provided in the head 16. Although it was worn, it is not limited to this. For example, the center pin tip protruding from the holder body 15 is formed in a non-circular cross section, and the center pin 17 is fitted into the non-circular fitting hole provided in the head portion 16. May be configured.

  Specific examples thereof are shown in FIGS. That is, as shown in FIG. 4A, the center pin tip portion 30 has a spline shape, and is fitted into the fitting hole 31 corresponding to the spline shape as shown in FIG. 4B. The Further, as shown in FIG. 5 (a), the center pin tip 32 has a polygonal shape (for example, a hexagonal shape), and as shown in FIG. 5 (b), the fitting corresponding to the polygonal shape. Fit into the hole 33. Further, as shown in FIG. 6A, the center pin tip 34 has a shape having a protrusion 35 on the outer peripheral surface, and as shown in FIG. 6B, a fitting hole corresponding to the shape. 36. Even in such a configuration, the head unit 16 can be selectively held in a plurality of different rotation positions with the center pin 17 as a reference in the holder body 15 so as to be in a non-rotatable state.

  -In above-mentioned embodiment, although the cutting holder 14 was a structure divided into 2 by the holder main body 15 and the head part 16, as a structure (for example, the structure where the holder main body 15 consists of a plurality of members) more than 3 divisions Also good.

  In the above-described embodiment, the head unit 16 is held in the non-rotatable state on the holder body 15 by using the set screw 23 as a detent pin. However, the present invention is not limited to this. For example, the head unit 16 may be held in a non-rotatable state by another anti-rotation mechanism such as a coupling or a fixing hook.

  Next, in addition to the technical ideas described in the claims, the technical ideas grasped by the embodiments described above are listed below.

  (1) A holder main body, a head portion arranged on the tip side of the holder main body, to which a cutting insert can be attached, and a central axis in the longitudinal direction of the holder main body, connecting the holder main body and the head portion. The head portion is selectively held in a non-rotatable state at a plurality of different rotation positions with reference to the center pin that is arranged and the center pin arranged on the center axis in the longitudinal direction of the holder body. The centering pin is formed with the material whose Young's modulus is higher than the formation material of the said holder main body.

  (2) In the above (1), the center pin has a center pin tip part protruding from the holder body, and the center pin tip part has a shape to be rotated with its axis as a target axis, A cutting holder, wherein the cutting holder is fitted in a fitting hole provided in the head portion.

  (3) The cutting holder according to (1) or (2), wherein a scale is displayed in a circumferential direction at a connection portion between the head portion and the holder body.

The side view which shows the cutting tool of one Embodiment which actualized this invention. Sectional drawing in the AA of FIG. Sectional drawing in the BB line of FIG. (A) is a perspective view which shows the center pin front-end | tip part in another embodiment, (b) is sectional drawing which shows the fitting state of the center pin front-end | tip part. (A) is a perspective view which shows the center pin front-end | tip part in another embodiment, (b) is sectional drawing which shows the fitting state of the center pin front-end | tip part. (A) is a perspective view which shows the center pin front-end | tip part in another embodiment, (b) is sectional drawing which shows the fitting state of the center pin front-end | tip part. The side view which shows the conventional cutting holder.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Cutting tool 12 ... Cutting insert 14 ... Cutting holder 15 ... Holder main body 16 ... Head part 17 ... Center pin 20, 30, 32, 34 ... Center pin front-end | tip part 21 ... Male screw part 22 ... Screw hole 23 ... Non-rotating pin Threaded screw 31, 33, 36 as fitting hole

Claims (6)

A holder body;
A head portion that is disposed on the tip side of the holder body and to which a cutting insert can be attached;
A central pin disposed on a central axis in a longitudinal direction of the holder main body and connecting the holder main body and the head portion;
A detent for selectively holding the head portion in a non-rotatable state at a plurality of different rotation positions with reference to a center pin disposed on a central axis in the longitudinal direction of the holder body. A cutting holder comprising a mechanism.   2. The cutting holder according to claim 1, wherein the center pin is made of a hard material mainly composed of ceramic particles having a higher elastic modulus than the holder body.   The center pin has a male screw portion at a center pin tip portion protruding from the holder body, and the center pin tip portion is screwed into a screw hole provided in the head portion. The cutting holder according to claim 1 or 2.   The center pin has a center pin tip portion having a non-circular cross-section projecting from the holder body, and the center pin tip portion is fitted into a non-cross-section fitting hole provided in the head portion. The cutting holder according to claim 1, wherein the cutting holder is provided.   5. The anti-rotation mechanism is a non-rotation pin inserted along a radial direction of the holder body to fix the head portion and the holder body. 6. The cutting holder according to 1.   The cutting tool provided with the cutting holder of any one of Claims 1 thru | or 5, and the cutting insert attached to the said cutting holder.

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