JP2009066668A - Throwaway type cutting tip - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a throwaway type cutting tip which has an acute angle corner portion having a small tip end angle coping with the cutting operation of the portion having the large depth of cut, and is fixed to a holder by increasing its stiffness. <P>SOLUTION: The throwaway type cutting tip is configured such that the cutting tip has first corner cutting edges 6 having an acute tip end angle α1, and second corner cutting edges 7 having a tip end angle α2 (>α1). The first and second corner cutting edges 6, 7 are arranged on a first diagonal line Di1, and other two corner portions 8, 9 are arranged on the second diagonal line Di2 perpendicular to the first diagonal line in the opposed directions respectively. The center O of a mounting hole 5 is arranged on the position shifted to the corner cutting edge 6 side than the intersecting point I of the first diagonal line Di1 and the second diagonal line Di2. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a cutting edge-exchangeable cutting tip employed for a cutting tool as a component of a cutting edge, particularly a cutting edge replacement having a corner cutting edge with a small tip angle suitable for partial machining with a deeper digging depth. It relates to a type cutting tip.

As a cutting tip used for processing a portion having a deep digging depth, a diamond-shaped tip as disclosed in Patent Document 1 below is known. An example of an existing rhombus chip is shown in FIGS. In this type of chip, the center between the two acute corner portions 15 and 15 forming a rhombus (the first diagonal line Di1 connecting the two acute corner portions 15 and 15 and the second diagonal line Di2 connecting the other two corner portions). A mounting hole 5 having a hole center O disposed at the intersection I) is provided, and the chip is fixed to the holder using the mounting hole 5.
JP 2001-30101 A

  A diamond-shaped tip that is provided with a mounting hole in the center between two acute corner portions and is fixed to the holder using the mounting hole is from the fixing position with respect to the holder to the tip of the blade edge (the tip of the sharp corner portion involved in cutting). The distance gets longer. For this reason, there is a problem that the tool vibrates (so-called chatter occurs) in processing where the rigidity of the blade edge portion is reduced and the load is increased. The chatter causes a reduction in processing stability, deterioration in processing accuracy, breakage of the cutting edge, and the like.

  Accordingly, an object of the present invention is to make it possible to increase the rigidity of a cutting edge-exchangeable cutting tip having an acute corner portion with a small tip angle that can be used for processing a portion where the digging depth is deep and to fix it to the holder. Yes.

  In order to solve the above-described problems, in the present invention, a blade-tip-exchangeable cutting tip having a mounting hole penetrating from the upper surface to the bottom surface is configured as follows. That is, it has a first corner cutting edge having a sharp tip angle and a second corner cutting edge having a tip angle larger than that of the first corner cutting edge, and the first corner cutting edge and the second corner cutting edge are provided. The cutting edge is disposed in the opposite direction on the first diagonal line, and further has two corner parts that are symmetrical with respect to the first diagonal line, and the two corner parts are orthogonal to the first diagonal line. It is arranged in the opposite direction on the second diagonal, and the hole center of the mounting hole is arranged at a position deviated to the first corner cutting edge side from the intersection of the first diagonal and the second diagonal. .

  The hole center of the mounting hole may be arranged at a position that coincides with the center of the inscribed circle with respect to the second corner cutting edge. The specifications (tip angle and size) of the second corner cutting edge are The holder design can be advantageously performed by adopting the same arrangement as the specification of the acute angle corner.

  Note that the tip angle α1 of the first corner cutting edge and the tip angle α2 of the second corner cutting edge may be set arbitrarily, but considering the requirements in general machining, the first corner cutting edge The tip angle α1 of the second corner cutting edge is preferably 35 ° or less, and the tip angle α2 of the second corner cutting edge is preferably about 55 to 90 ° in view of widespread demand.

  In the conventional rhombus tip, the hole center of the mounting hole is arranged at the intersection of the first diagonal line connecting the two acute corner parts and the second diagonal line connecting the other two corner parts. On the other hand, in the cutting tip of the present invention, the hole center of the mounting hole is arranged at a position that is biased toward the first corner cutting edge side with respect to the intersection of the first and second diagonal lines. The distance from the position to the tip of the cutting edge is shorter than that of a conventional diamond-shaped tip having an acute corner portion having the same tip angle at the diagonal position, and the rigidity of the portion involved in cutting is increased. As a result, the stability of fixing to the holder and the stability of processing are improved, and chattering is suppressed, so that the processing accuracy is improved and the cutting edge is prevented from being damaged.

  Moreover, the cutting tip of this invention has the 1st corner cutting edge and the 2nd corner cutting edge from which a tip angle differs, and has a cutting depth by using the two corner cutting edges properly. Two different forms of cutting can be performed. Therefore, it is excellent in economic efficiency as compared with the case where a tip provided with a dedicated corner cutting edge having a small tip angle only on one side is employed.

  Further, when the tip angle of the second corner cutting edge is made larger than the tip angle of the first corner cutting edge, the first corner cutting edge is compared with a structure in which the first corner cutting edge is provided in a diagonally symmetrical shape. Since the chip width (W in FIG. 1A) becomes wider, the size of the mounting hole can be increased and the clamping force of the chip can be increased by using a large-sized clamping means.

  The specifications of the second corner cutting edge are the same as the specifications of the sharp corner of the general-purpose rhombus tip, and the center of the mounting hole is located at the position that matches the center of the inscribed circle with respect to the second corner cutting edge Can be used as a holder when the second corner cutting edge is used, with a base for a general-purpose rhombus tip changed only in the mounting seat of the tip, and the design change of the holder can be minimized. There are also advantages.

Embodiments of the blade-tip-exchangeable cutting tip according to the present invention will be described below with reference to FIGS. 1A is a negative type tip in which the upper surface 2 and the bottom surface 3 are parallel and the side surfaces 4 intersect at right angles to the top surface 2 and the bottom surface 3. 2 is a positive type chip in which the side surface 4 intersects the upper surface 2 at an acute angle. Both chips are
A mounting hole 5 is provided through the top surface 2 to the bottom surface 3.

  Each of these cutting tips 1A and 1B has a first corner cutting edge 6 having a sharp tip angle α1 and a second corner cutting edge 7 having a tip angle α2 larger than the first corner cutting edge 6. The first and second corner cutting edges 6 and 7 are disposed in opposite directions on the first diagonal line Di1. Further, two corner portions 8 and 9 having a symmetrical shape with respect to the first diagonal line Di1 are provided, and the two corner portions 8 and 9 are placed on a second diagonal line Di2 orthogonal to the first diagonal line Di1. Arranged in opposite directions. Further, the hole center O of the mounting hole 5 is arranged at a position that is biased toward the first corner cutting edge 6 side from the intersection I of the first diagonal line Di1 and the second diagonal line Di2.

  The illustrated cutting tips 1A and 1B set the tip angle α1 of the first corner cutting edge 6 to 35 ° or less, while the second corner cutting edge 7 standardizes the tip angle α2 in the standard diamond tip. The angle of the second corner cutting edge 7 is also standardized by setting the same angle as the angle of the sharp corner portion, for example, 55 °, 75 °, 80 ° or 86 ° as defined in JIS. Match the size. The hole center O of the mounting hole 5 is arranged on the center of the inscribed circle S1 at the base end portion of the second corner cutting edge 7, and the hole center O is the intersection point I of the first diagonal line Di1 and the second diagonal line Di2. Rather than the first corner cutting edge 6 side.

  The inscribed circle S1 of the illustrated tip is equal to the diameter of the inscribed circle of a standard diamond-shaped tip having an acute corner portion with the same tip angle as the tip angle of the second corner cutting edge 7, and for this reason comparison A chip width W substantially equal to the target standard rhombus chip is ensured, and a reduction in the rigidity of the chip is suppressed.

  Even in the structure in which the first corner cutting edge 6 has a symmetrical shape and is provided at a diagonal position, and the hole center O of the mounting hole 5 is disposed at the intersection of the first and second diagonal lines, the distance from the fixed position to the holder to the tip of the blade edge (Distance L from the hole center O of the mounting hole 5 to the tip of the first corner cutting edge 6 involved in cutting) can be shortened. However, in this structure, the chip width becomes narrower than the invention product and the rigidity of the chip decreases, so the size of the mounting hole must be reduced, and the size of the mounting hole and the clamping means are reduced. The chip fixing force is reduced. On the other hand, in the structure of this invention, since the reduction | decrease of a width | variety is suppressed by employ | adopting the 2nd corner cutting edge with a big tip angle on one side, said malfunction is avoided.

  The present invention can be applied to both the negative type chip and the positive type chip shown. The material of the chip is not particularly limited. A hard sintered body such as a CBN sintered body or a diamond sintered body is attached to a corner of a base metal made of a cemented carbide, including the cutting edge, or a cemented carbide. What formed the blade edge | tip etc. can be utilized suitably.

  FIG. 3 shows an example of a cutting tool using the cutting tip 1A of FIG. The illustrated tool is a turning tool and is configured by attaching a cutting tip 1A to a holder 11. A tip mounting seat 12 is provided at the tip of the holder 11, the second corner cutting edge 7 side is seated on the mounting seat 12, and the seating portion is pressed with a presser foot 13 to clamp the cutting tip 1A, The first corner cutting edge 6 is involved in the cutting. The presser foot 13 is fastened to the clamp bolt 14 and clamps the portion of the mounting hole 5. The cutting tip 1A is pressed against the seat bottom 12a of the mounting seat 12 by the clamping force at this time, and at the same time, two adjacent side surfaces on the second corner cutting edge 7 side are pressed against the seat side surface 12b of the mounting seat 12 to hold the holder. 11 is fixed.

  In this structure, the fixed position of the cutting tip 1A with respect to the holder 11, that is, the distance L from the hole center O of the mounting hole 5 to the tip of the first corner cutting edge 6 involved in cutting is the first corner cutting edge 6 Is shorter than a conventional diamond-shaped tip having a corner cutting edge with the same tip angle as the diagonal (the distance from the center of the tip mounting hole to the tip of the cutting edge corresponds to L3 in FIG. 1A). The rigidity of the part involved in cutting is increased. For this reason, the stability of fixing to the holder is improved, and chatter is suppressed, so that the stability of processing, the accuracy of processing, and the breakage of the cutting edge can be prevented.

  FIG. 4 shows a cutting tool in which the cutting tip 1 </ b> A of FIG. 1 is mounted on the holder 11 in a direction in which the second corner cutting edge 7 is involved in cutting. The holder 11 can be used with a part of the design modified for a diamond-shaped chip provided with a corner cutting edge having the same specifications as the second corner cutting edge 7 at a diagonal position. The part to be redesigned is the part where the first corner cutting edge 6 is seated, that is, only the countersink part of the mounting seat 12, and the other parts use the same specification holders as those standardized. Can do.

The results of confirming the effect of the cutting tip of the present invention will be listed below. A cutting tip (invention) having the following dimensional specifications in FIG.
Tip angle α1 of the first corner cutting edge 6 = 27 °, tip angle α2 of the second corner cutting edge 7 = 55 °, diameter of the inscribed circle S1 = 12.7 mm, first from the hole center O of the mounting hole The distance L to the tip of the corner cutting edge 6 is 19.154 mm, the distance from the hole center O of the mounting hole to the tip of the second corner cutting edge 7 is L2 = 12.827 mm, L3 = 21.697 mm, the first Distance L4 = 31.981 mm from corner cutting edge 6 to second corner cutting edge 7 and mounting hole diameter d = 5.16 mm.
For comparison, in the shape shown in FIG. 9, the tip angle α1 of the acute corner portion 15 = 27 °, the distance L from the hole center O of the mounting hole to the tip of the acute corner portion 15 = 21.697 mm, the mounting hole A cutting tip (conventional product) having a diameter d = 5.16 mm was also prepared.

Next, using these two types of cutting tips, test processing (turning with a cutting tool) was performed under the following conditions.
・ Work material: FCD 700
・ Processing content: Intermittent cutting ・ Processing conditions Cutting speed Vc = 100m / min, Feed f = 0.3mm / rev, Incision a _p = 2mm Dry cutting Test method The following tests are performed for each of the above invention products and conventional products It was.
I. Two workpieces are cut for 300 seconds each for the inventive product and the conventional product, and the wear / destruction state of the chip during cutting is 20 seconds, 40 seconds, 60 seconds, 90 seconds, 120 seconds, 150 seconds, 180 seconds, 240 seconds. Measurement and photographing at intervals of 300 seconds. The processing machine used in this test is NC lathe SL-250 manufactured by Mori Seiki Seisakusho. The vibration was measured using a Keyence vibration measuring instrument NR600.

  FIG. 5 shows how the flank wear width fluctuates in the above test. Further, FIGS. 6 and 7 show the wear state of the chip after cutting for 20 seconds and after cutting for 300 seconds. 6 (a) shows the wear situation after 20 seconds of cutting of the invention, FIG. 6 (b) shows the wear situation after 300 seconds of the invention, and FIG. 7 (a) shows the wear situation after 20 seconds of the conventional product. FIG. 7B shows the state of wear after cutting for 300 seconds of the conventional product, and the invention product has a smaller amount of wear.

(A) The top view which shows an example of the cutting tip of this invention, (b) Sectional drawing along the XX line of the tip same as the above (A) The top view which shows the other example of the cutting tip of this invention, (b) Sectional drawing along the YY line of the tip same as the above (A) A plan view of a cutting tool (bite) using the cutting tip of FIG. 1, (b) a side view of the same bite. (A) A plan view of a cutting tool (bite) in which the cutting tip of FIG. 1 is used in the direction opposite to that of FIG. 3, (b) a side view of the same bite. Diagram showing the fluctuation of flank wear width in test cutting (A) is the state of wear after 20 seconds of cutting of the invented product, (b) is a diagram showing the state of wear of the invented product after 300 seconds of cutting. (A) is a state of wear after cutting for 20 seconds of a conventional product, (b) is a diagram showing a state of wear after cutting for 300 seconds of a conventional product. Plan view showing an example of a conventional rhombus chip The top view which shows the other example of the conventional rhombus chip | tip

Explanation of symbols

1A, 1B Replaceable cutting tip 2 Top surface 3 Bottom surface 4 Side surface 5 Mounting hole 6 First corner cutting edge 7 Second corner cutting edge 8, 9 Corner portion 11 Holder 12 Mounting seat 12a Seat bottom 12b Seat side surface 13 Presser foot 14 Clamp bolt 15 Acute corner portions α1, α2 Tip angle Di1 First diagonal line Di2 Second diagonal line I Intersection of first and second diagonal lines O Mounting hole center S1 Inscribed circle L Corner cutting edge tip involved in cutting from mounting hole center Distance to

Claims (3)

  A cutting edge replaceable cutting tip having a mounting hole (5) penetrating from the top surface (2) to the bottom surface (3), the first corner cutting edge (6) having a sharp tip angle, and the first corner cutting A second corner cutting edge (7) having a tip angle larger than that of the blade, and the first corner cutting edge (6) and the second corner cutting edge (7) are opposite to each other on the first diagonal line (Di1); And has two corner portions (8, 9) that are symmetrical with respect to the first diagonal line (Di1), and the two corner portions (8, 9) are the first corner portions (8, 9). The second corner line (Di2) orthogonal to the diagonal line (Di1) is disposed in a direction opposite to the first diagonal line (Di1), and the first corner cutting edge (I) from the intersection (I) of the first diagonal line (Di1) and the second diagonal line (Di2) ( 6) The hole center (O) of the mounting hole (5) is arranged at a position biased to the side. Indexable cutting chips.   The hole center (O) of the mounting hole (5) is arranged at a position coinciding with the center of the inscribed circle (S1) with respect to the second corner cutting edge (7). Replaceable cutting tip.   A cutting edge-exchangeable cutting tip in which the tip angle (α1) of the first corner cutting edge (6) is set to 35 ° or less and the tip angle (α2) of the second corner cutting edge (7) is set to 55 to 90 °.