JP4906690B2 - Throwaway tip - Google Patents

Description

  The present invention relates to a throw-away type cutting tip used for cutting cast iron or steel.

  Conventionally, throw-away type cutting tips are used for cutting cast iron and steel, and some of them have a chip breaker formed on the rake face of the chip for the purpose of preventing damage to the rake face due to chips, or cutting. In order to prevent the cutting blade from being damaged due to a large resistance, a tip having a change in the shape of the rake face of the tip is known, such as a land provided near the cutting edge on the outer periphery of the rake face.

  Here, in the throw-away tip used on both sides formed with a chip breaker and a land, in order to prevent the cutting edge portion from coming into contact with the holder side seating surface and being lost when the tip is turned over, 4, the height of the land surface 25 is configured to be lower than the height of the rake face central portion 27 (sitting surface) (see, for example, Patent Document 1).

  However, with the above-mentioned conventional throw-away inserts, especially when machining under high impact cutting conditions, the peripheral edge of the rake face that has the greatest effect on the fixation (sitting) of the insert, particularly the height of the insert corner, is the height of the center of the rake face. As a result, when the holder is mounted, there is a gap between the cutting edge located on the bottom surface (sitting surface) of the chip and the seating surface on the holder side. As a result, the chip is not stable and the chip vibrates during cutting. In addition, the cutting edge part located on the lower surface of the chip intermittently collides with the holder side seating surface and breaks (back chipping), or chipping occurs on the cutting edge involved in cutting due to chatter vibration of the chip during cutting, etc. The problem occurred.

Therefore, in a so-called all-round breaker provided with a land and a central surface having a similar shape to the land, the height of the land and the central surface is made the same to stabilize the chip, and the vibration of the chip during cutting A throw-away tip that suppresses the damage and prevents damage to the cutting blade has also been proposed (see, for example, Patent Document 2).
JP-A-8-39306 Japanese Patent Laid-Open No. 11-277307

  However, even with this all-round breaker type throw-away tip, if the lands on the rake face are damaged due to chipping of the cutting edge or crater wear during the first cutting, the tip will most likely sit when the tip is turned over. Since the corner lands that affect it are damaged, they will not become the installation surface, so the stability of the sitting will be reduced, and problems such as damage to the cutting edge due to chip vibration during cutting and deterioration of the machining surface will occur. Was not improved sufficiently.

  In addition, since the land surface on one side of the main surface is long, the rigidity becomes insufficient and it becomes easy to bend. Therefore, when machining under cutting conditions with particularly high impact, the vibration of the land surface causes micro vibrations and damages the cutting edge. There were also problems such as

In particular, in the throw-away tip having a rhombus shape in which the length of one side of the main surface is relatively long, the phenomenon appears remarkably.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a throw-away tip that is excellent in sitting stability during processing, is difficult to damage the cutting blade, and provides a smooth processed surface. There is.

  As a result of studying the above problems, the present inventor provided a land surface at the peripheral portion of the main surface of the throw-away tip and provided at least one protrusion extending from the center surface of the throw-away tip toward the land. In addition, by providing at least two types of connecting portions in which the protruding portions and the land surfaces are connected to each other so that the positions with respect to the nose for cutting are different and the widths of the connecting portions are different, the sitting stability during processing is improved. In addition, the present inventors have found that the land surface can be reinforced, the occurrence of fine vibration of the land surface due to cutting can be suppressed, and chipping of the cutting edge involved in cutting can be prevented, and a smooth finished surface can be obtained.

That is, the throw-away tip of the present invention has a substantially flat plate shape, and two main surfaces having a rhombus shape including a sharp corner portion and a side portion including a nose for cutting include a rake surface and a seating surface, and a side surface. In a throw-away tip that has a flank and has a cutting edge at the intersection ridgeline between the two main surfaces and the flank, and can be used on both sides, it is formed at the peripheral edge of the two main surfaces. A land surface, a central surface formed at a central portion of the two main surfaces, and a recess formed between the land surface and the central surface, and the central surface is the land in a top view. At least one projecting portion extending toward the surface, and a connecting portion that partially connects at least one of the projecting portions and a side portion of the land surface, and the connecting portion has the acute angle. 2 of a 1st connection part and a 2nd connection part in order close to a corner | angular part. At least a connecting portion of, when placed on the holder, the land surface of the main surface serving as a seating surface and said connecting portion is placed face to said holder.

  In addition, it is preferable that the protrusion has a first protrusion that extends toward the nose and is separated from the land surface through the recess.

  Furthermore, it is preferable that the protrusion further includes a second protrusion that extends toward a side portion of the main surface and is separated from the land surface via the recess.

In addition, when placed on the holder, be pre-Symbol protruding portion of the main surface serving as a seating surface is placed face to the holder desirable.

  As described above in detail, in the throw-away tip according to the present invention, a land surface is provided on the peripheral portion of the main surface of the throw-away tip, and a central surface having at least one protrusion extending toward the land surface is provided. And providing at least two types of connecting portions in which at least one of the protrusions and the land surface of the side portion of the throw-away tip are connected so that the positions with respect to the nose for cutting are different and the widths of the connecting portions are different. As a result, the stability of the chip is improved, and the rigidity of the land surface is increased. Therefore, it is possible to prevent the occurrence of fine vibrations on the land surface, to prevent the cutting blades involved in cutting from being lost, and to be smooth. A finished surface is obtained.

  A cutting throw-away tip 1 (hereinafter simply referred to as a tip 1) of the present invention will be described using the plan view of FIG. 1 and the enlarged sectional view of FIG. 2 ((a) AA section, (b) BB section). explain.

According to FIG. 1, the tip 1 has a substantially flat plate shape, and is a polygonal main surface composed of a corner portion 10 forming a rake face and a seating surface (the corner portion 10 to be cut is called a nose 12) and a side portion 11. 2 and a flank 3 on the side surface, and a cutting edge 4 on the intersecting ridge line between the flank 3 and the main surface 2. Furthermore, the peripheral surface of the main surface 2 has a flat land surface 5 parallel to the seating surface and in the thickness direction. Further, according to FIG. 2 (a), the central portion of the main surface 2 of the chip 1 has a flat central surface 7 parallel to the seating surface and the thickness direction, and between the land surface 5 and the central surface 7. A recess 6 that functions as a breaker is provided.

  According to the present invention, the central surface 7 is provided with one or more protrusions 8 extending toward the land surface 5 and, as shown in FIGS. 1 and 2, the connecting portion between the land surface 5 and the protrusion 8 is provided. The feature is to provide. And the connection part 9 in this embodiment has at least the two connection parts 9 of 9 A of 1st connection parts and the 2nd connection part 9B in order in the vicinity of the nose 12, as shown in FIG. The width of the connecting portion 9B is larger than the width of the first connecting portion 9A. With such a configuration, the land surface 5 can be reinforced by the connecting portion 9 and the rigidity can be increased. In addition, the protruding stability 8 on the same surface from the center portion of the rake face improves the sitting stability of the chip. The generation of fine vibration of the land surface due to the impact of cutting can be suppressed, and chipping of the cutting edge 4 on the land surface 5 and the occurrence of chipping can be prevented.

  Here, the connecting portion 9 in the present embodiment is a flat surface as shown in FIG. 2B and has the same height as the protruding portion 8. Furthermore, the land surface 5 is not connected by reinforcing the land surface 5 by connecting the center surface 7 and the land surface 5 over the entire circumference region, but by connecting the protrusion 8 and the land surface 5 which are a part of the center surface 7. 5 and the protrusion 8 can be provided with a portion that is not connected, and the sharpness of the side 11 of the main surface 2 is prevented from being lowered by the connection 9, and the effect of maintaining the sharpness at the cutting edge of the side 11 is also maintained. Have.

  In addition, when the chip 1 is placed, at least the protrusion 8 and the connecting part 9 of the main surface 2 that serves as a seating surface become an installation surface, so that the sitting of the chip 1 is stabilized, and the chip 1 and the chatter vibration are suppressed. The damage of the chip 1 can be prevented. Here, in order to further stabilize the sitting of the chip 1, it is preferable that the central surface 7, the land surface 5, the protruding portion 8, and the connecting portion 9 are all installed surfaces.

  In addition, S-type square chips and T-type triangle chips have the same distance from the center of the chip to each corner, so there is little deformation during firing and good stability, but the angle of the nose 12 is 80 °. The following diamond-shaped tips are different in distance from the center of the tip to each corner, so that deformation during firing is likely to occur, and the stability is poor, so that the above-mentioned problems such as cutting edge damage are likely to occur. In particular, in a D-type all-round breaker chip having an angle of 55 ° of the nose 12, as described above, in addition to poor sitting stability, the length a of the side of the main surface 2 is long. Rigidity is insufficient and micro vibrations are likely to occur on the land surface 5. Therefore, when the main surface 2 has a rhombus shape, the effect of the present invention is particularly easily exhibited. Therefore, it is desirable that the main surface 2 has a rhombus shape, particularly a rhombus shape with an apex angle of 55 ° or less.

  Further, when the width of the land surface 5 is b, 0.2 ≦ b ≦ 0.5 mm increases the strength of the cutting edge and the stability of the land surface 5 to increase the strength against back chipping, as well as chips. It is desirable in terms of preventing chipping and chipping by improving the discharging performance and preventing the cutting resistance from increasing.

  Further, in order to prevent the sharpness of the chip 1 from being lowered and the cutting resistance from being increased, assuming that the length of one side of the chip 1 is a and the distance from the nose 12 to the connecting portion 9 is c, 0.25a ≦ c ≦ 0. .75a is desirable.

  Furthermore, when the width of the connecting portion 9 is d in terms of enhancing the strength of the connecting portion 9 and the sharpness of the cutting edge, 0.5 mm ≦ d ≦ a / 3, preferably 0.5 mm ≦ d ≦ a / 5. It is desirable.

  (Example) A mixed powder obtained by adding 11% by weight of Co to WC powder is molded so that the shape after firing by press molding becomes the shape (model, size) shown in FIGS. After vacuum firing, Sample Nos. 1 to 4 were adjusted to substantially the same height by polishing the central surface and the land surface of both main surfaces of the sintered body. In addition, No. Reference numerals 1 to 8 are shapes (FIG. 1) having a connecting portion in the form of a rhombus with a nose angle θ = 55 °. Sample No. No. 5 is a conventional shape having no breaker as shown in FIG. No. 6 is an all-round breaker having no projection as shown in FIG. 7 and 8 have shapes that do not have a connecting portion as shown in FIG.

  In addition, all samples were subjected to honing treatment (blade edge treatment) on the peripheral portion of the land surface, and then a hard film made of TiCN-Al2O3-TiN was sequentially coated on the sintered body surface by a CVD method. ˜8 throwaway chips were produced.

Moreover, the cutting test on the following conditions was performed using the obtained chip | tip, and the cutting time until a chip | tip reached a chip | tip and the processing surface state of a workpiece were observed. The results are shown in Table 1. Cutting conditions Cutting speed: 250 m / min Cutting depth: 4 mm Feeding: 0.35 mm / rev Work material: FC250 Cutting with four grooves: Dry type Samples in which the chip shapes of samples 1 to 8 in Table 1 are changed to C type The same cutting test was performed by 1'-7 '. The results are shown in Table 2.

  From Table 1 and Table 2, the sample No. in which the width d of the connecting portion is 0.5 to a / 3 mm, the width b of the land surface is 0.2 to 0.5, and the height of the protrusion and the land surface is the same. . 1-4, Sample No. In 1 'to 4', the cutting life was as long as 300 seconds or more, and there was no back chipping or chipping of the cutting edge portion, which showed excellent fracture resistance.

Further, as a result of observing the machined surface of the work material, the machined surface was uniformly smooth.

  On the other hand, sample no. In 5 and 5 ', the processed surface of the work material was rough due to chatter.

Further, chipping occurred on the chip mounting surface.

  Sample No. In 6-8, 6 'and 7', the cutting edge was damaged early and the chipping resistance was poor, and the surface condition of the machined surface was also deteriorated due to chipping and chattering.

Sample No. In 6, 6 ', 8, and 7', chipping occurred on the chip mounting surface.

It is the schematic plan view which showed the example of the throw away tip of this invention. (A) It is a general | schematic expanded sectional view between AA of the throw away tip of FIG. (B) It is a general | schematic expanded sectional view between BB of the throw away tip of FIG. (A) It is a schematic plan view of the throw-away tip without a breaker. (B) It is a schematic plan view of a general circumference breaker. (C) It is a schematic plan view of a throw-away tip with a protrusion without a connecting portion. It is a principal part expanded sectional view of the conventional throw away tip.

Explanation of symbols

1: Throw away tip 2: Main surface 3: Flank surface 4: Cutting edge 5: Land surface 6: Recessed portion 7: Center surface 8: Projection portion 9: Connection portion between land surface and projection portion 9A: First connection portion 9B: Second connecting portion 10: Corner portion 11: Side portion 12: Nose a: Length of one side of the throw-away tip b: Width of land c: Length from corner portion to connecting portion d: Width of connecting portion θ: Nose angle 24: Cutting edge 25: Land surface 27: Center surface h: Difference in height between the land surface and the center surface

Claims (4)

The two main surfaces that form a substantially flat plate shape and include a rhombus shape including sharp corners and sides including a nose for cutting are rake surfaces and seating surfaces, and the side surfaces are flank surfaces, In the throw-away tip that has a cutting edge at the intersecting ridge line of the flank, and can be used on both sides used by attaching to a holder
A land surface formed at a peripheral portion of the two main surfaces; a central surface formed at a central portion of the two main surfaces; and a recess formed between the land surface and the central surface. ,
The central surface has at least one or more protrusions extending toward the land surface in a top view, and a connecting portion that partially connects at least one of the protrusions and a side portion of the land surface. And
The connecting part has at least two connecting parts of a first connecting part and a second connecting part in order of approaching the acute corner part ,
The throw-away tip , wherein the land surface of the main surface serving as a seating surface and the connecting portion serve as an installation surface for the holder when placed on the holder . The throw-away tip according to claim 1, wherein the protrusion has a first protrusion that extends toward the nose and is spaced apart from the land surface through the recess. The said protrusion part further has the 2nd protrusion part which spaces apart from the said land surface through the said recessed part while extending toward the edge part of the said main surface, The Claim 1 or 2 characterized by the above-mentioned. Throw away tip. When placed on the holder, the throw-away tip according to any one of claims 1 to 3 before Symbol protruding portion of the main surface serving as a seating surface is characterized by comprising a mounting surface to the holder.

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