JPH08118113A - Cutting tool with chip breaker - Google Patents

Abstract

PURPOSE: To improve without worsening machining accuracy and worsening sharpness, cutting chip processing performance of a cutting tool with chip breaker forming a cutting edge of superhigh hardness sintered material. CONSTITUTION: To a seat groove 2 in a corner upper surface of a base metal 1, a superhigh hardness sintered material 3 is connected so that its upper surface is protruded from an upper surface of the base metal to generate a step difference (h), to provide a chip breaker 5 and a cutting edge 8 in this superhigh hardness sintered material 3. The step difference (h) is equal to a necessary height H of a breaker wall. Accordingly, a center lowering amount of an edge point from the upper surface of the base metal is made zero, to form the breaker 5 of proper size in a proper position, and while obtaining good cutting chip processing performance, worsening machining accuracy and sharpness due to center lowering can be eliminated.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention is used for finish cutting of aluminum alloys and non-ferrous metal materials, especially for finish cutting requiring forced processing of chips such as boring processing in automatic machine lines and copying of aluminum wheels. The present invention relates to a cutting tool with a chip breaker.

[0002]

2. Description of the Related Art A tool having an ultrahigh hardness sintered body obtained by sintering polycrystalline diamond or cubic boron nitride under high pressure is generally used for finish cutting. In this finish cutting, thin and hard-to-break chips are generated. Therefore, in most cases, a chip breaker is provided at the tip of the cutting edge to forcefully process the generated chips with the breaker.

FIG. 5 and FIG. 6 show a conventional tool (throw-away tip) shown in FIG.
The seat groove 2 is provided in the upper corner of the base metal 1 that is the tool body,
The ultra-high hardness sintered body 3 is bonded thereto. Then, the chip breaker 5 is processed on the upper surface corner portion of the ultra-high hardness sintered body 3, and the cutting edge 8 is constituted by the cross edge of the rake face 6 and the side face 7.

Reference numeral 4 denotes a back plate integral with the ultra-high hardness sintered body 3. The back plate 4 is brazed to the base metal 1 to form the ultra-high hardness sintered body 3.
Is fixed to the base metal 1.

[0005]

In the above-mentioned conventional cutting tool, the upper surface position of the ultra-high hardness sintered body 3 is aligned with the upper surface position of the base metal 1 and the chip breaker 5 is dug down on the surface. Therefore, the cutting edge is in a so-called center-down state in which the cutting edge is below the upper surface of the base metal 1, and the cutting edge position retreats, resulting in poor machining accuracy.

[0006] Further, since the biting angle with respect to the work material becomes dull by the amount of the cutting edge being lowered, the sharpness is deteriorated.

Further, as shown in FIG. 5, in the case where a breaker having a rake angle of 0 ° is attached, the height H of the breaker wall becomes the centering down amount as it is, so that the wall height cannot be set large and the chips It is difficult to improve processing performance.

As shown in FIG. 6, when the rake angle θ is added to the breaker 5, the centering down amount of the cutting edge can be reduced and the height H of the breaker wall can be increased, but in this method, when θ is increased. The wedge angle γ of the cutting edge is reduced, resulting in a decrease in the cutting edge strength and the cutting edge is damaged. From the viewpoint of the edge strength, the minimum value of this wedge angle γ is limited to about 70 °, so θ cannot be increased to secure the required wall height H, and therefore the breaker width W needs to be increased. As a result, the chip disposal range is narrowed.

An object of the present invention is to provide a cutting tool with a chip breaker that eliminates these problems.

[0010]

In order to solve the above problems, in the present invention, the difference in height between the tip position of the cutting edge made of an ultra-high hardness sintered body and the upper surface of the tool body is zero or almost zero. In addition, the upper surface of the chip breaker is located higher than the upper surface of the tool body. This configuration requires the height of the chip breaker that requires the upper surface position of the ultra-high hardness sintered body to be higher than the upper surface of the tool body (when the breaker is dug below the cutting edge, the height after the dug is subtracted). It is desirable to make it higher by an amount corresponding to the above, and to create it by a method of setting the tip breaker so that the amount of centering of the cutting edge becomes zero or almost zero.

In addition, the maximum permissible value for the centering of the cutting edge is 0.2.
It is desirable to set it to about mm. An error of this degree is included in the range of almost zero in the present invention.

In the case of this type of cutting tool, the chip breaker has a wall height H of 0.1 mm to 1.5 mm, a width W of 0.2 mm to 3.0 mm, and a radius of curvature r of the breaker surface of 0. It is desirable to set it in the range of 1 mm to 1.5 mm.

Besides, the chip breaker and the rake face are
It is also effective from the viewpoint of stabilizing the chip treatment to perform uniform processing with WEDM (wire electric discharge machining), EDM (electrical discharge machining), or polishing.

[0014]

Since the centering amount of the cutting edge is zero or almost zero, the position of the cutting edge can be accurately determined, and the biting angle with respect to the work material does not become blunt. Therefore, processing accuracy and sharpness do not deteriorate.

Further, since the upper surface of the chip breaker is located higher than the upper surface of the tool body, the chip disposal performance is excellent and the processing range is widened.

Incidentally, the reason why the allowable maximum value of the centering of the cutting edge is set to about 0.2 mm is that the processing error can be kept within the allowable value at this level.

With regard to the size of the chip breaker, a preferable value is given as a numerical value at which the chip disposal capacity is maximized in consideration of the type of work material and the conditions of finish cutting with this type of tool.

In addition, the rake face and the chip breaker are W
If the surface is finished to a uniform surface roughness by EDM, EDM, polishing, etc., the chips will flow out smoothly with less resistance, and the stability of the process will increase.

[0019]

1 to 4 show examples in which the present invention is applied to a throw-away tip. In the figure, 1 is a base metal made of cemented carbide or the like, 2 is a seat groove provided in a corner portion on the upper surface of the base metal, and 3 is a super-hard sintered body.

The ultra-high hardness sintered body 3 is attached to the seat groove 2 by brazing the integrated back plate 4 to the base metal 1. With the conventional tool, the height position of the upper surface of the sintered body 3 is aligned with the upper surface position of the base metal, but in the present invention, the upper surface position of the sintered body 3 is raised so as to have a step h.

The chip breaker 5 is attached by bonding the ultra-high hardness sintered body 3 to the seat groove 2 and then processing it by WEDM, EDM, polishing or the like. This chip breaker 5 includes a breaker for obliquely sharpening shown in FIGS. 1 and 3, a breaker for sharpening one side edge parallel shown in FIG. 2, a breaker for parallel sharpening both sides edge shown in FIG. 4, and a breaker with a rake angle of 0 ° ( Various shapes are conceivable, such as a breaker with a rake angle θ (FIGS. 1 and 4) (FIGS. 2 and 3) and a two-step breaker (FIG. 4). Although it is easy to machine, the optimum shape and value are selected for the shape, the height H of the breaker wall, the breaker width W, and the radius of curvature r of the breaker surface in consideration of cutting conditions.

In the throw-away tip of FIGS. 1 and 4 in which the rake angle is 0 °, if the step h is made equal to the height H of the breaker wall, the amount of centering of the cutting edge becomes zero. In addition, in the throw-away inserts of FIGS. 2 and 3 with the rake angle θ, the descending amount from the blade edge of the groove bottom of the breaker 5 is set to H ₁
If h ₁ = h is set, the amount of centering of the cutting edge becomes zero.

In the figure, 6 is a rake face, and 8 is a cutting edge constituted by a ridge intersecting the rake face 6 and the side face 7.

In the tool of the present invention, the ultra-high hardness sintered body and the base metal are set to the same height, and then the breaker groove and the top surface of the base metal are ground into a shape as shown in the figure. be able to. However, this method cannot use the standard base metal,
Since a base metal grinding step is also required and the manufacturing cost becomes high, it is desirable to manufacture by the method described above.

Further, the cutting tool of the present invention is not limited to the illustrated indexable insert. The present invention can also be applied to a body in which a shank supported by a holder is used as a main body and an ultra-high hardness sintered body is fixed to a seat groove at the tip of the shank.

The results of the comparative test of tool performance will be described below.

The test was carried out using the product of the present invention shown in FIG. 1 and the conventional product shown in FIGS. 5 and 6 under the following conditions.

Work Material: ADC12 Cutting Style: Inner Diameter Cutting Cutting Conditions: Tool Material Used: Polycrystalline Diamond Sintered Body Chip Breaker Dimensions: W = 1.0 mm, H = 0.
3 mm, r = 0.5 mm Cutting speed: 300 m / min Feed: 0.06 mm / rev Depth of cut: 0.35 mm Wet cutting-Test results-The conventional product of FIG.
Was set to 0.15 mm, the chips were curled, but were connected to a length of about 60 mm and discharged, which was not preferable. Further, in the conventional product of FIG. 6, when W was expanded to 2.0 mm in order to set H to 0.3 mm, which is the same as the product of the present invention, the chips did not curl well and extended long under the above cutting conditions. It was On the other hand, in the cutting by the product of the present invention shown in FIG. 1, the chips curl cleanly and were broken at a length of about 2 to 3 mm, and the discharge was very smooth. Also,
Regarding the finished surface roughness and processing accuracy, the product of the present invention also showed very good results as compared with the conventional product.

[0029]

As described above, in the cutting tool of the present invention, the upper position of the ultra-high hardness sintered body is set higher than the upper position of the tool body, and a chip breaker of an appropriate size is attached to the appropriate position. Since the centering of the cutting edge is set to zero or almost zero, there is no deterioration in processing accuracy and sharpness, chip processing is performed well, and ideal finishing cutting of aluminum alloy and non-ferrous metal can be performed. Became.

[Brief description of drawings]

FIG. 1A is a plan view showing an example of a cutting tool of the present invention, and FIG. 1B is a view seen from the direction I in the drawing.

FIG. 2A is a plan view of another embodiment. FIG. 2B is a view from the direction of the arrow II in the above drawing.

FIG. 3A is a plan view of still another embodiment, and FIG. 3B is a view from the direction of arrow III in the above drawing.

FIG. 4A is a plan view of still another embodiment. FIG. 4B is a cross-sectional view taken along line IV-IV of the above drawing.

FIG. 5A is a plan view of a conventional cutting tool, and FIG. 5B is a view from the direction V in FIG.

FIG. 6A is a plan view of another example of a conventional cutting tool, and FIG. 6B is a view from the direction of arrow VI in the above figure.

[Explanation of symbols]

 1 Base metal 2 Seat groove 3 Ultra high hardness sintered body 4 Back plate 5 Chip breaker 6 Rake face 8 Cutting edge θ Rake angle H Breaker wall height w Breaker width r Breaker surface curvature radius h Step γ Wedge angle

Claims (4)

[Claims] 1. An ultra-high hardness sintered body containing polycrystalline diamond, cubic boron nitride or the like as a main component is joined to a seat groove formed on the upper surface of the tip corner of the tool body, and the ultra-high hardness sintered body is joined. In a cutting tool with a cutting edge and a chip breaker attached, the height difference between the tip position of the cutting edge made of the ultra-hard sintered body and the upper surface of the tool body is zero or almost zero, and the upper surface of the chip breaker is A cutting tool with a chip breaker whose position is higher than the top surface of the tool body. 2. The maximum amount of downward movement of the cutting edge is 0.2 mm.
A cutting tool with a chip breaker according to claim 1. 3. The chip breaker has a wall height H of 0.1 mm to 1.5 mm and a width W of 0.2 mm to.
3.0 mm, the radius of curvature r of the breaker surface is 0.1 mm to
The cutting tool with a chip breaker according to claim 1 or 2, wherein each cutting tool is set in a range of 1.5 mm. 4. A chip breaker and a rake face are WED
The cutting tool with a chip breaker according to any one of claims 1 to 3, which is processed by M, EDM or polishing to have a uniform surface roughness.