JPH0771772B2 - Tips for metal cutting circular saws - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a cemented carbide tip for a circular saw blade used for cutting ferrous and non-ferrous difficult-to-cut materials, and has been improved particularly suitable for thin saw blades. Related to carbide tips.

2. Description of the Related Art When cutting a material with a generally used chip dividing grooved blade, chips having different widths are generated one by one on both sides of the groove, but the chips do not always flow parallel to the cutting surface. For this reason, the cutting chips generally try to stick out of the saw thickness range at a distance of several mm or more from the cutting edge. Also, since the blade is chamfered on both sides, it flows easily to the side and when the cutting powder hits the cutting surface, it is pulled out by the cutting surface and is caught between the cutting surface and the circular saw blade. The powder may adhere to the cut surface, impairing the accuracy and aesthetics of the cut surface. The shape of the cutting edge described in the rotary milling tool device of Japanese Patent Laid-Open No. 56-114613 (Fig. 13A) is known to improve the welding phenomenon of the chips contacting the cutting surface. . Further, as a turning tip technology for parting and grooving, JP-A-63-16903 (Fig. 13B, C) and JP-A-62-161902
The shape of the cutting edge of the tip, which is mentioned as the prior art in the specification of No. 13 (Fig. 13D), also has the same improvement. Further, in cutting difficult-to-cut materials, the cutting edge temperature rises at high speed cutting, and the cutting chips become welded to the chip rake face and the bottom of the blade chamber of the base metal, making the cutting edges unusable and cutting chips becoming unusable. Japanese Patent Laid-Open No. 62-277216, which the applicant previously proposed, is known for preventing such a welding phenomenon.

The first problem is that the rake face 2 is formed on the cutting edge portion of the tip 1 as shown in FIG. 13A, and the rake face 2 has a flat portion of 50 to 70% of the width of the tip. A wide rectangular recess 3 is formed, and the inner part of this recess is rounded in the flow direction of the chips and rises up, and is continued by the chip breaker 4, and the width of the recess is increased according to the depth of the bottom. Narrows. A bank portion 5 is formed on both sides of the recess 3 so that the upper width is the same and the depth is changed. The second and third ones are almost the same.

When cutting with a milling machine equipped with such chips, chips of a size corresponding to the chip width are generated, and immediately thereafter, the chips are pushed into the recesses 3 and correspond to the shape of the recesses. , The shape of Fig. 19 is transformed, and the width of the chips becomes smaller than that just after being cut out. That is, since the chips are rapidly deformed while flowing over a distance about the length of contact with the chips, as a reaction thereof, a strong pressing force and a frictional force act on the bank portion 5 forming the concave portion 3 and the bank portion 5 is heated to a high temperature. Become. Even if the cutting fluid is not used, when the cutting edge comes out of the material to be cut, it is cooled by the air flow. In the rotary cutting, there is a problem that so-called thermal fatigue cracks are generated in the bank portion 5 by repeating such heating and cooling temperature cycles, and the cracks grow due to the pressing force, resulting in chipping.

The fourth one has a second rake face 7 following the first rake face 6 as shown in FIG. 15, and then an up step 8 having a large arc step. However, the steel type of the material to be cut is steel with a carbon content of 0.10% or less and high chromium steel (SU
(S403, SUS405) completely annealed material, or when the saw thickness T is small, especially if T ≤ 2.5 mm, the chip width is small and the chamfer width on the side of the cutting edge is easier than the chip width. As the size of the chips becomes relatively large, the chips tend to skew. For this reason, there is a problem that the chips having narrower width, which are generated on both sides of the chip dividing groove, are likely to cause welding.

Furthermore, it is necessary to supply a large amount of cutting fluid to prevent welding, and even if the cutting fluid is supplied, if the cutting heat increases with the wear of the cutting edge, welding of cutting chips on the cut surface is unavoidable. Further, there is a problem that the working environment is easily polluted by the use of cutting fluid and the chips are rapidly cooled by the cutting fluid, so that the life of the cemented carbide tips is shortened.

The present invention is a circular saw blade of a cemented carbide tip, especially when the saw thickness is 2.5 mm or less, the welding of the cutting chips to the cutting surface does not occur in so-called dry cutting without using a cutting fluid and an abnormal heat is generated. It is an object of the present invention to provide a tip for a circular saw which has a stable and long life and which can obtain a highly accurate and beautiful cut surface without causing an early cutting edge defect due to crack generation and growth. Also, the work material is a bar material with a diameter of 20φ to 100φmm,
Saw blade size 200φ to 400φmm, number of blades 40 to 140, cutting condition V =
It is an object of the present invention to provide a tip for a circular saw blade which is particularly suitable for 50 to 200 m / min and Sz = 0.05 to 0.15 mm described later.

Means for Solving the Problems In order to achieve the above-mentioned object, a cemented carbide tip for a circular saw according to the present invention has a first rake surface of a negative sieve over the entire cutting edge width at the tip of the cutting edge of the rake surface. 2 In a chip in which a concave portion for leading out chip deformation is formed in the center of the width of the rake face and a chip breaker is formed after the second rake face, the concave portion (13h) has a substantially arc-shaped or substantially V-shaped cross section. The maximum length of the first rake face (13a) (S ₁ ) is 0.125
1.0 mm, and 0.025~0.24mm with minimal portion (S _7), the central portion is said minimum portion of width (S ₆₎ of (13f) not more than 0.20T of the cutting edge width (T) of the chip (13) , The first on both outer sides
The rake face (13a) has a front end opening where the length (S ₁ ) gradually increases, and the recess (13h) has a constant width at the center bottom and gradually maintains a constant bottom cross-sectional shape from the front end opening. It is formed deeply, and the bank portions on both sides of the concave portion (13h) are gradually higher than the second rake face and rise up (13g)
The chip breaker and the step (13c) following the ascending step (13g) reduce the chip width by lifting and deforming both blades of the chip during the chip outflow process.

The depth of the front end opening of the recess (13h) d ₁ = 0.2 to 0.6 mm, the depth of the rear end opening d ₂ > 0.3 mm, the radius of the arc of the rising step (13g) R = 2 to 4 mm, ( Second rake angle γ ₂ −First rake angle γ
₁ ) It shall be ≧ 25 °.

Action When the iron material is cut with a circular saw brazing this tip to the blade chamber on the circumference of the base metal, chips equivalent to the tip thickness are generated.
In the process of flowing out of the chip from the first rake face, the left and right sides are drawn into the central recess and both wings are lifted and deformed, reducing the chip width and making it smaller than the chip thickness, that is, the saw thickness, at the chip breaker part. At the same time while curling, both chips were lifted to reduce the chip width, so that the chips can be discharged smoothly without contacting the cutting surface.

Embodiment An embodiment of the present invention will be described below with reference to FIGS. 1 to 6.

A large number of blade bodies 12 are formed at equal intervals on the circumference of the base metal 11, and a cemented carbide tip 13 as a saw blade is partially embedded in the base metal and fixed to the blade body by brazing. Tooth back from face
In addition, a blade chamber 15 is cut in a shallow shape with a smooth curve so that chips do not deeply fit into the blade bottom 15a and become difficult to discharge.
The carbide tip 13 of this saw blade forms a flat first rake face 13a of length S ₁ at the first rake angle γ ₁ ° of the negative chisel in order to suppress the cutting resistance and maintain the strength of the blade at the top of the cutting edge. 1st rake face 13a followed by a second rake face γ ₂ ° and a second rake face 13b having a length of S ₂ and a step of an arc face having a radius R, which is a chip breaker following the second rake face 13b Make a step 13c that is raised by 13g. Further, an outer diameter flank 13d having a clearance angle γ ₄ is formed on the rear side with respect to the first rake face 13a.
Then, chamfers 13e having a size S ₅ are formed on both ends of the width of the cemented carbide tip 13 from the first rake surface 13a along the outer diameter flank surface 13d to prevent chipping. The bottom 15a of the blade chamber 15 has a step 13
It forms a smooth large curved surface that is concave and has a blade chamber depth of Q from the position S ₃ lower than the step of c and rises at an angle θ with the second rake face 13b and is connected to the tooth back 14 of the adjacent blade 12. .

The process up to this point has been disclosed in JP-A-62-277216, and the present invention is a chip of this type in which a recess 13h is formed. That is, the concave portion 13h forms a tip opening portion on the first rake surface 13a, the opening edge 13k is the central portion, and the length of the first rake surface 13a (hereinafter referred to as negative land length) is a slight length S ₇ and the flat surface 13i.
Has a slight width S ₆ and is bilaterally symmetrical on both sides and has an arc of a radius R _{0 in} a right-angled cross section, and the shape of the tip opening is a convex circle or a similar circle. That is, the opening edge 13k is such that the negative land length gradually increases on both sides of the central portion. Recess
13h is a step 13 extending over the second rake face 13b and the arc-shaped step 13g.
A rear end opening is formed in c. The bottom of the recess 13h is the first
Rake face central portion 13f from the flat surface of the same width S ₆ on the second rake face side 13i, the depth of the concave portion forms a concave arc shape having at arcuate faces 13j of the radius R ₁ of the same width S ₆ followed sequentially deeper rearward The depth d ₂ at the rear end is deeper than the depth d ₁ at the front end. The radius is measured along the left and right sides of the flat surface 13i of the recess 13h and the arc surface 13j.
A curved surface of R ₀ is formed.

Further, as another embodiment of the concave portion 13h, as shown in FIG. 7, the arcuate surfaces on both sides of the flat surface 13i at the bottom and the arc surface 13j are straight surfaces, and the cross-section has a chevron shape. The angle of V is 90
Degrees of 120 to 120 are preferred.

Another embodiment of the recess 13h is shown in FIGS. 8 and 9 in which the flat surface 13 is formed by eliminating the arc surface 13j following the bottom flat surface 13i.
i and the arcs on both sides are extended as they are to open on the bottom surface of the chip 13.

Further, as another embodiment of the second rake face 13b and the chip breaker, the step 13g of the circular arc shown in FIG.
The flat surface of the rake face 13b is in contact with an arc having a radius of 2 to 4 mm.

When the tip 13 of such a shape projects a predetermined blade edge into each blade chamber 15 of the base metal 11 and brazes a circular saw attached to the saw blade to cut the metal, the blade tip of the first rake face formed on the negative tip The chips cut by 3 become thin chips at the central portion 13f with a narrow length of negative land. On both sides of this, thick chips are generated corresponding to the length of the negative land. Central part of the first rake face
In 13f, since the negative land length is narrow, the frictional force is small and the chip deformation is small and the chip remains relatively thin. On the other hand, the negative land length gradually widens on both sides of the flat part, so the closer to both sides the chips are. The frictional force between and is large and the chips are compressed to increase the thickness. Further, since the thin chips in the center of the recess flow faster, the behavior of the chips on both sides tends to flow toward the center. For this reason, the width of the left and right chips is reduced appropriately. The action of the chips on both sides being drawn toward the center has a corresponding action when the negative land length changes rapidly, but the width S ₆ of the flat surface 13i of the recess 13h is
Is narrow and the both sides are formed by arcuate surfaces with R ₀ , and the negative land length gradually increases from the center to both sides, so the retraction force is gentle, and in this process, the cutting chips strongly strengthen the inner surface of the groove. There is no pressing.

Further, in the process in which the cutting chips flow on the recesses 13h and the second rake face 13b after that, the second rake faces 13b, which are high on both sides, lift up both blades of the chips and the chips float on the steps 13g from the recesses 13h, Due to the action of the step of the upward arc, the lifting force is large and the chips are bent and deformed in the width direction and curled.
At this time, the chip width is greatly reduced. At this time, since the thickness of the central portion of the chips is thin, bending deformation of the chips is facilitated and the chips are evenly deformed on the left and right sides. This chip deformation process becomes the state of chips shown in FIG. 12 at the chip cross-sectional position of FIG.
The chips in this figure are made by cutting S45C steel with a diameter of 360 mm, a saw blade thickness of 2.50 mm and 60 chips with a circular saw blade having a diameter of 80 mm. The cutting conditions are V = 110 m / min and Sz = 0.10 mm. The shape of the chip is similar to that of chip I in Table 1 below.

FIG. 12 (a) is a position where the cutting chips have advanced almost the contact width from the cutting edge at the position OO in FIG. 11, and the central portion is drawn into the recess 13h and slight deformation is observed, but both blades are Rake face 13
It is parallel and close to the negative land surface of a. The same (b) is P
At the -P position, the arcuate step 13g serving as a chip breaker lifts both blades at an angle of about 4 ° as the flow of the chips causes them to rise above the step surface, and only the shoulder of the recess 13h is in contact. The width dimension was further reduced by bending and retracting. The same (c) is in the Q-Q position, and the same (d) is in the R-R position. It is clear that the chips are lifted by about 8 to 9 degrees at both blades and pulled toward the center. Is. And the dimension of the left and right width is 0 from the saw thickness by actual measurement.
It was confirmed to be reduced by 11 mm. Then, the chips do not come into strong contact with the recess 13h and do not cause friction. V with this saw blade
Durability cutting of S45C steel with a diameter of 32 mm was carried out under the conditions of = 110 m / min, Sz = 0.08 mm, but no wear or crack development was observed in any of the recesses after cutting up to 12,000 continuous cuts. Now, description will be made in comparison with the state of chips under the same cutting conditions as the tip of the present invention and the conventional tip.

Intermittent cutting of S10C steel with a cutting tool in which each tip is brazed or fixed to the shank with a mechanical clamp. Cutting speed V
= 113m / min, Sz = 0.09mm.

The conventional chip A (FIGS. 16, 17, 18 and Table 2) and the chips H and I of the present invention in FIG. At the stage, when the chips fall into the groove and are deformed as shown by the arrow, the width of the groove bottom becomes narrower, so that the slope of the bank portion acts to forcibly reduce the width of the chips, resulting in strong friction. On the other hand, in the chips H and I, the cross-sectional shape of the groove has a constant groove bottom shape and becomes wider as the groove depth increases, so that strong friction does not act on the bank slope.

Further, in FIG. 20 showing the cross-sectional shape of chips cut by chips A, H, and I and the chip width reduction amount ΔT, FIG. As shown in Fig. 20 (b), the chips are squeezed out due to the strong friction with the slope of the embankment, resulting in a beard. Since the frictional resistance when the chips flow out is large, the chips are compressed and become abnormally thick, and at the same time, the movement of the chips along the slope of the bank is obstructed and the width of the chips is sufficiently reduced. Absent.

As shown in FIG. 20 (C), the chip I of the present invention and the chip I of the present invention improved the action at the chip contacting stage as shown in FIG. 20 (D), and the subsequent chip outflow process. The chip width is lifted and deformed by the method, and the reduction of the chip width is almost satisfactory.

When the iron material is cut with a circular saw brazed with the tip of the present invention in the blade chamber on the circumference of the base metal, chips having a width equal to the tip thickness, that is, the saw thickness are generated in the entire chip contact area, and then the left and right parts thereof are It is drawn into the recess in the center and deforms, and while it is further drawn, both wings are gradually lifted and deformed, the chip width is reduced and it becomes smaller than the saw thickness, and it is curled at the step and is harmful to the cut surface. It is discharged smoothly without contact. Further, since the cutting chips flow out without causing strong friction with the chip surface, there is no local growth of thermal cracks.

As a result of various experiments and trials, the width S ₆ of the central portion 13f of the first rake face with a reduced negative land length is 0.2 with respect to the cutting edge width T of the tip 13.
It is preferably 0 or less. The recesses in the retracted retracted gradually deeper in a central portion of the chip, the depth of the recesses to avoid contact with the bottom gradually deeper toward the rear when the depth d ₁ of the blade tip side opening is 0.2~0.3mm And the depth d ₂ of the rear end opening is
0.4 mm or more is preferable. The radius R of the arc of the step of the chip breaker is preferably 2 to 4 mm.

The shape and dimensions of each part of the chip are shown in Table 3.

In this range, S ₇ = 0.025 to 0.24 mm and S ₁ = 0.125 to 1.0 mm.

The cutting of metal with this tip is applicable to all, but the work material is a bar with a diameter of 20φ ~ 100φ mm, and the saw blade size is 200φ ~ 40
0φmm, number of blades 40-140, cutting condition V = 50-200m / min, Sz =
It is preferable for 0.05 to 0.15 mm.

Note that the chip is not limited to this embodiment, and is widely applicable to those that are expected to have an effect equivalent to this, for example, those that are cut off and grooved.

Effect As described in detail above, the chip of the present invention has its width reduced appropriately until it passes the length S ₁ of the first rake face 13a, and while it flows out on the second rake face and on the step, both blades Is lifted and deformed, the width is greatly reduced, and the chips are prevented from welding to the cutting surface and the rake surface until they are curled and stored in the saw chamber and discharged, and the cutting surface is damaged by strong friction. Absent.

In particular, if S ₇ = 0.025 to 0.24 and S ₆ is 0.20 T or less, the deformation at the cutting center portion is even and relatively easy. The chips that have passed through the first rake face are lifted by the shoulders of the recesses and do not come into contact with the second rake face and the recesses, so that frictional heat is less generated and the effect of preventing damage due to heat history is great, and the chips have a particularly long life. .

[Brief description of drawings]

1 is a front view of the chip portion, FIG. 2 is a side view of the same, FIG. 3 is a sectional view taken along the line AA of FIG. 1, and FIG. 4 is a sectional view taken along the line BB of FIG. 6 is a sectional view taken along the line CC of FIG. 3, FIG. 6 is a sectional view taken along the line DD of FIG. 3, FIG. 7 is a front view of the chip showing another shape of the concave portion of the chip, and FIG. 8 is the chip. 9 is a front view showing another shape of the concave portion of FIG. 9, FIG. 9 is a sectional view taken along the line EE of FIG. 8, FIG. 10 is a side view of the chip showing another shape of the step, and FIG. Fig. 12 is a diagram showing the chip observing position, Fig. 12 is a diagram showing the state of chips in each part of Fig. 11, Fig. 13 is a perspective view of a conventional chip, and Fig. 14 is the cutting by the chip of Fig. 13. Cross section of the powder, No. 15
FIG. 16 is a side view of a conventional chip, FIG. 16 is a conventional chip view of the chip symbol A, FIG. 17 is a cross-sectional view taken along the line FF of FIG.
FIG. 18 is a sectional view taken along line VV of FIG. 16, FIG. 19 is a sectional view showing the relationship between chips and chips by the conventional type and the chip of the present invention, and FIG. 20 is a conventional type and the present invention. It is sectional drawing of the cutting powder produced | generated by the chip. 13a …… 1st rake face 13b …… 2nd rake face 13c …… Step, 13h …… Recess 13f …… 1st rake face central part 13g …… Step 13i …… Flat surface of recess bottom 13j …… Recess bottom Arc surface

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP 62-277216 (JP, A) JP 57-201121 (JP, A) JP 59-187419 (JP, A) JP 56- 27727 (JP, A) Actual development Sho 63-57024 (JP, U) British patent 1166145 (GB, A)

Claims (2)

[Claims] 1. A rake face has a first rake face of a negative sieving over the entire width of a cutting edge at the tip of the cutting edge, and a recess for deriving chip deformation is formed at the center of the width of the second rake face behind the rake face. 2 In a chip in which a chip breaker is formed after the rake face, the recess (13h) has a substantially arc-shaped or V-shaped cross section.
In terms of shape, the length (S ₁ ) of the first rake face (13a) is 0.125 to 1.0 mm at the maximum portion and 0.025 to 0.24 mm at the minimum portion (S ₇ ), and the length of the central portion (13f) is the minimum portion. The width (S ₆ ) is set to 0.20T or less of the cutting edge width (T) of the tip (13), and the front end opening portion where the length (S ₁ ) of the first rake face (13a) on both outer sides of the cutting edge width (S ₁ ) gradually increases is provided. Further, the recess (13h) is formed so that the width of the central bottom is constant and the cross-sectional shape of the bottom is constant from the front end opening and is gradually deepened, and the bank portions on both sides of the recess (13h) are the second rake face. The chip breaker has a rising step (13g) that gradually increases, and the rising step (13g).
A chip for a metal cutting circular saw, which is formed in a step portion (13c) following the step (3c), and lifts and deforms both blades of the chip during the chip outflow process to reduce the chip width. 2. The depth d ₁ = 0.2 to the front end opening of the recess (13h).
0.6mm, depth of the rear end opening d ₂ > 0.3mm, rising step (13g)
_2. The tip for a metal cutting circular saw according to claim 1, wherein the radius R of the circular arc is 2 to 4 mm, and (the second rake angle γ 2 −the first rake angle γ ₁ ) ≧ 25 °.