JP4758549B2 - Press die for throw-away tip and method for manufacturing throw-away tip using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a press-molding die for forming a throw-away tip employed in a throw-away cutting tool and a method for manufacturing a throw-away tip using the same .
[0002]
[Prior art]
Throw-away inserts used as cutting tools for turning tools such as cutting tools and turning tools such as end mills, milling cutters, and drills are chamfered to increase the strength of the corners on the outer peripheral ridges. It is common. The chamfering can be done by grinding the chip after manufacturing, but the cemented carbide throwaway chip and ceramic throwaway chip manufactured through the press molding process are chamfered at the same time in the press molding process. This method is adopted because it is better to do it.
[0003]
[Problems to be solved by the invention]
The above chamfering is preferable because the corner portion is strengthened when viewed from the throw-away tip side, but when chamfering is performed at the time of press molding of the chip, a press die suitable for the shape of the chamfering portion is required. There is a problem with the durability of the mold.
[0004]
FIG. 5 shows an example of a press mold for a positive throw-away tip. In the figure, 11 is an upper punch for forming the upper surface side of the chip, 12 is a die for forming the side surface of the chip, and 13 is a lower punch for forming the lower surface of the chip.
[0005]
When using this mold to mold a throw-away tip having a chamfered surface 5 ′ at the peripheral edge of the lower surface 2 as shown in FIG. 7, the lower punch 13 has a tip outer periphery as shown in FIG. Becomes an acute angle, and the low-strength tip tends to break during press molding. Further, the tip of the lower punch often hits the die or the like when the mold was attached, and micro chipping often occurred.
[0006]
Due to the breakage and chipping, the frequency of changing the mold is increased, and the productivity of the throw-away tip is adversely affected.
[0007]
This invention makes it a subject to provide the manufacturing method of the throwaway tip using the press molding die of the throwaway tip effective in solving said problem.
[0008]
[Means for Solving the Problems]
In order to solve the above problems, in the present invention, the vicinity of the lower end of the side surface is stepped down, the ridge line portion between the stepped portion and the lower surface is chamfered, and the chamfered surface obtained by the chamfering and the step connected to the chamfered surface are obtained. A press die for molding a throw-away tip with a reinforced corner part composed of a surface,
An upper punch for molding the upper surface of the throw-away tip, a die for molding the side surface of the tip, and a lower punch for molding the lower surface of the tip,
The tip of the lower punch, have a stepped surface molding surface for molding the stepped surface of the reinforced corner portion, the stepped surface molding surface, toward the outer periphery of the tip end of the lower punch, the corner angle of the tip outer periphery least 90 ° It was made to incline in the direction of 0 ° to 5 ° .
[0009]
This press die has a chamfering width b satisfying the relationship of b> a and α> β, a flat chamfered surface having an inclination angle α, a step-down amount a connected to the chamfered surface, an inclination angle on a throw-away tip to be formed. What is molded so as to produce a reinforced corner portion formed by two surfaces of the step surface of the plane of β is preferable.
[0010]
The inclination angles α and β are angles with respect to the lower surface, and the inclination of the chamfered surface is considered to be positive, and the inclination opposite to the inclination is considered to be negative.
[0011]
[Action]
If the lower area of the side surface of the throw-away tip is stepped down, a stepped surface is created between the stepped portion and the portion that is not stepped down, and a surface for molding the stepped surface is required at the tip of the lower punch. The sharp tip of the lower punch is removed. Therefore, breakage of the lower punch tip and minute chipping hardly occur, and the durability of the mold is improved.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a specific example of a throw-away tip manufactured using the press die of the present invention.
[0013]
The throw-away tip T is a positive tip whose side 3 intersects with an upper surface 1 at an acute angle, and is made by sintering after press molding.
[0014]
The throw-away tip T is stepped down by an appropriate amount in the region along the lower edge of the side surface 3, and the intersection between the stepped portion and the lower surface 2 is chamfered and removed.
[0015]
In FIG. 2, the reinforced corner part C which consists of two surfaces of the level | step difference surface 4 and the chamfering surface 5 is expanded and shown. In this figure, the step surface 4 is parallel to the lower surface 2 (inclination angle 0 °), and the chamfered surface 5 for edge removal is connected to the inner end of the step surface 4.
[0016]
FIG. 3 is an enlarged view of the tip shape of the lower punch 13 of the press mold according to the present invention for forming the lower surface of the chip and the reinforced corner portion having the shape shown in FIG. In this way, a flat molding surface 13a for shaping the step surface is attached to the forefront of the lower punch 13, and the sharp edge existing in the conventional punch is eliminated, and the tip of the lower punch is strengthened.
[0017]
If the width of the stepped surface 4, that is, the stepped amount a of the side surface 3 is too large, the area of the lower surface that becomes the seating surface of the chip is reduced, and the strength of the portion where the side surface 3 and the stepped surface 4 intersect is reduced. It is preferable to set a = 0.01 mm to 0.3 mm, and the lower punch tip is sufficiently strengthened.
[0018]
The chamfering width b of the chamfered portion is considered to be about 0.3 mm to 3.0 mm considering the purpose of corner reinforcement.
[0019]
Further, the chamfered surface 5 may be an R surface, but it is easier to increase the tip strength of the lower punch if it is a flat surface than the R surface.
[0020]
In the flat chamfered surface 5, the strength of the tip of the lower punch decreases as the inclination angle α increases. On the other hand, if α is too small, the reinforcing effect of the corner portion of the chip decreases, so α = about 30 ° to 70 °. preferable.
[0021]
FIG. 4 shows the stepped surface 4 with an inclination of β. If the step surface 4 is inclined by β in the negative direction, the corner angle of the outer periphery of the tip of the lower punch becomes 90 ° or more, and the strengthening effect of the lower punch is further enhanced. However, if β is excessive, the surfaces 4 and 5 are formed. Since the punch strength of the portion and the strength of the portion where the side surface 3 and the step surface 4 of the chip intersect with each other decrease, β is set to 0 ° to −5 ° .
[0022]
Incidentally, the throw-away tip T in FIG. 1, is provided with the cutting edge land 6 and the breaker groove 7, the mold of this invention is also applicable to the molding of the chip without breaker grooves and the breaker projection. The shape of the chip to be molded is not limited. In addition to triangles, quadrilaterals, rhombuses, parallelograms and round pieces, it is also effective for molding specially shaped chips.
[0023]
Further, the main subject of application is a positive type chip, but a negative type chip can be provided with a reinforced corner portion of the shape of the present invention as needed (in this case, the advantage of using both sides of the negative type chip is No longer).
[0024]
【The invention's effect】
As described above, the press die of the present invention, by Chi paragraph sides of the indexable insert part, since the corner edge portion between the stepped portion and the lower surface is shaped so as to be chamfered, reinforced corner It is possible to increase the tip strength of the lower punch for forming the portion, to reduce the damage of the lower punch at the time of molding and work, and to reduce the frequency of changing the mold to increase the productivity.
[Brief description of the drawings]
1A is a plan view showing an example of a throw-away tip formed by the mold of the present invention, FIG. 1B is a side view of the same tip, and FIG. 2C is a bottom view. FIG. Fig. 3 is an enlarged sectional view showing the tip shape of the lower punch of the press die of the present invention . Fig. 4 is an enlarged sectional view showing a modification of the reinforced corner portion. Fig. 5 is a chip forming press. Model drawing of the mold [Fig. 6] Enlarged sectional view showing the tip of the lower punch of the conventional mold [Fig. 7] Enlarged sectional view of the reinforced corner of the conventional chip [Explanation of symbols]
T throw-away tip 1 upper surface 2 lower surface 3 side surface 4 step surface 5 chamfer surface 6 cutting edge land 7 breaker groove C reinforced corner portion 11 upper punch 12 die 13 lower punch 13a step surface molding surface

Claims (2)

A throw-away tip having a stepped portion near the lower end of the side surface, chamfered the ridge line portion between the stepped portion and the lower surface, and a reinforced corner portion comprising a chamfered surface obtained by the chamfering and a stepped surface connected to the chamfered surface. A press mold for molding
An upper punch for forming the upper surface of the throw-away tip, a die for forming the side surface of the tip, and a lower punch for forming the lower surface of the tip,
The tip of the lower punch, have a stepped surface molding surface for molding the stepped surface of the reinforced corner portion, the stepped surface molding surface, toward the outer periphery of the tip end of the lower punch, the corner angle of the tip outer periphery least 90 ° A throw die for a throw-away tip, which is inclined by 0 ° to 5 ° in the direction to be . A method for manufacturing a throw-away tip using the press die for a throw-away tip according to claim 1 ,
A method for manufacturing a throw-away tip, wherein the chamfered surface of a reinforced corner portion of a tip and a stepped surface connected to the chamfered surface are simultaneously formed by the lower punch during press-forming of the throw-away tip.

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