JPH05285708A - Joined throw away tip and its manufacture - Google Patents

Abstract

PURPOSE:To mass-produce double-sided positive throw away tips and double- sided phase shifted throw away tips, at a low price, by laying two truncated conical or truncated pyramid pressingly formed bodies or sintered bodies, one upon another, and joining them. CONSTITUTION:In manufacture of a double-sided positive or double-sided phase shifted positive tip made of hard metal or thermet, original powder is pressingly formed, and at least one pair of a projection 3 and a recession 4 are formed on a truncated pyramid pressingly formed body 5. Next, two pressingly formed bodies 5 are laid one upon another as the projections 3 and the recessions 4 are fitted in with each other, and sintered to provide a desired joined throw away tip. In this way, double-sided positive throw away tips and double-sided phase shifted throw away tips which prevent tip interference of the both sides by means of phase shift can be mass-produced at a low price, by laying two truncated pyramid pressingly formed bodies 5 one upon another and joining them.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a throw-away tip made of cemented carbide or cermet, in which the upper and lower surfaces of the throw-away tip are positive, or the phases of both sides are positive and the phases are deviated. The present invention relates to a throwaway tip with a complicated shape.

[0002]

2. Description of the Related Art Cemented carbide and cermet are materials that are difficult to grind and hard to work, and their processing requires an expensive grinding wheel and a long time. Therefore, when manufacturing a cemented carbide tool or a part, a binder such as wax is added to the raw material powder, and the die is pressed and sintered by a die that is as close as possible to the shape of the finished product. However, in order to emboss a shape close to the shape of a finished product with a die, there is a limit in shape, and at least it is limited to a shape capable of discharging the embossed body after embossing. In order to further approach the shape of the finished product, the embossed body is once subjected to a heat treatment for dewaxing, and then molded and sintered.
Usually, the finished product is then ground.

However, the dewaxed embossed body has a low strength, and therefore, it must be handled with care and processed with great care. Usually, it is attached and detached and processed manually. The major difference between the production of a product having a normal shape and a product having a complicated shape lies in the necessity of the above-mentioned molding process. on the one hand,
There is a method such as injection molding as a method of manufacturing a complex shaped part, but in the case of a double-sided positive type product like the present application, the mold structure for easy removal from the mold becomes complicated. In addition, there were problems such as the trace of the runway during injection molding and the trace of the seam of the mold.

When the throw-away tip of the present application is manufactured by such a conventional technique, it is usually manufactured as follows. In order to obtain a throw-away tip with positive upper and lower surfaces and a cemented carbide product with a complicated shape in which the upper and lower surfaces are out of phase, a shape close to the final shape is obtained by molding after dewaxing. In order to manufacture a throw-away tip having positive and negative upper and lower surfaces and the same phase, the negative shape is stamped, the wax is dewaxed, and the side surface is molded into a V shape with a molding grindstone.
After that, it is sintered. In the case of the square throw-away tip, which is out of phase, it was necessary to mold eight locations from both sides. Since it takes time and manpower to mold, cemented carbide products with complicated shapes are about 1.5 to 2 times more expensive than simple shapes, their applications are limited, and the production quantity is limited. Therefore, its use was limited.

Further, the dimensional accuracy of the product after being pressed by the metal mold after the sintering has a variation of about 50 μm at the maximum with respect to the target value (hereinafter, for the total length of 10 mm),
In the case of molding, the dimensional accuracy varies up to about 200 μm. Therefore, the dimensional accuracy in the case of molding is extremely poor, and polishing of the entire surface after sintering was indispensable. Further, the unequal-sided shape is one of the products that cannot be mass-produced because the molding process becomes more difficult and the molding process by NC control is required or a special molding grindstone is used.

[0006]

DISCLOSURE OF THE INVENTION The present invention is directed to a throw-away tip that can be used for the upper and lower side surfaces, in which the upper and lower surfaces are positive, and a throw-away tip that can be used for milling and the like and has a phase difference between the upper and lower surfaces. Is provided at a low price. Further, the present invention provides a method for manufacturing a throw-away tip having a complicated shape that does not require the above-mentioned molding step.

[0007]

DISCLOSURE OF THE INVENTION In the present invention, in a double-sided positive or double-sided phase shift positive chip made of cemented carbide or cermet, two frustoconical or truncated pyramidal embossed bodies or sintered bodies are used. It is a bonded throw-away chip that is made by stacking and bonding. The dimensional accuracy of the product stamped by the above-mentioned mold is very high, so the entire surface can be used as a sintered surface, but when a more accurate throw-away tip is required, the upper and lower surfaces, the outer peripheral portion, the flank surface The object can be achieved by polishing a part of the. With respect to the dimensional accuracy due to the molding as described above, the variation with respect to the target value is up to about 200 μm in the size of the normal throw-away tip, while the maximum accuracy of 50 μm is obtained when the die is pressed by the die. Therefore, the throw-away tip obtained in the present application can be used as a throw-away tip without polishing and having a sintered surface.

Further, in the present application, it is possible to stack the embossed bodies and simultaneously perform sintering and joining. In this case, since the sintering and the bonding are performed at the same time, the throw-away tip of the present invention can be obtained at low cost. As a matter of course, the sintered body may be first produced and then joined. It is desirable that the embossed bodies or the sintered bodies to be superposed have the same shape.
The reason is that the upper and lower embossed bodies or sintered bodies can be obtained with one die. Further, in the present application, in a double-sided positive or double-sided phase shift positive made of cemented carbide or cermet, a raw material powder is embossed and molded, and the embossed body is fitted with at least one set of projections and recesses, and is overlaid. Provided is a method of manufacturing a bonded throw-away tip that is sintered together. Here, the effects of the present application can be obtained even if the embossed body is first sintered and then joined.

More specifically, the present invention provides a throw-away tip having positive type cutting blades on both upper and lower surfaces as shown in FIG. As another shape, as shown in FIG. 2, the cutting edges on the upper and lower surfaces are displaced at a constant angle. It provides a so-called throw-away tip that is out of phase with what is called the top and bottom. For such a throw-away tip, the embossing body 5 having a shape as shown in FIG. 3 is first produced. That is, the projections 3 and the recesses 4 are formed on the bottom surface of the truncated pyramid shape, that is, on the concentric circle on the side having a small area. At this time, the projection 3 and the recess 4 are dimensioned so as to fit with each other.

Next, the two embossed bodies are superposed and the recesses 4 and the projections 3 are fitted to each other and superposed and sintered. Since the protrusion and the recess are formed by a mold, their shape and dimensional accuracy are extremely high. Therefore, a combined body having high dimensional accuracy can be obtained even in the case of overlapping. Also, the protrusion 3 and the recess 4
As shown in FIG. 4, when an angle of α is provided with respect to the center line, a throw-away tip with a phase shift can be manufactured when these are stacked vertically. In addition to the roles of the projection 3 and the recess 4, when they are overlapped once, the mutual positional deviations are less likely to occur, so that they are not only easy to handle, but also vibration in a sintering furnace and vacuum baking are performed. There is also an effect that mutual displacement does not occur even when shocked when degassing when binding.

The projection 3 and the recess 4 of the present application are not particularly limited, but a clearance of about 20 μm is sufficient for fitting them to each other. The shape may be polygonal or cylindrical. The object of the present application can be achieved even with the shapes shown in FIG. 5 and FIG. However, in the case of the shape shown in FIG.
There is a drawback in that it cannot prevent lateral movement. The present invention can also be applied to cemented carbide and so-called cermet alloys containing TiC and TiN.

However, some alloys contain components that are not easily joined. In such a case, in order to promote bonding at the interface of the bonding surfaces, a cemented carbide composition powder or Ni or Co powder as a binder component is applied to facilitate diffusion bonding during sintering. can do. Further, in order to perform more reliable joining, a more reliable and firm joining can be obtained by placing a weight on the above-mentioned superposed assembly at the time of sintering to such an extent that the combination does not deform during the joining. Be done.

Cemented carbide can be said to be a brittle material compared to ordinary metals. In such brittle materials, notch-like cracks and defects are the starting point of fracture, so
It was said that it could not be used in the field of high impact tools. Also, various techniques have been developed for joining cemented carbides, but there was no idea to apply such joining technique to the throw-away tip. The present inventors, by challenging such conventional wisdom,
The present invention has been completed.

When a cross section of the end portion of the joint surface is observed with a microscope, a notch-shaped notch is often formed. The reason for this is that the etched portion of the embossing body is chamfered in consideration of the life of the die and the like, so the chamfered portion forms a notch as shown in FIG. In the case of normal use, such a notch does not pose a practical problem. Needless to say, the present application can also be applied to a throw-away tip that uses two corners on both sides and a screw-fastening tip that has a hole in the center.

[0015]

The present invention provides a throw-away tip with high dimensional accuracy by stacking at least one set of a molded body or a sintered body having a projection and a recess and fitting the recess and the projection together. Further, even in the case of a phase-away throw-away tip, the shift angle is determined by the positional relationship between the projection and the recess described above, so that the same throw-away tip can be mass-produced using the same die. At this time,
There is no need for molding that takes a long time. On the other hand, since the die-pressed bodies that are still pressed by the die are overlapped and joined together, the dimensional accuracy of the sintered body itself is high, and part or all of the outer peripheral polishing process can be omitted.

Another feature of the present application is that, in the case of producing a double-sided positive throw-away tip having a particularly nose radius or a tip of an isosceles shape, it is practically impossible to carry out by molding in consideration of mass productivity and cost. Met. Therefore, in order to form a nose radius or an isosceles shape, it had no choice but to use grinding after sintering. However, in the present application, if these shapes can be formed in advance with a mold, It is possible to manufacture it very easily as with the throw-away tip. The throw-away tip of the present invention thus obtained can be further polished depending on the conditions used. In the throw-away tip obtained in the present application, the upper and lower surfaces, the V groove surface and the nose radius portion can be polished as necessary.

[0017]

EXAMPLE A mixed powder of WC-10% Co
The die was pressed into the shape shown in the figure. At this time, the diameter of the protrusion was 2.98 mm and the height was 0.49 mm. On the other hand, the recess had a diameter of 3 mm and a height of 0.5 mm. The phase shift angle α was 8 °. The two embossing bodies thus obtained were superposed so that the respective projections and recesses fit into each other. Place a carbon plate as a weight on top of this combination and put it in a vacuum.
Sintered at 00 ° C. for 1 hour. WG thus obtained
G51 could be used as a throw-away insert for turning, as it was as a side sintered body. On the other hand, the same WGG51 was created by a method using a conventional molding process. WGG51 at this time
The cost required to make one was 75 when the conventional method was set to 100 and manufactured by the method of the present invention.

When the joint surface of the product obtained in the present application was observed, it was not possible to find a peculiar structure showing a joint interface in the central portion of the sintered body. On the other hand, at its end,
The portion corresponding to the chamfered portion of the mold as shown in the figure had a notch shape. However, no difference in performance was observed between the throw-away tip prepared by the conventional method and the throw-away tip obtained in the present application.

[0019]

As described above in detail, according to the present invention, when the embossed bodies of the powder alloy come into contact with each other and are sintered,
At the contact surface, the constituent components are diffused into each other to form a bond as if they were the same embossed body. Therefore, it is effective to mass-produce the double-sided positive throw-away tip and the phase-shiftable low-away tip that prevent the interference of the cutting edges on both sides due to the phase shift, which were conventionally impossible to manufacture with a die, at low cost.

[Brief description of drawings]

1 shows a double-sided positive throw-away tip obtained according to the present invention.

FIG. 2 is a phase shift double-sided positive chip obtained by the present invention.

FIG. 3 is an embossing body obtained by the present invention, which has the shape of a truncated pyramid and has protrusions and recesses.

FIG. 4 is a front view of the embossing body obtained in FIG. 3, in which the line connecting the center lines of the protrusion and the recess has an angle α with respect to the center line.

FIG. 5 is an example of the embossing body of the present application.

FIG. 6 is the same as FIG.

FIG. 7 is a view showing a state of an end face of a joint portion in a cross section AA of the double-sided positive throw-away tip of FIG.

8 is a drawing showing a state of a joint end face in a BB cross section of the phase-shifting throw-away tip shown in FIG. 2;

[Explanation of symbols]

 1: Double-sided positive throw-away tip upper side 2: Double-sided positive throw-away tip lower side 3: Protrusion 4: Recess 5: Embossed body 6: Joined part

Claims (4)

[Claims] 1. A double-sided positive or double-sided phase shift positive chip made of cemented carbide or cermet, in which two frustoconical or truncated pyramidal embossed bodies or sintered bodies are superposed and joined. Joining throw-away tip that is characterized by. 2. The bonded throw-away tip according to claim 1, wherein at least the flank side has a sintered surface or a partially polished finish. 3. A double-sided positive or double-sided phase shift positive chip made of cemented carbide or cermet, wherein the raw material powder is embossed and the embossed body has at least one set of protrusions and recesses. A method for manufacturing a bonded throw-away tip, comprising: stacking two of the embossed bodies with the projections and the recesses fitted to each other and stacking them together, and sintering. 4. A double-sided positive or double-sided phase shift positive chip made of cemented carbide or cermet, wherein the raw material powder is embossed and the embossed body has at least one set of protrusions and recesses. A method for manufacturing a bonded throw-away chip, comprising sintering the embossed body, stacking the two embossed bodies with the projections and the recesses fitted to each other, and then performing diffusion bonding.