DD202642A1 - METHOD FOR PRODUCING TOOLS WITH A STRENGTHED SHANK - Google Patents

Abstract

The invention relates to a method for producing twist drills made of hard metal with reinforced shaft. The aim of the invention is to simplify the manufacturing process, starting from the task to provide for the production of an axial frictionally acting press connection between a cutting part and a shank part a method by which the joining of these parts Fuze technologically simple, but effective and possible also economically feasible. This object is achieved according to the invention in that the joining of the cutting part to the shaft part is carried out by using the high-speed technology, preferably by means of electrical shock waves. The invention finds application in the production of tools for cutting and non-cutting machining, preferably for the production of twist drills whose cutting part consists of hard metal. The invention is also applicable, for example, in the manufacture of cutting needles for cutting and forming tools.

Description

Title of the invention

Method for producing tools with reinforced shank

Field of application of the invention

The invention relates to a method for producing four-bladed with reinforced shank for cutting and non-cutting machining.

A preferred field of application of the invention is the production of hard-metal twist drills with reinforced shank, in which a thinned cutting part is pressed into an axially arranged and undersized receiving bore of a thicker shank part.

Characteristic of the known technical solutions

For producing tools with a reinforced shank for cutting and / or chipless machining, e.g. for the manufacture of twist drills made of hard metal find for solid and permanent connection of the usually thinner running cutting part with the thicker executed shaft part various types of connection or connection method application.

In these with a shank part e.g. tool steel tooling, for example, the cutting tool-carrying cutting part may be made of a highly wear-resistant material, e.g. Hard metal, of which

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Bonding with the shank part, for example · the shank part of the twist drill in an axially arranged and possibly executed with undersize receiving bore of the shank part by soldering, welding or gluing · These types of connections have in the manufacture of such tools various disadvantages »These exist in the solder joint Priority is that by the Lötnahtdicke the parts to be joined together are difficult to produce in the intended accuracy of fit, which in rotating cutting tools in concentricity errors *

In welded joints, the difficulties of product control of this joining process are similar and with the same negative effects. In addition, in some cases, welding of the two different materials is technically not practicable at all.

Things are very similar in the production of adhesive bonds. Here comes the circumstance of the relatively low thermal load capacity of the produced joint compound added *.

Finally, it is already known to produce such connections between a cutting part and the shank part of a tool by pressing and / or shrinking.

Thus, from DE-OS 28 11 977 a joint connection between a spiral drill shank made of hard metal and an associated clamping shank has become known, the characteristic feature. Essentially consists in that the drill shank held in a bore of the clamping shank with a defined excess and the connection means In addition, the drill shank can have on its lateral surface a suitable surface roughness, by knurling, which should bring about an additional safeguarding of the load capacity of the joint connection.

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In addition, it should be advantageous to provide the drill shank end with a cutting edge, which causes during the pressing process, ie under axial pressure, in the Aufnähmebohrung the clamping shaft progressing chip removal until the drill shank has taken its end position in the mounting area of the receiving bore.

The application of this method is partly preceded by a relatively prefabricated tool parts and on the other hand makes it necessary to constantly control the pressing force within certain limits during the joining process and also to continuously check the strength of the joint connection produced »It is obvious that these latter requirements that Considerably complicating the process and making the economic viability of this process questionable.

Object of the invention

The object of the invention is to avoid the disadvantages existing in the known production methods with regard to the production accuracies to be achieved and the process technologies which are difficult to control.

Explanation of the essence of the invention

The invention is based on the object to provide for the production of an axial non-positively acting press connection between a relatively thin cutting part and an associated relatively thicker shaft part, a method with which the joining of the two joining parts in a technologically simple manner effectively possible and also economically feasible. This object is achieved in that the pressing of the thinner cutting part is made in the thicker shaft part by using the high-speed technology.

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In this case, as is provided by a further feature of the invention, the high speed can be generated by an explosive, electrical or pneumatic force, for example by explosion pressure or preferably by electrical shock waves.

A "particularly advantageous effect in terms of ensuring a solid and highly load-bearing joint connection is achieved according to a further feature of the invention in that the thicker shaft part is heated to hardening temperature preferably by induction heat before pressing the thinner cutting part and the thicker shaft part is made of an air-hardening material *

This brings in the process implementation the desired advantage that the pressing with relatively low axial force is possible and by the subsequent hardening process a shrinkage effect is generated. It is clear that this procedure leads to an easily produced but also durable solid and highly resilient joint connection ·

A further perfection of this joining technique and the joint connection produced therewith can also be achieved in that the thinner cutting part is provided on the end faces with a chamfer and / or on the peripheral surface partially with flats »

For carrying out the method according to the invention, finally, according to a further feature of the invention, a device is used whose characteristic design features are that a respective guide bushing for the thinner cutting part and the thicker shaft part at a distance der''er than the length of the thicker shaft part, is arranged axially aligned, each guide bush is assigned a Zuführungsund plunger and each feed and plunger with a magazining and feeding device, for example, with a conveyor belt or a stacking magazine in operative connection ·

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Between the two guide bushings, an induction coil is arranged according to the invention.

exemplary embodiment

The inventive method for producing tools with reinforced shank, preferably for the production of twist drills made of hard metal will be explained in more detail below using an exemplary embodiment.

The accompanying drawing shows in

1, the individual parts of the Y / erkzeuges, consisting of

the thinner cutting part and the thicker shaft part

Fig. 2 shows the tool in the assembled state

Fig. 3 shows the apparatus for performing the method in a schematic representation.

The process according to the invention, z. B. for producing a carbide twist drill blank with reinforced shank, is that a thinner cutting part 1, z «B, a carbide blank, is made into a thicker shank part 2, e.g. made of tool steel, pressed in by means of high speed or »shot in.

The introduced into the thicker shaft part 2 bore 12 is suitably carried out with an undersize relative to the diameter of the thinner cutting part 1. The undersize need not be precisely defined, which is to be compensated by the size of the pressing force F, which is generated by explosive, electric or pneumatic effect. In extreme cases, the thinner cutting part 1 can be injected into the full material of the thicker shaft part 2. especially when the latter is e.g. is heated to hardening temperature, whereby the intrinsic strength strong

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The thinner cutting part 1 carries on the end face a tapered chamfer 3 and may be provided on the peripheral surface partially with a flattening 4, whereby the transmission of maximum torques is achieved.

To ensure the centricity and concentricity of the assembled parts according to FIG. 2, a suitable device according to FIG. 3 is used. For this purpose, depending on a guide bush 5; 6 is provided, which is arranged axially aligned. The thicker shaft part 2, in the embodiment of the steel shaft is brought by a Zuführstempel 7 in Fügelage and the thinner part of the blade 1, in the embodiment of the carbide blank, is pressed by means of a plunger 8 in the steel shaft and injected. For the automation of the method, suitable feed devices 9, 10 are provided. The heating of the thicker composite body part 2 to hardening temperature is advantageously brought about by means of induction heating via a suitable induction coil 11.

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Claims (7)

2356 45 A Claim for invention 1 · Method for producing tools with reinforced shank for cutting and non-cutting machining, in particular for the production of twist drills made of hard metal with reinforced shaft, in which a thinner cutting part is pressed into an axially arranged and undersized bore of a thicker shaft part _s thereby characterized in that the pressing of the thinner cutting part (1) into the thicker shaft part (2) is carried out by using the high-speed technique. 2, method according to item 1, characterized in that the high-speed by an explosive, electric or pneumatic force, for example by explosion pressure or by electrical shock waves? is produced. 3- Method according to item 1 and 2, characterized in that the thicker shaft part (2) is preferably heated by induction to hardening temperature before the pressing of the thinner cutting part (1), 4 · Method according to points 1 to 3, characterized in that the thicker shaft part (2) consists of an air-hardening material · Method according to points 1 to 4, characterized in that the thinner blade part (1) has a chamfer (3) on the end face and / or is partially provided with a flattening (4) on the peripheral surface. i 235645 k 6, device for carrying out the method according to item 1 to 5, characterized in that a respective guide bush (5 ^ 6) for the thinner cutting part (1) and the thicker shaft part (2) at a distance which is smaller than the length of the thicker Shaft part (2) is arranged axially aligned, each guide bush (5, 6) is associated with a feed and pressure plunger (7 | 8), and that each feed and pressure plunger (7, 8) with a Magazinierungs- and feeding (9-10), for example consisting of a conveyor belt or a stacking magazine, is operatively connected · 7. The device according to item 6, characterized in that between the two guide bushes (5% 6) an induction coil (11) is arranged. - 2 sheets of drawings for this -