DE102010041164B4 - Method of making a drill - Google Patents

Abstract

Method for producing a drill with the following method steps: 1.1 a piece of wire (1) is prepared with a length corresponding to the length of the drill to be produced, 1.2 the piece of wire (1) is inserted between a point at a distance from one end of the piece of wire (1) and chip grooves (5) are rolled into the other end of the piece of wire (1) along a helix,1.3 a drill point (12) is formed onto the latter end of the piece of wire (1),1.4 the slug (9) formed when the drill point (12) is formed becomes sheared off, 1.5 the piece of wire (1) is hardened.

Description

The invention relates to a method for producing a drill and a drill.

The most common drills are so-called twist drills. These have a drill bit that has two curved drill bits, in front of which chip flutes are arranged in the direction of rotation. These extend helically over a large portion of the length of the drill shank. Drills of this type are machined from high-quality tool steel. This type of production is expensive because of the high-quality material and the complex machining process. Such expensive drills are often simply thrown away because there is no possibility of regrinding them instead of being ground afterwards.

A drill is already known ( EP 304702 A1 ), which features a cylindrical shank with a cold-forged tip. This tip has a shape that is unusual for drills. Due to the lack of chip flutes in the shank adjoining the drill point, this drill is only suitable for thin sheet metal.

A method of cold rolling a drill is known ( DE 696 07 539 T2 ) in which a slot is formed in a cutting end of the drill and then an insert is placed in the slot and secured by brazing or welding.

A method for roll-forging drill bits is also known ( DE 697 12 389 T2 ), in which the drill is roll-formed from a blank between two forging wheels. The drill point is also created by profile rolling between the two forged discs.

A method for producing drill bits is also known ( WO 2010/142458 A2 ), in which a blank is introduced into a guide die without prior heating and is subsequently cold-formed in a jaw tool with at least two movable jaws, the inner wall of which has at least one section with a negative contour for the formation of helical grooves. The helical grooves on the lateral surface of the blank are thus produced by plastic cold deformation. After completion of the drill, a cutting plate can be attached to the drill tip.

A method for producing three-spiral and multi-spiral drills is known ( DE 10 2009 055 746 A1 ), in which the grooves of the drill head are produced by cold and/or hot forming of a wire section in forming dies of a forming machine. Four cutting edges arranged at right angles to one another and made of a harder cutting edge material should be used on the drill bit.

Another method of making a drill is known ( DE 10 2009 055 748 A1 ), in which a raw groove running parallel to the longitudinal axis of the wire is made in a wire, with the blank then being twisted into a drill helix by means of a twisting device.

A drill bit made of harder cutting material with four cutting edges arranged at right angles to one another is inserted into the drill.

Another method of making a drill is known ( DE 198 59 885 A1 ), in which a blank is produced in a non-cutting forming process such as drawing, rolling, extrusion or forging. One or more cutting edges made of harder material are inserted into the blank at the drill point.

Another method of making a drill is known ( DE 2 244 159 A1 ) in which the drill is intended for inserting a blind rivet and in which the blind rivet is arranged on the shank of the drill. The drill is then used to deform the tubular rivet in order to rivet it. The drill bit is formed by a thin plate formed between opposed dies.

Another method of making a drill is known ( U.S. 3,504,575 ) in which oil passages are formed in a drill by making large diameter bores in a blank, then forging or rolling the drill and thereby forming the oil passages of smaller diameter than the bores in the blank.

Another method of making a drill is known ( EP 2 213 392 A1 ), where the drill is made from a one-piece blank.

Another method of making drills is known ( DE 224 576 ), in which a drill is produced by an extrusion process. An extrusion device for producing drills is known ( DE 956 641 ), which is used to press a blank through a die, thereby creating coils on the outside of the blank.

A method for manufacturing a drill bit is known ( DE 10 2012 219 121 A1 ), in which a drill point is made between a pair of jaws.

The invention is based on the object of creating a possibility of being able to produce drills more cheaply.

To solve this problem, the invention proposes a method with the features mentioned in claim 1 and a drill with the features mentioned in claim 10 . Developments of the invention are the subject of dependent claims.

The invention uses a wire as the starting material, from which a corresponding piece of wire is cut to length. This piece of wire serves as a blank for making the drill. Chip flutes are rolled into the piece of wire. The rolling is done in such a way that the chip flutes at one end of the piece of wire reach up to the end, while at the other end they are spaced apart. This end then later forms the clamping end. A drill bit is formed at the other end by cold forging. This creates a slug that remains connected to the drill bit. This slug is then sheared off. Post-processing in the manner of grinding the drill bit is no longer absolutely necessary. The drill is then hardened. The flutes also do not have to reach all the way to the end, otherwise pinching the point is more difficult.

All types of steel that can be hardened and formed can be used as the starting material. These are usually steels with a carbon content of 0.15% or more (e.g. SAE 1018; SAE 1016; CK 15 DIN 17210).

As a result of the method proposed by the invention, one has a drill which is manufactured much more cheaply. Because of the flutes extending along the shank, the drill can be used in exactly the same way and for the same applications as a conventional twist drill.

Due to the changed manufacturing process, different cutting edge geometries can also be realized, which previously could not be realized because of the production by grinding. An example of this is a cutting angle of 180°. In addition, it is possible to realize a wide variety of shank shapes for accommodating drives.

To produce the chip flutes by rolling, according to the invention it can be provided in a further development that the chip flutes are rolled along helical lines with the aid of at least two rollers and a relative movement between these and the piece of wire. In this case, either the rollers themselves can be moved along helical lines, or the piece of wire can be guided past the rollers in a corresponding movement.

Another way of producing the chip grooves can consist in placing the piece of wire between two flat rolling dies and moving them linearly towards one another to produce the chip grooves.

In a further development of the invention, it can be provided that the drill tip is formed using at least two pinch jaws, which are moved towards one another transversely to the axis of the piece of wire until they touch. In this way, a symmetrical drill bit can be created.

With this type of production of the drill bit, a slug is created in front of the later cutting edges, which then has to be removed. After removal of the slug, the cutting edges of the drill bit are finished without the need for finishing grinding.

In a further development of the invention, it can be provided that the piece of wire is heated before the flutes are rolled, with inductive heating being particularly preferred here. This makes it easier to roll the flutes, especially with the help of the rotating rolls.

According to the invention, it can be provided that the drill bit is formed on before the chip flutes are rolled.

The slug can be removed by shearing it off, for example by holding the slug in a type of fork and twisting the piece of wire. Conversely, if the piece of wire is held tight, the slug may shear off as a result of its own twisting.

If the drill is to be used for a special receptacle and the cylindrical end of the piece of wire is not suitable for this purpose, a receptacle for the chuck of a drive device can be formed on the end remote from the drill bit according to the invention. This molding can also be done before molding the drill bit.

The invention also proposes a drill that can be produced by the method described.

• 1 schematisch das Herstellen der Spannuten in einem Drahtstück;
• 2 das Anformen der Bohrspitze;
• 3 das Entfernen der Backen nach dem Herstellen der Bohrspitze;
• 4 das Abscheren des Butzens;
• 5 den fertig gestellten Bohrer;
• 6 den Beginn der Herstellung eines Bohrers nach einer zweiten Ausführungsform des von der Erfindung vorgeschlagenen Verfahrens;
• 7 das Drahtstück nach Herstellen der Bohrspitze;
• 8 das Walzen der Spannuten;
• 9 den fertigen Bohrer vor dem Härten;
• 10 das Walzen von Spannuten mithilfe zweier Flachwalzbacken bei dem Herstellungsverfahren nach einer dritten Ausführungsform;
• 11 das Anformen der Bohrspitze;
• 12 das Entfernen der Kneifbacken;
• 13 das Abscheren des Butzens;
• 14 das Entfernen des Butzens und den fertigen Bohrer;
• 15 einen nach dem erfindungsgemäßen Verfahren hergestellten Bohrer mit einer Sechskantaufnahme.

Further features, details and advantages of the invention result from the claims and the summary, the wording of both of which by reference to the content of the description Exercise is made, the following description of preferred embodiments of the invention and with reference to the drawing. Here show:

• 1 schematic of the production of the chip flutes in a piece of wire;
• 2 the shaping of the drill bit;
• 3 removing the jaws after making the drill bit;
• 4 the shearing of the slug;
• 5 the finished drill;
• 6 the start of the manufacture of a drill according to a second embodiment of the method proposed by the invention;
• 7 the piece of wire after making the drill bit;
• 8th the rolling of the chip flutes;
• 9 the finished drill before hardening;
• 10 the rolling of chip grooves using two flat rolling dies in the manufacturing method according to a third embodiment;
• 11 the shaping of the drill bit;
• 12 the removal of the jaws;
• 13 the shearing of the slug;
• 14 the removal of the slug and the finished drill;
• 15 a drill with a hexagon socket made by the method according to the invention.

First, with reference to the 1 until 5 a first embodiment of the method proposed by the invention is described. A piece of wire 1 of a certain length was severed from a longer wire. It is arranged between rollers 2 which can be driven in rotation and which can be driven about twisted axes. After arranging the piece of wire, the rollers 2 are moved towards each other. The piece of wire is inductively heated using a heating device 3 . The piece of wire 1 is pulled upwards in the direction of the arrows 4 and twisted in the process. In this way, the two rollers 2 roll opposing helical flutes 5 into the piece of wire. These flutes 5 are up to the in 1 lower end of the piece of wire 1 rolled.

This creates an intermediate product in which the piece of wire 1 has at least two opposite chip flutes 5 which extend to the lower end of the piece of wire 1 . At the opposite upper end, a section 6 of the piece of wire 1 has remained free from chip flutes 5 . This cylindrical part 6 of the piece of wire 1 is later the clamping end of the drill, see 2 .

Two jaws 7 are now moved towards one another transversely to the longitudinal axis of the piece of wire 1 . The two jaws 7 have in the mutually directed surfaces 8 indentations that reflect the shape of the drill bit to be produced. As soon as the jaws 7 are moved towards one another until the surfaces 8 touch one another, the front end of the piece of wire has been provided with a deformation already containing the shape of the drill bit. Then the jaws 7 are moved away from each other again, see 3 .

The now formed drill bit is still connected to the slug 9. The connection is made along the later drill bits. The slug 9 now has to be removed. A slotted shaft 10 is used for this purpose, which is pushed forward axially until the slug is arranged in the slot of the front end of the shaft 10. The shaft 10 is then rotated in the direction of the arrow 11 and the slug is sheared off, see 4 . As a result, the drill bit 12 is completed. It contains two drill bits 13 that no longer require post-processing. The shape of the drill is now complete, see 5 . He is now being hardened. The drill is then produced using the method described here.

In the following 6 until 9 a second embodiment of the method proposed by the invention is described and illustrated. First, in this variant in the piece of wire 1 using the two jaws 7 in the same way as in the embodiment of the 2 one end of the piece of wire 1 is deformed to form the drill bit 12 . The result shows the 7 . The slug 9 is sheared off during the subsequent spiral rolling of the chip flutes 5 using the rollers 2 rotating about crossed axes. As soon as the chip flutes 5 are finished, the rollers 2 move apart and the drill is finished to the point where it only needs to be hardened.

In the following figures, a further possibility of designing the method proposed by the invention is shown. Two flat rolling dies 17 are used here, which have ribs 19 on their inner sides 18 facing one another, which correspond to the flutes 5 . The piece of wire 1 is inserted between the two flat-rolling dies 17 and one of the two flat-rolling dies 17 is displaced in the direction of the arrow 20 . As a result, in the surface of the piece of wire 1 the flutes 5 rolled. The result shows the 11 .

Now in the same way as this too 2 described, the drill tip is formed at the front end of the future drill using the two jaws 7. After removing the jaws, see 12 , the slug 9 is still hanging at the front end of the future drill. It is removed in the same way as this in 4 was presented, so that in the final result in 14 the almost finished drill is shown. It is then also hardened.

the 15 shows that a hexagonal socket 16 is formed on the clamping end of the finished drill. The shaping of this hexagonal attachment can be carried out, for example, as the first method step. Of course, other shapes of the clamping end can also be formed, e.g. B. Inside or outside drives.

Reference List

1

piece of wire

2

rolls

3

heating device

4

arrows

5

chip flutes

6

Cylindrical section of the piece of wire

7

pinched jaws

8th

surfaces of the jaws

9

hickeys

10

Slotted Shaft

11

arrow

12

drill bit

13

drilling cutting

16

Hexagon attachment as a recording

17

flat roll jaws

18

Inner sides of the flat rolling dies

19

Ribs of the flat rolling dies

20

arrow

Claims (10)

Method for producing a drill with the following method steps: 1.1 a piece of wire (1) with a length corresponding to the length of the drill to be produced is prepared, 1.2 chip flutes (5) are rolled into the piece of wire (1) along a helix between a point at a distance from one end of the piece of wire (1) and the other end of the piece of wire (1), 1.3 a drill bit (12) is formed onto the latter end of the piece of wire (1), 1.4 the slug (9) formed when the drill bit (12) is formed is sheared off, 1.5 the piece of wire (1) is hardened. procedure after claim 1 , in which the chip flutes (5) are rolled using at least two rotating rollers (2), which are moved past the piece of wire (1) along helical lines. procedure after claim 1 , in which the chip flutes (5) are rolled using at least two rotating rollers (2), past which the piece of wire (1) is moved in a screwing motion. procedure after claim 1 , in which the piece of wire (1) is placed between two flat rolling dies (17) and these are moved linearly towards one another to produce the chip grooves (5). Method according to one of the preceding claims, in which the drill bit (12) is formed by means of two pinching jaws (7) which are moved towards one another transversely to the axis of the piece of wire (1). Method according to one of the preceding claims, in which the piece of wire (1) is heated, in particular inductively heated, before the flutes (5) are rolled. Method according to one of the preceding claims, in which the drill bit (12) is formed on before the chip flutes (5) are rolled. Method according to one of the preceding claims, in which the slug (9) produced during manufacture of the drill bit (12) is sheared off by a rotary movement. Method according to one of the preceding claims, in which a receptacle (16) for the chuck or a drive of a drive device is formed on one end of the piece of wire (1). Drills made by a method according to any one of the preceding claims.

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