Metal Drill

A metal drill includes a cutting section and a drive section pointing away therefrom. The metal drill has at least two different functional coatings are provided which are designed at least in regions and are designed to permit machining of a metallic workpiece adapted to a respective application material. The drive section has, at least in sections, a polygonal, preferably hexagonal cross-sectional geometry.

This application claims priority under 35 U.S.C. § 119 to application no. DE 10 2022 211 783.2, filed on Nov. 8, 2022 in Germany, the disclosure of which is incorporated herein by reference in its entirety.

BACKGROUND

The disclosure relates to a metal drill having a cutting section and a drive section extending therefrom.

Twist drills are generally known from the prior art.

For example, WO 2019/147885 A1 shows a twist drill having a first end with a drill point and a second end directed away therefrom. An axis of rotation extends centrally from the first end to the second end through a base body of the drill. A shaft is provided in the region of the second end for rotatably driving the drill by a tool, such as a hand tool, a pillar drill, or the like. The drill bit has a plurality of axially progressive steps receding toward the shaft or second end, including a first step and a final step. A radial diameter of the stages increases from the first stage to the final stage, the final stage having a diameter less than or equal to an outer diameter of the base body.

SUMMARY

The present disclosure relates to a metal drill having a cutting section and a drive section extending therefrom. At least two different and at least regionally formed functional coatings are designed to enable machining of a metallic workpiece adapted to a respective application material, the drive section having at least in sections a polygonal, preferably hexagonal cross-sectional geometry.

This allows a wide range of different metallic workpieces to be machined quickly and easily with the metal drill. In addition, a long service life of the metal drill is given. The at least two functional coatings of the metal drill are preferably designed without overlap. In the context of the description, the term functional coatings defines not only the application of at least one additional functional layer to the surface of the metal drill, at least in some regions. Rather, the term functional coating is also intended here to comprise the penetration or diffusion of the chemical substances used for this purpose into a near-surface edge zone of up to 5 μm, preferably in a range of 1 μm to 2 μm, of the metal drill and/or a chemical-physical transformation of the near-surface edge zone of the metal drill. Such a chemical-physical transformation of the near-surface edge zone takes place, for example, during so-called carburizing or burnishing to form black oxide.

A large number of metal drills, each with at least two different and at least regionally designed functional coatings, can be combined in a storage unit in order to be able to address an even broader range of applications and to further optimize handling. The storage unit may also include at least one metal drill that is free of any functional coating. The storage unit may be in the form of a mobile and preferably resealable hard or soft case and may have metal drills of different diameters in a suitable gradation. In addition, a product presentation unit appealing to prospective buyers, in which metal drills provided with functional coatings and metal drills without coatings are combined, can be provided for use in stationary retail.

Preferably, the at least two functional coatings are designed to increase a surface hardness of the metal drill.

As a result, the feed rate as well as the service life of the metal drill increases considerably. In addition to increasing the hardness of the surface layer, the functional coatings can also have other functions, such as reducing friction. The functional coatings of the metal drills allow optimal machining of workpieces designed with an application material such as steel, iron, cast iron, stainless steel, titanium, aluminum, copper, lead, etc., as well as metal alloys.

Preferably, a first functional coating of the at least two functional coatings is formed with titanium nitride and a second functional coating of the at least two functional coatings is formed with aluminum titanium nitride.

Alternatively or in addition, a variety of other functional coatings are possible to increase the hardness of the surface layer. Titanium nitride enables a hardness of 2300±300 HV 0.5, while with aluminum titanium nitride a hardness of 2500±500 HV 0.5 can be achieved. In comparison, an uncoated metal drill is in a hardness range <1000 HV 0.5. The functional coatings can be applied over the entire surface, in any geometric pattern in certain regions and, if necessary, overlapping each other at least in certain regions.

In a technically advantageous further development, the cutting section has a cutting head with two cutting edges and a guide section is preferably designed between the cutting section and the drive section.

This provides an effective drilling process due to improved guidance of the metal drill in the workpiece to be machined with the aid of the cylindrical guide section. The guide and drive sections preferably together form the shaft of the metal drill.

Preferably, the cutting section has two spiral flutes.

This allows chips produced during drilling to be discharged and a coolant and lubricant to be easily supplied if required. Each of the two flutes preferably has a ground guide chamfer directed radially outward. The guide chamfers also reduce the friction between the metal drill and the workpiece to be machined.

Preferably, the metal drill has an approximately constant diameter at least in the region of the cutting head and the cutting section.

As a result, high dimensional accuracy of the holes produced in the workpiece being machined is ensured.

Preferably, the cutting head is designed in the manner of a cone shell ground or a surface ground.

This allows conventional manufacturing processes to be used and proven cutting geometries to be realized. Preferably, the cutting head of the metal drill is designed according to DIN 1412:2001-03 Form C.

Preferably, the metal drill is formed with a high-speed steel.

Due to the temperature resistance provided by this, a high feed rate is possible with nevertheless low wear.

According to a technically advantageous embodiment, the drive section and the cutting section are roll-rolled, forged, and/or at least partially machined from solid.

As a result, common manufacturing processes can be used to produce the metal drill, with roller burnishing in particular offering particular cost advantages.

According to a technically advantageous embodiment, a metal drill is identified by a unique marking that identifies a metallic workpiece to be machined with the metal drill.

A single or multi-colored marking allows a user to clearly and easily select the most suitable metal drill for drilling a workpiece formed with a particular application material. The marking can comprise geometric surface elements, any characters (letters and numbers) and/or graphics, pictograms as well as combinations thereof, from which the suitability of the metal drill for a metallic workpiece to be machined is immediately apparent to the user. Alternatively, an indirect assignment of a marking that is not immediately “self-explanatory” can be made by means of an external table, a (smartphone) app, or the like. The marking can be machine-readable for this purpose, for example as an optical barcode, QR code, or the like. In this case, for example, a plain text name of an application material to be processed in the best possible way with the metal drill in question can be output using the (smartphone) app. The external table or marking may also be associated with an optional storage unit for a plurality of metal drills according to the disclosure. For example, accommodation spaces of the storage unit for one metal drill each can be provided with a corresponding marking. In addition or alternatively, the marking can be designed to be haptically perceived by a user.

DETAILED DESCRIPTION

FIG.1shows a metal drill100having a cutting section120and a drive section140directed axially away therefrom. These are preferably designed to be rotationally symmetrical with respect to a longitudinal central axis110.

The cutting section120has a cutting head122with a (drill) tip S, the cutting head122being adjoined by a flute section132pointing in the direction of the drive section140and having, by way of example, two flutes128,130spirally coiled around one another. Illustratively, the cutting head122has two cutting edges124,126oriented radially outwardly from the tip S for machining a hole168in a metallic workpiece170formed with an application material172.

The flute128has a ground guide chamfer152and the flute130has a corresponding ground guide chamfer154.

A cylindrical guide section146extends between the cutting section120and the drive section140. This is preferably also designed to be rotationally symmetrical to the longitudinal center axis110. At least in the region of the cutting head122and the cutting section120, the metal drill100preferably has an approximately constant diameter D1, which here essentially corresponds to a diameter D2of the guide section146. The guide section146, together with the drive section140, forms a shaft section160of the metal drill100.

The drive section140of the metal drill100has, at least in sections, a polygonal cross-sectional geometry142that is merely hexagonal by way of example here. This preferably has two axial sections A1,2, between which a fillet-like annular groove142extends. In principle, the drive section140can have any regular or irregular polygonal cross-sectional geometry that provides a form-fit connection with a tool holding of a tool that rotationally drives the metal drill100, such as a hand drill or a pillar drill.

In the region of the cutting section120of the metal drill100, a first functional coating F1and a second functional coating F2are provided, wherein the functional coatings F1,2butt against each other here only exemplarily, forming a first boundary line148. Illustratively, the first functional coating F1extends from the tip S of the metal drill100to the boundary line148over an axial length L1, while the second functional coating F2extends from the boundary line148to a second boundary line150and has an axial length of L2. The second boundary line150is between the cutting section120and the shaft section160of the metal drill100, which is uncoated in this example. Both boundary lines148,150have the form of a circular line here as an example. The sum of the axial lengths L1,2of the functional coatings F1,2corresponds here only by way of example to an overall length L of the cutting section120, but may also deviate from the overall length.

The length L1of the first functional coating F1is preferably smaller than the length L, so that there always remains an axial circumferential area, albeit a small one, for forming the second functional coating F2with the axial length L2. In addition, the shaft section160may also be provided with the first and/or the second functional coating F1,2, as appropriate. Among other things, this can reduce any wear in the region of the guide section146of the metal drill100when making deep holes in the metallic workpiece170. The boundary lines148,150can have a course deviating from the circular line shape and, for example, be rectangular, triangular, or sinusoidal, so that the functional coatings F1,2are interlocked with one another, in particular in the region of the first boundary line148, or engage in one another in the manner of interlocking without overlapping. Nevertheless, an overlapping formation of the functional coatings F1,2is possible.

In principle, the at least two functional coatings F1,2can be designed in any pattern on the metal drill100. For example, a pattern in the form of continuous or interrupted axial longitudinal stripes running essentially parallel to the longitudinal center axis110is conceivable, with the functional coatings F1and F2alternating on the circumferential side in each case. As a result, the different physical properties of the functional coatings F1,2can be used in close spatial proximity. Accordingly, for example, a spiral formation of the functional coatings F1,2analogous to the course of the flutes128,130of the metal drill is also possible.

The functional coatings F1,2are preferably designed to increase the surface hardness of the metal drill100in a region near the surface of the cutting section120of the metal drill100, but may also have friction-reducing or other functions. The first functional coating F1can be realized with titanium nitride, for example, and the second functional coating F2can be realized with aluminum titanium nitride, for example, wherein the aluminum titanium nitride can be provided with additives. Other possible material combinations for forming the first and second functional coatings F1,2include, for example, titanium carbon nitride, titanium aluminum carbon nitride, chromium carbon nitride, zirconium nitride, titanium aluminum nitride, aluminum chromium nitride, aluminum titanium chromium nitride, aluminum titanium nitride-zirconium carbon nitride, tungsten carbide-carbon, aluminum nitrate silicon, and aluminum titanium nitride.

At least the cutting section120of the metal drill100is preferably designed with a high-speed steel (HSS). The cutting section120and the drive section140may be roll-rolled, forged, and/or at least partially machined from solid. The cutting section120and the drive section140may be integral or joined together in a suitable manner, which may be by friction welding, thermal shrinking, compression molding, or the like.

Preferably, the metal drill100has a unique marking180in the region of the guide section146that identifies a metallic workpiece170to be optimally machined with the present metal drill100that is designed with the application material172. Due to the marking180, the user can intuitively select a metal drill for machining that is best suited in each case. The marking180may comprise geometric area elements, any characters (letters and numbers) and/or graphics, pictograms, and combinations thereof. In the illustration ofFIG.1, the marking180is implemented only exemplarily with the four capital letters “X”. Deviating from the illustration ofFIG.1, the marking can also be implemented in the region of the drive section140.

FIG.2shows the cutting head122of the metal drill100ofFIG.1, which is designed here in exemplary rotational symmetry with respect to the longitudinal center axis110and is ground illustratively in the manner of the standard cone shell ground200. As a result, the two cutting edges124,126are formed and a front surface202of the cutting head122forms an approximately cone-shaped enveloping surface.

FIG.3shows the cutting head122of the metal drill100ofFIG.1, which here, by way of example, is designed rotationally symmetrical to the longitudinal center axis110and, in contrast to the representation ofFIG.2, is ground illustratively in the manner of the so-called surface ground210. This forms two cutting edges212,214. Due to the surface ground210, two approximately trapezoidal planar surfaces216,218are created, wherein the cutting edge212forms a longitudinal side of the planar surface216and the cutting edge214forms a longitudinal side of the planar surface218.

FIG.4shows an exemplary drilling system400, which here merely exemplifies a total of five metal drills100,420,422,424,426that are combined or housed in a storage unit402for convenient use by the user. The metal drills100,420,422,424,426each preferably in turn have a hexagonal drive section that is not designated for the sake of a better drawing overview.

Illustratively, the metal drill100has the functional coating F1in the region of its cutting head122and the functional coating F2in the remaining region of the cutting section120(see in particularFIG.1). Deviating therefrom, the metal drill420has exemplary functional coatings F3,4, the metal drill422has exemplary functional coatings F5,6, and the metal drill424has exemplary functional coatings F7,8, while the metal drill426has exemplary design without coating.

The area proportions of the functional coatings F3, . . . , 8in the region of the cutting sections of the metal drills420,422,424may differ from those of the metal drill100as shown. Each of the coated metal drills100,420,422,424preferably has at least two or more functional coatings F1, . . . , 8designed at least in some regions, at least in the region of its respective cutting section.

The functional coatings F3, . . . , 8, for example, are realized with other chemical compounds or substances compared to the first and second functional coating F1,2and consequently have other physical parameters such as (micro-)hardness HV 0.5 according to Vickers, maximum permissible application temperature, coefficient of friction against 100Cr6 steel, or the like. Thus, each of the differently coated metal drills100,420,422,424as well as the metal drill426without coating is particularly suitable for drilling a metallic workpiece made of a special application material such as steel, iron, cast iron, stainless steel, titanium, aluminum, copper, lead, etc., as well as metal alloys.

Due to the marking180of the metal drill100and the corresponding markings432,434,436,438of the metal drills420,422,424as well as426, an unambiguous selectability of the metal drill100,420,422,424,426best suited for the machining of a given metallic workpiece made of a certain application material by the user for achieving best possible working results is ensured. In order to permit particularly easy and convenient access by the user to the differently coated metal drills100,420,422,424as well as the metal drill426without coating, these are preferably combined in a storage unit402in the form of a hard case406shown here only by way of example. In this example, the hard case406has a cuboid bottom portion408for holding the metal drills100,420,422,424,426and a transparent top portion410. Instead of the hard case406, a case-like or pocket-like soft case or other storage unit, such as a revolver magazine-like or cylindrical or cassette-like storage unit, may also be provided.