WO2005089973A1

WO2005089973A1 - Flow moulding drilling method with simultaneous thread and flow moulding drilling tool for carrying out said method

Info

Publication number: WO2005089973A1
Application number: PCT/DE2005/000442
Authority: WO
Inventors: Josef Grüner
Original assignee: Gühring, Jörg
Priority date: 2004-03-19
Filing date: 2005-03-11
Publication date: 2005-09-29
Also published as: DE102004013640A1

Abstract

The invention relates to a method, tool and device for producing threaded holes, particularly in workpieces of low material strength. The workpiece is heated in a substantially extensive manner with the aid of a friction and expansion section of the tool by means of frictional contact and the heated material is displaced by the tool in a radial and axial direction. A thread is created in an eye arising from the displacement of said material, using a thread configuration section. The device is configured in such a way as to receive and drive the tool and to provide control according to said method.

Description

FLOW-FORMING DRILLING METHOD WITH SIMULTANEOUS THREADING AND FLOW-FORMING TOOL FOR IMPLEMENTING THE METHOD

description

The present invention relates to a method, a tool and a device for producing threaded holes, in particular in workpieces of low material thickness, preferably in workpieces made of a metallic material. 10 It has always been a problem to create holes with an internal thread in components with a thin cross-section, since the method of first drilling a hole using a machining process and then cutting a thread in it, because of the short thread length and therefore the small number of usable threads is often unsuitable. The use of so-called machine taps, which combine the process of drilling and tapping, encounters the same problems with low 20 material thicknesses.

To increase the thread length, it has long been known to double thin workpieces by soldering or welding additional material thicknesses 25 or to solder or weld bushings into boreholes or to insert rivets. All of these processes are energy, material and time consuming and cause noise and waste and are therefore not optimal from an economic point of view. 30 For very thin sheets, cold-forming tools or self-tapping screws are known that perforate a sheet, displace it through cold forming and press a thread into the displaced sheet metal part. A tool and a screw of this type, as disclosed, for example, in US Pat. No. 3,429,171

IΞrsatΞ .IWÜ i a mandrel of conical or concave contour with a sharp tip, which is followed by a cylindrical section with a threaded molded part raised on it. However, this tool is only suitable for very thin sheet metal, not too strong. There are also limits to the tool life and the working speed due to the rapid blunting of the tip.

In order to be able to equip thin-walled workpieces with bores, which provide improved guidance for a part to be accommodated therein, it was early adopted to use tools which at the same time form a kind of bushing when a borehole is drilled.

From documents DE-OS 23 59 794 and DE-OS 25 52 665, such a tool is known in the form of a mandrel rotatable about its axis, with the aid of which a hole can be formed in a metal plate or the wall of a metal tube. This well known

The tool is shown in FIGS. 8A to 8D in a side view and in three cross-sectional variants. As shown in FIG. 8A, the tool 910 has a conical section 912 with a centering tip 911. The cone section 912 is followed by a first cylinder section 914, which is followed by a second cylinder section 916 of larger diameter. This is followed by a likewise cylindrical shaft section 918, which is provided for receiving in a hand drilling tool or a machine tool. According to DE 23 59 794, the cone section 912 and the first cylinder section 914 have a triangular cross section, the tips of the triangle either being cut off by a circular path as shown in FIG. 8B or, as shown in FIG. 8C, at an obtuse angle than the corner angles of the triangle are sharpened. In the DE 25 52 665 further develops this cross-sectional shape, which is defined by the basic shape of an equilateral triangle, in that the triangle sides are convexly curved and merge into one another in the shape of an arc. With this cross-sectional shape shown on an enlarged scale in FIG. 8D, the aim is to increase the tool life and to improve the suitability of the tool for processing hard materials such as iron and steel.

The process sequence of a drilling method with the above-mentioned tool 910 according to the prior art is shown schematically in FIG. 9, which is modeled on a display on the website of Kavon CZ s.r.o., CZ. A subsequent thread forming step is also indicated in the figure.

The figure shows how the tool 910 drills a hole in a flat plate 900. If the tool 910 is placed with its tip on the surface of the workpiece 900 and rotated at a sufficient speed, the material heats up due to the friction between the tool tip and the surface. With a suitable selection of the speed, the material begins to flow immediately and evades the pressure of the tool tip, being pushed back downwards and radially outwards and thrown upwards and radially to the side until the tool breaks through the comparatively thin wall and with the second cylinder section ^' on the bead-like material thrown outwards and flattened thereby. The displaced material of the workpiece takes on the overall shape of a collar or eye or bush 905, which nestles against the outline of the tool and is retained after the tool is removed. The length or thickness of the resulting Collar or eye or the resulting bush 905 exceeds the thickness of the workpiece itself.

This process, which forms the basis of the so-called "Flowdrill" or "flow form drilling" technology (the term "Flowdrill" is a protected trademark of Flowdrill B.V., NL), was further developed and refined in the following years. For example, European Patent EP 0 057 039 B1 discloses a flow form drill for providing sheet metal material with holes, the cross section of which in the cone section or the first cylinder section has a polygonal shape of the number of corners 3 or 4 with convex sides and rounded corners, the lines of which correspond to a certain complex harmonic Function obeys. EP 0 015 518 AI discloses a flow form drill, the tip of which has a short cutting edge.

Other special forms are known from the publications of Flowdrill BV, NL, Frictiondrill Inc., US, and Kavon CZ sro, CZ, including their Internet rarities. In the end face defined by the second cylinder section, a shaped section in the manner of a groove can be provided, which gives the depressed material a defined shape. The shape of the resulting hole can be controlled by the length of the first cylinder section 914. If the first cylinder section is short, the hole may have a cross section which tapers in a conical manner in the tool feed direction. On the other hand, if the first cylinder section is long, a continuous cylindrical hole can be produced. Instead of the second cylinder section 914, a second cone section can also be provided, the cone angle of which is more acute than that of the first cone section 912. Also, instead of the second A flat or conical countersunk part can be provided in the cylinder section 916 in order to plate the material portion thrown outwards and to remove any burr that may have arisen.

The advantages of this procedure are obvious. The material in the area of the hole is used to form a bushing, the length of which considerably exceeds the material thickness. The material flows under the influence of great frictional heat and solidifies again, which contributes to the final strength and shape retention of the bush, especially when compared to cold-formed structures. An introduced in such a ^'hole thread has a greater effective length, and does not break as easily as from a cut in a thin wall thread. Additional energy, material and time-consuming process steps such as soldering, welding or riveting are no longer necessary. As can be seen from FIG. 9, the flow drilling process is followed by a thread formation process. The thread is produced with the aid of a separate thread-forming tool 920, which does not work by cutting material, but by displacing or flow-forming the material ("flowtapping").

Such thread formers, also called thread formers or thread pressers, are known in the art. The differences in geometry between a thread tapping tool and a machining tap performing machining are described below with reference to FIGS. 10A to IOC on the one hand and 11A to 11C on the other hand. Figure 12 shows the flow behavior of the material during pressure forming by thread forming, in particular the mode of action of a start of the thread former. These figures are the Company brochure No. 300 087/02123-VIII-15 taken from Gühring oHG. This application makes full reference to this brochure, in particular with regard to details of the technology of thread grooving.

FIGS. 10A to IOC show the tool geometry of a tap and the geometry of a thread produced with a tap according to the prior art. FIG. 10A shows a cross section of a tap 950, FIG. 10B shows a longitudinal section of a front part of the tap 950, and FIG. IOC shows a longitudinal section through a few teeth of a thread produced in a workpiece 960 using the tap 950. In a known manner, the tap 950 has a plurality of flutes 952, which define a plurality of cutting studs 954, each with a cutting edge 954a. In FIGS. 10A and 10B, reference number 956 denotes an outer diameter of the tool. The reference number 958 in FIG. 10B denotes the line of a chamfer which serves to make it easier to screw the tool into the workpiece, and the reference number 957 denotes a core diameter. As can be seen from FIG. 10B, the gate 958 is formed by conically cutting off the tips of the first teeth, while the core diameter 957 remains unchanged in the region of the gate.

FIGS. 11A to 11C show the tool geometry of a thread turret and the geometry of a thread produced with a thread turret according to the prior art. FIG. 11A shows a cross section of a thread groove 970, FIG. 11B shows a longitudinal section of a front part of the thread groove 970, and FIG. 11C shows a longitudinal section through a few teeth of a thread produced in a workpiece 980 with the aid of the thread groove 970. The thread cutter 970 has a polygonal cross section in a known manner, which defines a plurality of pressure studs 972 in its raised parts. Lubrication grooves 974 are formed in the recessed portions of the polygonal cross section. In Figures ILA and 11B, reference number 976 denotes an outer diameter of the tool. The reference number 978 in FIG. 11B denotes the line of a run-up, which serves to make it easier to screw the tool into the workpiece, and the reference number 977 denotes a core diameter. As can be seen from FIG. DB, the geometries of the teeth are completely preserved in the area of the run-up 978, and the core diameter in the area of the run-up 978 tapers parallel to this.

Figures IOC and 11C show the differences in geometry between a thread made by cutting and a thread made by grooving.

In the thread produced in the workpiece 960 by cutting, grooves 962 are formed by cutting material, which in turn define tooth flanks 964. At a point 966, the tooth flanks merge into the tooth base. The cutting action of the thread cutter 950 cuts the "fiber course" 968 in the structure of the material of the workpiece 960, as a result of which the load-bearing capacity of the thread is reduced, in particular by an increased notch effect at a transition point 966.

In contrast, when furrowing the thread in the

Workpiece 980, the fibers 988 are only compressed, but not cut off. Material is therefore present in a compressed state at a transition point 986 between the tooth flank 984 and the tooth base. As a result, this points Transition point high toughness compared to the cut thread. Therefore, the teeth of a grooved thread are more stable and do not break out as easily as the teeth of a cut thread.

The details of the formation of a thread by furrows are shown in FIG. Here, the front part of the thread formation 970 is shown in the area of the start-up, namely with its first three teeth or gears 972a, ₍ 972b and 972c. The tool 970 is rotated and translationally moved in the direction of an arrow "III". Each of the Gears 972a, 972b, 972c penetrate deeper into the material of the workpiece 980. As a result, the processed material is thrown up and on until it overlaps in a kind of wave motion between the two tooth flanks and forms a groove 990. The state of the formation of the groove 990 becomes Generally regarded as the ideal condition of a grooved thread, any further deformation, such as a further displacement of the material so that the groove 990 closes, deteriorates the properties of the thread.

However, the methods of threading into through holes made by flow drilling are not limited to furrows. Rather, thread cutters can also be used, provided the material temperature permits such a process.

Furthermore, the method of thread milling is known, in which the tool (the thread milling cutter) has a geometry similar to a tap, but the outer diameter of the tool is smaller than the inner diameter of the hole to be machined and not a helical over the length of the Grooves extending thread part, but a plurality of circumferential grooves are formed on the outer surface of the tool. FIGS. 13 and 14 each show the threaded part of a tap and a thread milling cutter in a side view, and FIG. 15 shows a process sequence for thread milling. These figures are taken from the company brochure no. 111 905/0145-IX-06 "Solid carbide thread milling cutter" from the company Gühring oHG or representations based on them. This application makes full reference to this brochure, in particular with regard to details of the technology of thread milling. As shown in Figure G, when thread milling, the milling cutter is inserted axially into a hole, moved radially to the hole wall with the tool already rotating, and then the tool is guided in a complete circular arc, the outer contour of the tool describing the core diameter of the thread and the feed rate is selected so that the tool advances by exactly one thread pitch when the circular arc is completed. Finally it will

Tool moved radially away from the ^'wall and axially from the bore. It goes without saying that the special kinematics of the process require a specially equipped machine tool.

A technology related to thread grooving uses the kinematics of thread milling and combines this with the principle of thread grooving. A tool with a geometry similar to that of a thread cutter is used, in which, as with the thread milling cutter, the

Thread grooves are not helical, but are formed in the circumferential direction and the cross section of the threaded part has a polygonal cross section with several pressure studs. If the tool is now passed through the machine in a circular manner as with thread milling, the thread is not cut by cutting, but, as with thread grooving, formed by plastic deformation of the material, in that the press studs "hammer" the contour of the thread into the material, so to speak. This type of thread formation, which is called "chipless thread MiHing" or "circular thread grooves", is the subject of the German patent application No. 103 18 203.9 of the applicant of the present invention. The above description makes it clear that for the formation of high-quality and heavy-duty threads, especially in thin-walled workpieces, it is very important to match the thread-forming operation as precisely as possible to the previously drilled hole. So far, this has only been possible by using different tools sequentially, the geometry of which must be selected and put together by specialist personnel and positioned separately in the manufacturing process. It has been shown that this often results in the desired

The quality of the thread in terms of accuracy and strength could not be achieved.

The invention is therefore based on the object to provide a particularly economical method and a corresponding device for producing high-quality threads in workpieces, in particular of low material thickness, with or with which it is possible to significantly increase the accuracy and quality of the thread to be produced.

The object is solved by the features of the independent claims. Preferred embodiments and advantageous further developments of the invention form the subject of the subclaims. According to a first aspect of the present invention, a method for producing a thread in a workpiece, preferably of thin material, has the steps of claim 1.

According to the invention, the tool for producing the “bushing” in the thin-walled workpiece is combined with the thread forming tool by the so-called flow form drilling method. This eliminates not only machine sub-steps, but also sources of error when selecting the tool and when positioning the tools. This is because the tool modified according to the invention already has an optimally coordinated geometry of the different tool functional sections, with the additional advantage that these functional sections, i. Bore widening section and thread forming section are automatically centered exactly to one another. This alone improves the quality of the thread in a simplified process.

In addition, the method according to the invention can advantageously utilize the plasticized state of the material, because the thread formation section engages in the freshly formed hole with little delay. This can be used to significantly increase the processing speed without compromising on quality. By forming the thread with the same tool as that for forming the through hole by flow molding, the process steps and the number of tools required are thus reduced, and even the flow properties of the heated material can be advantageously used if required. The process step of forming the thread can be carried out using all techniques known hitherto, such as, for example, furrowing, circular furrowing, cutting or milling, the tool geometries described in the introduction to the description essentially being able to be retained. A modification of the thread formation sections in comparison to the conventional formation can, however, result from the fact that the thread is introduced into a possibly still plastic material. In this case, for example, a thread forming section can cause a larger material displacement in comparison to the conventional geometry of a thread former. It has been shown that by simple geometric coordination of the two main functional sections of the tool according to the invention, ie the bore insertion section and the

Thread formation section, the process flow can be controlled so that the workpiece temperature is optimally adapted to the needs of the respective process step.

When using a thread taper, which engages in a through hole made by previous flow drilling, the condition of the material to be machined can be used particularly advantageously to increase the economy of the manufacturing process.

The heating and displacement steps are preferably carried out at a first speed and a first feed rate which are adapted to the melting temperature and the flow behavior of the material of the workpiece, while the step of forming a thread at a second speed and a second feed rate are carried out, which are additionally adapted to the pitch of the thread. The method can further comprise a step of shaping the edge of the hole with the same tool, in particular by milling or countersinking, and a step of removing the tool from the borehole. The step of forming the hole rim may include a step of controlling the axial force of the tool.

Finally, the method can have a step of setting the tool and workpiece temperature in all steps. The step of setting the temperature can comprise the steps of adjusting the rotational speed and / or adjusting the feed rate and / or cooling the tool. The temperature setting can be adjusted so that the optimum tool and workpiece temperature is achieved for the respective process step.

The above object is achieved according to a second aspect of the present invention by a rotary tool according to claim 16. With such a tool, the method of the first

Aspect of the present invention can be carried out without a tool change or a repositioning of the workpiece and / or the tool is required. When setting the optimal machine parameters to be determined empirically, such as speed and feed, there are automatically the cheapest

Tool engagement conditions with exact positioning of the tool functional sections, so that the Tool not only works extremely economically, but also with previously unattainable quality.

The friction and shaping section preferably has a friction concentration section at its tip and a widening section adjoining it. The friction concentration section can be designed as a centering tip or also spherical, in particular with the design in the form of a centering tip it is possible to drill into the solid material with high precision.

The expansion section can have a conical shape. The cone angle is preferably between 10 ° and 60 °, in particular between 10 ° and 30 °, in a particularly preferred manner 20 ° +/- 5 °. It has been shown that the cone angle when machining steel sheet should advantageously be varied in this area and delivers the best results with regard to the expansion function. The cone of the expansion section can be convex or concave to allow adaptation to the particular flow properties of the material to be processed and to control the displacement speed and direction.

The friction and molding section can furthermore have a cylindrical molding which adjoins the widening section. The cylindrical molded part can have an essentially cylindrical shape. The length of the shaped cylinder part can be used to control the state in which the thread formation section adjoining the friction and form section comes into engagement with regard to the shape, smoothness and temperature of the through hole. The diameter of the cylindrical molded part or the largest diameter of the expansion section is preferably adapted to the core diameter of the thread to be formed.

The special feature of the tool according to the invention is thus that the diameter of the cylindrical molded part or the largest diameter of the widening section corresponds to the inside diameter of the exit bore that is optimally adapted for the subsequent thread forming work step, such as when milling or cutting. This creates an optimal engagement situation for the subsequent thread formation section.

When the thread is cut or formed or pressed, the thread formation section of the tool has at least one groove with a substantially notch-shaped cross section which extends helically over the length of the thread formation section. The cross section is preferably of polygonal shape, which defines a plurality of pressure studs. The number of polygons is preferably between 4 and 12, particularly preferably between 4 and 8. With such a profile, the thread can be produced in the manner of a conventional thread tapping.

Lubrication grooves can be provided in the flanks of the plurality of pressure studs. So it is possible to

Apply lubricant that prevents material from depositing on the thread flanks.

The thread formation section can have a cylindrical contour in a main section and a conical shape in a start-up section arranged in front of it Have a contour. The angle of the outer contour in the run-up section can be between 1 ° and 12 °, preferably 6 ° +/- 2 °. The start-up section facilitates the formation of the thread shape in the workpiece.

A conical intermediate section can be provided upstream of the starting section or, if no starting section is provided, the main section. The cone angle of the intermediate section is preferably 60 ° +/- 10 °. The intermediate section serves on the one hand for easier access for a tool for forming the grooves in the thread forming section. On the other hand, the intermediate section can be designed such that the material of the workpiece is heated again by pressure and friction after passing through the cylinder forming section.

The thread formation portion may also have a circular cross section. This is possible if the heated material is still so flexible after the flow form drilling that it can be displaced without the flexing effect of the press studs. The geometry of the tool that is simplified in this way allows the tool to be manufactured more cheaply.

Alternatively, the thread formation section of the tool has a circular cross-sectional profile, one or more flutes that extend axially or helically over the length of the thread formation section and that have a cutting edge, and at least one groove that extends helically over the length of the thread formation section with a substantially notch-shaped cross section , With such a profile, the thread can be produced in the manner of a conventional thread cutter. As a further alternative, the thread forming portion of the tool has a circular cross-sectional profile of smaller diameter than that of the cylinder forming portion, one or more flutes that extend axially or helically along the length of the thread forming portion and that have a cutting edge and a plurality of circumferentially extending Grooves with a substantially notch-shaped cross-section. With such a profile, the thread can be produced in the manner of a conventional thread milling cutter.

Finally, the thread forming portion of the tool may have a polygonal cross-sectional profile of a smaller circumferential diameter than that of the cylinder forming portion, the polygonal cross-sectional profile defining a plurality of press studs, and a plurality of circumferentially extending grooves having a substantially notch-shaped cross-section. With such a tool, the thread can be produced using the circular groove method. The polygon number is preferably between 4 and 12, particularly preferably between 4 and 8.

The tool can also have one or more cooling channels for supplying a cooling medium. The temperature of the tool and thus also the temperature of the material to be machined can be controlled by supplying the cooling medium.

According to an advantageous development of the invention, the tool can be combined with a hole edge shaping device, advantageously according to claim 43. Thus, in addition to the formation of the thread, the top of the threaded hole can also be in the desired shape be designed with one and the same tool. The hole edge shaping device can be designed as a face mill, countersink, countersink or other form cutter.

The hole edge shaping device can connect to the thread formation section and can be formed in one piece with the tool or can be firmly connected to it. In this form, the hole edge shaping device is particularly suitable for use in connection with the tool forms of the thread milling cutter and the circular thread turret.

On the other hand, the tool can have a rotation locking device and the hole edge shaping device can have a separately designed hole edge shaping part with a rotation locking counterpart, which cooperates with the rotation locking device of the tool in such a way that a relative movement of the hole edge shaping part with respect to the tool is prevented in the direction of rotation, while a relative movement of the hole edge shaping part with respect to the tool in Axial direction is made possible. The hole edge shaping device can furthermore have a bearing part and a spring part, the bearing part being formed in one piece with the tool or preferably axially adjustable with it but being axially fixedly connectable and the spring part being arranged such that the hole edge forming device is resiliently supported against the bearing part. Due to the axial adjustability of the bearing part, the force exerted by the cutting edges can be controlled without running the risk of damaging the thread. This design therefore also has advantageous effects on the machine control system, because it enables the process of thread formation to be decoupled from the deburring process. The rotary locking device can be a flat radial flattening on the circumference of the tool, wherein the rotary locking counterpart can be formed by an adjusting element, preferably an adjusting screw, which is arranged in the perforated edge molded part and can be adjustable to a predetermined distance from the rotating locking device. Alternatively, the rotary locking device can be a pin protruding in the radial direction on at least one side from the circumference of the tool and the rotary locking counterpart can be a groove made on the hole edge molded part, which comes into engagement with the pin when the hole edge molded part is fitted onto the tool.

Advantageous developments of the bearing part are the subject of claims 46 and 47.

The tool preferably consists of a high-strength material, such as solid carbide. This material is able to withstand the high temperatures and mechanical loads that occur. For machining softer materials such as aluminum, copper, brass or plastic, the tool can also be made of a less resistant material such as HSS. Of course, other high-strength materials such as cermets, i.e. Sintered materials or ceramics are used.

The tool can also wear a wear protection layer and / or a soft material layer, in particular in the area of the threaded part. The applicant's coatings according to patent applications DE 102 12 383.7 and DE 103 47 981.3 are particularly effective layers and EP 03 006 383.8, to which express reference is made here and the disclosure of which is intended to be part of this application. According to a third aspect, the above-mentioned object is achieved by a device according to claim 54.

To illustrate the features, objects, mode of action and advantages of the present invention, the accompanying drawings show: in FIGS. 1A to 1E, a method according to the present invention with a tool according to a first preferred embodiment of the present invention; in Figure 2, the tool according to the first preferred embodiment of the present invention in an overall side view; in FIGS. 3A to 3C, components of a milling attachment arrangement for use on the tool from FIG. 2; in Figure 4 is a plan view of the component of Figure 3A in the direction of an arrow I in Figure 3A; 5 shows an enlargement of the front region of the tool from FIG. 2 with the milling attachment arrangement from FIGS. 3A to 3C in the assembled state; in Figure 6 the tool of the present invention according to a second embodiment thereof; in Figure 7 the tool of the present invention according to a third embodiment thereof; in Figures 8A to 8D a tool according to the prior art; FIG. 9 shows a method using the tool according to the prior art; in FIGS. 10A to IOC a cross-sectional profile and a longitudinal-sectional profile of a conventional thread cutter and a geometry of a thread produced with such a tool; in Figures ILA to LLC a cross-sectional profile and a longitudinal section profile of a conventional thread turret and a geometry of a thread produced with such a tool; in Figure 12 is a schematic representation of the

Thread forming process with a tool according to Figures ILA and 11B; in Figures 13 and 14, the threaded part of a conventional tap or a conventional thread mill, each in a side view; 15 shows steps of a known thread formation process with a conventional thread milling cutter.

Preferred embodiments of the present invention will be explained below with reference to the drawings. First, method steps of the method according to the invention are explained with reference to FIGS. 1A to 1E. It should be noted that in the figures 1A to 1E, reference numerals have been omitted for the sake of clarity. The reference numerals mentioned in this section refer to the tool shown in FIGS. 2 to 5.

A tool, such as the tool 100 shown in FIG. 2, which is already referred to at this point in advance, has a cone 144 with a friction tip 142, for example in the form of a centering tip, in a manner known per se rotated at a certain speed and placed on a workpiece to be machined at a certain feed rate. This state is shown in Figure 1A.

Pressure and, in particular, friction generate heat at the contact point, which heats the workpiece (and the tool) until the material of the workpiece begins to flow at this point and yields to the contact pressure of the tool 100. The tool 100 pierces the workpiece, the material of the workpiece being displaced downwards and outwards and to a lesser extent upwards and outwards. FIG. 1B shows the state in which the tip of the tool breaks down. The upper area of the resulting hole is already in engagement with a cylindrical part 146 of the tool 100, which adjoins the cone 144 in a manner known per se, while the lower area of the hole nestles around the cone 144 of the tool 100. In this state, the tool moves at a feed rate that can differ from the feed rate when the tool 100 is placed on. In the state shown in Figure IC, the formation of the cylindrical shape is also completed in the lower part of the hole. The upper region of the hole is now in engagement with a thread formation section 160 of the tool 100, as a result of which an internal thread is introduced into the hole in this region. With the start of thread forming, the speed of the tool and the feed rate are adapted to the thread pitch.

It should be noted that the thread is formed in the still warm material. Mechanical stresses on the tool are therefore reduced, even if there is a larger amount of material shift compared to conventional thread formers. However, the thermal load, especially on the fine tooth profile of the thread formation section 160, is comparatively high. It is therefore important to choose a suitable material for the tool, possibly combined with suitable cooling.

The principle of the functioning of the tool shown in FIG. 1 is not restricted to a specific type of thread production. If the thread formation section 160 functions as a thread turret or circular thread turret, a further displacement or expansion of the hole results in the thread forming process. By means of a short, conical extension 162 after the cylindrical section 146 and before the actual thread forming part 164, 166, "heating of the material by friction can be achieved once again.

Towards the end of the feed movement of the tool 100, a cutting or milling attachment 200 reaches the

Tool 100 fixed in the direction of rotation, but axially is flexibly attached, the upper edge of the hole or the material thrown outwards. (The storage of the milling attachment will be described in more detail later.) As a result, the milling attachment removes the upper edge of the hole. The resilience of the milling attachment in the axial direction is dimensioned such that material removal is possible, but the thread-forming part is not blocked in the thread which has just been formed and thereby destroys it. When the desired milling depth is reached (in the present case flat with the workpiece surface), both the feed and the rotary movement of the tool 100 end. The state just before the movement of the tool is ended is shown in FIG. 1D.

The rotation and feed movement is then reversed to remove the tool from the finished threaded hole, as shown in Figure 1E. It goes without saying that the speed and the feed rate in each phase of the process must be coordinated with a view to the highest possible production speed, optimal control of the flowability of the material of the workpiece and the properties of the tool used.

FIG. 2 shows a tool 100 according to a first preferred embodiment of the present invention.

It is a rotationally drivable tool 100 of elongated, essentially rotationally symmetrical

Shape.

A substantially cylindrical shaft part 120 is provided with a driver section 122. The driver section 122 is shown here as an outer square. However, the driver section can be different Take shapes, such as a plate, a slot, a hexagon, one or a plurality of longitudinal grooves, etc. A driver section can also be completely missing. The rear end can also be designed conically. The shaft part can also have a different cross section overall, such as a hexagonal cross section or the like.

Hereinafter, the shaft part 120 is to define the rear end of the tool in the axial direction thereof. The opposite axial end is thus defined as the front end of the tool.

The front end of the tool has a machining part that can be divided into a flow drilling part 140 and a thread forming part 160. The flow drilling portion 140 is also referred to as a friction and form section, and the thread forming portion 160 is also referred to as a thread forming portion.

The flow drilling portion 140 has a friction concentration portion 142, an expansion portion 144, and a cylindrical shape portion 146.

The friction concentration section 142, as shown in FIG. 2, is designed as a cylindrical grinding. The friction concentration portion 142 may also be a grain tip or other shape.

The expansion section 144, which is connected to the

Friction concentration section connects is a

Cone. A cone angle WK of 10 to 30 °, measured from the center line LM, has proven to be particularly advantageous for the currently preferred applications. exposed. The cone angle depends on the process parameters, in particular on the material to be processed. The general cone shape can also have a convex or concave curvature. The direction of curvature can also change in the course of the axial extension of the widening section. The displacement speed and direction can thus be controlled as a function of the diameter of the hole to be formed which has already been reached.

The expansion section 144 is followed by a cylindrical shape section 146. This section 146 is preferably of a substantially cylindrical contour. The smoothness of the hole wall and the material temperature during the transition into a thread-forming part 160 (see below) can be controlled via the length of the cylindrical shape section 146, since the deformation activity of the cylindrical shape section 146 is limited only to the smoothing of unevenness. The cylindrical shape portion 146 can also be completely absent, so that the

Expansion section passes directly into the thread forming part 160.

Instead of the cylindrical shape section 146, a second substantially conical expansion section with a smaller cone angle than that of the expansion section 144 can also be provided.

In the preferred embodiment, the widening section and the cylindrical shaped section have a circular cross section. However, depending on the material processed, it may be advantageous to provide a polygonal cross section according to the type of documents cited in the introduction to the description or similar. In any case, the largest circumferential diameter or the largest width of the friction and molding section 140 of the tool is optimally adapted to the core diameter of the thread to be formed.

The thread formation part 160 adjoins the flow drilling part 140. This first has a further conical intermediate section 162, a run-up section 164 and a cylindrical main section 166. The run-up portion 164 and the main portion 166 are collectively referred to as the threaded portion of the tool.

The cone angle WKZ of the intermediate section 162 (see FIG. 5) is preferably between 40 and 80 °. The intermediate section 162 serves to protect the first gear of the threaded part. In addition, the intermediate section 162 can also take over the task of widening the hole cross section again and bring about a renewed heating and increasing the flowability of the material.

The run-up section 164 and the main section 166 form the actual thread forming part of the tool 100 and are with a thread forming profile with a geometry known per se. At this point, reference is expressly made to the explanation of how a thread tapping works in the introductory part of this application and in the company brochure No. 300 087/02123-VIII-15 of Gühring oHG. In particular, the threaded part can have a polygonal cross section, wherein lubrication grooves can be made in the side surfaces of the polygon. The number of polygons can start at 4 for threads of the order of M4 or M6 and grow with the thread diameter. However, the cross section of the threaded part can also be circular if the fluidity of the processed material allows it. ^'' In particular with small thread diameters, a polygonal cross-section can be dispensed with anyway.

As an alternative to the designs of the tool shown in FIGS. 2 and 5, the section 146 can also be followed directly by the thread forming section 166 with a substantially constant outer diameter, which is tapered in a transition region (for example from one to three threads).

The tool 100 of the preferred embodiment is also provided with a flattening 180 in the transition area to the shaft part 120. This flattening 180 serves as a counter bearing for an adjusting screw in a component 220, which is described below with reference to FIGS. 3A to 3C and FIG. 4. In FIGS. 3A to 3C, the components of a milling attachment arrangement 200, which is shown in FIG. 5 when assembled with the tool 100, are shown individually.

FIG. 3A shows in longitudinal section a milling attachment 220 which is designed as an essentially rotationally symmetrical component and has an axial through hole 228. An end face carries at least one cutting edge.

For example, in an end face of the

Milling attachment 220 arranged a plurality of cutting jaws 222. The cutting jaws 222 have cutting edges

222a, as in the plan view shown in FIG

Direction of an arrow I shown in Figure 3A. The

Through hole 228 is in its inner diameter at the

Adjusted the outer diameter of the threaded part so that the milling attachment can be pushed onto the threaded part easily, but not with too much play. In a A set screw 230 is arranged in the threaded bore, which extends radially through a flank of the milling attachment 220. If the threaded attachment 220 is now pushed onto the tool 100 until it is in the area of the flattening 180, the adjusting screw 230 is screwed in so far that it protrudes into the bore 228 and is easily placed on the flat surface of the flattening 180. As a result, the milling attachment is axially displaceable, but is secured in the direction of rotation relative to the tool 100. The milling attachment 220 can also have means (not shown) for securing the set screw.

The milling attachment 220 has a groove 224 in the vicinity of the second end face, which is in line with the second

Front defined a collar 226. The groove 224 is provided for receiving a coil spring 240, which in

Figure 3B is shown. FIG. 3C shows a locking ring 260 which, in a manner analogous to the groove 224 in the milling attachment 220, has a groove 264 which defines a collar 266 with an end face of the locking ring 260. The same coil spring 240 is to be inserted in this groove 264 in order to connect the milling attachment 220 to the locking ring 260 via the coil spring 240. Furthermore, a locking screw 270 is arranged in a threaded hole which extends in the radial direction through a flank of the locking ring 260.

FIG. 5 shows the entire milling attachment arrangement 200 consisting of the milling attachment 220, the set screw 240, the helical spring 240, the locking ring 260 and the locking screw 270, together with the tool 100. As can be seen in FIG. 5, the entire milling attachment arrangement 200 is above the tool 100 pushed that the milling attachment 220 comes to rest even in the area of the flattening 180 so that the latter is opposite the adjusting screw 230. The adjusting screw 230 is screwed in so far that it comes to rest loosely on the flattening 180, as a result of which the milling attachment is secured against twisting, but is just slightly axially displaceable. Held at a distance from the milling attachment 220 by the helical spring 240, the locking ring 260 comes to rest in the region of the shaft part 120 and is fixed with the aid of the locking screw 270. Thus, the milling attachment 220 is resiliently supported on the locking ring 260 and thus on the tool 100 itself via the helical spring 240. It is understood that the locking ring can also be formed in one piece as a bearing section (not shown) of the tool.

The resilient mounting of the milling attachment 220 is necessary in order to be able to implement shaping of the hole edge in one operation with the flow form drilling and the thread production process. If the milling attachment were firmly connected to the tool 100 or were made in one piece with it, an axial force would arise between the milling attachment and the thread former, which would block the forward movement of the tool and ultimately tear the thread. Due to the resilient mounting, however, the axial force can be absorbed and the milling attachment can still exert its cutting effect in order to design the edge of the hole.

It goes without saying that the spring force of the

So spring on the material to be machined

Process parameters Speed, feed speed and workpiece temperature must be coordinated so that the milling attachment experiences a sufficiently large axial force to perform its task can meet, but this axial force is not so great that the integrity of the thread is jeopardized. For this purpose, the control of the machine can also include coupling the axial force.

FIG. 6 shows a second embodiment of the present invention with a tool 500. The tool has a shaft section 520 and a friction and shaping section 540 similar to the tool 100. In contrast, the thread formation section 560, however, is implemented in its main section 566 in the form of a thread cutter. The flutes 568 can be clearly seen in FIG. Furthermore, a variant is shown in FIG. 6, which can also be used for the first embodiment. No flattening is provided on the tool 500 of this embodiment. Instead, a pin 585 extends in the region of the shaft part 520 in the radial direction through the tool 500. This pin 585 comes into engagement with two longitudinal grooves which extend in an inner bore of a milling attachment (not shown) which is modified from the illustration in FIG. 3A. The interaction of the pin 585 with these longitudinal grooves realizes the rotation of the milling attachment on the tool 500, but allows an axial displacement. Such a modified milling attachment would have no threaded hole, and thus the set screw in the milling attachment arrangement can be dispensed with. As a result, the difficult, mostly manual adjustment of the screw-in depth of the adjusting screw 230 from FIGS. 3A and 5 can be omitted, which contributes to the economy and safety of the tool and the method. If necessary, the length of the modified milling attachment must be adjusted. The rest of the milling attachment arrangement with the Coil spring 240 and the locking ring 260 remains essentially unchanged.

FIG. 7 shows a third embodiment of the present invention with a tool 300. In the tool 300, the thread formation part 360 is designed as a circular groove. To illustrate the principle and the design options of a circular furrow, reference is made here to the statements in the introductory part of this application and to the German patent application DE 103 18 203.9 of the applicant of the present application cited there. It can clearly be seen in FIG. 7 that the threaded part 366 of the thread forming section 360 is designed in the form of circumferential grooves. Furthermore, the cross section of the threaded part is designed as a polygon in a known manner. The characteristic of the thread formation corresponds essentially to that of thread milling, as shown in FIG. 15.

In order to have sufficient space for the circular guidance of the tool after the through-hole has been formed with the aid of the friction and molding section 340, the circumferential diameter of the threaded part 366 is smaller than the largest diameter of the friction and molding part 340. Furthermore, FIG. that the thread forming part 360 is offset from the cylinder forming section 346 via a chamfer 348, which later serves to make it easier to execute the tool from the finished threaded hole, and an intermediate section 362.

A further variant is shown in FIG. 7, which can be used for the present embodiment and for a further embodiment described below. It is clear that if, in the case of Embodiment according to FIG. 7, the thread is finished and the tool 300 has been placed in the center, the thread no longer has to be taken into account as in the case of the first and second embodiment, since the threaded part 366 is no longer in engagement with the material of the Workpiece is located. A resilient mounting of a possible element for processing the edge of the hole is therefore unnecessary. In the case of the tool 300, the shaft part has a transition section 326 directly following the thread formation part 360, which has a diameter of at most the circumferential diameter of the main section 366. This is followed by a perforated section 324, which has a plurality of cutting elements 324a in its lower end face. In this way, a face milling element is realized, which allows the edge of the threaded hole to be plated or deburred after the thread has been formed. The hole edge forming portion 324 is included

Tool receiving section 328, the diameter of which is adapted to a tool holder.

Instead of the hole edge shaping section 324, a separate milling attachment can also be used, which is fixed in the area of the shaft part 320. In this case, it is advantageous if the entire shaft part 320 has a diameter which does not exceed the circumferential outer diameter of the main section 366 of the thread forming part 366.

A fourth embodiment of the present invention will now be explained without being shown in a figure. This fourth embodiment differs from the third embodiment in that

Thread formation section 360 the profile of a conventional thread milling cutter. With regard to the operating principle of thread milling, reference is made here to the explanations in the introductory part of this application and to the company catalog No. 111 905/0145-IX-06 "Solid carbide thread milling cutter" from Guhring oHG, already cited there. The other configuration of the tool follows the third embodiment.

In addition, further modifications that are apparent to the person skilled in the art will be apparent

Boundary conditions such as material, machine environment, clamping conditions etc. result.

In the process, the edge of the threaded hole was deburred or clad with the help of an end mill. It is understood that such an operation is optional. There may be applications in which no deburring or plating of the threaded hole is required. In such a case, the tool is used without the milling attachment or a tool without a shaped section is used, and the edge of the hole is retained.

Of course, besides plating, other finishing of the hole edge is also possible, such as a conical or cylindrical depression. The latter may be necessary for pipes with an uneven outer contour in order to provide a corresponding contact surface for a screw or nut, for example.

It is also understood that cooling channels and / or lubricant channels (not shown) are provided in the tools described above for controlling the temperature profile and the material behavior, as required. The supply of threading tools with cooling and lubrication channels is well known in the art and can For example, the company brochures of Guhring oHG mentioned above can be found. In the tools of the present invention, cooling channels in particular can also extend into the area of the friction and molded part, in order, for example, to achieve rapid cooling before a subsequent machining thread forming process, where this is necessary. The following tool was developed and tested for the machining of thin steel sheet with a wall thickness of 3 mm: Solid carbide tool in the design according to Fig. 5 with threaded molded part for forming a M8 6HX thread. The threaded molded part with nine threads and the number of polygons 4 passes over a cone with a cone angle of 60 ° into a cylindrical section (146) with an axial length of 3 mm. On this

Section includes a conical

Expansion section (144) of variable length from 3 to 8 mm, with a centering tip with a maximum diameter of 2 mm.

List of reference numbers

100 tool according to the first embodiment 120 shaft part

122 driver section

140 flow drilling or friction and molded part

142 friction concentration section

144 expansion section 146 cylindrical molding section

160 thread forming part or section

162 intermediate section

164 startup section

166 main section 180 flattening

200 milling attachment arrangement

220 milling attachment

222 cutting jaws

222a cutting edge 224 groove

226 collar

228 hole

230 screw

240 coil spring 260 locking element

264 groove

266 collar

268 bore

270 screw 300 tool according to the third embodiment

320 shaft part

324 hole edge molding section

324a cutting element

326 transition section 328 tool receiving section

340 flow molded part or friction and molded part 346 cylinder molding section

348 chamfer

360 thread forming part or section

362 intermediate portion 366 main portion of the thread forming part

500 tools according to the second embodiment

520 shaft part

540 flow molded part or friction and molded part

560 thread forming part or section 566 thread part

568 flute

585 pen

900 workpiece

905 eye 910 flow form drill according to the prior art

920 thread formers according to the state of the art

950 thread taps according to the state of the art

952 flute

954 cutting studs 954a cutting edge

956 outer diameter line

958 gate line

960 workpiece

962 tooth groove 964 tooth flank

966 transition from tooth flank to tooth base

970 thread taps according to the state of the art

972 press studs

972a first tooth or thread 972b second tooth or thread

972c third tooth or thread

974 grease groove

976 outer diameter line 978 stop line 980 workpiece

982 tooth groove 984 tooth flank

986 transition point from tooth flank to tooth base

990 furrow

Claims

Expectations

1. A process for the preparation of a ^'thread in a workpiece, preferably thinner material thickness comprising the steps of: substantially continuous heating of an area of the workpiece by frictional contact with a rotationally drivable tool (100; 300; 500); Displacing the heated material in the radial and axial direction by the tool; and

Form a thread in an eye created by the displacement of the material using the same tool.

2. The method according to claim 1, characterized in that the step of forming the thread comprises a step of thread grooving.

3. The method according to claim 1, characterized in that the step of forming the thread comprises a step of a circular thread grooving.

4. The method according to claim 1, characterized in that the step of forming the thread comprises a step of tapping.

5. The method according to claim 1, characterized in that the step of forming the thread comprises a step of thread milling.

6. The method according to any one of the preceding claims, characterized in that the steps of heating and displacing are carried out at a first speed and a first feed rate, which are adapted to the melting temperature and / or the flow behavior of the material of the workpiece, and the step of forming a thread with a second speed and a second feed speed are carried out, which are additionally adapted to the pitch of the thread.

7. The method according to any one of the preceding claims, further characterized by a step of forming the edge of the hole with the same tool, in particular by milling or countersinking.

8. The method according to claim 7, characterized in that the step of forming the edge of the hole is carried out during the step of forming the thread.

9. The method according to claim 8, characterized in that the step of forming the edge of the hole includes a step of controlling the axial force of the tool.

10. The method according to claim 7, characterized in that the step of forming the edge of the hole is carried out after the step of forming the thread.

11. The method according to any one of the preceding claims, further characterized by a step of removing the tool from the threaded hole.

12. The method according to any one of the preceding claims, characterized in that the step of removing the tool from the threaded hole is carried out at a third speed, the direction of which is opposite to that of the second speed.

13. The method according to any one of the preceding claims, further characterized by a step of grading the tool and workpiece temperature.

14. The method according to claim 13, characterized in that the step of adjusting the temperature comprises the steps of adjusting the speed and / or adjusting the feed rate and / or cooling the tool.

15. The method according to any one of claims 13 or 14, characterized in that the step of setting the temperature sets the optimum tool and workpiece temperature depending on the respective process step.

16. Tool (100; 300; 500) for producing a thread in a workpiece, preferably of thin material, the tool being drivable in rotation and comprising: a shaft section (120; 320; 520) provided in the region of a rear end; a friction and molding section (140; 340; 540) provided in the region of a front end; and an adjoining thread formation section (160; 360; 560).

17. Tool according to claim 16, characterized in that the friction and molding section (140; 340; 540) has a friction concentration section (142) at its tip and an adjoining expansion section (144).

18. Tool according to claim 17, characterized in that the friction concentration section (142) is designed as a centering tip.

19. Tool according to claim 17, characterized in that the friction concentration section (142) is spherical.

20. Tool according to claim 17, characterized in that the widening section (144) has a conical shape.

21. Tool according to claim 20, characterized in that the cone angle of the widening section (144) is between 10 ° and 60 °, in particular between 10 ° and 30 °, preferably at 20 ° +/- 5 °.

22. Tool according to claim 20 or 21, characterized in that the cone of the expansion section (144) is convexly curved.

23. Tool according to claim 20 or 21, characterized in that the cone of the widening section (144) is concavely curved.

24. Tool according to claim 20 or 21, characterized in that the cone of the expansion section (144) has one or more convex and / or concave curved sections.

25. Tool according to one of claims 17 to 24, characterized in that the friction and molding section (140; 340; 540) has at least one second expansion section with a smaller cone angle than that of the first expansion section (144).

26. Tool according to one of claims 16 to 25, characterized in that the friction and molding section (140; 340; 540) has a cylindrical molded part (146) which adjoins the widening section (144).

27. Tool according to claim 26, characterized in that the cylindrical molded part (146) has a substantially cylindrical shape.

28. Tool according to one of claims 16 to 28, characterized in that the friction and shaping section (140; 340; 540) has a substantially circular cross section.

29. Tool according to one of claims 16 to 28, characterized in that the friction and shaping section (140; 340; 540) at least in one section. section has a cross section that follows an essentially polygonal line, the polygon number between 3 and 12, preferably between 4 and 8.

30. Tool according to claim 29, characterized in that the polygonal line has substantially convex sides.

31. Tool according to claim 29 or 30, characterized in that the tips of the polygonal line are rounded.

32. Tool according to claim 31, characterized in that the rounding of the tips of the polygonal line passes smoothly into the sides of the polygonal line.

33. Tool according to one of claims 16 to 32, characterized in that the largest diameter of the friction and forming section (140; 340; 540) is adapted to the core diameter of the thread to be formed.

34. Tool according to one of claims 16 to 33, characterized in that the thread formation section (160; 360; 560) of the tool has at least one groove which extends helically over the length of the thread formation section (160; 360; 560) and has a substantially notch-shaped groove Has cross-section

35. Tool according to claim 34, characterized in that the thread formation section (160; 360; 560) in a main section (166; 366; 566) has a cylindrical shape and in a start-up arranged in front of it section (164) has a conical shape, the helical groove continuing in the run-up section and the cone angle of the run-up section (164) preferably being between 1 ° and 12 °, particularly preferably 6 ° +/- 2 °.

36. Tool according to claim 34 or 35, characterized in that a conical intermediate section (162) is provided upstream of the starting section (164) or, if no starting section is provided, the main section (166), the cone angle of the intermediate section preferably Is 60 ° +/- 10 °.

37. Tool according to one of claims 34 to 36, characterized in that the thread formation section (160; 360; 560) has a circular cross section.

38. Tool according to one of claims 34 to 36, characterized in that the cross section of the thread formation section (160; 360; 560) follows an essentially polygonal line which defines a plurality of press studs, the number of polygons preferably between 4 and 12 , is particularly preferably between 4 and 8.

39. Tool according to claim 38, characterized in that lubrication grooves are provided in the flanks of the pressure tunnels, wherein lubricant channels are preferably arranged in the interior of the tool, which open in at least one, preferably all, of the lubrication grooves.

40. Tool according to claim 34, characterized in that the thread formation section (160; 360; 560) of the tool has a circular cross section and one or more flutes (568) which are

5 extend axially or helically over the length of the thread formation section and which have a cutting edge.

41. Tool according to one of claims 34 to 40, characterized in that the largest circumferential diameter of the thread formation section (160; 360; 560) is smaller than the largest circumferential diameter of the friction and shaping section (140; 340; 540).

42. Tool according to claim 41, further characterized by a hole edge forming device (324) which 5 adjoins the thread formation section (160; 360; 560) and is formed in one piece with the tool or is firmly but releasably connected to it, for forming the edge of one threaded hole made with the tool.

'0 43. Tool according to one of claims 16 to 39, further characterized by a hole edge forming device (200) for forming the edge of a threaded hole produced with the aid of the tool, the tool further comprising a rotation locking device 5 (180; 585) and the hole edge forming device ( 200) a separately designed perforated edge shaping part (220) with a rotational locking counterpart (230) which interacts with the rotational locking device of the tool in such a way that relative movement of the perforated edge shaping part (220) with respect to the tool in the direction of rotation is prevented, while a relative movement of the perforated edge shaping part (220) against - Above the tool in the axial direction is made possible to have a bearing part (260), which is formed in one piece with the tool or is fixedly but releasably connected to it, and a spring part (240), the hole edge forming part (220) springing in the axial direction via the spring part (240) against the bearing part (260).

44. Tool according to claim 43, characterized in that the rotation locking device is a flat radial flattening (180) in the circumference of the tool and the rotation locking counterpart is an adjusting element, preferably an adjusting screw (230), which is in the hole edge forming part (220) is arranged and can be set to a predetermined distance from the flattening (180).

45. Tool according to claim 43, characterized in that the rotary locking device is a pin (585) protruding in the radial direction on at least one side from the circumference of the tool and the rotary locking counterpart is a groove made on the perforated edge molding, which when the perforated edge molding part is plugged onto the Tool engages with the pin (585).

46. Tool according to one of claims 43 to 45, characterized in that the bearing part is a locking ring (260) with a locking element, in particular a locking screw (270), and the spring part is one between the bearing part (260) and the hole edge forming part (220) is arranged coil spring (240).

47. Tool according to claim 46, characterized in that the bearing part (260) and the perforated edge shaping part (220) are designed such that the helical spring (240) is held there both in the pushing and pulling directions, preferably by a respective groove ( 224, 264) into which the screws eder (240) are locked.

48. Tool according to one of claims 42 to 47, characterized in that a machining part of the hole edge shaping device (200; 524) is designed as a face milling cutter, countersink, countersink or milling cutter.

49. Tool according to one of claims 16 to 48, further characterized by one or more cooling channels for supplying a cooling medium, which extend at least in the region of the thread formation section (160; 360; 560).

50. Tool according to claim 49, characterized in that the cooling channels extend into the area of the friction and molded part (140; 340; 560), preferably at least in the area of a cylinder forming section (146) thereof.

51. Tool according to one of claims 16 to 50, characterized in that the tool consists of solid carbide.

52. Tool according to one of claims 16 to 50, characterized in that the tool consists of steel, in particular tool steel, particularly preferably HSS.

53. Tool according to one of claims 16 to 51, further characterized by a wear protection layer and / or a soft material layer, in particular in the region of the threaded part.

54. Device for producing a thread in a workpiece, preferably of thin material, which has: a tool holder for receiving a rotatable tool (100; 300; 500); a drive unit for driving the tool (100; 300; 500) accommodated in the tool holder in the direction of rotation and feed direction; and a control unit for performing the steps of the method according to one of claims 1 to 13.