EP1597020B1 - Cylindrical grinding method for producing hard metal tools and cylindrical grinding machine for grinding cylindrical starting bodies during the production of hard metal tools - Google Patents

Abstract

A grinding method and to a cylindrical grinding machine grinds metal rod that is pushed through a chuck of a workpiece spindle head. Two backrest seats are ground on and two backrests are then seated. The support of an end area enables a front cone to be ground. A grinding wheel comprised of two different individual wheels serves to grind the front cone and is advanced toward the round rod in the X-direction. The front cone is lodged in a hollow punch at a front end of a quill by displacement of the quill. The desired cylindrical grinding a final contour of the end area is done. Working the rod is done with a single chucking and the end area is cut off from the round rod by one of the individual wheels.

Description

The invention relates to a method for cylindrical grinding in the production of carbide tools on a cylindrical grinding machine, which has a workpiece headstock and a tailstock, starting from a round rod consisting of hard metal as starting material, according to the preamble of claim 1.

According to the state of the art known from industrial practice, one generally starts from round rods of sintered hard metal. These rods then have a Schleifäufmaß for the shaft area and are cut to the required tool length, or the starting body are brought in their entire length by centerless grinding, the so-called centerless grinding on the required shank dimension and then cut to length. From the individual cut to length rod pieces, the tool is then made by grinding from the full. For this purpose, the carbide tools are taken during grinding between hollow grains, tips or in a chuck. Grinding takes place either by conventional grinding or peeling grinding using diamond grinding wheels. In any case, a repeated Umspannen is required because first the individual pieces of bars by grinding and cutting, possibly in reverse order, are prepared and then in subsequent grinding operations, which take place on other machines, the grinding out of the tool contours and the cutting, gradations, spiral grooves and the like takes place.

The known methods of the prior art work satisfactorily, but bring with them the risk of concentricity errors. These errors are mainly due to the repeated reloading. Even when working with great effort in terms of precision, such concentricity errors are not always avoid. They are quite uncomfortable on the finished tool. This is especially true for high-speed machining, for example in aircraft construction. It works with milling tools that operate at speeds of 30,000 to 60,000 revolutions per minute. In the processing of the widely used in aircraft light metal parts makes even the smallest concentricity error on the tool very disturbing.

The invention is therefore based on the object to improve the known from the prior art method in the direction that concentricity errors at comparable manufacturing costs are avoided with certainty.

• a) Einspannen des Rundstabes, dessen Länge ein Vielfaches der Länge eines einzelnen Werkzeugs beträgt, in ein Spannfutter des Werkstückspindelstocks, das bei gelöstem Spannfutter ein axiales Verschieben des Rundstabes ermöglicht, wobei ein aus dem Werkstückspindelstock herausragender Endbereich des Rundstabes dem Reitstock zugewandt ist;
• b) Anschleifen mindestens eines Lünettensitzes an dem aus dem Werkstückspindelstock herausragenden Endbereich des Rundstabes und Anstellen der Lünette an den Lünettensitz;
• c) Anschleifen eines ersten Stirnkonus an die dem Reitstock zugewandte Stirnfläche des Rundstabes;
• d) Festspannendes Ineinanderfahren des ersten Stirnkonus mit einem Hohlkömer, der sich an einer Pinole des Reitstockes befindet;
• e) Rundschleifen des aus dem Werkstückspindelstock herausragenden Endbereiches des Rundstabes über etwa die dem einzelnen Werkzeug entsprechende Gesamtlänge bis auf dessen Rundschleif-Endkontur;
• f) Abstechen des insoweit fertiggeschliffenen einzelnen Werkzeugs von dem Rundstab;
• g) Lösen des bis dahin gespannt gebliebenen Spannfutters des Werkstückspindelstocks, Verschieben des Rundstabes in dem Werkstückspindelstock in Richtung auf den Reitstock und anschließendes Spannen des Spannfutters, wobei ein weiterer zu bearbeitender Endbereich des Rundstabes aus dem Werkstückspindelstock herausragt.

The solution of this object is achieved according to the characterizing part of claim 1 by the following method steps:

• a) clamping the round rod, the length of which is a multiple of the length of a single tool, in a chuck of the workpiece spindle, which allows an axial displacement of the round rod with dissolved chuck, with an outstanding from the workpiece headstock end of the round rod faces the tailstock;
• b) grinding at least one steady rest seat on the end region of the round rod protruding from the workpiece headstock and adjusting the steady rest against the steady rest seat;
• c) grinding a first end cone to the tailstock facing end face of the round rod;
• d) clamping the first end cone with a hollow body, which is located on a quill of the tailstock;
• e) cylindrical grinding of the projecting from the workpiece head end portion of the round rod over about the individual tool corresponding total length up to the round grinding end contour;
• f) parting of the so far fertiggeschliffenen individual tool from the round rod;
• g) releasing the hitherto tightened chuck of the workpiece headstock, moving the round rod in the workpiece headstock in the direction of the tailstock and then tightening the chuck, with another end region of the round rod to be machined protruding from the workpiece headstock.

The process of the invention thus "worked from the running rod". For this purpose, consisting of sintered carbide round rod, which may for example have a length of 300 to 400 mm, gradually pushed through the chuck of the workpiece spindle stock and tightened in each case when a certain, the length of the tool to be produced approximately corresponding end portion of the round rod from the workpiece headstock protrudes and faces the tailstock. The special feature of the method according to the invention is that the outstanding end portion, while it is still connected to the rest of the round rod, is ground to its round grinding final contour. The round grinding end contour of the carbide tool to be produced is that contour of the finished tool that is to be produced by cylindrical grinding. Then you have to cut, spiral grooves and The like can be incorporated in subsequent processes in the tool. Since the protruding from the workpiece headstock end can have a considerable length depending on the tool, it is necessary to clamp it at its free end, which in turn requires a contour of high accuracy. For this reason, in the method according to the invention, at least one steady rest seat is first ground to the freely protruding end region. If the end region is then supported on one or more steady rests by means of the at least one steady rest seat, the grinding of a first end cone onto the end face of the round rod or its end region facing the tailstock can be carried out with the required accuracy. The front cone is then screwed together with a hollow grains on a sleeve of the tailstock. The end region is now clamped at its two ends, without loosening the first clamping in the workpiece headstock was required. Now, the cylindrical grinding can be made to the already explained round grinding final contour with the required accuracy.

Subsequently, the so far finished finished single tool is tapped by the round rod; the hitherto taut chuck of the workpiece headstock is released and the round rod is advanced in the loosened chuck a bit further towards the tailstock, with another end portion of the round rod to be machined protruding from the workpiece headstock.

As used herein, the provision of a "single tool finished to size" means something other than finish grinding in the sense of sizing as opposed to roughing. It also does not mean that the carbide tool to be produced must already be ready for use. Rather, the term of finish grinding here only means that the resulting carbide tool in its first Clamping is finished out as far as the task is by cylindrical grinding, just up to its desired round grinding final contour.

The advantages of the method according to the invention are, above all, that multiple clamping is avoided. Thus, Umspannfehler be avoided, and there are best concentricity results and shape and position tolerances in relation to the shaft and the cutting part. Despite the higher acquisition costs of the cylindrical grinding machine, the costs for the individual workpiece are reduced because the resulting tool is processed in a single machine from raw to semi-finished part or finished part. Furthermore, the throughput times are reduced, and it can be reacted very quickly to the order of a specific carbide tool, because the desired end portions can be tapped in different lengths of the round rod. Thus, finally, the storage of semi-finished products can be reduced because flexible and can be made quickly.

An advantageous development of the method according to the invention is that during the cylindrical grinding of the projecting from the workpiece headstock end portion of the round rod, the bezel is moved back from the steady seat. Above all, the steady rest serves to grind the clamping end of the round rod projecting from the workpiece headstock with the greatest possible accuracy toward the tailstock. By contrast, the grinding of the tool contour can be done without additional support by steady rests. As a result, the machining process is simplified, and it can be easily achieved a perfect surface of the round grinding end contour.

With high demands on the accuracy of even thin rods can be axially spaced at the end of the round rod two lunette seats be sanded. In many cases, ie with shorter carbide tools, but a single Lünettensitz will be sufficient.

A further advantageous embodiment of the method according to the invention is that the protruding from the workpiece headstock end portion of the round rod is separated after the cylindrical grinding of the remaining round rod by using a single grinding wheel first finished with a rotating round rod a second end cone to the workpiece headstock facing end surface of the extent Tool is ground, then after moving back and axial displacement of the grinding wheel relative to the round rod attached only a central connecting collar leaving separating cut and finally after stopping the rotation of the round rod of the separation process is completed by grinding away of the connection collar.

In this procedure, the outstanding end of the round rod remains connected to the last possible time with the rest of the round rod, namely via the central connection collar. Thus, until the last two-sided clamping of the end without re-tightening guaranteed, and the processing accuracy is further improved without additional effort. Furthermore, as long as possible be ground on the rotating rod, which is advantageous for the thermal load of the resulting tool.

In the final parting of the finished ground single tool then the tailstock and / or quill are returned from the resulting finished tool, and this is held by a gripper unit. After the end of the separation process, the gripper unit can remove and deposit the finished tool from the machine, thereby further increasing the cost-effectiveness of the method.

For the most important process of cylindrical grinding according to method step e) in claim 1, the known cylindrical grinding techniques can be used. Thus, the cylindrical grinding for producing the tool contour can be done with a narrow grinding wheel in the peel grinding process and / or with a wide grinding wheel in pendulum grinding process.

The inventive method can also be carried out in an almost manual approach as in a highly automated design. In the latter case, care should be taken to ensure that the last piece of bar to be machined is not clamped in the chuck of the workpiece headstock only with too little axial extent. In this case, errors can occur, which are due to a poor concentricity due to too short clamping length. Imperfect tightening can cause damage to the machine or even accidents unless the necessary care is taken. In order to prevent this, according to a further embodiment of the method according to the invention, the residual length of the round rod still available for pushing the round rod through the chuck of the workpiece headstock is checked at least for each clamping operation and when falling below a minimum residual length a signal is given and / or the Cylindrical grinding machine is stopped.

In this way, the greatest possible security of the procedure is guaranteed.

The invention also relates to a cylindrical grinding machine for grinding cylindrical starting bodies in the manufacture of tools made of hard metal, for carrying out the method according to one of claims 1 to 7.

According to claim 8, such a machine according to the invention is provided with a machine bed, with a movable on the machine bed grinding table on which a work headstock and a tailstock are arranged, with a chuck on the workpiece headstock, the axial pushing through a serving as a starting material round rod and its clamping in a different axial position, with at least one arranged in the region between the workpiece headstock and the tailstock and a gripper arranged in the same area gripper unit, with a pushed through the chuck of the workpiece spindle stock and clamped end of the round rod either by the tailstock and / or the steady rest and or the gripper unit can be additionally held, and with at least one wheelhead having one or more grinding spindles through which one or more different grinding wheels are attached to the R andstab are adjustable.

In the case of the machine according to the invention according to claim 8, a multiplicity of features thus cooperate so that the described advantages of the method can be achieved. In addition to the chuck of the workpiece headstock, which allows a push-through and gradual tightening of existing round carbide rod, the numerous facilities for supporting the outstanding end of the round rod are required, so the tailstock, the one or more steady rests and optionally also the gripper unit. The interaction of all these items in the prescribed sense is required so that the carbide tools can be produced economically and yet with high precision.

In principle, it is possible to make do with the cylindrical grinding machine according to the invention with a single grinding wheel, if this can be brought into oblique position with the round bar in engagement.

In this way, namely, the front cone at the two ends of the resulting tool attach, while in parallel position of grinding wheel and round rod, the cylindrical grinding can be performed on the desired final contour. However, it is preferred if according to an embodiment of the cylindrical grinding machine according to the invention a grinding headstock is provided which carries two grinding spindles and is pivotable about a pivot axis which is directed perpendicular to a plane in which the common axis of the workpiece headstock, round rod and tailstock.

In this way, quickly bring two different grinding spindles in operative position, each of these grinding spindles can still wear more grinding wheels.

Particularly preferred is the arrangement of a multiple grinding wheel, in which two or more grinding wheels of different diameter, different width and / or different outer contour are located directly next to each other on a common driven axle.

In this way, in each case a very specific, specially trained for a particular process grinding wheel used, without causing the immediately adjacent next grinding wheel must interfere. For example, one of the two adjacent individual disks may be designed for cylindrical grinding in the peel-grinding process, while the other may optimally take on the sanding of a front cone with a conical grinding roller.

If there is a need for larger quantities of these multiple grinding wheels, it may also be advantageous that the different grinding wheels are combined to form a common grinding wheel. It lies then an adapted sanding mold before, in which only a single carrier body is required.

The cylindrical grinding machine according to the invention can be advantageously provided with a CNC control, which then the entire grinding process is largely automated.

In view of the already described problem, according to which it is necessary to monitor the grinding process automatically, especially in a highly automated process, a sensor is assigned to the chuck of the workpiece headstock by which the round rod is still available for pushing through the chuck Residual length of the round rod controlled at least during each clamping operation and given falling below a minimum residual length a signal and / or the cylindrical grinding machine is set still.

In such a configuration is avoided with certainty that the last remnant of a round rod is ground with a too small clamping length, which can easily result in errors or even accidents.

In the case of the cylindrical grinding machine according to the invention, a tailstock with a quill carrying a hollow grains is also advantageously used. A hollow grains is particularly well suited to centering and secure the end cone of a cylindrical part to be ground.

The inventive method and the cylindrical grinding machine according to the invention are not only excellent for grinding carbide tools, but also for all workpieces with similar stored contour and problem.

Fig. 1

ist eine Ansicht von oben auf eine Schleifinaschine zur Durchführung des erfindungsgemäßen Verfahrens.

Fig. 2

stellt Einzelheiten der Schleifmaschine gemäß Fig. 1 beim Anschleifen von Lünettensitzen dar;

Fig. 3

ist eine der Fig. 2 entsprechende Darstellung, wobei das Anschleifen eines Stirnkonus an den Rundstab gezeigt wird.

Fig.4

zeigt alle Möglichkeiten, den aus dem Werkstückspindelstock herausragenden Endbereich des Rundstabes einzuspannen.

Fig.

5 stellt zusätzlich die Greifereinheit dar, die beim Abtrennen des Endbereichs von dem Rundstab zum Einsatz kommt.

Die Figuren 5a, 5b und 5c

zeigen den Ablauf des Trennvorgangs nach dem Rundschleifen des entstehenden Werkzeugs.

Fig. 6

gibt schematisch den Übergang zum Rundschleifen des folgenden Endbereichs an dem Rundstab wieder.

Fig. 7

veranschaulicht zwei verschiedene Hartmetall-Werkzeuge im Zustand ihrer Rundschleif Endkontur

The invention will be explained in more detail with reference to exemplary embodiments illustrated in the figures. In the figures, the following is shown:

Fig. 1

is a top view of a grinding machine for carrying out the method according to the invention.

Fig. 2

shows details of the grinding machine of Figure 1 when grinding lunette seats.

Fig. 3

is a representation corresponding to FIG. 2, wherein the grinding of a front cone is shown to the round rod.

Figure 4

shows all possibilities for clamping the end area of the round rod protruding from the workpiece spindle.

FIG.

Figure 5 additionally illustrates the gripper unit used in separating the end portion from the round bar.

Figures 5a, 5b and 5c

show the sequence of the separation process after the cylindrical grinding of the resulting tool.

Fig. 6

schematically represents the transition to the cylindrical grinding of the following end region on the round rod again.

Fig. 7

illustrates two different carbide tools in the state of their round grinding final contour

Fig. 1 is a simplified top view of a grinding machine for carrying out the method according to the invention. The reference numeral 1, the machine bed is shown on the front of a grinding table. 2 is attached. The grinding table 2 can be moved in the direction of the axis Z by means of a CNC control. On the grinding table 2, a workpiece headstock 3 is placed on the left side, which receives a chuck 4, which is rotationally driven by means of an electric motor, not shown. The chuck 4 can be seen on the front of the workpiece headstock 3. It serves to clamp the workpiece, in this case the round rod 6. The chuck 4 is designed such that the round rod 6 pushed through the chuck and in the desired axial positions by means of the clamping jaws 5 (Figure 2) can be tightened. The workpiece headstock 3 opposite a tailstock 7 is mounted on the grinding table 2, which receives a movable sleeve 8 in the axial direction. The quill movement is shown by the arrow 9. The work spindle 3 facing the outer end of the sleeve 8 is formed as a hollow grains 10 and serves to receive the ground as Stirnkonus end of the round rod.

With 11 and 12 two lunettes are designated, which can be employed for additional support to the end portion of the round rod 6. The displacement movement of the lunettes 11 and 12 is indicated in Fig. 2 by the arrows 13 and 14.

The round bar 6, the workpiece headstock 3 and the chuck 4 and the sleeve 8 and the tailstock 7 form a common central axis 15, which can also be referred to as a common functional axis.

From Fig. 1 further shows a wheel spindle 16, which carries a first grinding spindle 17 and a second grinding spindle 18. The first grinding spindle 17 is equipped with a first grinding wheel 20 and the second grinding spindle 18 with a second grinding wheel 21. The wheel spindle 16 is pivotable about a pivot axis 19, which is directed perpendicular to a plane in which the common axis 15 of Workhead 3, round rod 6 and tailstock 7 is located. As is readily apparent from the illustration of FIG. 1, can be brought into operative position by pivoting the grinding headstock 16 about the pivot axis 19 optionally the first grinding wheel 20 or the second grinding wheel 21. In addition, the wheel spindle 16 is also linearly movable in the direction of the X-axis. The process in the direction of the X-axis is also CNC-controlled. The grinding spindles 17 and 18 contain integrated electric motors, whereby the grinding wheels 20, 21 are rotationally driven.

Additional details of the cylindrical grinding machine shown in Fig. 1 will be apparent from Figs. 2 to 4.

Thus, in Fig. 2, the clamping jaws 5 of the chuck 4 can be seen, by which the round rod 6 is clamped for the grinding process. As already mentioned, the round rod 6 can be pushed through the chuck 4 and tightened in selectable axial position. In each case, an end region 23 of the round rod 6 projects out of the chuck 4 or the workpiece headstock 3. The length of the end region 23 corresponds approximately to the length of the carbide tool to be produced plus a specific clamping and machining length, cf. Fig. 5.

In Fig. 5 also schematically a gripper unit 22 is shown, the clamping parts 24 and 25 engage around and hold the end portion 23 of the round rod from the outside. The movement of the clamping parts 24, 25 is indicated by arrows 26, 27.

Fig. 2 shows how the first grinding spindle 17 of the grinding headstock 16 is moved into the operative position. The first grinding wheel 20 is shown enlarged here. It has a main body 28 of greater axial extent and a radially projecting from this narrow region 29. Of the narrow region 29 carries the abrasive coating 30 of cylindrical contour. The grinding wheel 20 is designed for example as a diamond grinding wheel with a height of the abrasive coating of about 5 mm.

In contrast, in Fig. 3, the second grinding spindle 18 is brought into operative position with the second grinding wheel 21. The second grinding wheel 22 has a first single disk and a second individual disk 32. The second grinding wheel can be designed as a multi-grinding wheel. The two individual disks 31 and 32 can also be parts of a common abrasive body with a single body. With 33 and 34, the abrasive coatings of the two individual disks 31 and 32 are designated. The two individual disks 31 and 32 have a different axial thickness and are both equipped with conical grinding surfaces of oppositely directed inclination.

Also in the illustration according to FIG. 5, the second grinding spindle 18 is in use with the second grinding wheel 21.

The other machine parts, which are shown in FIGS. 2 to 5, carry the previously mentioned reference numerals and are therefore not explained in detail.

The grinding process to be carried out on the grinding machine according to FIGS. 1 to 6 proceeds in the following way:

Starting material is already mentioned round rod 6 made of a sintered carbide. Such a round rod, which may for example have a length of 300 to 400 mm, is pushed through the chuck 4 of the workpiece spindle stock 3 until an end region 23 (FIG. 2) of desired length protrudes from the chuck 4. In this position the jaws 5 are moved to the rod 6 so that it is tightened.

Then, the first grinding spindle 17 of the grinding headstock 16 is brought into operative position. By means of the first grinding wheel 17 located on the first grinding wheel 17 and driven in rotation, which has a cylindrical grinding surface, a first steady seat 35 is then ground to the end region 23 of the round bar 6. Subsequently, the first bezel 11 is moved in the direction of the arrow 13 against the first steady seat 35, so that the end portion 23 is securely supported in further grinding operations.

If necessary, even a second steady seat 36 or other lunette seats can be sanded at the end portion 23 of the round bar 6. For this purpose, for example, the second bezel 12 is provided. In this case, then first the steady seat 36, which is arranged closer to the chuck 4, and then the steady rest seat 35 is ground.

According to the illustration according to FIG. 3, both steady rests 11 and 12 are set against the associated lunette seats 35, 36. The end portion 23 is thus securely supported. Now, the second grinding spindle 18 is brought into operative position with the second grinding wheel 21. Their first individual disk 31 then serves to grind a first end cone 37 against the end face of the round rod 6 or its end region 23 facing the tailstock 7. The first end cone 37 is dimensioned such that it fits into the hollow grains 10 of the quill 8, which is arranged displaceably in the tailstock 7 in the direction of the arrow 9.

Fig. 4 shows the state in which the free end of the end portion 23 is clamped to the first end cone 37 in the hollow grains 10. In operative position is again the first grinding spindle 17 of the grinding headstock 16, which is now CNC-controlled in the direction of the X-axis to the end portion 23rd is delivered. At the same time, the grinding table 2 is moved in the direction of the Z-axis CNC-controlled. In this way, nearly the entire length of the end region 23 is ground by means of the first grinding wheel 20 in the peel grinding process. This means that this length is ground in a single operation of the grinding wheel 20 at the end portion 23. However, it is also possible to use a wider grinding wheel and perform the process in the pendulum grinding process. In this case, a plurality of radial infeed movements take place, and the longitudinal movement has to be repeated several times until the grinding allowance 38 has been removed and the desired surface state of the end region 23 has been reached.

FIG. 4 shows a state in which the steady rests 11 and 12 are also engaged on the end region 23 during this parting operation. This is by no means mandatory. The use of the steady rests 11 and 12 is unavoidable, especially when grinding the first end cone 37. In the following operations can also be worked in such a way that the steady rests are then retracted.

The process of cylindrical grinding shown in FIG. 4 is by no means limited to obtaining only a continuous cylindrical contour of desired surface quality. Rather, the entire cylindrical grinding final contour of the resulting finished carbide tool is to be achieved in this process step. That is, depending on the final contour of the tool already at this stage of the process in which the end portion 23 is still on the rod 6, portions with gradations of cylindrical, conical or spherical contour can be ground out. All contours that can be achieved by cylindrical grinding are conceivable. This can also be done in such a way that set grinding wheels with certain contours are used. This is not shown in Fig. 4.

Examples of such cylindrical grinding end contours are shown in FIG. 7.

The end portion 23 of the round rod 6 and thus the resulting carbide tool are so far finished ground. The term "finish grinding" here does not mean a finish grinding in the sense of finishing as opposed to roughing, but that final stage, which is achievable for the resulting tool by grinding in the extreme case. After that cutting edges, spiral grooves and the like have to be sanded in separate processes. For the time being, however, it is necessary that tools cut to size from the round rod 6 should be separated.

This process is explained with reference to FIGS. 5 and 5a to 5c. The end portion 23 of the round rod 6 is initially clamped at both ends, as shown in Figure 4. One or more lunettes may be employed at the end portion 23; this is not mandatory. Notwithstanding the representation according to FIG. 4, the second grinding spindle 18 is now again brought into operative position by the grinding spindle 16 being pivoted about the pivot axis 19. Of the second grinding wheel 21, which is a multi-grinding wheel, but now comes the second single disc 32 is used, which has a larger diameter than the first single disc 31. The rotating second single disc 32 is then against the likewise rotating end portion 23 of the round rod. 6 hired. This first setting process is interrupted as soon as the second individual disk 32 has ground the second end cone 39 (FIG. 5a).

Then, the second grinding wheel 21 is moved back from the end portion 23 of the round rod 6. There is an axial mutual offset of rod 6 and second single disc 32. The offset is about the thickness Then the single disc 32 is again delivered against the end portion 23 of the round rod 6 and this time causes a separating cut 40. The process is continued until the connection between the remaining remaining length of the round rod 6 and its end portion 23 only in one narrow connection collar 41 consists. Until this time, the end portion 23 of the round rod 6 was clamped at both ends and driven for rotation (Figure 5b).

Finally, the rotary drive of the work spindle is stopped, and the tailstock 7 with the sleeve 8 is moved back from the clamping position. The end portion 23 of the round rod 6 with the first end cone 37 are now free and are encompassed by the clamping parts 24, 25 of the gripper unit 22 and held securely. By further advancing the second single disc 32, the separation process is then continued and even the connecting collar 41 is ground away (Figure 5c). The completed in terms of cylindrical grinding tool is now separated from the remainder of the round rod 6 and so far finished. The resulting carbide tool is held in the gripper unit 22 and is removed from this and removed from the machine, see. FIG. 5.

Subsequently, the round rod is moved out a bit from the chuck 4 again, so that the next end portion 23 can be edited (Figure 6).

In Fig. 7, two different carbide tools are shown in one stage, as it should be achieved with the inventive method and the cylindrical grinding machine according to the invention. The illustrated, so far fertiggeschliffenen tools can still recognize the second Stirnkonus at one end. The original cylindrical contour of the round rod 6 is shown in phantom, so that it can be seen how the desired round grinding final contour solely by cylindrical grinding has come about. The figure clearly shows that graded cylindrical, conical or spherical contours are readily achievable. The special feature is that these varied forms have come about, wherein at least at one end a single, on which the starting material forming round rod acting clamping has been sufficient.

It should be noted that the implementation of the method is not limited to the measures shown in FIGS. 1 to 5. It is even possible to make do with a single grinding wheel for all operations, if there is the possibility to deliver this grinding wheel in an oblique direction to the round rod.

List of reference numbers

1

machine bed

2

grinding table

3

Workhead

4

chuck

5

jaws

6

workpiece

7

tailstock

8th

Pinole

9

Arrow (quill movement)

10

hollow grains

11

first bezel

12

second bezel

13

Arrow (adjusting movement of the bezel 11)

14

Arrow (adjusting movement of the bezel 12)

15

common axis (functional axis)

16

Wheelhead

17

first grinding spindle

18

second grinding spindle

19

Swivel axis of the grinding headstock

20

first grinding wheel

21

second grinding wheel

22

gripper unit

23

End of 6

24

Clamping part from 22

25

Clamping part of 22

26

arrow

27

arrow

28

body

29

narrow area

30

abrasive coating

31

first single disc

32

second single disc

33

Abrasive coating of 31

34

Abrasive coating of 32

35

first steady seat

36

second steady seat

37

first forehead cone

3S

grinding allowance

39

second end cone

40

separating cut

41

connection Bund

Claims (14)

1. A method of cylindrical grinding in the manufacture of tools of cemented carbides on a cylindrical grinder comprising a workpiece headstock and a tailstock, wherein a cylindrical rod of a cemented carbide is assumed as a starting material, characterised by the steps of:

   a) clamping the cylindrical rod (6) having a length of a multiple of the length of each individual tool in a chuck (4) of the workpiece headstock (3) which enables axial displacement of the cylindrical rod (6) when the chuck (4) is released, wherein an end portion (23) of said cylindrical rod (6) protruding from said workpiece headstock (3) faces said tailstock (7);

   b) grinding at least one support surface (35, 36) at said end portion (23) of said cylindrical rod (6) protruding from said workpiece headstock (3), and advancing a rest (11, 12) to abut at said support surface (35, 36);

   c) grinding a first end cone (37) at the end face of said cylindrical rod (6) facing said tailstock (7);

   d) bringing said first end cone (37) into clamping engagement with a hollow body (10) which is positioned on a sleeve (8) of said tailstock (7);

   e) cylindrical grinding of said end portion (23) of said cylindrical rod (6) protruding from said workpiece headstock (3) along a length corresponding to about the overall length of the individual tool, to its cylindrically ground net shape;

   f) slicing the individual tool, ground up to this point, from said cylindrical rod (6);

   g) releasing said chuck (4) of said workpiece headstock (3), having remained clamped up to this point, advancing said cylindrical rod (6) in said workpiece headstock (3) toward said tailstock (7), and subsequently tightening said chuck (4), so that a further end portion of said cylindrical rod (6) to be processed protrudes from said workpiece headstock (3).
2. The method according to claim 1, characterised in that when said end portion (23) of said cylindrical rod (6) protruding from said workpiece headstock (3) is ground, the rest (11, 12) is retracted from said support surface (35, 36).
3. The method according to claim 1 or 2, characterised in that two support surfaces (35, 36) are ground on said end portion (23) of said cylindrical rod (6) axially spaced from each other.
4. The method according to any one of claims 1 to 3, characterised in that said end portion (23) of said cylindrical rod (6) protruding from said workpiece headstock (3) is cut off from the remaining cylindrical rod (6) after cylindrical grinding by first grinding, with a single grinding wheel (21), a second end cone (39) on the end face facing said workpiece headstock (3) of the tool, finished so far, then, after retracting and axially displacing said grinding wheel (21) with respect to said cylindrical rod (6), by forming a cut (40) leaving only a central linking collar (41), and finally, after stopping the rotary movement of said cylindrical rod (6), completing the separating operation by grinding away the linking collar (41).
5. The method according to any one of the preceding claims, characterised in that, during slicing of said individual finished ground tool, said tailstock (7) and/or said rest (8) is retracted from the processed emerging tool which is held by a gripper unit (22).
6. The method according to any one of the preceding claims, characterised in that said cylindrical grinding operation for producing the tool contour is carried out with a thin grinding wheel using the rough grinding method and/or with a thick grinding wheel using the pendulum grinding method.
7. The method according to any one of the preceding claims, characterised in that the remaining length of said cylindrical rod (6) still to be advanced through said chuck (4) of said workpiece headstock (3) is checked at least at each clamping operation and, when less then a minimum length remains, a signal is provided and/or the cylindrical grinder is stopped.
8. A cylindrical grinder for grinding cylindrical starting bodies in the manufacture of tools of cemented carbides for carrying out the method according to any one of claims 1 to 7, comprising a machine foundation (1), a grinding table (2) able to be traversed on said machine foundation (1), and having a workpiece headstock (3) and a tailstock (7) arranged thereon, with a chuck (4) on said workpiece headstock (3) enabling axial displacement of a cylindrical rod (6) as a starting material and clamping thereof in different axial positions, comprising at least one rest (11, 12) arranged between said workpiece headstock (3) and said tailstock (7), and a gripper unit (22) arranged in the same area, wherein an end portion (23) advanced through, and clamped by, said chuck (4) of said workpiece headstock (3) is able to be additionally supported by said tailstock (7) and/or said rest (11, 12) and/or said gripping unit (22), and said gripping unit (22) is configured such that it can remove from the machine, and depose, the tool finished up to this point while its rotary movement is stopped, and comprising at least one grinding spindle head (16) with one or more grinding spindles (17, 18), whereby one or more different grinding wheels (20, 21) can be applied to said cylindrical rod (6).
9. The cylindrical grinder according to claim 8, characterised by a grinding spindle head (16) which carries two grinding spindles (17, 18) and is pivotable about a pivoting axis (19) which is aligned perpendicular to a plane in which the common axis (15) of the workpiece headstock (3), the cylindrical rod (6) and the tailstock (7) is disposed.
10. The cylindrical grinder according to claim 8 or 9, characterised by the arrangement of a multiple grinding wheel (21) at which two or more individual wheels (31, 32) of different diameters, different widths and/or different outer contour are directly adjacent to each other on a commonly driven shaft.
11. The cylindrical grinder according to claim 10, characterised in that the different grinding wheels are combined in an integral grinding body.
12. The cylindrical grinder according to any one of the preceding claims, characterised in that the grinder is equipped with computer numerical control (CNC).
13. The cylindrical grinder according to any one of the preceding claims, characterised in that a sensor is associated with said chuck (4) of said workpiece headstock (3) for checking the remaining length of said cylindrical rod (6) still to be advanced through said chuck (4) at least at each clamping operation, and, when less then a minimum length remains, a signal is provided and/or the cylindrical grinder is stopped.
14. The cylindrical grinder according to any one of the preceding claims, characterised in that said tailstock (7) has a sleeve (8) carrying a hollow body (10).

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