DE4430113A1 - Tool machine for rotationally symmetrical work pieces - Google Patents

Abstract

The machine tool consists of a machine bed (1) carrying two in compound slide rests (2,3) resting work piece spindle heads which are movable independent from each other in two directions (X,Z). The work piece spindle heads are supported rotatable around another axis (B) and carry clamping devices (11,23) for the workpieces and dressing devices (13,26) for grinding wheels (43,44) carried on the tool turret. The machine tool carries a tool turret (32) which can be loaded with different tools (36,43,44) for the machining of different workpieces. The tool turret is supported on a machine column with two parallel supporting posts (31) and is vertically movable. The tool turret carries coupling devices (37) on the circumference for tool holders (34).

Description

The invention relates to a machine tool for machining processing of essentially rotationally symmetrical workpieces, especially of workpieces made of hardened steel or others hard materials according to the preamble of claim 1.

DE-33 20 940 A1 is a so-called two-spindle rotation machine known. This machine has two workpiece spindles sticks, one of which is stationary on the machine bed attached and the other on a cross slide in two mutually perpendicular axes can be moved. The workpiece spindles rotate around horizontal axes and are with clamping means for clamping one work to be processed piece. Every workpiece headstock is a tool assigned to the head with a floating tool turret, the one on its face to the associated workpiece headstock aligned tool holders and tools. One of Tool heads are in the traversing plane of the movable workpiece headstocks fixed, the other on a cross slide arranged movably. The stationary tool head is vertical movably guided to the level of the cross slide. The plant Turrets carry fixed or rotating tools, with rotating tools for milling and drilling work ten are provided. This machine is especially for Stan conceived work, i.e. for the processing of work piece blanks in the form of a rod through the stationary Workpiece headstock fed, there with the tools of the movable tool head machined from one side, after this processing directly on the movable workpiece headstock handed over and in this clamping with the factory testify to the stationary, but vertically movable tool are processed at the back of the head.

This machine offers only a limited range of machining,  because relative movements of workpiece and tool only in the Cartesian coordinates are possible, it is relatively expensive dig, because it is a double machine with two workpiece and two Tool units is built and it is not in view on the hard machining of workpieces made of hardened steel or other hard materials designed and equipped.

For hardened workpieces made of steel or for workpieces made of other hard materials is essentially only one Finishing or finishing required. Because the ones to be processed Areas are mostly mating areas, are accordingly narrow Tolerances specified. Hard machining requires high Machining pressures to make economically sound material removal rates and processing times to come. To do the required due to the narrow tolerances To achieve this, the machine and its units have to do a lot be stiff and stable. The finishing of the Workpieces on a machine also require high flexibility lity.

The present invention has for its object a specify another machine tool.

This task is solved by the in the indicator of the To pronounced 1 specified characteristics. This makes it very compact built machine tool proposed after a new like concept with a single tool turret numerous different machining processes on the front and back of clamped in the two workpiece headstocks, in particular can execute short workpieces.

Features of continuations and refinements of the machine according to the invention are contained in the subclaims.  

The features of claims 2 to 4 relate to the equipment the machine with degrees of freedom, which is a universal machining processing of the workpieces on their front and back in both Allow workpiece headstocks. With this structure according to the Invention cylindrical, conical and profiled interior and outer surfaces as well as front and shoulder surfaces of the turned clamped workpieces.

The features of claim 5 create the possibility of ver perform various operations on the workpiece, whereby special emphasis on the finishing or finishing of the plant pieces from both sides.

The features of claim 6 serve the rational use of Machine and the tools by direct transfer of the Workpieces between the two workpiece headstocks as well the simultaneous interaction of the in the workpiece spindle work pieces clamped on the tool turret in the the respective machining position enable.

The features of claims 7 and 8 create the necessary control engineering requirements.

The features contained in claims 9 to 11 are esp particularly advantageous in connection with the hard machining of Workpieces. They bring about the stability and rigidity of the Machine that meets the required high accuracy under high Ensure machining pressures.

The measures according to claim 12 offer an advantageous Arrangement of the tools on the tool turret, with which the simultaneous machining of two workpieces, the one in the two clamped on opposite workpiece headstocks are possible.  

Claims 13 to 17 contain further advantageous equipment features of the tool turret. Here are the characteristics of claims 15 to 17 especially for hard machining of workpieces of importance since they are the fine or hardbear optimize processing.

Claims 18 and 19 contain features of a further one partial equipment of the machine, which is fast and accurate Allow dressing of the grinding tools used. Claims 20 and 21 relate to additional processing units that can be accommodated on the tool turret and that Processing spectrum for the workpieces especially in Significantly expand towards fine and ultra-fine machining.

Claims 22 and 23 deal with the possibility of Workpiece change using a changer unit, which also is provided on the tool turret. The advantage of this arrangement is that for loading the machine with workpieces no additional space is required in the machine's work area appropriate unit is required. The according to the invention The changer unit provided on the tool turret is simple by turning the tool turret when machining Position a tool or a pair of tools can be moved out of the working area of the machine.

The claims 24 to 27 relate to the chip disposal, for grinding the workpieces on the one hand and dry turning and other processing of the workpieces on the other hand separately he follows. This makes the disposal of the chips essential lighter and improved from an environmental point of view. With the Features of claim 28 is the coolant supply especially for the high-performance grinding of the factory pieces optimized. The design of the workpiece spindle heads according to claim 29 enables a very safe strategy when Transfer the workpieces from spindle to spindle.  

The invention provides a machine tool for the com Complete fine and very fine machining of short rotational symmetry workpieces. With the machine you can Workpieces can be finished on both sides without they have to leave the machine in between. Special Weight is on the finishing operations on both Sides of the workpieces. With the arrangement of the tools volvers between the workpiece headstocks can in the workpieces clamped in both workpiece headstocks simul tan or of course also be processed one after the other. As a result their rigid and very stable construction and their tools the machine is particularly suitable for hard machining suitable for workpieces. On the other hand can also work pieces made of conventional materials with very high compliance tight tolerances can be finished with high accuracy. The versatility of the tools that can be used guarantees for each machining task the optimal machining strategy with the optimal tools. Of particular advantage is that the proposed machine according to the invention both Hard turning as well as hard grinding with the corresponding Tools. These are the ones for the Hartbear processing of the most common machining processes to implement on the machine proposed according to the invention. The material removed from the workpiece can vary depending on the machining be disposed of separately, for environmental reasons protection is an advantage. The machine is in construct relatively simple and despite their versatility very compact design.  

The invention will now be explained in more detail with reference to the drawing.

Show it:

Fig. 1 is a schematic front view of a machine tool according to the invention,

Fig. 2 shows a tool head with a tool turret in a perspective view;

Fig. 3 is a schematic side view of the tool turret with the positions of various tools and

Fig. 4.1 to 4.4 different working positions of the workpiece changer on the turret during a workpiece change.

In the drawing is a currently preferred embodiment game of the machine tool according to the invention. In the figures are the same parts, each with the same reference characters. The machine is a Rotary grinder for the complete finishing of rotationally symmetrical workpieces. It says in particular the hard machining of workpieces made of hardened steel or other hard materials in the foreground.

The rotary grinding machine shown in the drawing has a machine bed 1 on which two cross slides 2 and 3 are arranged opposite one another. The cross slide 2 has a lower, on the machine bed 1 in the direction Z₁ movable carriage 4 with a Z₁ drive 6 and on the carriage 4 an upper carriage 7 with an X₁ drive, not shown in the drawing, which in the X₁- Direction is movable across to Z₁. The upper carriage 7 carries a workpiece headstock 8 with a workpiece spindle 9 rotatable about a C₁ axis. This carries at its free end as a workpiece clamping device a clamping head 11 in which a workpiece 12 is clamped. On the clamping head, a dressing ring 13 is introduced , which concentrically surrounds the axis C₁ of the workpiece spindle 9 . The dressing ring 13 is preferably exchangeably attached to the clamping head 11 . The workpiece headstock 8 is on a turntable 14 , which is supported by the upper carriage 7 , rotatable about a vertical axis B₁.

The second cross slide 3 consists of a lower, parallel to or in alignment with the direction Z₁ in the direction Z₂ movable carriage 16 and a carriage 17 on the carriage 16 transversely in the X₂ direction. With 18 the Z₂ drive of the unte ren carriage 16 is designated. The drive of the upper carriage 17 is not shown. The cross slide 3 carries a second workpiece headstock 19 which is rotatably mounted on a rotary table 21 about a vertical axis B₂. In the workpiece spindle delstock 19 , a workpiece spindle 22 is provided with a clamping head 23 for clamping a workpiece 24 . On the clamping head, the dressing ring 26 concentrically surrounding the spindle axis C₂ is interchangeably attached.

The cross slide 2 and 3 are designed and arranged so that the axes of rotation C₁ and C₂ of the workpiece spindles can be brought into alignment with one another, so that they form a common workpiece spindle axis C₁-C₂ and enable a direct workpiece transfer.

The machine bed 1 is assigned a vertical machine column 27 (see FIG. 2) on which a tool head 28 can be moved vertically to the plane of the X and Z axes in the Y direction. For reasons of stability, the column will be firmly connected to the machine bed 1 .

Two parallel walls or support arms 31 and 31 a of the tool head 28 form a yoke 29 in which a tool turret 32 is mounted on both sides. The axis 33 of the tool turret 32 runs parallel to the above-mentioned common axis C₁-C₂ of the two workpiece spindles 9 and 22 or parallel to the two linear axes Z₁ and Z₂ of the two lower slides 4 and 16 . The two-sided mounting of the tool turret 32 increases the rigidity of the system compared to the flying mounting and also ensures high accuracy when machining workpieces with large machining forces.

The tool turret 32 can be equipped with several different tools according to the invention. Fig. 1 shows that in some circumferential positions 38 a to 38 d two receptacles 37.1 and 37.2 are provided axially next to each other. These receptacles are used for inserting tool holders 34 for different tools 36 with geometrically determined cutting edges (turning tools). In Fig. 3 are in the circumferential positions 38 a to d, the tool holder 34 a to 34 d with rotating mechanism witness 36 a to 36 d. These are pairs of holders and tools. This is because behind the holders 34 a to d shown in FIG. 3 there is an axially offset second row of holders. These are inserted in the receptacles 37.2 shown in FIG. 1. For clarification, Fig. 1 shows in the circumferential position 38 b axially next to each other, both tool holders, which here bear the reference numerals 34 b.1 and 34 b.2 and are equipped with the tools 36 b.1 and 36 b.2. Positions 34 b.1 and 36 b.1 of FIG. 1 are identical to positions 34 b and 36 b shown in FIG. 3. The tools 36 b.1 and 36 b.2 extend in the axial direction opposite to both ends of the tool turret verse 32 , so that they can be brought into contact with the workpiece 12 and 24 .

In addition to turning, especially hard turning of workpieces grinding from hard materials is an important task processing for finishing the workpieces on both Pages. In addition to the usual inside and outside round work flat surfaces can also be ground on the workpieces.

In two further circumferential positions 38 e and 38 f ( FIG. 3), the tool turret 32 therefore has two receptacles 39 a and 39 b for two oppositely oriented grinding spindles 41 and 42 with grinding tools 43 and 44 ( FIG. 1). The grinding spindle axes can run essentially parallel to the axis 33 of the tool turret, but are preferably inclined by a small angle of approximately 1 ° to 5 ° to this axis or to the Z axis. This ensures a circumferential sanding when grinding flat surfaces. As a rule, small-diameter CBN grinding wheels (CBN = Cubic Boron Nitride) are used, which can machine both external and internal and plane surfaces. Mittelfre frequency motor grinding spindles are preferred for the grinding tools. The arrangement of the grinding spindles in such a way that the grinding tools 43 and 44 are oriented axially towards the opposite side to the tools clamped in the clamping heads enables surfaces to be ground on both the front and rear workpiece sides. By oscillating the tool head with the tool turret 32 in the Y direction, peripheral surfaces, for example wrench surfaces, can be ground flat. The drives of the axes X₁, X₂, Z₁, Z₂ and Y and the axes of rotation B₁ and B₂ are what is not shown in the drawing, numerically controlled and can be programmed according to the desired machining operations.

The grinding of the workpieces requires cooling Lubrication through cooling lubricant nozzles, not shown is realized. For optimal cooling of the grinding process to ensure the cooling lubricant nozzles ent according to the grinding progress numerically controlled leads. For the sake of clarity, they are Cooling lubricant nozzles and their tracking in the drawing not shown, because the expert verbally refers to this possibility is sufficient for a realization.

The cooling lubricant loaded with material removed from the workpiece is collected in the space below the working area of the grinding tools in a channel 46 and discharged. The hard turning of workpieces with CBN tools is preferably carried out dry according to the knowledge of modern process research. In order not to mix the turnings with the cooling lubricant for grinding, according to the invention, a box 47 with a chip conveyor belt 48 is moved above the channel 46 into the work area and withdrawn again for carrying out grinding work, so that the cooling lubricant during the turning process Loops to the filter and can run back into the coolant system.

The dry turnings and the one loaded with the removal material Cooling lubricants can therefore be separated according to the invention to be disposed of.

In a further circumferential position 38 g of the tool turret, a handling device 49 is provided for the automatic workpiece change. This handling device 49 is attached to the outer circumference of the tool turret 32 and can be pivoted about an axis 51 that is essentially radial to the axis of rotation of the tool turret. This handling device 49 is designed as an angle sensor with two mutually perpendicular holding arms 54 , 56 , on which workpiece holders 52 and 53 are attached. This arrangement causes the two pick-up arms 54 and 56 , each with a workpiece holder 52 and 53 and a swivel range around the axis 51 of 90 °, to carry out the workpiece loading on both workpiece spindles. The workpiece transfer to the workpiece holders 52 and 53 of the angle sensor 49 from the outside can be done manually or automatically by means of a robot (not shown).

The machine shown as an embodiment is used for complete fine machining preferably of short rotationally symmetrical workpieces, in which the ratio of length to diameter is less than 3. The machine is designed so that workpieces made of hardened steel or other hard materials are machined with high accuracy can be. Such a workpiece, for example workpiece 12 in FIG. 1, is first clamped in the clamping head 11 of the left workpiece spindle 9 . By pivoting the tool turret 32 , all the necessary tools are brought one after the other into the working position, so that the various machining operations on the surfaces of the "front" of the workpiece can be carried out one after the other. The rigid construction of the machine allows large machining forces with high accuracy. If the "Before the side" of the workpiece 12 is finished, the workpiece headstocks 8 , 19 move back and the tool head moves upward in the Y direction and makes the way for the transfer of the workpiece 12 to the spindle 22 of the second workpiece headstock 19 free. For this purpose, the workpiece headstocks move towards each other in the Z 1 or Z 2 direction until the clamping head 23 of the workpiece spindle 22 detects the workpiece on the front. The workpiece spindles can stand still or rotate synchronously at the same speeds. It is particularly advantageous if the speed of one workpiece spindle deviates from the other by a small amount, so that when the workpiece is gripped with the clamping head 23 of the second workpiece spindle delstock, a change in torque occurs on the workpiece, which determines with a sensor provided in a workpiece spindle becomes. Depending on this change in torque, a signal is generated which causes the clamping head 11 of the first workpiece spindle 9 to open. In this way, a secure transfer of the workpiece from one workpiece spindle 9 to the second workpiece spindle 22 is ensured. This transferred to the clamping head 23 , semi-finished workpiece is designated in Fig. 1 with 24 net. Then in the clamping head 11 of the first workpiece spin del 9, a new, unprocessed workpiece, again with 12 be marked, clamped, the "front" to be processed.

In Fig. 1, these machines situation is shown in operation during a tool change. The workpiece headstocks 8 and 19 are retracted in the Z₁ or Z₂ direction, so that the tool turret 32 can be moved between them in the Y direction and rotated about its axis 33 . In the illustrated case, it is assumed that the workpieces 12 and 24 have already been turned and the turret 32 has now been brought into the working position for the grinding work, in which the grinding tools 43 and 44 are located opposite the workpiece surfaces to be machined. According to an advantageous machining strategy, the workpiece 12 clamped in the clamping head 11 is still unprocessed on its “rear side”. Its "front" faces the tools for machining. The workpiece 24 is clamped with its already finished "front" in the clamping head 23 and is processed here on its "back". By moving the workpiece headstocks 8 and 19 in the axes X₁ and Z₁ or X₂ and Z₂, the workpieces 12 and 24 are brought into contact with the grinding tools 43 and 44, respectively. The machining of the workpieces 12 and 24 can be carried out simultaneously or in succession. The rotation of the workpiece headstocks about the pivot axes B₁ or B₂ can also be used, provided that the machining operations on the surfaces of the workpieces to be ground require this. The linear axes X₁ and Z₁ and the axis of rotation B₁ of the workpiece headstock 8 and the Linearach sen X₂ and Z₂ and B₂ of the workpiece headstock 19 are controlled by the common machine control. If necessary, this also applies to the linear axis Y of the tool head 28 and for the tracking movements of the cooling lubricant nozzles not shown. In this way, very complex machining processes can be carried out on the workpieces. The Ka most 47 with the chip transport 48 is moved out during this machining process from the working area of the machine, so that the cooling lubricant gets into the collecting channel 46 and runs from there.

If other types of machining are to be carried out on the workpieces, the workpiece headstocks 8 and 19 are moved back in the Z1 and Z2 directions and the turret 32 is rotated about its axis 33 until the tools required for the new machining operations are brought into their working position. In general, according to the invention, the shaping relative movement of workpieces and tools is carried out by programmed movement of the workpieces in their axes X, Z and B, to which a Y movement of the tool can be added if necessary.

The machine therefore offers the possibility of one machining operation follow one after the other to machine both sides of a workpiece, without the workpiece leaving the machine in between got to.

To complete the machining options, honing and / or orbital grinding units can also be attached to the tool turret 32 . This means that fine machining of individual surfaces is possible in the same workpiece clamping, which leads to particularly low roughness depths. Depending on the workpiece quality requirements, these last machining options can be provided for one or both sides of the workpiece. In addition, an additional assembly for driven tools can optionally be used on the tool turret. This enables the use of honing stones, which are used in connection with an oscillating movement of the tool head in the Y direction. Hard fine boring bars can also be used, with a fine feed in the Y direction.

If the workpiece 12 is finished on its front side and the workpiece 24 on its rear side, a workpiece change is carried out. For this purpose, the handling device 49 is brought into its changing position by rotating the tool turret 32 , which is on the underside of the tool turret. Fig. 4.1 shows a top view of the turret in this position. In order to make the handling device 49 visible, the tool turret 32 is broken open to represent Darge. As already mentioned above, the handling device 49 is designed as an angle pickup which carries two workpiece receptacles 52 and 53 . The workpiece holder 52 on the holder arm 54 is aligned with the clamping head 23 of the workpiece spindle 22 . By moving the workpiece headstock 19 in the Z₂ direction towards the handling device 49 , by clamping the workpiece 24 on the workpiece holder 52 and releasing the workpiece from the clamping head 23 , the workpiece 24 finished on both sides is transferred to the workpiece holder 52 . The work headstock 19 then moves back so that the Winkelaufneh mer 49 about its axis 51 according to the arrow 57 in the clockwise direction can be pivoted by 90 °. The workpiece holder 52 is now at the front, so that an operator or a robot can conveniently remove the finished workpiece 24 , which is indicated by the arrow 58 in FIG. 4.2. Meanwhile, the workpiece passes headstock 8 the finished on its "front side" workpiece in the already above-described manner to the workpiece spindle head 19, so that in the clamping head 23 of the workpiece spindle head 19 now again a semi-finished workpiece is clamped, the "back side" too is edit. The clamping head 11 of the workpiece headstock 8 is free.

After the handling device 49 has been pivoted counterclockwise into the position shown in FIG. 4.3, the operator or a robot places a new, unprocessed workpiece 12 a on the workpiece holder 53 in the direction of the arrow 59 . With this workpiece, the handling device pivots clockwise by 90 °, so that the workpiece holder 53 is aligned with the workpiece spindle 9 of the workpiece headstock 8 . The workpiece headstock 8 is moved in the Z₁ direction to the workpiece holder 53 and takes over the completely unworked new workpiece 12 a for processing its "front". In this way, a quick workpiece change is possible without the semi-machined workpiece having to be removed from the machine and re-clamped. This leads to highly precise machining results with very efficient use of the machine options. In particular, a robot is used for workpiece removal and loading, and fully automatic operation is also possible.

Claims (29)

1. Machine tool for machining essentially rotationally symmetrical workpieces, in particular workpieces made of hardened steel or other hard materials, with a machine bed, two workpiece headstocks that can be moved relative to one another on the machine bed in two mutually crossing directions (X and Z axes), in which each have a workpiece spindle with a workpiece clamping device and can be driven, a tool head that can be moved transversely to the plane of the X and Z axes (Y axis), a tool turret mounted on the tool head with tool holders, means for rotating the tool turret into various predetermined positions , in each of which a selected tool relative to a clamped workpiece assumes a predetermined working position and means for moving the workpiece and tool relative to one another depending on a workpiece shape to be produced, characterized in that the tool turret ( 32 ) is assigned to both workpiece headstocks ( 8 , 19 ) and that it has tools ( 36 , 43 , 44 ) for the simultaneous or sequential machining of workpieces ( 12 , 24 ) clamped in the workpiece spindle. 2. Machine tool according to claim 1, characterized in that each workpiece headstock ( 8 , 19 ) independently of the other on a cross slide ( 2 , 3 ) in both directions (X, Z) can be moved. 3. Machine according to claim 1 or 2, characterized in that the tool head ( 28 ) with the tool turret ( 32 ) on a machine column ( 27 ) is vertically movable. 4. Machine according to one of claims 1 to 3, characterized in that each workpiece headstock ( 8 , 19 ) is rotatable about an axis perpendicular to its travel plane (XZ plane) (B axis). 5. Machine according to one of claims 1 to 4, characterized in that the tool turret ( 32 ) receptacles ( 37 ) for fixed tools ( 36 ) with geometrically determined Schnei and receptacles ( 39 ) for other tools ( 42 , 43 ) . 6. Machine according to one of claims 1 to 5, characterized in that the axes (C₁, C₂) of the workpiece spindles ( 9 , 22 ) of both workpiece headstocks ( 8 , 19 ) in a common, to the axes of rotation (B₁, B₂) radial Level run and that the two workpiece headstocks ( 8 , 19 ) can be positio to each other that the workpiece spindle axes coincide in a common axis. 7. Machine according to one of claims 1 to 6, characterized in that at least the linear axes (X₁, X₂; Z₁, Z₂) and the rotating axes (B₁, B₂) of the workpiece headstocks ( 8 , 19 ) are numerically controlled machine axes. 8. Machine according to one of claims 1 to 7, characterized in that the linear axis (Y) of the tool head ( 28 ) is a numerically controlled machine axis. 9. Machine according to one of claims 1 to 8, characterized in that the tool turret ( 32 ) is mounted on both sides. 10. Machine according to one of claims 1 to 9, characterized in that the tool head ( 28 ) as a movable yoke on vertical guides with two parallel support arms ( 31 , 31 a) is formed and that the tool turret ( 32 ) between the support arms arranged and mounted on both sides in the support arms. 11. Machine according to one of claims 1 to 10, characterized in that the axis of rotation ( 33 ) of the tool turret ( 32 ) runs parallel to a common axis (C₁-C₂) of the two workpiece spindles ( 9 , 22 ). 12. Machine according to one of claims 1 to 11, characterized in that the tool turret ( 32 ) has pairs of receptacles ( 37 , 39 ) for pairs of tools ( 36 , 43 , 44 ) or tool holders ( 34 , 41 , 42 ) and that one of the tools and one of the other of the other workpiece spindles ( 9 , 22 ) is assigned to the tools inserted into the receptacles for machining a workpiece ( 12 , 24 ) clamped there. 13. Machine according to one of claims 1 to 12, characterized in that the tool turret ( 32 ) on its circumferential surface coupling devices ( 37 ) for coupling tool holders ( 34 ). 14. Machine according to one of claims 1 to 13, characterized in that the tool turret ( 32 ) on its two end faces axially opposite receptacles ( 39 ) for tools ( 43 , 44 ) and / or tool holder ( 41 , 42 ). 15. Machine according to one of claims 1 to 14, characterized in that the tool turret ( 32 ) has at least one grinding spindle ( 41 , 42 ) with a receptacle for a rotating grinding tool ( 43 , 44 ), supply connections and a spindle drive. 16. Machine according to claim 15, characterized in that two grinding spindles ( 41 , 42 ) substantially parallel to the turret axis ( 33 ) opposite to the two end faces of the turret ( 32 ) are mounted in the tool turret and that the grinding spindles ( 41 , 42 ) clamped grinding tools ( 43 , 44 ) protrude axially sideways from the end faces of the turret. 17. Machine according to claim 15 or 16, characterized in that the grinding spindle axes are inclined by a small angle (approximately 1-5 °) to the Z axis of the machine in the tool turret ( 32 ). 18. Machine according to one of claims 1 to 17, characterized in that at least one workpiece spindle ( 9 , 22 ) for holding a workpiece ( 12 , 24 ) for machining purposes has a chuck ( 11 , 23 ) and that a dressing tool ( 13 , 26 ) for dressing a grinding wheel ( 43 , 44 ) provided on the tool turret ( 32 ). 19. Machine according to claim 18, characterized in that a dressing ring is provided as a dressing tool ( 13 , 26 ) which concentrically surrounds the workpiece spindle axis (C₁, C₂). 20. Machine according to one of claims 1 to 19, characterized in that the tool turret ( 32 ) has receptacles with supply connections for at least one orbital grinding unit. 21. Machine according to one of claims 1 to 20, characterized in that the tool turret ( 32 ) has receptacles with supply connections for tools for honing and / or hard fine boring. 22. Machine according to one of claims 1 to 21, characterized in that the tool turret ( 32 ) carries a handling device ( 49 ) for the automatic or semi-automatic workpiece change. 23. Machine according to claim 22, characterized in that an attached as a handling device (49) for the workpiece change on the tool turret periphery, pivotable two-armed change-over unit is provided around a verachse to Werkzeugrevol (33) substantially radially extending axis (51), whose arms (54 , 56 ) extend in a radial plane to the pivot axis ( 51 ) approximately at right angles to one another and have at their free ends means ( 52 , 53 ) for gripping and holding a workpiece ( 12 , 12 a, 24 ) and by moving the tool head ( 28 ) and method and rotation of a workpiece spindle stock ( 8 , 19 ) can be moved into a workpiece-transferring position. 24. Machine according to one of claims 1 to 23, characterized in that a chip disposal device with means ( 46 , 47 , 48 ) is provided for separate collection and removal of the chips produced during grinding on the one hand and during other workpiece processing on the other hand. 25. Machine according to claim 24, characterized in that the bottom and the side boundaries of the working space of the machine Ma form a collecting and trough ( 46 ) for the fed during grinding fen, loaded with removal material cooling lubricant and that in addition a collecting container is provided, which for receiving chips, which arise in the other machining operations, can be positioned over the trough ( 46 ) in the working area of the machine. 26. Machine according to claim 25, characterized in that a revolving conveyor belt ( 48 ) is arranged in the collecting container ( 47 ) for conveying the collected chips out of the working area of the machine. 27. Machine according to one of claims 24 to 26, characterized in that the chip disposal device is arranged between the workpiece headstocks ( 8 , 19 ). 28. Machine according to one of claims 1 to 27, characterized in that cooling lubricant nozzles for the supply of cooling lubricant to the contact zones between the workpieces ( 12 , 24 ) and the tools ( 43 , 44 ) are provided in the workpiece processing and that the cooling lubricant nozzles accordingly the shifting of the contact zones during workpiece processing in the sense of an optimal supply of cooling lubricant to both contact zones can be moved in a numerically controlled manner. 29. Machine according to one of claims 1 to 28, characterized in that the workpiece headstocks ( 8 , 19 ) can be moved towards one another in the direction of a common spindle axis (C₁, C₂) into a position in which the clamping devices ( 11 , 23 ) both workpiece spindles ( 9 , 22 ), a workpiece initially held in a spindle, grip on axially opposite sides, that the workpiece spindles ( 9 , 22 ) can be driven at the workpiece transfer with different rotational speeds, that at least one workpiece spindle has a sensor for detecting a between the spindle and a clamped workpiece has a resulting torque change, which emits a corre sponding signal when the clamping device of the second workpiece spindle has gripped the workpiece for takeover, and that means are provided for releasing the clamping device holding the workpiece when the signal occurs.