Abstract:
In a method of machining a blank from all directions using at least one machine tool, such as a milling machine, production of the ready-to-use, measured component which is controlled and classified with regard to quality, such as a turbine blade, occurs in as few steps and setups as possible with the use of machine tools and milling machines that as far as possible are of identical design. The blank, in a first machining step, is held by at least one first adapter and a first region is given its final partial shape corresponding to the intended use by a machine tool or milling machine. In a second machining step, the partly machined blank is held by at least one second adapter in the first, finally machined region, and the remaining region is given its final overall shape corresponding to the intended use by a machine tool or milling machine.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application is a continuation of the U.S. National Stage designation of co-pending International Patent Application PCT/CH03/00052 filed Jan. 23, 2003, the entire content of which is expressly incorporated herein by reference thereto. 

   FIELD OF THE INVENTION 
   The present invention relates to a method of machining blanks or pre-machined workpieces from all directions using at least one machine tool, such as a milling machine for example, in order to produce ready-to-deliver components which are finally machined in their three-dimensional shape. 
   BACKGROUND OF THE INVENTION 
   During the production of turbine blades, work is normally carried out with multi-spindle machining. This means that a blank is first of all subjected to rough pre-machining, then the airfoil region is processed in detail, and then the tip and finally the root are produced. Between these individual machining steps, the workpiece must be reset in each case by hand or by a robot; this is because the milling machines are often only able to carry out individual machining steps, and in particular because each mounting of the workpiece always only allows the machining of a certain region. This type of production is normally referred to as “box production”, since in each case one machine is normally responsible for a certain machining step, and because the workpiece can be temporarily stored in a box after each machining step. 
   A problem with such production is, inter alia, the fact that the speed of such a production line is always determined by the speed of the slowest machining step. In addition, the multiplicity of processes for the transfer of workpieces between the individual units, such as milling machines, measuring station, washing stations, etc., requires complicated devices and leads to considerable time losses in the production process. 
   SUMMARY OF THE INVENTION 
   The present invention therefore relates to providing a method and an apparatus for machining a blank from all directions using at least one machine tool, e.g. a milling machine, which method makes possible the production of the ready-to-use component in as few machining steps and setups as possible, and with the use of machine tools, such as, for example, “milling machines (machining cells), which as far as possible are of identical design. In this case, the machine tool is able to carry out different operations such as milling, drilling, turning and/or electrical discharge machining, etc. In this context, the expression “milling machine” is therefore to be given a wide interpretation, i.e. it relates to machine tools which are not only able to carry out milling operations but if need be can also carry out turning, drilling, electrical discharge machining, grinding, hardening operations, etc. 
   In the present invention, the blank being given its finished shape in two machining steps. This is done by said blank, in a first machining step, being held by at least one first adapter and by a first region being given its final partial shape corresponding to the intended use by a machine tool or milling machine, and by the partly machined blank, in a second machining step, being held by at least one second adapter in the first, finally machined region, and by the remaining region being given its final overall shape corresponding to the intended use by a machine tool or milling machine. 
   The invention consists in mounting the blank in the first step, for the machining, or in fastening it in the machining space of a machine tool or milling machine by means of an adapter, in such a way that that region of the workpiece which is not concealed as a result of the fastening by the adapter or is not inaccessible as a result of the machining by the machine tool or milling machine is already machined in the first machining step into its final three-dimensional shape corresponding to the intended use. Consequently, this enables the workpiece, for further machining, to be fastened by means of a further adapter which grips the workpiece in certain, already finally machined zones. Of course, the fastening in this case must take place in such a way that the entire region of the partly machined blank which is still unmachined is accessible in an unrestricted manner for the final further machining by the same or another machine tool or milling machine. It is thus then possible in the second machining step, without further resetting, for the partly machined blank to finally be given its overall three-dimensional shape. 
   This is quite surprising, for the individual machining steps comprise milling operations and also, inter alia, roughing and finishing, which exert considerable forces on the workpiece and which have hitherto always prevented the person skilled in the art from giving the workpiece its final shape in only two setups. Normally, it has always been assumed that the forces produced during the machining lead either to damage to the workpiece or to inadequate quality of the final workpiece (e.g. as a result of vibrations, moments, etc.). However, it has been found that it is possible, in a first machining step, to already give functional surfaces their final shape and to immediately use precisely these functional surfaces for the mounting for the second machining step. 
   The reduction in setups leads to a considerable simplification in the production process and to cost savings (less downtime, fewer means for the transfer of components, etc.) and nonetheless permits the production of final shapes which meet the highest quality requirements. 
   The overall shape which is in accordance with the intended use and which can be achieved with the method according to the invention involves any desired component which can be obtained from a blank by the abovementioned operations. The method is especially suitable for the production of components as used in a turbine (steam turbine or gas turbine). Thus the component is preferably a moving or guide blade of a turbine. 
   According to a first preferred embodiment of the invention, the blank is a blank made of metal or a ceramic material in the form of a cylindrical or polyhedral, in particular preferably parallelepiped-shaped, block or is a cast blank or forged blank. It is likewise possible to feed the blank to the method according to the invention in an already pre-machined form. Surprisingly, the method according to the invention is also successful with such difficult-to-machine components, and this without loss of quality of the final shaped parts. 
   According to a further preferred embodiment of the invention, the partly machined blank is cleaned and/or measured after the first machining step, for which purpose it is in particular preferably removed in a defined mounting from the machining region of the machine tool or milling machine and cleaned and/or measured in a measuring station. This step between the two actual machining steps permits, on the one hand, final quality control of the already machined region of the workpiece, this in an especially simple manner if the partly machined workpiece is removed in a defined manner from the machining space of the machine tool or milling machine. In this context, “defined manner” means that the means for removing the partly machined workpiece grip the latter at a well-defined location, so that the partly machined workpiece can then be fixed and measured in a likewise well-defined position in a measuring station. This is in particular possible in a very effective manner if, for the defined mounting during the first machining step, defined (temporary) gripping surfaces are prepared in the remaining regions, i.e. in those regions which have not yet been machined into an actual functional surface in the first machining step, via which gripping surfaces transport means, in particular in the form of grippers, and/or mounting means of the measuring station or of a cleaning unit, respectively, in particular in the form of grippers, can mount the partly machined blank in a defined position. 
   A further preferred embodiment of the invention is characterized in that the final overall shape involves a turbine blade with or without shroud band, in particular a turbine blade having a surface within the range of N4 to N5 at tolerances of ±0.002 mm, a length within a range of 10 to 400 mm, or even up to 2400 mm, with a rotating diameter of 50 to 400 mm and a weight of 0.01 to 40 kg, or even up to 240 kg. In other words, the method can surprisingly be used even in the case of such complex shapes which are very demanding in particular with regard to the quality requirements, and this also within a very large size range (in particular with regard to length), weight range, and also for very small tolerances. 
   In another preferred embodiment, the final overall shape is cleaned and/or measured and/or packed after the second machining step, as a result of which the component can then be delivered indirectly for storage, dispatch or a fitting process. 
   A particular embodiment of the method according to the invention works in such a way that the blank is first of all shaped on its one side in the first machining step and is then shaped on its other side in the second machining step. That is to say the first adapter grips the blank at a first end, in the first machining step the second end of the blank is given its final partial shape corresponding to the intended use, the second adapter then grips the partly machined blank at the partial shape and, in the second machining step, the first end is processed into the final overall shape. If the final overall shape involves a turbine blade, the root region is preferably processed in the first machining step, then this root region is used for the mounting for the second machining step, and the tip region is processed in the second machining step. The opposite process can also be realized, in particular in the case of a turbine blade with a shroud band; that is to say that the tip region with shroud band is processed in the first step. In addition, it proves to be advantageous, in this case, in the first machining step, for two defined gripping surfaces in the form of blind holes or recesses to be milled on each of two opposite sides of the blank (of course in such a way that the functional surfaces to be subsequently provided in the second machining step are not affected by these recesses), a first (top) pair being used for the gripping with the gripper for removing the partly machined blank from the machining region of the machine tool or milling machine and for reinserting said partly machined blank, and a second (bottom) pair being used for the defined fixing of the partly machined blank on the measuring station. In this case, if appropriate, in the second machining step, a center hole can be milled on the side remote from the root, and a traversable and/or pivotally mounted tailstock for the mounting can be moved into this center hole at least during some stock removal steps during the second machining step. It can thus be ensured that the moments occurring during such machining can be reduced or that possible vibrations can be prevented. 
   On the other hand, another particular embodiment of the method works in such a way that the blank is mounted during the first machining step on one side or, if appropriate, at its two ends (via a tailstock), the entire center region of the workpiece is processed except for the respective projecting portions, which if need be are already provided with recesses which already define the terminal regions. This component is then fed to the second machining step and is held via an adapter during this second step in this center region, in which the final functional surfaces are already processed. In other words, the procedure is such that the first adapter grips the blank at a first end, and, if appropriate, the second end is fixed via a traversable and/or pivotally mounted tailstock and a center hole, that, in the first machining step, the center region and, if appropriate, one of the end regions of the blank is given its final partial shape corresponding to the intended use, that the second adapter grips the partly machined blank at the center partial shape and the one end region or, if appropriate, the two end regions are processed into the final overall shape. For example, the partial shape may involve a turbine blade, with unmachined projecting portions being left at the tip part and/or at the root part, recesses being provided between the projecting portions and the turbine blade in particular preferably during the first machining step. In this case, the second adapter advantageously grips the partly machined turbine blade by means of two gripping jaws, the axis of the partly machined turbine blade coming to lie essentially perpendicularly to the fastening axis of the second adapter in the machine tool or milling machine. 
   According to an additional preferred embodiment, the method is carried out in a machining cell or machining unit which has a plurality of machine tools or milling machines, for example 2, 4 or even 6 or more. That is to say that at least two machine tools or milling machines are used simultaneously in a cell, the blanks, the partly machined blanks and the final overall shapes being fed by means of a handling system via a handling portal and via a central control to machine tools or milling machines available in each case and being subjected to a first or second machining step, respectively, in said machine tools or milling machines. In other words, the handling portal serves the at least two machine tools or milling machines, in which case this can take place in an optimized manner, and thus precisely the problem mentioned at the beginning, which occurs in an arrangement in which a certain function is assigned to a respective machine tool or milling machine, can be avoided. This is because both machine tools or milling machines are able to carry out both the first and the second machining step, and thus the machining means available can always be used in an optimum manner via the central control. In this case, the cell may comprise even further units, thus, for example, at least one measuring unit and/or at least one cleaning unit and/or at least one workpiece buffer location and/or a loading belt (a paternoster is also possible) and/or an adapter magazine and/or a discharge station and/or a washing and preserving unit and/or a material-code-reading station and/or an inscription unit. All of these components are in this case connected to the handling portal, and the central control also assigns the parts to these units in a manner adapted to the respective conditions. If appropriate, a plurality of handling portals may also be arranged, but in any case a plurality of handling systems. 
   Furthermore, the present invention relates to an apparatus for carrying out the method as described above. In particular, this is an apparatus in which the at least one machine tool or milling machine and, if appropriate, a measuring unit and/or, if appropriate, at least one cleaning unit and/or, if appropriate, at least one workpiece buffer location and/or, if appropriate, at least one loading belt and/or, if appropriate, at least one adapter magazine and/or, if appropriate, at least one discharge station and/or, if appropriate, at least one washing and preserving unit and/or, if appropriate, at least one material-code-reading station and/or, if appropriate, at least one inscription station are served with the blanks, the partly machined blanks and the final overall shapes, in each case possibly already cleaned or measured or packed, via a single handling portal of linear or circular design, in particular in the form of a belt or a rail on which at least one handling system but preferably a plurality of handling systems having in each case at least one gripper are mounted in a traversable manner. 
   Furthermore, the present invention relates to the use of an apparatus as described above for producing a turbine blade, in particular a turbine blade with or without a shroud band, having a surface within the range of N4 to N5 with tolerances of ±0.002 mm, a length within the range of 10 to 400 mm, with a rotating diameter of 50 to 400 mm, and a weight of 0.01 to 40 kg. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention is to be explained in more detail below with reference to exemplary embodiments and in connection with the figures. In the drawing: 
       FIG. 1  shows a cell layout with two milling machines; 
       FIG. 2  shows a cell layout with four milling machines; 
       FIG. 3  shows a cell layout with six milling machines; 
       FIG. 4  shows individual machining steps of a blank according to the first exemplary embodiment:
         a) a typical blank to be machined;   b) a gripping adapter with blank from the front;   c) a gripping adapter with blank from the side;   d) a gripping adapter with blank machined on one side from the front;   e) a gripping adapter with blank machined on one side from the side;   f) a gripping adapter with blank machined on one side from the front, with engaging gripper;   g) a gripping adapter with blank machined on one side from the side, with engaging gripper;   h) operation for releasing from gripping adapter, with gripper;   i) operation for depositing the blank machined on one side on the measuring station from the front;   k) operation for depositing the blank machined on one side on the measuring station from the side;   l) measuring operation on the measuring station from the front;   m) measuring operation on the measuring station from the side;   n) insertion of the blank machined on one side into the special gripping adapter by means of the gripper;   o) fixing of the blank machined on one side in the blade milling machine;   p) finish-machined blade in the blade milling machine; and       
       FIG. 5  shows individual machining steps of a blank according to the second exemplary embodiment:
         a) centrally machined blank in the blade milling machine;   b) measuring of the centrally machined blank in the measuring station;   c) special gripping adapter with centrally machined blank, clamped in place, from the front;   d) special gripping adapter with centrally machined blank, clamped in place, from the side;   e) special gripping adapter with finished blade, clamped in place, from the front;   f) special gripping adapter with finished blade, clamped in place, from the side.       
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   First of all, possible layouts of cells for the machining according to the invention of workpieces are to be shown and explained with reference to  FIGS. 1 to 3 , then the actual process sequences of the two essential exemplary embodiments are to be shown and explained with reference to  FIGS. 4 and 5 . 
     FIG. 1  shows the layout of a cell from above for carrying out the process according to the invention. This is a small cell having two blade milling machines  10  which are loaded with the workpieces to be machined and are respectively unloaded via a handling portal  18 . To this end, the handling portal  18  has a handling system with a gripper  16 . If appropriate, a plurality of such handling systems  16  can be mounted on the same handling portal  18  in a traversable manner. The handling portal  18 , via further units essentially remote from a working front  19 , is supplied with blanks by means of a loading belt  11  in the form of a paternoster. The blanks are gripped by the gripper of the handling system  16 , fed to the adapter magazine  12 , fixed there in an adapter, fed to a material-code-reading station  15 , in which the material code applied to the blank is read, and are then transferred to one of the two blade milling machines  10  for the first machining step. These transfer steps are coordinated and controlled by a central control unit (not shown). This is because the control unit, in accordance with the information which has been determined in the material-code-reading station  15  concerning the material condition of the blank, also activates the assigned blade milling machine, that is to say the milling program adapted to the material is started. 
   After the first machining step in one of the blade milling machines  10 , the partly machined blank is again seized by the handling system  16  and is fed to a washing unit  14 , either with or without an adapter (in this case an intermediate stop is made at the adapter magazine  12 ), is then measured in a measuring station, is mounted at the adapter magazine  12  with an adapter for the second machining step, and is then assigned again to one of the two blade milling machines  10  for the second machining step. This may be either the same blade milling machine which has already carried out the first machining step or else the second blade milling machine. After completion of the second machining step, the now finished workpiece is seized by the handling system  16 , washed in the washing station  14 , measured, and removed from the cell via a discharge station  13 , if need be after additional preserving or packing. 
   The fact that both milling machines can carry out both the first and the second machining step results in the advantage that the entire production process, i.e. the two machining steps and also washing, measuring, preserving, can in each case be run in an optimum manner via the handling system  16  in such a way as to be regulated and controlled via a control unit. In contrast to “box-type production”, the downtimes of the individual units can thus be minimized and the entire process can be carried out more quickly and more efficiently. 
     FIG. 2  shows a corresponding cell of medium size which is of essentially identical construction to the cell in  FIG. 1  but which has four blade milling machines  10  and also an inscription unit  20 , with which the finally machined, cleaned and fully measured workpiece can be provided with an inscription which enables the workpiece to be clearly assigned to a certain machining cycle and serves to document the quality control effected. In addition, the system has an independently designed cleaning unit  21 , preferably in the form of an ultrasonic bath, and also a measuring unit  22  and a discharge station  23 . A machining process carried out in a cell according to  FIG. 2  is again controlled by a control unit (not shown in the figure). 
     FIG. 3  shows a large cell, which now has six blade milling machines  10 , which are all served via the same handling portal  18 . Two handling systems  16  are required for this purpose. Cells having more than two milling machines  10  can be controlled in an even more optimum manner via the control unit, this in particular when the individual machining steps are of significantly different length. 
   The two following figures show two exemplary embodiments of the process according to the invention, the second for the production of turbine blades of any kind, such as, for example, moving or/and guide blades compressor blades, steam turbine blades, hot-gas blades, etc. 
     FIG. 4   a ) shows a blank  30  in the form of a parallelepiped. However, the blank  30  may also be round or have any other desired cross section. The blanks may also be rough forging blanks or cast blanks. Such a blank  30  is normally provided with a material code  31  for quality assurance (digits, letter code laser-cut, punched, rotationally stamped). 
   Depending on the blade type and in particular on the blade length, the method steps cited below are used in the same flexible production cell (cf.  FIGS. 1 to 3 ). 
   1. The blank  30  is placed on a loading belt  11  (paternoster) or a loading ramp, with which it passes to the handling system  16  at a transfer location  17 . 
   2. Here, the blank  30  is oriented with respect to the defined transfer position  17 . 
   3. After that, the blank  30  is clamped with a gripper of one of the two handling systems  16  running on a handling portal  18  and is brought to a material-code-reading station  15  by means of the handling system  16 . 
   4. The material code is read and signaled to the production control system, the control unit of the cell. 
   5. In this way, the blank  30  is recorded in a clearly defined manner and assigned a production number and series number. It is subsequently written on a defined surface by means of an inscription station  20 . With the latter, the blade and its quality data (documents) as well as all the production steps covered and their settings can be reproduced in a clearly defined manner, which is of great importance for the retrofit case. 
   6. After that, the blank  30  is brought to one of the blade milling machines  10  by means of the handling system  16 . 
   7. The blank  30  is then pushed by means of the ram of the handling system  16  into the loading and unloading region of the blade milling machine  10  at clamping level and then into a special gripping adapter  33 , as shown in  FIGS. 4   b ) and  c ). Here, it is fixed and clamped in a clearly defined manner by a gripping and clamping system. For this purpose, the gripping adapter  33  is fixed and clamped in a clearly defined manner in an adapter changer (in the loading and unloading region of the blade milling machine). In this case, the gripping adapter  33  consists of two gripping jaws  32  which have a jaw clamping stroke  35  and clamp the blank  30  laterally. A clamping screw mechanism  38  is provided for the movement of the gripping jaws  32 . For a fixed limit at the bottom, the gripping adapter  33  has a movable stop  34  which has a stroke  36 . The adapter  33  itself is split in two as it were and has a mounting part  40  not specific to the component (e.g. standard HSK) which is provided with a clamping cylinder  41  for fixing in the chuck of the blade milling machine  10 . In addition, the adapter  33  has a top part  39  which is specific to the component and carries the abovementioned gripping jaws  32 . In addition, one of the two elements of the adapter  33  has a gripper channel  37  which serves either to transfer the adapter  33  to the gripper in a well-defined position or to mount it in the adapter magazine. 
   8. The gripper of the handling system is released and moved out of the loading and unloading region of the blade milling machine  10 . It is assigned other tasks by the control system. 
   9. By means of the adapter changer, the gripping adapter  33  with the clamped blank  30  is then introduced as replacement into the A rotary axis of the machine tool, which is located in the working space of the machine. (Principle as during tool change.) 
   10. Here, the complete root part  42  and  43  of the turbine blade to be produced is then produced with the corresponding NC programs and tools (cf.  FIGS. 4   d ) and  e )). Furthermore, in the case of longer turbine blades, a part of the duct or airfoil contour  44  is rough-milled or finish-milled. 
   11. Finally, on two opposite sides of the outer contour of the blank  30 , in the unmachined part  53 , in each case two defined gripping surfaces  45  and  46  are produced for the subsequent gripper transfer and fixing of the measuring position (cf.  FIGS. 4   d ) and  e )). 
   12. After that, the turbine blade thus semifinished (root part is ready for fitting) is swung into the loading and unloading region of the blade milling machine again by means of the adapter changer. 
   13. The gripper  48  of the handling system  16  is then moved into the loading and unloading region of the blade milling machine and fixes and clamps the blank  30  in the two top gripping surfaces  45  by means of the two gripping arms  49 , which have a clamping stroke  50  (cf.  FIGS. 4   f ) and  g )). After that, the clamping of the blank  30  in the gripping adapter  33  is released and the handling system  16  moves the semifinished blank clamped in the gripper  48  out of the gripping adapter  33  and out of the loading and unloading region of the blade milling machine (cf.  FIG. 4   h )). 
   14. By means of the handling system  16 , the semifinished blank is brought into an ultrasonic bath  21  for cleaning. Here, the semifinished blank and part of the gripper are cleaned. 
   15. After the cleaning, the semifinished blank is brought by means of the handling system  16  to the measuring position, which is located on the measuring machine  22 . 
   16. Here, the semifinished blank is fixed and clamped in the two bottom gripping surfaces  46  in a special gripping and clamping station  56  (cf.  FIGS. 4   i ) and  k )). After that, the gripper  49  is released and moved by means of the handling system  16  out of the working region of the measuring machine  22 . It is assigned other tasks by the control system. 
   17. In this measuring position, the complete root part and here in particular the subsequent functional surfaces are measured with a measuring probe  58  having a measuring head  59  (cf.  FIGS. 4   l ) and  m )). The measuring reports are prepared by the measuring machine and transmitted to the control system. Furthermore, correction sizes, if appropriate, for further root machining are prepared and directed by means of the control system to the relevant blade milling machine in order to carry out the relevant NC program corrections here. Furthermore, reference size corrections are transmitted via the control system to the following duct or airfoil machine tool. 
   18. After the measuring of the turbine blade root, the semifinished blank or the semifinished blade is fixed and clamped in the two top gripping surfaces  45  by means of the gripper  48  of the handling system  16 . The clamping in the special gripping and clamping station  56  is released and the semifinished blank is brought into the loading and unloading region of the blade milling machine  10  by means of the handling system  16 . 
   19. Here, the handling system  16 , in the gripper  48  of which the semifinshed blank is clamped, pushes the semifinished blank or the root part of the semifinished turbine blade in a defined manner into a special gripping adapter  60  in such a way that the root part can be fixed and clamped in a clearly defined manner by means of the shaped gripping elements  61  of the special gripping adapter  60 . The adapter is again of two-piece design, having a mounting part  40  not specific to the component (e.g. with HSK cylinder) and having a top part  60 . The special gripping adapter  60  has special jaws  61  which are adapted to the respective workpiece and which, in the case shown in  FIG. 4   n ), also have a special jaw gripping stroke  62 , so that the root part  42  can be fixed in an optimum manner. The special gripping adapter is fixed and clamped in a clearly defined manner in an adapter changer in the loading and unloading region of the blade milling machine. 
   20. By means of the adapter changer, the special gripping adapter  60 , with the semifinished turbine blade, is then introduced as replacement into the A rotary axis of the blade milling machine  10 , which is located in the working space of the machine. (Principle as during tool change.) 
   21. Here, if necessary, in the first step, a center hole is provided on the free tip end of the semifinished blank. In most cases, this is done by a centering operation. 
   22. If a center hole is provided, the tailstock center  64  of a tailstock  63 , by swinging around and traversing said tailstock  63 , is then moved into the center hole and the semifinished workpiece is thus fixed and axially restrained in a clearly defined manner (cf.  FIG. 4   o )). 
   23. If the steps 21 to 22 are not necessary for the specific turbine blade, they may be omitted. 
   24. After that, in the case having a center hole, the complete duct or airfoil part of the turbine blade to be produced is then produced by means of the corresponding NC programs and tools. 
   25. To produce the tip part, the tailstock center  64  is then moved out of the center hole and the tailstock center  63  is tilted back along  66 , so that the tip part becomes freely accessible (cf.  FIG. 4   p )). 
   26. In the case of semifinished workpieces without a center hole, the tip part is produced immediately following the production of the duct or airfoil part by appropriate NC programs and tools. 
   27. After that, the thus completed turbine blade  68  is swung back again into the loading and unloading region of the blade milling machine  10  by means of the adapter changer. 
   28. The gripper  48  of the handling system  16  is then moved into the loading and unloading region of the blade milling machine  10  and fixes and clamps the special gripping adapter  60  having the finished turbine blade  68  at a specific position, so that it can bring the special gripping adapter  60  out of the loading and unloading region of the blade milling machine after it has been released from its clamping. 
   29. By means of the handling system  16 , the special gripping adapter  60  with the finished turbine blade  68  is brought into an ultrasonic bath  21  for cleaning. Here, it and the turbine blade  68  and part of the gripper  48  are cleaned. 
   30. After the cleaning, the turbine blade  68  is brought by means of the handling system  16  to the measuring position, which is located on the measuring machine  22 . 
   31. Here, the special gripping adapter  60  with the finished turbine blade  68  is fixed and clamped in a special gripping station. After that, the gripper  48  is released and moved by means of the handling system  16  out of the working region of the measuring machine  22 . It is assigned other tasks by the control system. 
   32. In this measuring position, the complete turbine blade  68  is measured. The measuring reports are prepared by the measuring machine  22  and transmitted to the control system. Furthermore, correction sizes, if appropriate, for further duct machining are prepared and directed by means of the control system to the relevant blade milling machine in order to carry out the relevant NC program corrections here. The blade documentation is then completed with these measuring data. 
   33. After the measuring of the turbine blade, the special gripping adapter  60  with the finished turbine blade  68 , after the release of said special gripping adapter  60  in the special gripping station, is brought to the inscription station  20  by means of the gripper  48  of the handling system  16 . Here, the finished turbine blade is provided with a clearly defined reproducible code by a laser method, engraving method or another inscription method. 
   34. After the inscription station  20 , the special gripping adapter  60  with the finished turbine blade  68  is brought to the discharge clamping station by means of the gripper  48  of the handling system  16 . Here, the special gripping adapter  60  is fixed and clamped in a clamping receptacle. The gripper  48  releases the special gripping adapter  60 . 
   35. The shaped gripping elements  61  are released by an unlocking unit, so that the ready-to-use turbine blade  68  falls downward into a receiving container of the washing and preserving unit  14  or  21 , respectively. If this is not effected automatically, the removal and insertion of the turbine blade  68  can also be effected by means of the gripper  48  of the handling system  16 . 
   36. As a last step, the turbine blade  68  is transported through the washing and preserving unit  14 , where it is washed and, if necessary, preserved. 
   37. If longer transport to a remote assembly location is involved, a packing welding station, where the turbine blade is welded in position for the further transport, is provided downstream of the normal discharge station, where the turbine blade is normally put into a detent pallet. 
   In summary, the method, in which first of all the one end and then the other end is machined and as shown in  FIG. 4 , comprises the following steps:
         Charge blank   Read test number of blank   Place blank in machine   Root machining   Remove workpiece and insert new part   Clean workpiece   Insert in measuring machine   Measure root (calculate corrections and transmit to machine)   Remove workpiece from measuring machine and insert into next machine   Airfoil and tip machining   Remove workpiece with adapter   Clean workpiece   Insert into measuring machine   Measure airfoil and tip (calculate corrections and transmit to machine)   Remove workpiece   Inscribe workpiece   Discharge workpiece (remove from adapter at washing machine)       

     FIG. 5  shows another exemplary embodiment of the method according to the invention, in which the center region of the workpiece is machined in the first machining step and the two end regions (or only one end region) (final gripping at the rhombic surfaces) are machined in the second machining step. In its entirety, the method comprises the following steps: 
   1. The blank  30  is placed on a loading belt  11  (paternoster) or a loading ramp, with which it passes to a transfer location  17  at the handling system  16 . 
   2. Here, the blank  30  is oriented with respect to the defined transfer position  17 . 
   3. After that, the blank  30  is clamped with a gripper of one of the two handling systems  16  running on a handling portal  18  and is brought to a material-code-reading station  15  by means of the handling system  16 . 
   4. The material code is read and signaled to the production control system, the control unit of the cell. 
   5. In this way, the blank  30  is recorded in a clearly defined manner and assigned a production number and series number. It is subsequently written on a defined surface by means of an inscription station  20 . With the latter, the blade and its quality data (documents) as well as all the production steps covered and their settings can be reproduced in a clearly defined manner, which is of great importance for the retrofit case. 
   6. After that, the blank  30  is brought to one of the blade milling machines  10  by means of the handling system  16 . 
   7. The blank  30  is then pushed by means of the ram of the handling system  16  into the loading and unloading region of the blade milling machine  10  at clamping level and then into a special gripping adapter  33 , as shown in  FIG. 5   a ). Here, it is fixed and clamped in a clearly defined manner by a gripping and clamping system. For this purpose, the gripping adapter  33  is fixed and clamped in a clearly defined manner in an adapter changer in the loading and unloading region of the blade milling machine  10 . In this case, the gripping adapter  33  consists of two gripping jaws  70  which have a jaw clamping stroke  71  and clamp the blank  30  laterally. A clamping screw mechanism (not shown), for example, is provided for the movement of the gripping jaws  32 . For a fixed limit at the bottom, the gripping adapter  33  may also have a movable stop as in the previous exemplary embodiment. The adapter  33  itself is split in two as it were and has a mounting part  40  not specific to the component (e.g. standard HSK) which is provided with a clamping cylinder  41  for fixing in the chuck of the blade milling machine  10 . In addition, the adapter  33  has a top part  72  which is specific to the component and carries the abovementioned gripping jaws  70 . In addition, one of the two elements of the adapter  33  has a gripper channel  37  which serves either to transfer the adapter  33  to the gripper in a well-defined position or to mount it in the adapter magazine. 
   8. The gripper of the handling system is released and moved out of the loading and unloading region of the blade milling machine  10 . It is assigned other tasks by the control system. 
   9. By means of the adapter changer, the gripping adapter  33  with the clamped blank  30  is then introduced as replacement into the A rotary axis of the machine tool, which is located in the working space of the machine. (Principle as during tool change.) 
   10. Here, if necessary, in the first step, a center hole is provided on the free tip end of the blank  30 . In most cases, this is done by a centering operation. 
   11. If a center hole is provided, the tailstock center  64  of a tailstock  63 , by swinging around and traversing said tailstock  63 , is then moved into the center hole and the blank  30  is thus fixed and axially restrained in a clearly defined manner. 
   12. If the steps 10 to 11 are not necessary for the specific turbine blade, they may be omitted. 
   13. After that, in the case with or without a center hole, the complete turbine blade (root, duct, airfoil, tip part) of the turbine blade to be produced is produced by means of appropriate NC programs and tools. A recess  76  and  77  is milled on the root and tip sides, so that the remaining parts  74  and  75  of the blank can subsequently be milled (cf.  FIG. 5   a )). 
   14. After that, the virtually finished turbine blade is swung into the loading and unloading region of the blade milling machine again by means of the adapter changer. 
   15. The gripper of the handling system is then moved into the loading and unloading region of the blade milling machine and fixes and clamps the gripping adapter  33  having the almost finished turbine blade at a specific position, so that it can bring the gripping adapter  33  out of the loading and unloading region of the blade milling machine after it has been released from its clamping. 
   16. By means of the handling system  16 , the gripping adapter  33  with the almost finished turbine blade is brought into an ultrasonic bath  21  for cleaning. Here, the gripping adapter  33  with the almost finished turbine blade and part of the gripper are cleaned. 
   17. After the cleaning, the gripping adapter  33  with the virtually finished turbine blade is brought by means of the handling system  16  to the measuring position, which is located on the measuring machine  22  (cf.  FIG. 5   b )). 
   18. Here, the gripping adapter  33  with the virtually finished turbine blade is fixed and clamped in a special gripping station. After that, the gripper is released and moved by means of the handling system  16  out of the working region of the measuring machine  22 . It is assigned other tasks by the control system. 
   19. In this measuring position, the complete turbine blade is measured. The measuring reports are prepared by the measuring machine  22  and transmitted to the control system. Furthermore, correction sizes, if appropriate, for further duct machining are prepared and directed by means of the control system to the relevant blade milling machine in order to carry out the relevant NC program corrections here. 
   20. The blade documentation is then completed with these measuring data. 
   21. The gripper of the handling system  16  is then moved into the measuring machine  22  and, after the release of the gripping adapter  33 , removes the virtually finished and measured turbine blade and fixes the latter in the second position in a clamped manner on the special gripping adapter  78  (cf.  FIG. 5   c ). In the process, the virtually finished turbine blade comes to lie transversely to the axis of the special gripping adapter  78  and is fixed by two interchangeable gripping jaws  79  which have a clamping stroke  80  and are displaceable relative to one another along  81 . In this case, the fixing is effected on the rhombic surfaces of the virtually finished turbine blade. 
   22. After it has been oriented, the turbine blade is then finally clamped in the special gripping adapter  78 . After that, the virtually finished produced turbine blade is moved out of the measuring machine  22  by means of the gripper of the handling system  16  and brought to the blade milling machine. 
   24. The gripper of the handling system is then moved into the loading and unloading region of the blade milling machine and fixes and clamps the special gripping adapter  78  with the virtually finished turbine blade in the adapter changer. 
   25. By means of the adapter changer, the special gripping adapter  78  with the virtually finished turbine blade is introduced as replacement into the A rotary axis of the machine tool, which is located in the working space of the machine. (Principle as during tool change.) 
   26. After that, the tip and root parts of the turbine blade are then finish-milled by means of appropriate NC programs and tools (cf.  FIGS. 5   e ) and  f )). 
   27. After that, the special gripping adapter  78  with the finished turbine blade is swung back again into the loading and unloading region of the blade milling machine  10  by means of the adapter changer. 
   28. The gripper of the handling system is then moved into the loading and unloading region of the blade milling machine and fixes and clamps the special gripping adapter  78  having the finished turbine blade, so that it can bring the special gripping adapter  78  out of the loading and unloading region of the blade milling machine after it has been released from its clamping. 
   29. By means of the handling system  16 , the special gripping adapter  78  with the finished turbine blade is brought into an ultrasonic bath  21  for cleaning. Here, the special gripping adapter with the finished turbine blade  82  and part of the gripper are cleaned. 
   30. After the cleaning, the special gripping adapter  78  with the finished turbine blade  82  is brought by means of the handling system  16 , if again necessary, to the measuring position, which is located on the measuring machine  22 . 
   31. In this measuring position, the remaining part of the turbine blade  82 , if necessary, is measured. The measuring reports are prepared by the measuring machine and transmitted to the control system. Furthermore, correction sizes, if appropriate, for further tip and root machining are prepared and directed by means of the control system to the relevant blade milling machine in order to carry out the relevant NC program corrections here. 
   32. The blade documentation is then completed with these tip and root measuring data. 
   33. After the measuring of the turbine blade, the special gripping adapter  78  with the finished turbine blade  82 , after the release of said special gripping adapter  78  in the special gripping station, is brought to the inscription station  20  by means of the gripper of the handling system  16 . Here, the finished turbine blade  82  is provided with a clearly defined reproducible code by a laser method, engraving method or another inscription method. 
   34. After the inscription station  20 , the special gripping adapter  78  with the finished turbine blade  82  is brought to the discharge clamping station by means of the gripper of the handling system  16 . Here, the special gripping adapter is fixed and clamped in a clamping receptacle. The gripper releases the special gripping adapter. 
   35. The shaped gripping elements  79  are released by an unlocking unit, so that the ready-to-use turbine blade falls downward into the receiving container of the washing and preserving unit. If this is not effected automatically, the removal and insertion of the turbine blade  82  can also be effected by means of the gripper of the handling system. 
   36. As a last step, the turbine blade is transported through the washing and preserving unit, where it is washed and, if necessary, preserved. 
   37. If longer transport to a remote assembly location is involved, a packing welding station, where the turbine blade is welded in position for the further transport, is provided downstream of the normal discharge station  13 , where the turbine blade is normally put into a detent pallet. 
   The individual production processes can be assigned to all the blade milling machines by the control system according to requirements. Fixed assignment as described above is not absolutely necessary. 
   If all the operation stations are covered to point  14 , the workpiece can also be temporarily stored in a workpiece buffer location. 
   If all the operation stations are covered to point  28 , the workpiece can also be temporarily stored in the adapter magazine  12 . 
   The abovementioned method is suitable for producing turbine blades of the following specification: 
   
     
       
             
             
             
             
           
         
             
                 
                 
             
           
           
             
                 
               Blade quality: 
               surface 
               N4–N5 
             
             
                 
                 
               tolerances 
               +/−0.002 mm 
             
             
                 
               Dimensions: 
               length 
               &gt;10 mm 
             
             
                 
                 
                 
               &lt;400 mm or &lt;800 mm 
             
             
                 
                 
               rotating diameter 
               &gt;50 mm 
             
             
                 
                 
                 
               &lt;400 mm or &lt;800 mm 
             
             
                 
                 
               weight 
               &gt;0.01 kg 
             
             
                 
                 
                 
               &lt;40 kg or &lt;140 kg 
             
             
                 
                 
             
           
        
       
     
   
   The method permits the production of a turbine blade in two production and measuring steps; the turbine blade is ready for fitting and documented with regard to quality at the end. All transport, gripping operations, measuring correction cycles, etc., take place within the cell. A blade documented with regard to quality and preserved if necessary can then be removed from the discharge station. 
   It is found that the throughput time of a series with the method proposed above is less than one day, whereas substantially more than one day and up to 14 days are necessary with conventional production of a turbine blade. 
   List of Designations 
   
       
         10  Blade milling machine 
         11  Loading belt 
         12  Adapter magazine 
         13  Discharge station 
         14  Washing and preserving unit 
         15  Material-code-reading station 
         16  Handling system with gripper 
         17  Transfer position 
         18  Handling portal 
         19  Working front 
         20  Inscription unit 
         21  Cleaning unit (ultrasound) 
         22  Measuring unit 
         23  Discharge station 
         30  Blank 
         31  Material code 
         32  Gripping jaws 
         33  Gripping adapter for blank 
         34  Movable stop 
         35  Jaw clamping stroke 
         36  Stroke of  34   
         37  Gripper channel for changer 
         38  Clamping screw mechanism 
         39  Top part of  33  specific to component 
         40  Mounting part of  33  not specific to component 
         41  Clamping cylinder of  41   
         42  Root geometry 
         43  Rhombic geometry 
         44  Duct/airfoil region 
         45  Top defined clamping surfaces 
         46  Bottom defined clamping surfaces 
         47  Surface for blade code 
         48  Gripper 
         49  Gripping arms of  48   
         50  Gripping stroke of  49   
         51  Handling ram 
         52  Handling or gripper z stroke 
         53  Unmachined parts of the blank 
         54  Withdrawal direction of the gripper 
         55  Handling stroke 
         55  Gripper pince 
         57  Gripping stroke of  56   
         58  Measuring probe 
         59  Measuring head 
         60  Special gripping adapter 
         61  Special jaws 
         62  Jaw gripping stroke of  61   
         63  Tailstock 
         64  Centering nose 
         65  Displaceability of  63   
         66  Tilting of  63   
         67  A axis of the blade milling machine 
         68  Finished blade 
         70  Gripping jaws 
         71  Jaw clamping stroke 
         72  Top part of  33  specific to component 
         73  Tip part of the blade 
         74  Unmachined projecting portion at the tip part of the blade 
         75  Unmachined projecting portion at the root part of the blade 
         76  Recess at the tip part 
         77  Recess at the root part 
         78  Special gripping adapter 
         79  Interchangeable gripping jaws 
         80  Clamping stroke of  79   
         81  Displacement of  79   
         82  Finished blade