The invention generally relates to electrical discharge machining (EDM: Electrical Discharge Machine) . More practically, the invention relates to a method for manufacturing and using a workpiece, in particular an EDM- (Electrical Discharge Machine) electrode. Further, the invention relates to a holder for holding a blank or a working piece such as an EDM-electrode for implementation of such method.

Electrical discharge machining is widely used to make a variety of metal structures in small volumes. Special shaped electrodes are used to cut complex surfaces into metal blanks or the like. Conventional EDM-electrodes usually have a mirror image of the desired shape of the workpiece to be machined by EDM. By moving the electrode into close proximity to the blank and by applying an electric pulse voltage to the gap arranged between the EDM-electrode and the blank, an electric discharge is caused removing material from the blank. The discharge area is flooded with a dielectric fluid which carries away the eroded material. EDM machining results in the capability of processing metals or alloys without necessity of high cutting force and/or corresponding tools. This leads to cost efficient and less complex machining process with respect to conventional machining tech- niques .

Precision of EDM machining strongly depends on precise production of the EDM-electrode. Usually, the EDM-electrode is produced starting from a bar stock, also termed as blank, which is machined in succession by conventional milling, CNC processing, grinding, wire EDM and/or sink EDM for instance. Manufacturing of the EDM-electrode requires high accuracy in positioning the blank, the semi-finished product and the EDM-electrode, respectively in corresponding machining appa ^¬ ratuses used in sequence to produce the EDM-electrode with high shape precision.

Accordingly, clamping of the blank, the semi-finished prod- uct and the workpiece, in particular the EDM-electrode, re ^¬ spectively, to subsequent machining centers requires high precision and time consuming alignment of the workpiece with respect to corresponding machining centers. It is one of the objects of the present invention to facilitate production and usage of workpieces, in particular of EDM-electrodes utilized for electrical discharge machining.

According to one aspect of the invention, a method is pro- vided for manufacturing and using a workpiece, in particular an EDM- (Electrical Discharge Machine) electrode, comprising the steps of: providing a holder for holding a blank;

providing a blank; clamping said blank in said holder; machining of said blank clamped in the holder, into said work- piece at a plurality of processing machines, wherein the holder holding said blank and the machined blank, respectively, is clamped in a chuck of the respective processing center, and wherein said machined blank remains in the hold ^¬ er during the processing steps of said workpiece performed by at least two of said processing machines such as a conventional milling center, a CNC center, a wire EDM center, a sink EDM center, a grinding center and/or a polishing center; using said workpiece, in particular using said EDM electrode, for manufacturing of a component. In one embodiment, one of the at least two processing machines is an EDM center. Since the blank and the semi-finished product, respectively, remains in the same holder during the manufacturing process on at least two processing machines, a fixed geometrical position of the respective part (i.e. blank, semi-finished product, respectively) relative to the holder is defined and maintained. Thus, only the holder has to be adjusted in at least two processing centers, whereby the blank, the semi-finished product, respectively, are automatically adjusted with respect to the processing machine. As a result, otherwise necessary time consuming procedures for positioning and aligning at the respective processing machines can be omitted. Such component manufactured by using said workpiece produced by the inventive method can be a product of any kind, in particular a product in the field of automotive industry. Depending on the embodiment, said work- piece may be a tool of a processing machine for manufacturing the component. In another embodiment, said workpiece may be designed as a part of the component. As an example, said workpiece may be processed further by injection moulding of plastic around the workpiece.

According to a second aspect of the invention, a method is provided for producing and using an EDM-electrode comprising the steps of providing a holder for holding a blank; providing a blank; clamping said blank in said holder; machining of said blank clamped in said holder into said EDM-electrode at a plurality of working centers (machines) wherein said holder holding said blank and the machined blank, respectively, is clamped in a chuck of the respective processing machine, and wherein said machined blank remains in the holder during all processing steps of said EDM-electrodes; clamping of said holder, which clamps said EDM-electrode in a tool chuck of an EDM center; performing EDM machining, in particular sink EDM machining by said EDM-electrode.

Since the blank, the semi-finished product and the EDM- electrode, respectively, remain in the same holder during the entire manufacturing process and the usage of the EDM- electrode, a fixed geometrical position of the respective part (i.e. blank, semi-finished product and EDM-electrode, respectively) relative to the holder is defined and main- tained. Thus, only the holder has to be adjusted in each processing center, whereby the blank, the semi-finished product and the EDM-electrode, respectively, are automatically adjusted with respect to the processing machine. As a result, otherwise necessary time consuming procedures for positioning and aligning at the respective processing machines can be omitted.

It should be noted that terms "tool chuck" or "chuck" used in this application text is to be understood very broadly. On one hand, this term may refer to a common tool chuck or chuck comprising a predetermined number of clamping jaws for clamping the object. On the other hand, this term may generally refer to a fastening device for fixing the holder to the respective processing machine, e.g. in the form of a screw adapter or other fastening adapter of the processing center by means of which the holder is attached to the processing head of the respective processing machine. In the same sense, the term "clamping" is to be understood very broadly and correspondingly.

Expediently, the blank and the machined blank, respectively, may be treated at a plurality of processing centers such as a conventional CNC center, a conventional milling center, a wire EDM center, a sink EDM center, a grinding center and/or a polishing center. Accordingly, the inventive method can be conducted by utilization of all known processing centers (i.e. maehining centers) for producing and using an EDM- electrode of any kind.

Advantageously, the holder clamping the machined blank may be undamped from a chuck after completion of a processing step conducted in a corresponding processing center, and then clamped into a chuck of a different processing center in order to conduct different production steps in different processing centers for manufacturing said EDM-electrode.

In order to facilitate positioning of the machined blank and the finished EDM-electrode, respectively in a processing center, the method according to the invention may comprise the provision of a positioning device on the holder. Such positioning device may comprise one or more holes such as bores extending through said holder wherein said bore is sensed by a respective sensing device attached to the respective processing center. As an example, in case of a milling center, said sensing device may comprise a milling probe for probing the at least one positioning hole extending through the holder.

According to the invention, the blank may be fixed at the holder by different methods depending on the shape of the blank, the machined blank and the finished EDM-electrode, respectively as well as on the design of the holder. In a simple configuration, the holder is constructed as a frame comprising several webs or lands forming a central holding fixture for receiving the blank. In case of such construc- tion of the holder, the blank may be clamped between these webs of the holder by means of a plurality of bolts each extending through respective webs or lands.

If the holder is constructed as such a frame, the blank may advantageously be machined on both sides with respect to the major frame surface. Advantageously, the holder may be adapted to hold not only one single, but a plurality of blanks, machine blanks or EDM-electrodes, respectively, wherein a plurality of blanks is processed in a predetermined processing center, the holder being clamped by a chuck of said predetermined processing center. By conducting such method for producing and using EDM-electrodes, time consuming alignment of blanks, machine blanks or EDM-electrodes with respect to corresponding pro- cessing centers can be further decreased because such an alignment step for the plurality of blanks, machine blanks or EDM-electrodes clamped by the holder must only be accomplished once for each processing center. Furthermore, machining of corresponding blanks, machined blanks or EDM- electrodes is further facilitated because said machining of each object may be performed successively.

In a further embodiment, the machining is performed parallel, i.e. corresponding predetermined processing center com- prises several tools so that all objects clamped in said holder can be machined simultaneously, further saving production time.

Advantageously, after production of several EDM-electrodes being clamped in the holder, these EDM-electrodes may be used simultaneously for spark erosion applied to a work- piece .

According to a third aspect, the invention considers a hold- er for holding a blank for implementation of a method according to above-mentioned production methods. Advantageously, said holder may feature a frame-like structure and a plurality of bolts, each extending through a frame section of the holder provided for clamping said blank. Advanta- geously, the holder is designed so as to comprise a plurality of frame-like structures arranged in line, each adapted to hold a blank, a machined blank or an EDM-electrode, respectively. In order to enable positioning of the holder with respect to a processing machine, the holder may comprise at least one positioning hole or bore extending sub- stantially perpendicular to the main plane of the frame-like structure so that this hole or bore may be sensed by a corresponding sensing device of the processing center.

Said holder may comprise a plurality of machine adapter means to be fastened to the holder, each constructed for clamping said holder to a respective corresponding machining center. Moreover, said holder may further comprise holder adapter means constructed to cooperate with each of said respective machine adapter means selected from said plurali- ty of machine adapter means for clamping said holder to said respective machining center. Thereby it is made possible to mount said holder successively to each of said machining center in the course of manufacturing and using of said workpiece and said EDM-electrode, respectively.

Furthermore, said holder adapter means may comprise at least two mounting surfaces being at the right angles to each other, wherein each mounting surface is adapted to cooperate with a corresponding mounting surface of at least one of said plurality of machine adapter means for clamping said holder to said respective machining center. Accordingly, said one holder adapter means may be designed to cooperate successively with each of said plurality of machine adapter means during the manufacturing, in particular during machin- ing steps using a conventional milling center, a wire EDM center as well as a sink EDM center. One of said two mounting surfaces of said holder adapter means may be parallel to a main plane of said holder. In order to provide for precise adjustment between said holder adapter means and each of said machine adapter means, at least one tight fit bore and/or dowel pin, in particular at least two of which, may extend from and in right angle with respect to each of said two mounting surfaces of said holder adapter means and cooperate with corresponding at least one tight fit bore and/or dowel pin, in particular at least two of which extending from and in right angle with respect to said corresponding mounting surface of said machine adapter means. Accordingly, if the at least one tight fit bore is situated on the corresponding mounting surface of said holder adapter, the corresponding dowel pin may be situated at the corresponding mounting surface of said machine adapter means extending in the direction of the corresponding mounting surface of said holder adapter means, and vice versa.

Thus, in the assembled state of the holder adapter means and the machine adapter means, the at least one dowel pin may be received by the corresponding tight fit bore thereby mutual alignment between said holder adapter means and the respec- tive machine adapter means is achieved. In one embodiment, both components of said adapter means, i.e. said holder adapter means and said machine adapter means may be fixed together by at least one bolted joint, wherein respective machine adapter means is adapted to be mounted on corre- sponding machine table, chuck or tool chuck of corresponding machining center.

It should be noted, that the wording "chuck" and "machining table" may denote the same object in this application. Fur- ther, the wording "chuck" may denote a chuck for clamping a e.g. blank or semi-finished product as well as a chuck for clamping a tool, in particular said EDM electrode.

In one embodiment, said holder adapter means may be designed as a component part of said holder mountable thereto, in particular by bolted joint, wherein said holder adapter means may be designed as basically planar, in particular rectangular, plate comprising a plate extension on one side edge extending orthogonally to the plane of said plate.

Thereby, bolted joints between said holder adapter means and said holder may be arranged extending through said plate and through said plate extension, respectively, thereby securely fasten said holder adapter means to said holder. After mounted to said holder, the holder adapter means can be maintained on the holder thereby providing the possibility to mount said holder on a plurality of machining centers by means of a respective machine adapter means.

In one embodiment, at least one of said machine adapter means, in particular each of said machine adapter means mountable to said holder adapter means (for example by a bolted joint) may be designed as basically planar, in particular rectangular, plate or prism comprising two mounting surfaces. One of said mounting surfaces may cooperate with a corresponding mounting surface of said holder adapter means and the other mounting surface of the machine adapter means may be adapted to cooperate with a corresponding mounting surface of a mounting table or chuck of a respective machining center such that the holder is clamped on the respective machining center.

The invention will hereinafter be explained by describing an embodiment of the invention with reference to the accompanying figures, wherein Fig. 1 hows an inventively designed holder 1 holding our semi-finished products 50 on a milling cen ter,

Fig. 2 shows the holder 1 of figure 1 on a wire EDM cen- ter, Fig. 3 shows the holder 1 of figures 1 and 2 on a sink EDM center for usage of the produced EDM electrode being clamped in the holder 1, Fig. 4a shows the attachment of an inventively designed holder attached to a machine adapter prism of a milling center,

Fig. 4b shows the illustration of figure 4a in an exploded view,

Fig. 5a shows the attachment of an inventively designed holder attached to a machine adapter prism of a wire cut EDM center,

Fig. 5b shows the illustration of figure 5a in an exploded view,

Fig. 6a shows the attachment of an inventively designed holder attached to a machine adapter prism of a sink EDM center, and

Fig. 6b shows the illustration of figure 6a in an exploded view .

The embodiment described relates to a method for manufactur ^¬ ing and using an EDM- (Electrical Discharge Machine) electrode. Figure 1 illustrates a three dimensional view on a holder 1 to be used for implementation of the inventive method described in the following. In the described embodi ^¬ ment, the holder comprises a frame-like structure with two opposite longitudinal webs or lands 11 as well as transverse webs 12 and intermediate webs 13, both extending perpendicu ^¬ larly to the longitudinal webs 11. The longitudinally spaced webs 12, 13 extending in the transverse direction along with the longitudinal webs 11 form openings or holes 15, which are rectangular-shaped and arranged as respective through openings, resulting in the frame-like structure shown in Fig. 1 comprising four seats each receiving a blank .

At the beginning of the method for production and use of an EDM-electrode, a respective blank is inserted into an associated hole 15 of the holder 1 and is fixed and clamped, respectively, by means of bolts 30, 31.

Fig. 1 shows the parts to be machined being clamped in the holder as semi-finished products 50, i.e. each in a state of an already partly machined blank. In the given embodiment, the blanks as well as the semi-finished products are rectan- gular, wherein side faces 51 abut against corresponding rectangular inner surfaces defining the respective holes 15. Hereto, two bolts 30, each extending perpendicularly with respect to side surface 14 through a longitudinal web 11 and fixed thereto by corresponding thread, abut against a side surface 51 of the semi-finished product 50, thereby clamping respective blank in respective seat provided by corresponding hole 15. Similarly, respective bolt 31 extends in a diagonal direction with respect to hole 15 through web 11, fixed thereto by corresponding thread, and abuts against edge 52 of the semi-finished product, so that semi-finished product is firmly clamped within the hole 15. For clarity reasons it should be noted that bolts 31 shown in Fig. 1 have different lengths, such that they protrude differently from the frame-shaped holder 1. In all cases, these bolts are turned within the associated thread with the result that the bolts abut against corresponding edges 52 for clamping the respective semi-finished product in the associated hole 15. In the operating situation of Fig. 1, the holder 1 is clamped to the machine table of the milling machine not ex- plicitly shown in the figure. After clamping of the holder 1 to the milling machine, positioning of the holder and thereby of the semi-finished products 50 is accomplished by sampling the cylindrical inner surface defining the position hole 20 by use of a sensor (probe) 105 fixed to the milling head 100. After positioning, the machine control of the milling head exactly knows the position of all semi-finished products 50 so that they can be machined with pinpoint accuracy thereafter.

Fig. 2 shows the holder 1 of Fig. 1 in an EDM machine for carrying out wire-spark erosion wherein again the clamping of the holder 1 to the machine table of the processing center is not shown.

An operating situation is shown in which positioning of the holder 1 and thereby of the semi-finished products is accomplished by sampling the cylindrical inner surface defining the position hole 20 by use of a wire sensor (probe) 115 fixed to the EDM head 110 and extending through the positioning hole 20 of the holder 1 parallel to the hole axis.

After positioning, the machine control of the wire EDM head exactly knows the position of all the semi-finished products 50 so that they now can be machined with high accuracy by wire spark erosion.

In the following, an inventive method for producing and using an EDM electrode will be explained. First, a holder, as shown in Figs 1 and 2, is provided. In the embodiment shown, the holder comprises four rectangular recesses or holes 15, each of which adapted to receive a square-shaped blank clamped to the holder 1 by means of bolts 30, 31. In this clamping situation, side faces 51 of the semi-finished prod- ucts 50 abut against associated internal surfaces of the holes 15. This way of fixing the blanks to the holder is maintained during the complete production process of the EDM-electrodes as well as during the subsequent usage of the EDM-electrodes in an EDM center.

After clamping the holder 1 in a first processing center, cutting or chip removing processing is applied to the blank. To this end, the holder and the blanks clamped therein are positioned in the processing machine and its processing head as described in Fig. 1. Thus, the respective positions for precisely applying the cutting or chip removing processing on the blanks with respect to the alignment hole 20 are known. These positions remain unchanged during further pro- cessing of the blanks and semi-finished products, respectively, so that this fixed positioning of the blanks and semi-finished products, respectively, in relation to the alignment hole can be used for all further processing steps at the different processing centers, i.e. processing ma- chines. By using the method according to the invention, successive processing of blanks or semi-finished products in different processing centers such as CNC centers, conventional milling centers, EDM-centers, grinding or polishing centers is possible at very high accuracy despite the fact that, when one processing step is finished, the holder 1 has to be undamped from the respective processing center and then again fixed to a different processing center.

After processing of the EDM-electrodes, these electrodes can be used in an EDM-center for processing workpieces. This is principally described in Fig. 3. The holder 1 is fixed by means of an adapter 125 to a SINK EDM head by screw connections. Since these screw connections extend in a defined way to the alignment hole 20 of the holder, the position of each respective electrode 60 is defined by fixing the holder to the SINK EDM head 120. As shown in Fig. 3, the holder and the EDM-electrodes 60 fixed thereto are turned through 180° along their longitudinal axis in comparison to Fig. 1 and 2. semi-finished products 80 are fixed on the machine table 127 of the sink EDM center in relation to the spaced position of the electrodes 60 clamped in the holder 1. The semi-finished product 80 can be processed by means of the electrodes 60 according to the known electric discharge machining resulting in the finished component. This component can be of any kind, in particular a product in the field of automotive industry. According to the respective embodiments, processing by means of the electrodes clamped in the holder 1 can be conducted simultaneously or subsequently. Since the principles of EDM processing are known to the person skilled in the art, there is no need to describe in detail the pro- vision of the electrodes or the dielectric fluid used between the electrodes 60 and the semi-finished product.

With respect to figures 4a, 4b, 5a, 5b, 6a and 6b an inventive adapter means comprised by the inventive holder will be explained in the following used to clamped the holder to the plurality of machining centers maintaining the fixed positioning of the blank, the semi-finished product and the EDM electrode, respectively, in relation to the alignment hole 20. At that point the holder 1' is designed identical to the holder 1 shown in figures 1 to 3 despite the fact that holder 1' comprises only two holes 15 for receiving a blank, a semi-finished product 50 or finished workpiece as an EDM-electrode. Similar to the operating situation of figure 1, figure 4a shows the holder 1' being clamped to the machine table of milling machine, wherein details of the fixing are visible due to the rearview shown disclosing adapter means 200, 300 for mounting the holder 1' to the machine table (not shown) of the milling machine. Those features which are identical with respect to features shown in figures 1 to 3 have been labeled by the same reference signs in the subsequent figures. The precise construction of the adapter means comprising a holder adapter means 200 attached to the holder 1' and the machine adapter means 300 clamped to the chuck, i.e. the machine table of the milling machine (not shown) becomes clear by the exploded view of figure 4b. In the embodiment of figures 4a, 4b, the holder adapter means is designed as a component mountable to the holder 1' comprising a basically planar and rectangular plate 200 featuring a plate extension 201 on one side edge extending orthogonally to the main plane of said holder adapter plate 200. The base body of the holder adapter plate 200 comprises two spaced tight fit bores adapted to at least partially receive corresponding dowel pins 309. The holder adapter plate 200 is mounted to the holder 1' by bolted joints. Therefore, screws 210 extending through corresponding holes in the plate extension 201 are screwed into corresponding thread of thread holes 27 situated on the rear side of holder 1' . Furthermore, two screws extending through corresponding holes in the base body of the holder adapter plate 200 are screwed into corresponding thread of thread holes placed at the bottom face of the holder 1' (not shown) .

In the present embodiment shown, the holder adapter means 200 is designed as separate component part mountable to said holder 1' . In a further embodiment not shown in the figures, the holder adapter means may be integrally formed along with the holder 1' . The holder adapter means mounted to the holder 1' or produced along with the holder as an integral element serves as an interface for mounting the holder 1' to each of the plurality of processing machines for conducting the inventive method for manufacturing and using a workpiece as an EDM electrode, respectively. Therefore, the holder adapter means 200 provides two mounting surfaces 212, 214 each of which cooperating with at least one of a corresponding mounting surface of a machine adapter means. In the present embodiment, one of the two mounting surfaces is provid- ed by the outer surface 212 of the plate extension 201, the second mounting surface is provided by the bottom face, i.e. surface 214 of the base body of the holder adapter plate 200. In the mounting situation shown by figures 4a, 4b, the second surface 214 is used to mount the holder to the chuck or machine table of a milling machine by mounting corresponding machine adapter prism 300 to the holder 1' and the holder adapter plate 200, respectively. The machine adapter

300itself is mounted on the milling machine chuck or the machine table by a bolted joint, not shown in the figures.

Machine adapter prism 300 also comprises, as shown in figures 4a, b, one mounting surface 302 cooperating with mount- ing surface 214 for fixing the machine adapter prism 300 to the holder 1' and the holder adapter plate 200, respectively. In order to facilitate mutual alignment of the machine adapter prism 300 with respect to the holder adapter plate 200 when putting both parts against each other, part 300 comprises spaced tight fit bores 308 which can be brought into alignment to corresponding tight fit bores 208 of the holder adapter plate 200. Each dowel pin 309 is introduced into corresponding tight fit bores 208, 308 such that mutual alignment of holder adapter plate 200 and machine adapter prism 300 is secured.

It should be understood that it may also be possible to introduce the dowel pins first into the corresponding bore of the machine holder prism 300 or the holder adapter plate 200 such that the dowel pins extend above corresponding mounting surface 302, 214. Afterwards the machine adapter prism 300 is brought into aligned joint and abutment with holder adapter plate 200 such that the dowel pins are introduced in corresponding bores emanating from corresponding mounting surface 214 and 304, respectively. The whole assembly is bolted by screw 312 extending through the holder 1' , the holder adapter plate 200 and screwed into the thread of thread hole 310 of the machine adapter prism 300.

After clamping of the holder 1' to the milling machine, po- sitioning of the holder and therefore positioning of the semi-finished products 50 is accomplished by sampling the cylindrical inner surface defining the position hole 20 by use of a sensor 105 attached to the milling head 100. Figures 5a, 5b show the mounting of the holder 1' on a wire cut EDM machine for machining the semi-finished product 50, clamped in the holder 1' by EDM wire cutting. As already described by reference to figures 4a, b, the holder adapter plate 200 is mounted to the holder 1' by screws 210 extend- ing through the plate extension 201 as well as screws extending through the base body of the holder adapter plate 200 wherein all screws are screwed in corresponding thread holes machined in the holder. In figure 5b only thread holes 27 on the rear side edge of holder 1' are visible.

In contradiction to the situation shown in figures 4a, 4b, the machine adapter prism 320 is aligned and fixed on the outer surface 212 of the plate extension 201 of the holder adapter plate 200. For this purpose, adapter prism 320 com- prises tight fit bores 328 which are brought into alignment with tight fit bores 208 of the holder adapter plate 200. The dowel pins 329 are received by tight fit bores 208, 309 thus securing the alignment of both parts 200, 320 of the adapter means. In the present embodiment, screw 352 extend- ing through the machine adapter prism 320 to corresponding thread. hole machined in the plate extension 201 of the hold- er adapter plate 200, thus fixing the machine adapter prism 320 to the holder adapter plate 200. It can be obtained from figure 5b, additional adapter prism 335 is mounted on machine adapter prism 320 by bolted joint wherein screws 334 extending through the adapter prism 335 are screwed in corresponding thread of thread holes machined through mounting surface 324 of the machine adapter prism 320. Further, adapter prism 335 is mounted by bolted joint to the chuck or machine table of the wire cut EDM machine. After clamping of the holder 1' to the wire cut EDM machine, positioning of the holder and therefore of the semi-finished products 50 is accomplished by sampling the cylindrical inner surface defining the position hole 20 by use of a sensor fixed to the wire cut EDM head 110.

Figures 6a, 6b display the attachment of the holder 1' under usage of holder adapter plate 200 and a machine adapter prism 340 to a tool chuck, i.e. a head of a sink EDM center. As shown, the holder 1' and the EDM electrode 60 fixed thereto are rotated 180 degrees around an axis perpendicular to their longitudinal axis in comparison to the situation shown in figures 4a, 4b and 5a, 5b. Accordingly, figures 6a, 6b correspond to above figure 3. In the following details concerning the adapter means for attaching the holder 1' to the tool chuck of the sink EDM head are discussed. As obtained from the exploded view of figure 6b, the holder adapter plate 200 is fixed by four screws 210 to the holder 1' as already explained with respect to above descriptions of figures 4a, 4b and 5a, 5b. The machine side adapter part, i.e. the machine adapter prism 340 comprises two tight fit bores 348 which are brought into alignment to corresponding tight fit bores 208 of the holder adapter plate 200. It should be understood that bores 208 could be machined as blind holes. The mutual alignment of the adapter parts 200, 340 is secured by dowel pins 349 received by tight fit bores 208 and corresponding tight fit bores 348. As indicated by the figures, sink EDM head 120 is mounted on mounting surface 342 opposite to the mounting surface 344 which is adapted to cooperate with mounting surface 214 of the holder adapter plate 200. By clamping the holder 1' to the sink EDM machine as described, a defined alignment of the position of each respective EDM electrode 60 relative to the sink EDM head 120 is accomplished.

Method for manufacturing and using a workpiece, in particular an EDM- (Electrical Discharge Machine) electrode

Reference list

1, 1' holder

10 frame-like structure

11 longitudinal web

12 transverse web

13 intermediate web

14 face

15 hole

20 positioning/alignment

25 positioning/alignment

26 groove phase

27 thread hole

30, 31 bolt

50 semi-finished product

51 side face

52 edge

60 EDM electrode

80 semi-finished product

100 milling head

105 milling head probe

110 wire EDM-head 115 wire

120 Sink-EDM-Head

125 adapter

127 machine table

200 rectangular plate/holder adapter means

201 plate extension

208 tight fit bore

210 screw

212, 214 mounting surface

215 screw

216 thread hole

300 machine adapter prism

302, 304 mounting surface

308 tight fit bore

309 dowel pin

310 thread hole

312 screw

320 machine adapter prism

322, 324 mounting surface

328 tight fit bore

329 dowel pin

332 screw

335 additional adapter prism

340 machine adapter prism/machine adapter means

342, 344 mounting surface

348 tight fit bore

349 dowel pin

352 screw