EP2364070B1 - Electrode with cooling pipe for a plasma cutting device - Google Patents

Description

Field of the invention

The invention relates to a spacer for the cooling tube of an electrode of a plasma cutting device.

State of the art

Plasma cutters are used to separate all electrically conductive materials. The plasma cutter consists for example of an inverter, a handpiece, a ground cable, a power supply line and a compressed air supply line.

• Hervorragende Eignung im dünnen und mittleren Baustahlbereich (bis 30 mm)
• Schneiden hochfester Baustähle mit geringer Wärmeeinbringung
• Hohe Schneidgeschwindigkeiten
• Sehr gute Automatisierbarkeit.

The following points have proven to be significant advantages in plasma cutting:

• Excellent suitability in thin and medium structural steel area (up to 30 mm)
• Cutting high strength structural steels with low heat input
• High cutting speeds
• Very good automation.

A plasma is an electrically conductive gas in which an arc is ignited almost exclusively with high-frequency ignition and is pinched at the outlet by an insulated, usually water-cooled, copper nozzle. The high energy density melts the metal. The molten metal is blown away by a gas jet, creating the kerf.

The electrode of a plasma cutting apparatus has an elongate hollow body with an open end and a closed end. It is preferably formed of copper, but other materials such as copper and silver alloys are possible. At the bottom of the electrode is a cylindrical insert made of a material with high thermionic center Emissivity pressed in a hole. This material represents the electrode core and is preferably made of z. Hafnium, zirconium or tungsten.

It is thus already known from the state of the art that the cooling liquid is conducted to the lower end of the electrode via a cooling tube lying in the electrode. Due to the circulating liquid, sufficient cooling of the electrode takes place.

The internal cooling tube requires a relatively fixed position relative to the electrode in order to make good use of the characteristic of the circulating cooling flow. This is an important point in terms of increasing the life of the electrode.

From the prior art, a certain positioning of the cooling tube relative to the electrode body is already known.

The EP 2 082 622 shows an internal, cylindrically shaped cooling tube that has a predetermined position relative to the electrode body. This is achieved by a radially projecting shoulder on the peripheral surface of the cooling tube in conjunction with a mating stop on the electrode housing side. The cooling tube is thus held in the upper region and so selectively positioned relative to the electrode body.

However, this embodiment is very expensive and expensive to produce. Due to the heel on the peripheral surface of the cooling tube and the required stop on the electrode body side accurate positioning is difficult.

Subject of the invention

The invention is therefore based on the task of a simple and universal stop for the cooling tube ready.

To solve the problem, the invention is characterized by the technical teaching of claim 1.

The solution of the problem is achieved by the technical teaching of claim. 1

An essential feature of the invention is that at least one axial stop for the cooling tube is formed on the inside of the electrode body.

Although the invention also provides for the arrangement of a plurality of stops, the simpler description will be described only for the arrangement of a single stop closer. However, this is not intended to limit the scope of disclosure of the invention. Thus, if the following description refers to a single attack, it is to be understood as "one or more attacks".

In a first preferred embodiment, the electrode body has a central bore in the lower region, which accommodates an electrode core. The electrode core extends in the direction of the interior of the electrode body and is held by a cylindrically shaped receptacle in the electrode body. To ensure better cooling of the electrode, the receptacle of the electrode core is surrounded by an annular recess in the interior of the electrode body, in which the cooling liquid can circulate. This allows good heat dissipation and thus extends the life of the electrode.

New in the invention is now that the cooling tube is spaced by a stop in the annular recess on the side of the electrode. This allows a good circulation of the cooling liquid in the lower region of the electrode body.

Thus, the invention provides to displace the axial movement of the cooling tube limiting stop in the inside of the electrode body and that in the vicinity of the end face of the electrode body. The stop is thus laid in the circumferential annular recess in the vicinity of the end face of the electrode body inside.

The stop is thus located on the electrode side and may preferably be formed as a rectangular or round, extending in the axial direction tooth. It is crucial that the size of the stop largely does not affect the flow of the cooling liquid. The front end side of the cooling tube is now on the front side of the dipping into the cooling liquid, pointing in the axial direction tooth.

In order to achieve a good quality of the electrode together with the stop, in a preferred embodiment the electrode can be produced by a pressing process. By means of the pressing process, the special design of the electrode can be produced without cutting, together with the axially aligned stop, thus reducing the need for costly, post-machining machining. It is also possible to attach the stop for the cooling tube in a second process to the electrode body.

Instead of a pressing process, the tooth-shaped stop can also be achieved by a machining of the annular recess on the inside of the electrode body. In this case, an axially aligned end mill travels into the central inner bore of the electrode body and progressively mills the bottom of the annular recess in the circumferential direction by a circumferential angle of e.g. 355 degrees, so that in the remaining angular range of 5 degrees, the tooth-shaped stop stops as material increase.

In a further embodiment, a plurality of stops or stop teeth are present in the annular recess on the electrode body, which position the cooling tube on the front side stop limiting with respect to the electrode.

Instead of the formation of one or more axially directed attacks can also be provided that the stop is not located on the bottom of the annular recess in the electrode body, but instead on the side walls of the annular recess, which then in a radial direction in the interior of the annular recess protruding tooth results.

All the above-described embodiments relate to the fact that the stop is made of one piece material from the material of the electrode body out. The invention is not limited thereto. It may be provided in a development that the (axial or radial) stop is anchored as a stop screw or stop pin anchored in the material of the electrode body. Such an anchoring can be made detachable or non-detachable. It can be designed as gluing, welding, drilling or screwing. In this case, such a stop also consist of a different material than the material of the electrode body.

Finally, it is provided in a further embodiment that the stop is arranged on a ring which is inserted or pressed into the annular, circumferential recess in the electrode body or fixed in some other way. Of course, the ring can also be fixed in this recess by means of clamping means in order to avoid strike-off or flushing with the cooling liquid.

In the following the invention will be explained in more detail with reference to drawings showing only one embodiment. Here are from the drawings and their description further features essential to the invention and advantages of the invention.

Fig. 1:

Schematische Darstellung einer Plasmaelektrode mit stirnseitigern Anschlag am Elektrodenkörper

Fig. 2:

Schematische Darstellung einer Plasmaelektrode mit radialem Anschlag an der Innenwand des Elektrodenkörpers

Fig. 3:

Schematische Darstellung einer Plasmaelektrode mit einem radialen Anschlag an der Wand der mittigen Aufnahme

Fig. 4:

Schematische Darstellung einer Plasmaelektrode mit einem radialen, stirnseitigen Anschlag

Fig.5:

Schematische Darstellung einer Plasmaelektrode mit einem radialen, stirnseitigen Anschlage

Fig.6:

Darstellung einer geschnitten Ansicht der Ausführungsform aus Figur 1

Fig.7:

Perspektivische Darstellung eines Rings mit einem Anschlag für ein Kühlrohr

Fig.8:

Darstellung einer abgewandelten Ausführung eines Rings mit zwei radialen, innenliegende Anschlägen

Figur 9:

Schematische Darstellung einer Plasmaelektrode mit einem einseitigen, durchgehenden Anschlag

Figur 10:

Schematische Darstellung einer Plasmaelektrode mit einem beidseitigen, mittigen Anschlag

Figur 11:

Schematische Darstellung einer Plasmaelektrode mit einem beidseitigen, außenseitigen Anschlag

Figur 12:

Schnitt durch den Elektrodenkörper mit randseitigen Anschlägen

Figur 13:

Schnitt durch den Elektrodenkörper mit an der mittigen Aufnahme angeordneten Anschlägen

Figur 14:

Schnitt durch den Elektrodenkörper mit einem durchgängigen, einseitigen Absatz

Figuren 15 bis 19:

Schematischer Verfahrensablauf einer Herstellung eines Elektrodenkörpers

Show it:

Fig. 1:

Schematic representation of a plasma electrode with an end stop on the electrode body

Fig. 2:

Schematic representation of a plasma electrode with a radial stop on the inner wall of the electrode body

3:

Schematic representation of a plasma electrode with a radial stop on the wall of the central receptacle

4:

Schematic representation of a plasma electrode with a radial, end stop

Figure 5:

Schematic representation of a plasma electrode with a radial, front stop

Figure 6:

Representation of a sectional view of the embodiment of FIG. 1

Figure 7:

Perspective view of a ring with a stop for a cooling tube

Figure 8:

Representation of a modified version of a ring with two radial, internal stops

FIG. 9:

Schematic representation of a plasma electrode with a one-sided, continuous stop

FIG. 10:

Schematic representation of a plasma electrode with a double-sided, central stop

FIG. 11:

Schematic representation of a plasma electrode with a two-sided, outside stop

FIG. 12:

Section through the electrode body with marginal attacks

FIG. 13:

Section through the electrode body with arranged on the central receptacle attacks

FIG. 14:

Section through the electrode body with a continuous, one-sided paragraph

FIGS. 15 to 19:

Schematic procedure of a production of an electrode body

Fig.1 shows a plasma electrode 1, which consists essentially of an electrode body 2 and a cooling tube 3. The plasma electrode 1 can be fitted exchangeably by pressing fit in a cathode block to a burner, not shown here.

The elongated, axially extending electrode body 2 is made of copper in a preferred embodiment. However, materials such as silver or copper alloys are also possible.

The electrode body 2 has an open and a closed end, wherein the closed end is in the lower region.

In the lower region, the electrode body 2 has an inwardly axially extending receptacle 5. In the middle of the electrode body 2, a bore 8 is provided and serves to receive the electrode core 9. The bore 8 may be formed either as a blind hole or through hole.

The electrode core 9 is pressed in a preferred embodiment. Here, the invention is not limited to a press fit. It is also a soldering, welding or other connection technology possible. The receptacle 5 for the electrode core 9 is radially formed in the interior of the electrode body 2 and forms a part with the electrode body 2 from.

The electrode core 9 is designed as an insert and consists of a material with high thermionic emissivity. For this purpose, z. As hafnium, zirconium or tungsten can be used. The electrode core extends from the lower end axlai through the bore 5 in the direction of the interior of the electrode body. 2

In the interior of the electrode body 2, the axial receptacle 5 extends, wherein an annular recess 6 between the receptacle 5 and the housing wall of the electrode body 2 is formed. The annular recess 6 serves for better circulation of the cooling liquid and thus enables a more effective heat dissipation away from the electrode.

The cooling tube 3 inserted into the central center bore of the electrode body 2 is thin-walled, hollow, cylindrical and preferably exchangeable.
Due to its diameter, the cooling tube 3 forms in its interior a liquid channel 4, which allows the flow of a cooling liquid in the direction of arrow 19. The outer diameter of the cooling tube 3 is designed so that it is a backflow of the cooling liquid between the inner wall of the electrode body 2 and the outer wall of the cooling tube 3 by a radial annular gap 18 in the direction of arrow 23 allows. Thus, a circulation of the cooling liquid takes place within the electrode body 2.

Due to the design of the cooling tube 3, the cooling liquid is introduced through the liquid channel 4 in the direction of arrow 19 and impinges on the electrode core 8 and the receptacle 5 with its inner surface 7. Thereafter, the cooling liquid flows along the inner surface 7 of the receptacle 5 in the annular recess 6 and is due to the formation of the electrode body 2 deflected into the radially outer annulus.

The circulation or deflection of the cooling liquid in the annular recess 6 requires a certain axial positioning of the cooling tube 3 with respect to the electrode body 2. This is achieved by at least one stop 10, which is located at the bottom of the annular recess 25 of the electrode body 2.

According to the FIG. 1 If the axially extending stop 10 is drawn on the base 25 of the annular recess 6, however, other positions or orientations for the stop 10 within the electrode body 2 are also possible.

In a preferred embodiment, the stop 10 is formed as an axial, rectangular elevation and spaced, due to its design and position, the cooling tube 3 in the lower region of the electrode body. 2

The stop 10 has a longitudinal axis 27. which is parallel to the longitudinal axis of the electrode body 2.

In a preferred embodiment, the stop 10 is formed from the material of the electrode body 2.

Due to the positioning of the stop 10 on the base 25 of the recess 6, an outer ring groove bottom 13 forms between the inside of the electrode body 2 and the stop 10.

On the radially opposite side forms between the stop 10 and the inner surface 7 of the receptacle 5 on the base 25 of the recess 6, an inner Ringnutengrund 14.

The stopper 10 extends in the axial direction and has an axial distance 21. The distance 21 results from the end face 22 of the receptacle 5 and the end face 20 of the knockout 10. In a preferred embodiment, the distance 21 is about 2/3 of the total axial length of the receptacle 5. However, the invention should not be limited to this length specification. Rather, any distance is possible.
In addition to the rectangular shape of the stop 10, any other shape is to be claimed for the present invention, which is formed on the side of the electrode body 2.

Decisive in this embodiment is that the stopper 10 is part of the electrode body 2 and is arranged axially, on the bottom side in the recess 6 of the electrode body 2.

In a preferred embodiment, the stop 10 is formed on one side and as a rectangular shoulder on the base 25 of the recess 6.

Due to the design and positioning of the stop 10, the cooling tube 3 with its end face 26 is in direct contact with the end face of the stop 10 formed on one side. In this position, n

The cooling water can thus flow in the direction of arrow 19 through the liquid channel 4, strikes the bottom 25 of the recess 6, is deflected here and then flows through the annular gap 18 in the direction of arrow 23 again.

Characterized in that the stop 10 is formed only as a single, smaller, rectangular shoulder at the bottom of the recess 6, the coolant can circulate almost without resistance.

Fig.2 shows a second embodiment of the invention essential plasma electrode. Here, the same reference numerals as in FIG. 1 ,

What is new in this embodiment is that the stop 10a, starting from the inner surface of the electrode body 2, extends radially in the direction of the central longitudinal axis of the electrode body 2. The stopper 10a is thus directed radially inwardly with its longitudinal extent.

The side surface 24 of the radially inwardly directed stop 10a is in direct contact with the end face 26 of the cooling tube 3 and is thereby spaced from the base 25 of the recess.

The longitudinal axis (27) of the stop (10a) is formed perpendicular to the longitudinal axis of the electrode body (2).

Between the radially inwardly directed stop 10a and the receptacle 5, an annular gap 16 is formed, which is followed in the axial direction by a radial Hinterschnätigung 15. The undercut 15 allows the coolant to circulate in the recess 6 despite the stop 10a.

In a preferred embodiment, the stop 10a is formed as a one-sided, single paragraph, which keeps at a point the entire cooling tube 3 at a distance. By this arrangement, the coolant can circulate largely freely within the recess 6 and the entire electrode body 2.

In FIG. 3 a third embodiment is shown. In this case, the stop 10b extends, starting from the centrally arranged receptacle 5 radially in the direction of the inner wall of the electrode body 2. The stopper 10b is thus directed with its longitudinal extent radially outward. Between the stop 10b and the inner wall of the electrode body 2, an annular gap 17 is formed, which is followed by a radial undercut 15 in the direction of the longitudinal axis. The stopper 10b is thus formed as a freestanding, radial stop, around which the cooling water can circulate

The longitudinal axis (27) of the stop (10b) is formed perpendicular to the longitudinal axis of the electrode body (2).

Decisive in all embodiments is that the number of stops 10, 10 ', 10a, 10b, 10c, 10d, 10e, 10f is not limited to one, as well as a plurality of stops can be arranged distance limiting for the cooling tube 3 within the electrode body 2.

FIG. 4 shows a schematic representation of a plasma electrode 1 with an axial end face stop 10c. The stopper 10c extends both radially outgoing from the centrally disposed receptacle 5 in the direction of the inner wall of the electrode body 2, as well as axially starting from the base 25 of the recess. 6

In a preferred embodiment, the stop 10c is formed as a one-sided paragraph, which cooperates with the end face 26 of the cooling tube 3 and these spaced.

Between the stop 10c and the inner wall of the electrode body 2, a Ringnutengrund 13 forms.

Due to the one-sided, non-circumferential embodiment of paragraph 10c, the coolant can largely circulate in the recess 6 of the electrode body 2.

The longitudinal axis (27) of the stop (10c) is formed parallel to the longitudinal axis of the electrode body (2).

FIG. 5 shows a schematic representation of a plasma electrode 1 with an axial, end stop 10d. The stop 10d extends both radially outgoing from the inner wall of the electrode body 2 in the direction of the longitudinal axis, as well as axially starting from the base 25 of the recess. 6

Between the shoulder 10d and the receptacle 5, an annular groove 14 is formed, which allows a circulation of the cooling water. The annular groove 14 extends axially in the direction of the bottom 25 of the recess 6.

The stop 10d is in this case designed so that it cooperates with its side surface 24 and the end face 26 of the cooling tube 2 and this distance from the bottom 25 of the recess 6. By this one-sided spacing, it is possible for the coolant to circulate in the remaining recess 6.

The longitudinal axis (27) of the stop (10d) is formed perpendicular to the longitudinal axis of the electrode body (2).

In Flg. 6 is the electrode body 2 of the FIG. 1 shown in sectional view XI. Between the electrode body 2 and the central, inner receptacle 5 at least one stop 10 is arranged, which is arranged in the annular recess 6.

The cooling tube 3 is shown in phantom in this embodiment and is in contact with at least one stop 10 and 10 '.

The stop 10 extends in the axial direction and cooperates with at least one point of the end face of the cooling tube 3.

Between the cooling tube 3 and the central receptacle 5 is an inner annular groove bottom 14 and between the central receptacle 5 and the inner wall of the electrode body 2, an outer annular groove bottom 13 is formed
A liquid channel 4, which is part of the cooling tube 3, adjoins the inner annular groove bottom 14 in the axial direction. And on the outer Ringnutengrund 13 joins in the axial direction an annular gap 18, through which the coolant flows out again.

In a further embodiment, a plurality of stops 10 'are shown in the annular recess 6, which in FIG. 6 dashed lines are drawn.

FIG. 7 shows a ring 11, which is to form a stop 10 for the cooling tube 3 as another embodiment. The ring 11 has at least one stop tooth 12 and is in this case inserted between the cooling tube 3 and the electrode body 2. In the illustrated embodiment, two diametrically opposed stop teeth 12 are shown.

When installed, the cooling tube 3 can be positioned in alignment with the electrode body 2 in the axial direction by means of the ring 11 and the stop tooth 12. This allows a circulation of the liquid between the front end side of the cooling tube 3 and the electrode body 2, wherein the annular recess 6, the direction reversal of the coolant flow accomplished.

FIG. 8 shows a representation of a ring 11 with two radial, inner stops 10. In a preferred embodiment, the ring 11 is inserted into the recess 6 of the electrode body 2. By the radially inwardly directed stops 10, which are in direct contact with the end face 26 of the cooling tube 3, there is a spacing of the cooling tube 2 in the axial direction, starting from the bottom 25 of the recess 6 instead.

With the FIG. 9 a further embodiment of the electrode body is shown.
The electrode body 2 has in its interior in the recess 6, a stop 10e, which has a continuous shoulder between the inner wall of the electrode body 2 and the receptacle 5 forms. The stop 10e is in this case offset from the end face 22 by the distance 21 back.

In a preferred embodiment, the stop 10e is formed on one side or only in a partial region of the recess 6. The partial area can be for example 30 °.

It is crucial that the stop 10e cooperates with its end face 20 with the end face of the cooling tube 3 and this spaced apart in the axial direction relative to the base 25 of the recess.

On the opposite, radial side of the electrode body 2 between the receptacles 5 and the inner wall of the electrode body 2 has a recess 6, which allows a circulation of the cooling water.

The cooling tube 2 is thus held on one side by the stop 10e at a distance, while the recess 6 is free and allows a circulation of the cooling water.

With the FIG. 10 a double-sided internal stop 10f is shown. The stop 10f is either circumferential or is formed by two, single paragraphs. Decisive in this embodiment is that the stopper 10f is a part of the electrode body 2 and the receptacle 5 and is designed as a shoulder, which spaces the cooling tube 2 in the axial direction relative to the base 25 of the recess 6.

Between the stopper 10f and the inner wall of the electrode body 2, an annular groove 13 is formed, in which the cooling water can circulate.

The longitudinal axis (27) of the at least one stop (10f) is formed parallel to the longitudinal axis of the electrode body (2).

The FIG. 11 shows a schematic representation of the electrode body according to the invention. At two opposite points on the inner wall of the Electrode body 2 are two, formed radially inwardly, extending in the direction of the longitudinal axis stops 10d

However, an embodiment with only one stop 10a is also possible.

Between the stops 10d and the central receptacle 5, the electrode body 2 has an annular groove bottom 14 in which the cooling water can circulate.

The heels 10d are arranged so that they interact with their end face 20 with the end face 26 of the cooling tube 3 and this space in the axial direction of the base 25 of the recess 6.

The heels 10d can either be arranged completely circumferentially or only in certain partial areas around the receptacle 5.

The longitudinal axis (27) of the stop (10d) is formed perpendicular to the longitudinal axis of the electrode body (2).

The FIG. 12 shows a section through the in FIG. 12 illustrated embodiment of the electrode body.

The stops 10d are arranged opposite one another, extending radially outwardly on the central receptacle 5.

Between the stop 10d and the central receptacle 5, a ring groove bottom 14 is formed, which continues in the axial direction in the form of a liquid channel 4.

The cooling tube 3 is shown in dashed lines and is in contact with its end face at least two points with the at least two stops 10d. Between the inner wall and the cooling tube 3, an annular gap 18 is formed.

The FIG. 13 shows a section through the in FIG. 10 illustrated embodiment of the electrode body.

Starting from the central receptacle 5, at least one stop 10b, 10f extend in the radial direction.

Between the stops 10f and the inner wall of the electrode body 2, an outer annular groove bottom 13 is arranged, which is followed in the axial direction by an annular gap.

Crucial in all the above embodiments is that it is always at least one stop - but it can also find more than one stop use.

With the FIG. 14 will cut through the in FIG. 9 shown embodiment shown.

The electrode body 2 has in its interior in the recess 6, a stop 10 e, which forms a continuous shoulder or a continuous connection between the inner wall of the electrode body 2 and the receptacle 5.

The cooling tube 3 is here shown in dashed lines and lies with its front side on one side on the stop 10e and is thereby spaced from the bottom of the recess 6.

With the FIGS. 15 to 19 individual process steps for producing an electrode body essential to the invention are shown.

The production of the electrode body is a cold forming. Here, the material is brought into a geometric shape.

In a first process step ( FIG. 15 ) is the respective blank for the subsequent electrode body 2 of a rod-shaped material to the right one Length to cut. The electrode body 2 is now in its original form.

In a second process step ( FIG. 16 ), the blank is cold formed for the first time. In this case, an external, axial force acts on the blank. There is a structural change, which leads to an increase in strength and a reduction in elongation.

In a third process step ( FIG. 17 ), a first cupping of the electrode body takes place. In this case, a first cavity forms within the electrode body 2.

The term "cupping" generally refers to a massive forming in which the workpiece or the blank is deformed in a press between a pressing die and a die with considerable pressure. Is between the die inside and punch a cavity into which the material flows by pressing, the result is a cup-shaped bulge in the workpiece according to the shape of the punch. Depending on the direction of flow of the material, this is referred to as forward or reverse extrusion.

In a fourth process step ( FIG. 18 ), another cupping process takes place, whereby the cavity within the electrode body is further increased.

In a fifth process step ( FIG. 19 ) there is a combined cupping and upsetting process. Here, the central receptacle 5, the stops 10f and the outer Ringnutengründe 13 are formed. The electrode body 2 now has the same shape as in FIG FIG. 10 on.

drawing Legend

1.

plasma electrode

Second

electrode body

Third

cooling pipe

4th

liquid channel

6th

Recording (lower area)

6th

recess

7th

palm

8th.

drilling

9th

electrode core

10th

Stop (10a, b, c, d, e, f)

11th

ring

12th

stop tooth

13th

Ringnutgrund (outside) of 18

14th

Ring groove groove (inside)

15th

Behind quick extension

16th

Annular gap (inside)

17th

Annular gap (outside)

18th

annular gap

19th

arrow

20th

Front side of 10

21st

distance

22nd

Front side of 5

23rd

arrow

24th

Side area of 10

25th

Base of the recess 6

26th

Face of 3

27th

Longitudinal axis (stop)

Claims (9)

1. Plasma electrode (1) for a cutting device which consists of an electrode body (2) with an axial central mounting receptacle (5) for an electrode core (8) which is arranged in the end face there, wherein a liquid channel (4) lying radially on the inside is formed in the interior of the electrode body (2) by an exchangeable cooling pipe (3) through which a stream of cooling liquid flows in the axial direction (19), wherein the cooling pipe (3) is positioned by one or more stops (10, 12) on the electrode body (2) and the front end face (20) of which located nearest the electrode core (9) engages in a ring-shaped recess (6) in the electrode body (2) in which the stream of cooling liquid is turned round, wherein at least one axially aligned stop (10, 12) for the cooling pipe (3) is arranged on the inside of the electrode body (2), which stop cooperates with the front end face (26) of the cooling pipe (3), characterised in that the at least one stop (10) is arranged at the bottom of the recess (6) and is connected with at least one side face of the central mounting receptacle (5) so that its longitudinal axis (27) is aligned parallel to the longitudinal axis of the electrode body (2).
2. Plasma electrode (1) according to claim 1, characterised in that the stop (10, 12) is set back in the recess (6) in the electrode body (2) by an axial distance (21) from the end face (22) of the mounting receptacle (5).
3. Plasma electrode (1) according to one of claims 1 or 2, characterised in that an annular groove bottom (13) is formed between the stop (10, 12) and the internal wall of the electrode body (2), and the stop (10, 12) is embodied in the form of an unilateral shoulder which cooperates with the end face (26) of the cooling pipe (3) and distances the latter from the bottom (25) of the recess (6).
4. Plasma electrode (1) for a cutting device which consists of an electrode body (2) with an axial central mounting receptacle (5) for an electrode core (8) which is arranged in the end face there, wherein a liquid channel (4) lying radially on the inside is formed in the interior of the electrode body (2) by an exchangeable cooling pipe (3) through which a stream of cooling liquid flows in the axial direction (19), wherein the cooling pipe (3) is positioned by one or more stops (10, 12) on the electrode body (2) and the front end face (20) of which located nearest the electrode core (9) engages in a ring-shaped recess (6) in the electrode body (2) in which the stream of cooling liquid is turned round, wherein at least one radially or axially aligned stop (10, 12) for the cooling pipe (3) is arranged on the inside of the electrode body (2), which stop cooperates with the front end face (26) of the cooling pipe (3), wherein the at least one stop (10, 10a) is connected with at least one side face of the electrode body (2) and starting from the internal face of the electrode body (2) extends radially in the direction of the central longitudinal axis of the electrode body (2) so that the stop (10, 10a) is aligned with its longitudinal axis (27) perpendicular to the longitudinal axis of the electrode body (2),
   characterised in that an annular gap (16) is formed between the radially aligned stop (10, 10a) and the mounting receptacle (5),
   in which a radial undercut (15) is formed in the axial direction between the radially aligned stop (10, 10a) and the bottom of the recess (25).
5. Plasma electrode (1) according to one of claims 1 to 4, characterised in that the at least one stop is arranged in the form of at least one stop tooth (12) on a ring (11) which is fitted into the recess (6) in the electrode body (2).
6. Plasma electrode (1) according to claim 5, characterised in that the stop tooth (12) on the ring is aligned either axially or radially.
7. Plasma electrode (1) according to one of claims 1 to 6, characterised in that the stop (10, 10a) is made of the material of the electrode body (2).
8. Method for producing an electrode body (2) for a plasma electrode (1) according to claims 1 to 7, characterised in that through a cold-forming operation at least one central mounting receptacle (5), at least one stop (10) and at least one annular groove bottom (13, 14) is formed inside the electrode body (2).
9. Method for producing an electrode body (2) according to claim 8, characterised by the following method steps:

   - cutting of the blank for the electrode body (2);

   - cold-forming of the electrode body (2) in the form of an axial upsetting operation;

   - cold-forming of the electrode body (2) in the form of a first axial internal cup extrusion operation;

   - cold-forming of the electrode body (2) in the form of a second axial internal cup extrusion operation;

   - combined axial cup extrusion and upsetting to form the central mounting receptacle (5), the at least one stop (10f) and the at least one annular groove bottom (13, 14).

Images