Patent Application
20140338415
Applicant claims priority under 35 U.S.C. §119 of German Application No. 10 2013 008 345.1 filed May 16, 2013, the disclosure of which is incorporated by reference.
1. Field of the Invention
The invention relates to a method for operation of an indirect extrusion press and an indirect extrusion press.
2. Description of the Related Art
During indirect pressing of crude metal blocks, the forming procedure to produce the pressed product takes place with the formation of a shell, for example. The crude metal blocks may be made, for example, of copper, brass or corresponding alloys, and the shell is formed in order to avoid contaminants on the surface of the block to be formed from getting into the finished pressed product. In this connection, a tool head comprising a die plate is kept smaller in its diameter than the inside diameter of a block, to such an extent that a shell having a wall thickness of about 0.2 mm to 2.0 mm remains on the inner wall of the block holder, in each instance, as is also disclosed, for example, in EP 0 224 115 B1. The formation of a shell can also be correspondingly advantageous in the case of other materials, for example aluminum.
In this connection, a distinction should be made between direct and indirect pressing procedures, whereby in direct pressing, larger pressed products can generally be produced, with guidance of a pressing punch and of the metal to be formed in the same direction. In indirect pressing, in which the pressing punch is called an indirect punch and the material are guided in opposite directions, significantly lower friction forces generally occur, because the material does not need to be displaced relative to the block holder. In general, however, only smaller pressed products can be produced in indirect pressing, because the pressed product must be discharged through the indirect punch.
To reduce material tensions in the indirect punch, DE 101 31 901 A1 proposes screwing a clearing ring onto the indirect punch and relieving stress with a counter-nut. Alternatively, a wear plate and/or a die plate is attached by way of insertion bolts that are shrunk-fit into corresponding bores of the indirect punch.
After one or more pressing procedures, the shell that has formed as a result of pressing of the block material must generally be removed, in order to be able to implement operationally reliable pressing for subsequent pressing procedures. In known methods, in order to remove the shell, the latter is pulled out of the block holder together with the tool head, accompanied by great disassembly effort and assembly effort. Almost complete removal of the shell from the block holder, without remnant, however, is not possible in this way. Moreover, a remaining remnant of the shell has a detrimental effect on subsequent pressing procedures or on the operational reliability of subsequent pressing procedures. This detrimental effect results because the remaining remnant can lead, particularly during pressing, to undesirable block compression of the metal block or material block during the loading procedure that is intended for the subsequent pressing procedure. Furthermore, the remaining remnant of the shell can hinder secure introduction of a new tool head or of a cleaned or repaired tool head into the block holder. In particular, the tool head can become jammed on the remaining remnant.
It is the task of the present invention to indicate a method for the operation of an indirect extrusion press and an indirect extrusion press, with which operationally reliable removal of a shell that has been formed during one or more pressing procedures is possible.
This task is accomplished with a method for operation of an indirect extrusion press in accordance with one aspect of the invention, and with an indirect extrusion press in accordance with another aspect of the invention. Further advantageous embodiments are found in the following description.
In the operation of an indirect extrusion press, operationally reliable removal of the shell can be implemented, as compared with known methods, using the following steps,
In the known methods, a shell that has been formed by means of pressing of the material block(s) is removed, in complicated manner, by means of pulling the tool head, in each instance, out of the block holder. In contrast to the known methods, significantly more operationally reliable removal of the shell can be implemented by means of providing Steps A to D, particularly in that according to Step D, the shell or the shell that has formed can be pressed out of the material block accommodation, in part or in its entirety, by means of pushing the other tool head out of the material block accommodation, as provided. This reliability is particularly a consequence of the circumstance that pressing the shell out of the material block accommodation can be undertaken by the further tool head, in guided manner, in the material block accommodation. Complicated removal by means of pulling or partially pulling the shell out of the block holder together with the tool head, as provided in known methods—which is possible only with the acceptance of a certain unavoidable lack of operational reliability, such as, for example, the tool head falling out or tilting—can be advantageously eliminated.
The shell can furthermore be advantageously removed from the block holder or from the material block accommodation without remnant or almost without remnant, by means of suitable process management, particularly during the implementation of Step D.
Particularly by introducing the indirect punch, together with the accommodated further tool head, into the material block accommodation, and bringing the further tool head into contact with the other tool head by moving the block holder in the opposite direction, as undertaken in (C), it can be ensured that the further tool head performs a movement with regard to the block holder that corresponds to its movement during indirect pressing itself. As a result, possible shell remnants within the block holder are also treated in operationally reliable manner, just like the pressed material itself, in the case of suitable process management. In particular, a peeling ring of the further tool head can act accordingly on possible remnants within the material block.
If, in Step D, during the further movement, the shell is partially pressed out of the material block accommodation by the further tool head, then in Step D, after the shell is partially pressed out of the material block accommodation, an excess length formed by means of the shell being partially pressed out can be separated from a remnant of the material. This method of procedure is particularly advantageous if the existence of a certain remnant of the material cannot be avoided due to default values of the design or process technology, or if such a remnant is actually desired. It is particularly advantageous that the excess length can be sheared off by means of a shearing blade in order to separate it.
In Step B of the method, the further tool head can be disposed between indirect punch and material block accommodation block holder by a manipulator of an industrial robot, and accommodated on a further tool head. Step B can be carried out with very great process reliability by means of the use of a manipulator.
In Step D, the other tool head can be pushed into a predetermined position on a manipulator or in the surroundings of a manipulator of an industrial robot when it is pushed out. Subsequently, the other tool head can be grasped by the manipulator and moved away from the block holder. Step D can also be carried out with very great process reliability by the use of the manipulator of an industrial robot in Step D.
A high degree of automation can also be advantageously achieved by means of suitable inclusion in the entire method sequence, on the basis of provision of a manipulator in Steps B and C, in the manner described above.
Operationally reliable removal of the shell can particularly be implemented cumulatively or alternatively to the above explanations, by means of an indirect extrusion press that comprises an indirect punch having a tool head that can be accommodated on the indirect punch, a closure piece, and a longitudinally movable block holder having a material block accommodation for accommodating a material block. The block holder can be moved in a straight line, in a movement direction, by the closure piece, by way of the indirect punch. The indirect punch can be brought out of the material block accommodation by moving the block holder in the direction of the closure piece and introduced into the accommodation by being moved in the opposite direction. The closure piece can be moved in a straight line from a maximal position with a maximal distance from the indirect punch toward the indirect punch. The indirect extrusion press is characterized in that in the maximal position, the maximal distance between the closure piece and the indirect punch corresponds at least to the sum of the expanses of the tool head and of the block holder in the movement direction.
By means of providing this maximal distance, Step B of the above method can be carried out in operationally reliable manner, in simple manner, and thereby also operationally reliable removal of a shell that has been formed can be made possible. Operationally reliable implementation of Step B is made possible in that undisturbed placement of the further tool head between indirect punch and material block accommodation can be guaranteed by means of the maximal distance made available, if the closure piece is in the maximal position or was previously moved into this maximal position. Nevertheless, other ways of managing the method, which might not be quite as operationally reliable, are also possible. For example, a tool head may be at first ejected entirely and subsequently a new tool head may be inserted, after the block holder was displaced as far as possible in the direction of the closure piece.
Particularly preferably, the maximal distance is configured to be more than 2 mm greater than the sum, in order to be able to carry out the placement of the further tool head between indirect punch and material block accommodation in Step B of the method in very operationally reliable manner and, in particular, with sufficient play. In particular, a distance of 4 mm, in total, is advantageous for an operationally reliable sequence, so that 2 mm distance are available on both sides of the tool head on both sides, in each instance, for a normal tool head replacement.
Preferably, the tool head can have a conical section that narrows in the pressing direction of the indirect extrusion press or in the opposite direction. This section is provided for forming a shell chamber of the indirect extrusion press, which chamber is delimited by the narrowing section and the inner wall of the material block accommodation that delimits the material block accommodation. By means of providing the narrowing conical section, the tool head can advantageously be released from the clamping by the shell, specifically particularly by means of pushing the tool head out of the material block accommodation counter to the pressing direction, as is particularly provided for the other tool head in Step D.
Preferably, the indirect punch comprises a peeling ring that delimits the shell chamber in the pressing direction and can be released from the tool head. In this manner, separation of the tool head from the peeling ring or from the indirect punch can be undertaken in very simple manner. Likewise, it is easily possible to place a new tool head in front of the peeling ring.
It is understood that the characteristics of the solutions described above and in the claims can also be combined, if necessary, in order to be able to implement the advantages in correspondingly cumulative manner.
Further advantages, goals, and properties of the invention will be explained using the following description of exemplary embodiments, which are particularly also shown in the attached drawing. The drawing shows:
The exemplary embodiment of an indirect extrusion press 10 shown in
The material block 22 that can be pressed to produce a pressed product by means of the indirect extrusion press 10 is a material block 22 that can consist, at least in part or in its entirety, of a metallic material, such as, for example, aluminum, copper, brass or corresponding alloys.
The block holder 18 can be moved in a straight line by the closure piece 16, by way of the indirect punch 12. The indirect punch 12 can be brought out of the material block accommodation 20 by moving the block holder 18 in the direction of the closure piece 16. Therefore the indirect punch 12 can be introduced into the material block accommodation 20 by moving the block holder 18 in the opposite direction (see, in this regard, also
In the operating state illustrated in
To form the shell chamber 26, the tool head 14 has a conical section 38 that narrows in the pressing direction of the indirect extrusion press 10 or in the opposite direction, whereby the shell chamber 26 is delimited by the narrowing section 38 and the inner wall 40 of the material block accommodation 20, in other words the inner wall 40 that delimits the material block accommodation 20.
Thus,
In the situation shown in
In order to implement problem-free or operationally reliable placement of the further tool head 28 between indirect punch 12 and material block accommodation 20, and also problem-free or operationally reliable accommodation of the further tool head 28 on the indirect punch 12, the maximal distance is preferably configured to be 7% greater than the sum of the expanses of the tool head 14 and of the block holder 18 in the movement direction, in other words in the direction in which the block holder 18 can be moved in a straight line by the closure piece 16, by way of the indirect punch 12.
The shell 24 is pressed out of the material block accommodation 20, in part, by means of the further movement of the block holder 18 in the opposite direction, according to Step D of the method, by means of the further tool head 28, in the present case. In
Although only a few embodiments of the present invention have been shown and described, it is to be understood that many changes and modifications may be made thereunto without departing from the spirit and scope of the invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2013 008 345.1 | May 2013 | DE | national |
