Powder press having a cone-shaped substructure

Abstract

The invention relates to a powder press, comprising a tool structure, which has a conical substructure having lower rams nested in each other, wherein each lower ram has a longitudinal extent, in particular a cylindrical longitudinal extent, which is guided in a die, wherein, in the case of at least two longitudinal extents of the lower rams, each longitudinal extent is adjoined by a conical enlargement, wherein the conical enlargements can be guided in each other, wherein the region of the conical enlargement has an inner wall and an outer wall, which expand conically and which are preferably longer than the longitudinal extent. The invention further relates to a method for operating a powder press and to a computer program product having computer program code means that can be executed on a computer system in order to perform the method.

Claims

1. A powder press comprising a tool structure with punches nested in one another, wherein each punch has a longitudinal extent having a head piece which is guided in a die and at least two of the punches further each have a respective conical enlargement which is adjoined to the respective longitudinal extent, wherein the conical enlargements are able to be guided one in another, wherein the conical enlargement has a conically expanding inner and outer wall, and each respective conical enlargement is longer than the respective longitudinal extent.

2. The powder press as claimed in claim 1, wherein a conical extension is located on at least two respective punches, said conical extension continuing a corresponding conical inner and outer wall of the conical enlargement.

3. The powder press as claimed in claim 2, wherein a cone angle at which the conical enlargement and the conical extension extend away from a press axis is at least approximately the same.

4. The powder press as claimed in claim 1, wherein, in a common end position, feet of the respective punches end at different heights than one another.

5. The powder press as claimed in claim 1, wherein the punches that slide in one another have approximately the same elasticity in the conical enlargement.

6. The powder press as claimed in claim 1, wherein the punches, each with a conical structure that slide in one another, have approximately the same elasticity.

7. The powder press as claimed in claim 1, wherein feet of the punches end at the same height along a plane in a common end position.

8. The powder press as claimed in claim 1, wherein an outermost punch deflects approximately as much as an associated inner punch.

9. The powder press as claimed in claim 1, wherein an outermost punch deflects approximately as much as an associated inner punch wherein the outermost punch and the associated inner punch each have a respective conical structure that slide into one another.

10. The powder press as claimed in claim 1, wherein a punch holder directly adjoins the conical enlargement at an end opposite to the longitudinal extent.

11. The powder press as claimed in claim 1, wherein the conical enlargement of the respective punch increases to such an extent that an associated punch holder terminates flush with the punch laterally on an outside.

12. The powder press as claimed in claim 1, wherein the conical enlargement of the respective punch transitions into a cylindrical portion, wherein the cylindrical portion has a fastening structure for a punch holder.

13. The powder press as claimed in claim 12, wherein a punch holder is connected directly to the respective punch by a bayonet fastener.

14. The powder press as claimed in claim 1, wherein a connection between a punch holder and punch takes place without a pressure plate and clamping plate.

15. The powder press as claimed in claim 1, wherein at least one of the punches are produced in one piece.

16. The powder press as claimed in claim 1, wherein at least one of the punches are produced in a multipart manner.

17. The powder press as claimed in claim 1, wherein the punches that slide in one another are provided with in each case a different ratio of length of the head piece to length of the conical enlargement.

18. A method for operating a powder press according to claim 1, the method comprising: moving the punches that are nested in one another, and employing monitoring in the form of control or regulation, this effecting equalization between different elasticities of the punches that slide in one another when the pressure on a pressed workpiece is relieved.

19. The method as claimed in claim 18, further comprising electronically compensating for a difference in elastic deflection.

20. The method as claimed in claim 18, further comprising equalizing via position control while the punches are being moved.

21. The method as claimed in claim 18, further comprising creating a compact from powder metal using the powder press.

22. A method of setting up of the powder press according to claim 1, wherein said punches are first of all installed together and are then jointly set up.

23. The powder press as claimed in claim 1, wherein the punches that have conical enlargements are lower punches.

Description

(1) Further advantageous features and configurations can be gathered from the following figures. One or more features from one or more figures and also from the description above and below can, in this case, be combined to form further configurations. In particular, the figures serve to explain the invention and are not intended to limit the latter. Observations and statements which relate to lower punches and lower punches with a conical structure are not limited to lower punches but serve for clarification by way of example. The respective features and configurations are likewise able to be used in proposed upper punches or proposed upper punches with an additional conical structure of a powder press. In the figures:

(2) FIG. 1: shows a detail of a powder press as is known from the prior art,

(3) FIG. 2: shows an exemplary, schematic adapter structure without a tool and substructure but with adapter plates and column structure from the prior art,

(4) FIG. 3: shows an exemplary, schematic view of lower punches that are movable in one another, as are known from the prior art,

(5) FIG. 4: shows an exemplary, schematic configuration according to the invention of lower punches and attached structures compared to the illustration in FIG. 3,

(6) FIG. 5: shows an exemplary schematic design solution with expanding lower punches according to the proposed invention,

(7) FIG. 6: shows a comparison of the different springing behavior or elasticity the use of the different systems according to FIG. 3 and according to FIG. 4, and

(8) FIG. 7: shows a schematic view of a proposed powder press.

(9) FIG. 8: shows an enlarged view of the powder press from FIG. 7 in order to illustrate stops.

(10) FIG. 1 shows a detail of a powder press 1 as is known from the prior art. This detail shows a part of a tool 2, wherein, however, neither a die nor an upper punch or other components of the powder press 1 are illustrated. What is shown is an adapter plate structure 3 with a lower punch 4. As ancillary equipment, use is made of a screwed-on lock bush 5, a pressure plate 6 and a support ring 7. By means of the lock bush 5, a punch foot 8 is fastened to the pressure plate. The structure of the punches shows, for the one part, the necessary size that has to be provided for such a powder press. For the other part, the setup requires a certain effort, since, for this purpose, the lock bushes or clamping plates and pressure plates also have to be installed, this taking place individually.

(11) FIG. 2 shows an adapter plate structure from the prior art in a simplified, clear illustration. For the upper and also the lower punches, which are not shown in more detail here, an adapter plate has to be installed in each case per punch. Little by little, one adapter plate after another can be attached upwardly and also downwardly, for which purpose the respective structure has to be moved in the press. This operation is very time-consuming and requires a large number of individual parts.

(12) FIG. 3 likewise shows a simplified sectional view, for better understanding, of a structure, known from the prior art, with a lower punch 9 and attached structures 10. These extend, as already illustrated in FIG. 1, substantially along a movement axis of the press. In particular, the respective inner and adjacent outer wall of adjacent punches slide on one another, since, in such a structure, the punches are guided thereby.

(13) FIG. 4 shows a structure according to the invention with lower punches 11 which have a conical expansion, to which respective cone-shaped structures 12 are attached, to which a punch holder for example is then directly attachable. The structures 12 are connected here to the lower punches 11 by feet 13 that are illustrated only schematically. It is preferred, as illustrated, for an angle of the conical expansion of the respective lower punch 11 to be adopted and continued by the cone-shaped structure 12. An exemplary configuration is a substantially conical-rectilinear embodiment of the expansion. A bell-like design of the expansion is likewise possible. As illustrated, contact occurs only in the region of the lower punches, and in that case only in the region of the longitudinal extent 11.1 thereof. Otherwise, the walls are spaced apart from one another.

(14) FIG. 5 shows an exemplary, schematic design solution, in which the illustrated lower punches 13 move in one another and a conical expansion results overall. Attached to the punch feet are conical structures 14, the conical profile of which continues as far as the illustrated adapter plates 15.

(15) FIG. 6 shows a comparison of the respective elasticity firstly with the type 1 system from FIG. 3 and secondly with the type 2 system from FIG. 4. As illustrated, it is possible to bring the corresponding properties of the respective lower punches or lower punches with a structure very close to one another, as proposed. This can result, in particular, for example, in the press control not needing any elasticity equalization between the punches during movement, in particular during relief of pressure.

(16) FIG. 7 shows a schematic, simplified view of a powder press 17 according to the invention. For better understanding, the individual components of the powder press 17 are provided with reference signs in the figure and explained in the following text. The illustrated section is not planar, but partially rotated for the sake of clarity. As a result, those components are also visible which, arranged around a periphery of the powder press 17, would not otherwise be visible. A crosshead 18 of the powder press 17 is connected to a hydraulic main cylinder 19 for a pressing force. However, it is also possible for some other drive to be provided, for example a worm drive. Furthermore, the crosshead 18 is firmly connected to two illustrated guide columns 20. An upper top plate 21 is movable, wherein, for example, at least two diagonally opposite hydraulic cylinders 22 per level are used. Each level preferably has hollow cones 23 as a conical expansion of a structure or of a punch with in each case at least two stiff arms 24 with guide bearings 27, each with respect to two diagonally opposite columns. A die plate 25 with the die 26 is held in a movable manner. As a result, a take-off method can be implemented. A drive for this purpose can also be provided in a base plate. The machine base plate 28 of the powder press 17, also known as foundation plate, has at least two diagonally opposite cylinders, preferably hydraulic cylinders 29, per level, which are connected to a hollow cone 30, specifically one each per tool-punch level. The machine base plate 28 bears the hydraulic cylinders 29 and is firmly connected to the columns 31. The hydraulic cylinders 29 can be replaced for example completely or in part by some other drive, for example by a respective electric spindle drive. Also illustrated are the lower punches 32 with attached structures in the form of the hollow cones 30. In the region of the substructure, too, the lower punches or the hollow cones 30 are supported via stiff arms 33. Otherwise, it should be noted that, for the sake of clarity, only the sections through the shaping tools and the conical structure parts are illustrated in a hatched manner.

(17) According to a further concept, which can be independent of or dependent on the above and the following, a guide of the punch units is proposed, which has a first contacting region in the die as guide, in particular as an upper guide for lower punches and as a lower guide for corresponding upper punches. A second guide takes place as an external guide of the hollow cones, as explained and illustrated above. In this way, defined movability along a powder press axis can be created.

(18) FIG. 8 shows a detail of the illustration in FIG. 7. However, for better clarity, the hydraulic cylinders have been omitted and various stops 34 illustrated instead. Said stops can be used according to one configuration. A stop can be arranged in a stationary and also in an adjustable manner.