Isostatic pressing tool

Abstract

Pressing tool for isostatic pressing of objects made of, in particular, ceramic, granules, comprising: a first tool part (11) and a second tool part (12), wherein an elastic membrane (13) is arranged, attached, or inserted on the first tool part (11), which has a flange section (17) with a flange surface (16) which comes into contact with a counter-pressure section (14) associated with the second tool part (12) at least during a pressing operation, wherein the flange surface (16) and a counter-pressure surface (15) of the counter-pressure section (14) which is in contact with the flange surface (16) at least during the pressing operation are connected to each other by a positive locking mechanism at least during the pressing operation, wherein the counter-pressure section (14) is removable from the flange section (17).

Description

[0001] The invention relates to a pressing tool for isostatic pressing and a pressing method.

[0002] DE 10 2013 103 266 A1 describes a method for the isostatic pressing of objects made of ceramic granules. In this method, a filling space formed between a lower punch and an upper punch of a pressing tool is filled with granules. The granules are compacted by means of an elastic membrane arranged on the lower punch and / or the upper punch and subjected to a pressing pressure, forming a pressed object. The subject matter of the present invention can, in principle, function accordingly. In this and comparable methods and devices for isostatic pressing, the precision and reliability of the pressing process are considered to be in need of improvement.

[0003] The object of the invention is to propose a pressing tool or a corresponding pressing method for isostatic pressing, whereby the most precise and reliable pressing process possible is to be achieved.

[0004] This object is achieved in particular by the features of claim 1.

[0005] In particular, the object is achieved by a pressing tool for the isostatic pressing of objects made of, in particular, ceramic, granulate, comprising: a first tool part (e.g. lower punch) and a second tool part (e.g. upper punch), wherein an elastic membrane is arranged and / or fastened and / or inserted on the first tool part, which elastic membrane has a flange section with a flange surface which (in particular at least during a pressing process) comes into contact, in particular press contact, with a counter-pressure section assigned to the second tool part, wherein the flange surface and a counter-pressure surface of the counter-pressure section which is in contact with the flange surface (in particular at least during the pressing process) are connected to one another via a positive connection, wherein the counter-pressure section is preferably removable from the flange section.

[0006] Alternatively, the elastic membrane can also be arranged and / or attached and / or inserted on the second tool part. Likewise, an elastic membrane can be arranged and / or attached and / or inserted on both the first and second tool parts.

[0007] One idea of ​​the invention is to fix (or connect) the membrane and a part opposite the membrane to one another in a form-fitting manner (at least during the pressing process). Such a form-fitting connection can, in particular, center the membrane. Displacement and / or twisting during the filling and pressing processes can be counteracted. Preferably, the form-fitting connection (i.e., in particular the counterpressure section in conjunction with the membrane or its flange section) can act as a seal, which enables improved filling of the pressing tool, particularly when filled with compressed air and (simultaneously) vented with a vacuum. As a result, (at least almost) no granulate can escape from the filling chamber. Contamination on the top and / or bottom of the pressing tool is avoided or at least (significantly) reduced.The form fit (particularly the interaction between the structures of the counterpressure section and the flange section) can act as additional support and / or stabilizer (for the isostatic pressing forces acting on the membrane) during an isostatic pressing process. The specified geometry of a compact (green compact) can be better maintained in the upper area. Furthermore, a greater bulge, especially in the center of the object (article) to be pressed, can be achieved.

[0008] The first and second tool parts can form a filling space between them (during the pressing process or when the pressing tool is closed), in which the membrane(s), when subjected to a pressing pressure, compresses the granulate filled into the filling space such that it forms a pressed object. In particular, the membrane(s) compress(es) the granulate filled into the filling space between the two tool parts on one or both sides when the pressing pressure is applied toward the other tool part.

[0009] Specifically, the form closure can be achieved through mechanical locking and centering by means of a recess in the (movable) membrane on one side of the tool and a (stable) protruding geometry (mold lock) on the other side of the tool. When the tool is closed, this mold lock closes or locks the two tool parts (tool halves) together and can thus reduce membrane movement of the elastic membrane during the pressing process (whereby the membrane can be subjected to hydraulic pressure on one side to press a blank (green compact) from granulate).

[0010] The flange section is understood to mean, in particular, a section of the membrane which is at least substantially circumferential and / or in particular non-parallel, preferably at an angle of ≥ 30° or ≥ 60° or ≥ 80° or (at least substantially) 90°, to a main closing direction. A main closing direction is understood to mean, in particular, the direction in which the first tool part is moved relative to the second tool part when the pressing tool is closed. The main closing direction can run at least substantially vertically (from bottom to top or vice versa) or horizontally (from left to right or vice versa). Alternatively or additionally, the flange section can, in the assembled orIn the assembled state of the pressing tool, in the case of a vertically running main closing direction, they run at an angle of ≤ 60° or ≤ 30° or ≤ 10° to the horizontal, in particular they are aligned at least substantially horizontally, or in the case of a horizontally running main closing direction they run at an angle of ≤ 60° or ≤ 30° or ≤ 10° to the vertical, in particular they are aligned at least substantially vertically.

[0011] Preferably, an upper side of the flange section (flange surface) is in contact with the counter-pressure section (at least during the pressing process), preferably directly, in particular so that no filling space remains between the flange surface and the counter-pressure section (which does not necessarily exclude the possibility that small amounts of granulate can also penetrate into this area due to the process).

[0012] The counterpressure section is preferably designed to be circumferential. Specifically, the counterpressure section can be configured as described above in connection with the flange section (alternatively or in addition to the corresponding configuration of the flange section).

[0013] The counterpressure section preferably runs at least substantially circumferentially and / or non-parallel, preferably at an angle of ≥ 30° or ≥ 60° or ≥ 80° or (at least substantially) 90°, to the main closing direction. Alternatively or additionally, in the assembled or built-up state of the pressing tool, the counterpressure section can run at an angle of ≤ 60° or ≤ 30° or ≤ 10° to the horizontal in the case of a vertically running main closing direction, in particular be oriented at least substantially horizontally, or run at an angle of ≤ 60° or ≤ 30° or ≤ 10° to the vertical in the case of a horizontally running main closing direction, in particular be oriented at least substantially vertically.

[0014] The counterpressure surface in contact with the flange surface is preferably a side of the second tool part which points in the direction of the first tool part during the filling and / or pressing process (with the pressing tool assembled or mounted).

[0015] In particular, the positive locking prevents radial inward and / or radial outward movement of the flange portion of the diaphragm (at least during the pressing process). In specific embodiments, the positive locking can be designed such that it does not block relative movement between the counterpressure surface of the counterpressure portion and the flange surface of the diaphragm.

[0016] The flange surface and / or the counterpressure surface are, in particular, closed surfaces or annular surfaces (or at least substantially annular surfaces). The flange section or the flange surface are, in particular, adjacent to or located at one end of the membrane (in particular, facing away from the first tool part).

[0017] The counterpressure section is removable from the flange section (for example after a pressing process) (so that there is a distance between the counterpressure section and the flange section).

[0018] In embodiments, the flange portion has at least one (particularly circumferential) groove and / or at least one (particularly circumferential) projection. The (or a respective) groove of the flange portion can be engageable with a (complementary) projection of the counterpressure portion or can be engaged (particularly during a pressing operation). The (or a respective) projection of the flange portion can be engageable with a (complementary) groove of the counterpressure portion or can be engaged (particularly during a pressing operation).

[0019] In particularly preferred embodiments, the flange section has one (in particular exactly one), in particular circumferential, groove and the counterpressure section has one (in particular exactly one), in particular circumferential, projection.

[0020] The (respective) groove is preferably U- or V-shaped in cross-section. Alternatively or additionally, the (respective) projection is U- or V-shaped in cross-section, in particular complementary to the groove. The (respective) groove and / or the (respective) projection can vary in their geometry, in particular shape and size, around the circumference or be completely omitted in some sections.

[0021] The counterpressure section can be formed (at least partially, possibly completely) by a closed or (at least substantially) annular segment that is separate (or separable) from the second tool part, in particular removable from the second tool.

[0022] Furthermore, the counterpressure section can be formed (at least partially, optionally completely) by the second tool, in particular as an integral component thereof. In such an embodiment, the counterpressure section is in particular not detachable from the second tool (or a main body of the second tool) (detachable without destruction). In particular, in such an embodiment, the counterpressure section can be integrally connected to the second tool (at least in sections) and / or can merge monolithically into the second tool (at least in sections) (so that an adjacent section of a main body of the second tool part is monolithically connected to the counterpressure section).

[0023] The counterpressure section (closed or annular segment) can be formed at least partially (or completely) from metal, in particular steel.

[0024] In preferred embodiments, the form fit (at least during the filling and / or pressing process) creates a seal.

[0025] The form fit can vary in its geometry, especially shape and size, around the circumference or be completely omitted in some sections.

[0026] According to a further aspect of the present disclosure, a use of a pressing tool as described above and / or below for the isostatic pressing of objects made of, in particular, ceramic, granulate is proposed.

[0027] According to a further aspect of the present disclosure, a pressing method for the isostatic pressing of objects made of, in particular, ceramic, granulate is proposed, in particular using a pressing tool as described above and / or below, wherein a pressing tool (the) is provided with a first tool part and a second tool part, wherein an elastic membrane is arranged and / or fastened and / or inserted on the first tool part, which elastic membrane has a flange section with a flange surface which, during a pressing process, comes into pressing contact with a counter-pressure section assigned to the second tool part, wherein the flange surface and a counter-pressure surface of the counter-pressure section which is in contact with the flange surface during the pressing process are connected to one another during the pressing process via a positive connection.Further preferred method features emerge from the above and / or following explanations regarding the functionality of the pressing tool, wherein a respective function can be carried out by a corresponding method step.

[0028] According to a further aspect of the invention, a press for isostatically pressing objects made of, in particular, ceramic, granulate is proposed, comprising a pressing tool as described above and / or below.

[0029] Further embodiments emerge from the subclaims.

[0030] The invention is described below using an exemplary embodiment, which is illustrated by the accompanying figures. Herein: Fig. 1 a schematic representation of a pressing tool; and Fig. 2 the pressing tool according to Fig. 1 in a different position.

[0031] In the following description, the same reference numbers are used for identical and equivalent parts.

[0032] Fig. 1 shows (schematically, partly highly schematically) a pressing tool for isostatic pressing in the open position. The pressing tool has a first tool part 11 and a second tool part 12. A membrane 13 is arranged, inserted, or attached to the first tool part 11. A counterpressure section (closed or annular segment or metal ring) 14 is assigned to the second tool part 12. This counterpressure section can, for example, be firmly (detachably or permanently) connected to the second tool part 12.

[0033] The individual tool parts can be mounted on supports (not shown in the figures). For operation, a granulate injection device and lines for filling the pressure chamber formed between the wall of the first tool part and the membrane (press membrane) with a hydraulic fluid can be provided (not shown in the figures).

[0034] A counterpressure surface 15 of the counterpressure section 14 is (see Fig. 2 ) is positively connected to a flange surface 16 of a flange section 17 of the membrane 13 during the pressing process. Specifically, the counterpressure surface 15 has a (circumferential) projection 18, and the flange surface 16 has a (circumferential) groove (e.g., annular groove) 19.

[0035] In Fig. 2The second tool part 12 is connected to the counterpressure section (closed or annular segment or metal ring) 14, and the first tool part 11 is connected to the (shaping) membrane 13. Specifically, by closing the pressing tool, the counterpressure section (closed annular segment or metal ring) 14 and membrane 13 (or its flange section 17) are pushed into one another, resulting in a (closed) shape.

[0036] The Figures 1 and 2 Each shows an exemplary embodiment of a pressing tool according to the invention in an installed position with a vertical opening direction of the tool parts 11, 12. Specifically, the respective tool parts 11, 12 are moved (at least substantially) vertically (upward or downward) relative to one another. In an alternative embodiment, the pressing tool according to the invention can also be configured in an installed position with a horizontal opening direction. Imagine the tool parts 11, 12 according to Fig. 1 and 2each rotated by 90° (left or right). Specifically, the respective tool parts 11, 12 can be moved (at least essentially) horizontally (left or right) relative to each other.

[0037] At this point, it should be noted that all parts and functions described above, viewed individually and in any combination, particularly the details shown in the drawings, are claimed as essential to the invention. Modifications to these are familiar to those skilled in the art.

[0038] Furthermore, it is pointed out that the broadest possible scope of protection is sought. In this respect, the disclosure contained in the claims may also be further clarified by features that are described with additional features (even without these additional features being mandatory). It is explicitly pointed out that parentheses and the term "in particular" are intended to emphasize the optionality of features in the respective context (which does not imply, conversely, that without such identification, a feature is to be considered mandatory in the corresponding context). List of reference symbols

[0039] 11First tool part 12Second tool part 13Diaphragm 14Backpressure section 15Backpressure surface 16Flange surface 17Flange section 18Protrusion 19Groove

Claims

1. Press tool for the isostatic pressing of objects made of granulate, in particular ceramic granulate, comprising: a first tool part (11) and a second tool part (12), wherein an elastic membrane (13) is arranged and / or fastened and / or inserted on the first tool part (11), which elastic membrane has a flange section (17) with a flange surface (16) which, at least during a pressing process, comes into press contact with a counter-pressure section (14) assigned to the second tool part (12), wherein the flange surface (16) and a counter-pressure surface (15) of the counter-pressure section (14), which counter-pressure surface is in contact with the flange surface (16) at least during the pressing process, are connected to one another via a positive connection at least during the pressing process, wherein the counter-pressure section (14) is removable from the flange section (17).

2. Press tool claim 1, characterized in thatthe flange section (17) has at least one, in particular circumferential, groove (19) and / or at least one, in particular circumferential, projection (18), which can be brought into engagement with a complementary projection (18) or a complementary groove (19) of the counter-pressure section (14) or is / are engaged, in particular during the pressing process.

3. Press tool according to one of the preceding claims, characterized in that the counterpressure section (14) is at least partially formed by a closed or annular segment which is separate from the second tool part (12) and in particular can be removed therefrom.

4. Press tool according to one of the preceding claims, characterized in that the counterpressure section (14) is at least partially formed by the second tool part (12), in particular as an integral part thereof.

5. Press tool according to one of the preceding claims, characterized in thatthe counterpressure section (14) is at least partially made of metal, in particular steel.

6. Press tool according to one of the preceding claims, characterized in that the form fit ensures sealing at least during the filling and / or pressing process.

7. Press tool according to one of the preceding claims, characterized in that the form fit varies in its geometry, in particular shape and size, around the circumference or is completely omitted in some sections.

8. Use of a pressing tool according to one of the preceding claims for the isostatic pressing of objects made of, in particular, ceramic, granules.

9. Pressing method for the isostatic pressing of objects made of, in particular, ceramic, granulate, in particular using a pressing tool according to one of the preceding claims, wherein a pressing tool is provided with a first tool part (11) and a second tool part (12), wherein an elastic membrane (13) is arranged and / or fastened and / or inserted on the first tool part (11), which elastic membrane has a flange section (17) with a flange surface (16) which, during a pressing process, comes into press contact with a counter-pressure section (14) assigned to the second tool part (12), wherein the flange surface (16) and a counter-pressure surface (15) of the counter-pressure section (14), which counter-pressure surface is in contact with the flange surface (16) during the pressing process, are connected to one another by a positive connection during the pressing process.

10. Press for the isostatic pressing of objects made of, in particular, ceramic, granulate, comprising a pressing tool according to one of claims 1-7.

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