EP4056359A1 - Pressing tool - Google Patents

Abstract

The invention relates to a powder press device, in particular a metal powder and/or ceramic powder press device, comprising at least one die, at least one first punch (11) which, in a pressing position, is inserted from a first side into a cavity (20 ) of the die (13) is arranged such that it can be immersed, and at least one, in particular at least two-part, powder sealing device (18) that can be arranged at least in sections, preferably completely, around the cavity (20).

Description

The invention relates to a press device, in particular a metal powder and/or ceramic powder press device, and a method for powder pressing a powder pressed part, in particular a ceramic powder pressed part and/or metal powder pressed part.

Such powder press devices (powder presses) are known in principle from the prior art. In the prior art, a cavity (filling space) is filled in a die of the press device. A stamp (upper stamp) then dips into the filling space (cavity) filled in this way in order to press the pressed part.

In principle, different possibilities for filling the filling space are known. According to a standard procedure, a feed shoe (feed slide) travels over an open cavity, allowing the powder to trickle in. A corresponding filling is often comparatively irregular.

During suction filling, the filling shoe (filling slide or filler) can be moved over a cavity that is still closed. The die can then be lifted will. A filling space is then filled more evenly (than in the standard method described above).

When overfilling, the matrix can move (at least a little) higher, which results in a larger filling quantity. Before the filler (filling shoe or filling slide) is moved back, an actually required die height or filling height can be set. If necessary, excess powder can be wiped off the filling shoe.

When underfilling, the die can be raised after filling has taken place, so that the powder that is present sinks deeper into the die. The die can be closed before the stamp touches the powder. This can then possibly not escape.

Overall, the powder filling in the prior art is still considered in need of improvement, in particular with regard to the most precise possible setting of that powder quantity which is then ultimately also compressed.

The object of the invention is to propose a powder press device, in particular a metal powder and/or ceramic powder press device, in which the filling with powder, in particular also in the case of tapering and/or stepped punch geometries (upper punch geometries), is comparatively precise, in particular at least essentially without loss of powder or at least with only a comparatively small loss of powder. Furthermore, it is the object of the invention to propose a corresponding method.

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

In particular, the object is achieved by a powder pressing device (powder press), in particular metal powder and/or ceramic powder pressing device (metal powder and/or ceramic powder press), comprising at least one die, at least one (first) punch (upper punch), the (in a pressing position) from a first (upper) side into a cavity (die opening or cavity or filling space) filled with powder (ceramic and/or metal powder) of the die, and at least a powder sealing device that can be arranged at least in sections (preferably completely) around the cavity (or an upper edge of the same), in particular at least two-part powder sealing device.

One idea of the invention is to provide a powder sealing device that can be arranged around the cavity (or an upper edge thereof) in such a way that when the punch (upper punch) dips into the cavity, this is at least essentially prevented (or at least reduced). is) that powder is conveyed out of the cavity (e.g. spattered out and/or pushed out). As a result, a more precise setting of that powder volume can be achieved that is ultimately also pressed to form the pressed part. Furthermore, powder losses can be reduced.

An arrangement around the cavity (or an upper edge thereof) is to be understood in particular as an arrangement in which the powder sealing device runs along the (upper) edge of the cavity. At least in one position (e.g. an initial position when a tapered end portion of the punch or an end portion with a comparatively small diameter dips into the cavity), the powder sealing device can also overlap with a cross-sectional area of the cavity (at the level of an upper die surface) (in a projection of the sealing device onto this plane). In specific embodiments, the sealing device is arranged in such a way that it (at least in any sealing position) lies outside of this cross-sectional area of the cavity (but preferably directly adjoins the stamp, possibly apart from a smaller distance to form a gap compared to the stamp). In further embodiments, this is the case at least in a (sealing) position of the sealing device, in particular in an end position (in which the plunger has completed its maximum path into the cavity).

An at least sectional (partial) arrangement around the cavity is to be understood in particular as an arrangement in which the sealing device covers the edge of the cavity over an angular range of at least 180°, preferably at least 270°, even more preferably at least 350°, possibly at least Surrounds (or is arranged along the same) 359° or 360°.

The powder sealing device is preferably adjustable. If the powder sealing device is designed in two or more parts, these two or more parts of the powder sealing device can preferably move relative to one another (in particular in the direction of an upper die surface). The two or more parts can preferably completely separate from each other (so that they are no longer connected). If necessary, it would also be conceivable for the two or more parts to be connected to one another (at least over a specific range of a relative movement) by a connecting and/or coupling device (allowing a change in distance to the relative movement).

The sealing device is preferably movable (at least partially, in the case of two or more parts this preferably applies to several or all of these several parts) transversely to a direction of movement of the stamp (in the case of several parts this also applies in particular to a relative movement of the individual parts to one another), preferably along a surface adjacent to the cavity of the die. The sealing device (or parts thereof) is particularly preferably displaceable, in particular in such a way that during the movement or adjustment it is moved (slides) along a surface of the die adjoining the cavity. In this way, the sealing device can be precisely positioned in a particularly simple manner so that it can implement its sealing function.

The sealing device can remain in the same place within the cavity during a movement of the upper punch (or its distal end) (or in conceivable alternative embodiments can be moved during the same).

A movement transverse to a direction of movement of the ram is to be understood in particular as meaning that the sealing device can be moved at a 90° angle (possibly exclusively at such an angle) relative to the direction of movement of the ram (from top to bottom). However, it would also be conceivable for the movement to take place at an angle of at least 10° or at least 30° or at least 60° or at most 90° or at most 80° with respect to the direction of movement of the plunger. It is also conceivable that the movability of the sealing device or its specific movement changes during the bringing into a sealing position.

In general, the sealing device can also be implemented by pivoting the same or parts thereof (possibly relative to one another). Even more generally, the sealing device can be moved purely translationally or purely rotationally or both translationally and rotationally in order to bring it into a sealing position (this can also apply to several or all of possibly several mutually movable parts of the sealing device).

In a specific embodiment, at least part of the sealing device is or can be arranged on a filling shoe (filler), for example designed as an integral part thereof or attached or attachable to it. A first part of the sealing device is preferably arranged or can be arranged on a first filling shoe (filler), for example designed as an integral part thereof or attached or attachable to it, and a second part of the sealing device is arranged or can be arranged on a second filling shoe (filler), for example as a integral part thereof formed or attached or attachable.

Specifically, the sealing device or the (respective) first or second part can be screwed and/or welded to the (respective) filling shoe and/or attached by a clamping and/or tensioning device and/or in another way . With such an integration into a filling shoe structure, the corresponding filling shoe (or the overall structure, comprising the sealing device or its first/second/additional part) can fulfill a double function in a simple manner, namely, on the one hand, the powder in the direction of the hollow space (cavity) to transport to bring the powder into the cavity, on the one hand, and, on the other hand, to realize a seal. Particularly preferably, the same drive device can be used to realize both the movement of the filling shoe for filling the cavity and the movement of the filling shoe (or the structure with the sealing device or the part thereof) for sealing.

A distal end of the stamp (upper stamp) is preferably designed such that a projection of a cross section of this distal end onto a plane of the (upper) surface of the die or of an upper cross section of the cavity is at least partially spaced from an edge of the cavity. The spacing from the edge of the cavity can, for example, be at least 0.1 mm or at least 0.5 mm or at least 1.0 mm and/or at most 1.0 cm (over at least an angular area of 180° of the edge, possibly the entire edge). In such an embodiment, inserting the (upper) punch into the powder-filled cavity—without the sealing device according to the invention—would lead to a particularly marked extent to powder being pressed out of the cavity (or spraying out). This is advantageously prevented or at least reduced by the sealing device.

In a specific embodiment, the (upper) punch tapers at least in sections in the direction of its distal end. The stamp can be bevelled and/or have a step and/or at least one rounding and/or arc shape, at least in sections (in at least one longitudinal section; for example in a transition between two upper stamp sections), e.g. B. be rounded and/or rounded. A chamfer is preferably understood to mean a chamfer that is planar and/or in the shape of a truncated cone at least in sections. In embodiments, a distal end portion of the plunger can be formed by a cone or a truncated cone portion. It is conceivable that a distal end section of the stamp is formed by a (e.g. straight), in particular circular cylinder, which is adjoined by a further section of the stamp (e.g. another cylinder, in particular circular cylinder) which has a larger diameter (where a Transition between sections may be rounded).

The sealing device can be arranged around the stamp in such a way that there is a distance between the sealing device and stamp at least in sections (e.g. over an angular range of at least 180° or at least 270° or at least 350° or 360°), in particular in Form of a, possibly circumferential, gap is formed such that air can escape from the hollow space (the cavity). The distance is preferably at least 10 microns and/or at most 500 microns or at most 300 microns or at most 100 microns. Such a distance (gap) allows air to escape from the cavity despite the sealing device, so that (undesirable) air compression does not occur here.

Preferably, the sealing means (when sealing) is in close contact with a surface (top surface of the die) surrounding the cavity. In particular, the sealing device is flat on its underside, with this flat underside (tightly) abutting or being able to abut the (upper) surface of the matrix.

The sealing device can have at least two segments (parts) that can be adjusted relative to one another (particularly if necessary butt touching) and that preferably engage with one another when the sealing device is in the sealing state, in particular via at least one projection that engages with at least one recess. An engagement can preferably take place via a zigzag structure or sawtooth structure and/or via a tongue and groove connection. The engagement preferably takes place in such a way that the two segments are connected to one another in such a way that the engagement counteracts a force (pointing in the direction of a connection plane), in particular from the inside outwards.

In various embodiments, the sealing device can have at least or exactly two or at least or exactly three or at least or exactly four segments (parts) that can be adjusted relative to one another. If the sealing device has a plurality of segments (parts), these can preferably be adjusted independently of the other segments (parts). Alternatively, it is also possible that only a common (possibly synchronized) adjustment is possible or at least adjustable.

The above-mentioned object is also achieved in particular by a method for powder pressing a powder pressed part, in particular ceramic powder pressed part and/or metal powder pressed part, using the above press device. In the method, powder is preferably filled in a cavity of the die, the sealing device is arranged around a die opening, and (then) the punch (punch) is immersed in the cavity (cavity) for pressing. Further method features result from the above and/or following description of the press device. Functional features of the press device (or corresponding configurations of the same) can be implemented as concrete method steps. For example, if it is disclosed above and/or below that part of the press device can be arranged or adjusted, this should be the method means in particular that a corresponding arrangement (as a step, in particular comprising a change in position) can take place or a corresponding step for adjustment is carried out.

The above-mentioned object is in particular also achieved by using a press device of the above type for powder pressing a powder compact, in particular for pressing a ceramic powder compact and/or metal powder compact.

In embodiments, the press device can generate a pressing force of at least 1.0 tons or at least 10 tons or at least 100 tons and/or at most 1000 tons.

Further embodiments emerge from the dependent claims.

Fig. 1

eine erfindungsgemäße Presseneinrichtung in einem schematischen Schnitt (Querschnitt bzw. Vertikalschnitt);

Fig. 2

eine alternative Ausführungsform in einem Schnitt analog Fig. 1;

Fig. 3

die Presseneinrichtung gemäß Fig. 1 in einem schematischen Horizontalschnitt in einer ersten Stellung;

Fig. 4

die Presseneinrichtung gemäß Fig. 1 in einem schematischen Horizontalschnitt in einer zweiten Stellung; und

Fig. 5

eine alternative Ausführungsform in einem Horizontalschnitt.

The invention is described below using exemplary embodiments which are explained in more detail using the figures. Here show:

1

a press device according to the invention in a schematic section (cross-section or vertical section);

2

an alternative embodiment in a section analogous 1 ;

3

the press device according to 1 in a schematic horizontal section in a first position;

4

the press device according to 1 in a schematic horizontal section in a second position; and

figure 5

an alternative embodiment in a horizontal section.

In the following description, the same reference numerals are used for the same parts and parts with the same effect.

1 shows (in a schematic horizontal section) a press device comprising an upper punch 11, an (optional) lower punch 12, a die 13, a first filler 14 (filler shoe) and a second filler 15 (filling shoe). A first part 16 of a sealing device 18 is attached to the first filler 14 . A second part 17 of the sealing device 18 is attached to the second filler 15 . In the present example, the sealing device is designed in two parts (however, in alternative embodiments it can also have more than two parts). In particular, the first part 16 is movable together with the first filler 14 (along a die surface 19, in 1 to the left). The second part 17 of the sealing device 18 (together with the second filler 15) can also be moved (along the surface 19) (in 1 To the right). 1 shows a state of the press device before the upper punch dips into a cavity 20 within the die 13. As soon as the upper punch 11 enters the cavity 20 and touches the powder in this cavity 20, this leads to possible displacement and possible ejection of the powder from the cavity (if the sealing device 18 were not provided). However, the sealing device 18 prevents such a transport.

This is particularly pronounced with a stepped and/or beveled punch. For example, a punch with a beveled (truncated) end section and a step in 2 (in alternative embodiments only one bevel or only one step and/or several steps and/or several bevels with different gradients can also be formed).

A horizontal section of the press device according to 1 (or 2 ) is in Figures 3 and 4 shown. In figure 3 the parts 16, 17 of the sealing device 18 are removed from the cavity below the punch 11 (and not in sealing position). It can be seen in particular that the parts 16, 17 of the sealing device 18 are attached to the respective filler (filler shoes) 14, 15 (or are integrated into a corresponding filler structure), so that they can be moved together with the respective filler and are therefore a sealing position (according to 4 ) can be brought.

It is also conceivable to design the filling space seal separately from a (regular) filling shoe. This can be retracted parallel to the original filling shoe and/or in any twisted position in the plane, for example by an electric, hydraulic and/or pneumatic drive.

Alternatively or additionally, pivoting the device, e.g. B. with a corresponding rotary drive conceivable.

In figure 5 A cross section of an alternative embodiment of the sealing device 18 (in a schematic horizontal section) is shown. In particular, engagement structures 21, 22 (here for example in the form of in particular sawtooth-like interlocking projections) can be seen here, which bring the individual parts 16, 17 of the sealing device 18 into engagement with one another.

At this point it should be pointed out that all the parts described above, viewed individually and in any combination, in particular the details shown in the drawings, are claimed to be essential to the invention. Modifications of this are familiar to the person skilled in the art.

Reference sign

11

upper stamp

12

bottom stamp

13

die

14

filler (filler shoe)

15

filler (filler shoe)

16

first part

17

second part

18

sealing device

19

surface

20

cavity

21

engagement structure

22

engagement structure

Claims (12)

Powder press device, in particular metal powder and/or ceramic powder press device, comprising at least one die, at least one first punch (11) which, in a pressing position, extends from a first side into a powder-filled cavity (20) of the die (13). is arranged such that it can be immersed, and at least one at least two-part powder sealing device (18) which can be arranged at least in sections, preferably completely, around the cavity (20). Press device according to claim,
characterized in that
the sealing device (18) can be moved at least partially transversely to a direction of movement of the stamp, preferably along a surface (19) adjoining the cavity (20) of the die (13). Press device according to one of the preceding claims,
characterized in that
at least one part of the sealing device (18) is arranged or can be arranged on a filling shoe, for example is designed as an integral part thereof or attached or can be attached to it, preferably a first part (16) of the sealing device (18) is arranged or can be arranged on a first filling shoe is, for example as is formed as an integral part of the same or is attached or attachable to it, and a second part (17) of the sealing device (18) is arranged or can be arranged on a second filling shoe, for example is formed as an integral part thereof or is attached or attachable to this. Press device according to one of the preceding claims,
characterized in that
a projection of a cross-section of a distal end of the punch onto a plane of the top surface (19) of the die (13) is at least partially spaced from an edge of the cavity. Press device according to one of the preceding claims,
characterized in that
the plunger (11) tapers at least in sections in the direction of its distal end, in particular is beveled and/or has a step. Press device according to one of the preceding claims,
characterized in that
the sealing device (18) can be arranged around the plunger (11) in such a way that a distance is formed between the sealing device (18) and the plunger (11), at least in sections, in particular in the form of a possibly circumferential gap, such that air escapes can escape from the cavity (20), the distance preferably being at least 10 microns and/or at most 100 microns. Press device according to one of the preceding claims,
characterized in that
the sealing device (18) in the sealing state rests tightly against a surface (19) of the die (13) surrounding the cavity (20). Press device according to one of the preceding claims,
characterized in that
the sealing device (18) has at least two mutually adjustable segments which preferably engage with one another in the sealing state of the sealing device (18), in particular via at least one protrusion engaged with at least one recess and/or at least one corresponding protrusion. Press device according to one of the preceding claims,
characterized in that
the sealing device (18) has at least or exactly two or at least or exactly three or at least or exactly four segments that can be adjusted relative to one another. Method for powder pressing a powder pressing part, in particular ceramic powder pressing part and/or metal powder pressing part, using a press device according to one of the preceding claims. Method according to claim 10,
characterized in that
Powder is filled into a cavity of the die (13), the sealing device (18) is arranged around a die opening and the punch (11) dips into the cavity (20) for pressing. Use of a press device according to one of Claims 1 to 10 for powder pressing a powder pressed part, in particular for pressing a ceramic powder pressed part and/or metal powder pressed part.

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