WO2004112989A1

WO2004112989A1 - Lining plate for moulding chambers

Info

Publication number: WO2004112989A1
Application number: PCT/EP2004/006375
Authority: WO
Inventors: Martin Eschbach; Michael BUSENBECKER
Original assignee: Carl Aug. Picard Gmbh & Co. Kg
Priority date: 2003-06-16
Filing date: 2004-06-14
Publication date: 2004-12-29
Also published as: DE20309389U1

Abstract

The invention relates to a lining plate for moulding chambers in moulding machines that are designed to produce moulding blocks or casting moulds, which are pressed from moulding sand and then removed from the moulding chamber in an ejection direction. Certain sections of a plate base body (G) are provided with deaeration nozzles (7) comprising slits (9) that run in parallel. The deaeration nozzles (7) are arranged in the plate base body (G) in such a way that their slits (9) run transversally to the direction (AR) in which the moulding blocks or casting moulds are ejected from the moulding chamber.

Description

Carl Aug. Picard GmbH & Co. KG, Hasteraue 9, D-42857 Remscheid

Lining plate for mold chambers

The invention relates to a lining plate for mold chambers in molding machines for the production of mold blocks or casting molds, which are pressed from molding sand and then brought out of the molding chamber in a direction of extension, partial areas of a plate base body being provided with ventilation nozzles, each of which has slots which run parallel to one another.

Molding machines, in particular so-called boxless molding machines, are known in practice in various designs, for example from DE 42 28 749 C1. The molding machines are used to produce mold blocks or casting molds from molding sand. The molding machines mentioned have a molding chamber consisting of several lining plates, as a rule with a rectangular base plate, an upper plate and two side plates, which are also rectangular. Two vertical end faces are open. To produce a mold block, a press plate with an inner model plate is moved up to one end face, so that this end face is sealed. A corresponding press plate with a model plate also directed inwards also seals the other end face. Molding sand is then injected into the molding chamber via a feed hopper. Subsequently, the molding sand is compressed or compressed so much by the action of the two press plates and the two model plates that a dimensionally stable mold block is formed which can be pushed out in an extension direction after opening one end of the mold chamber. Any number of mold blocks can then be pushed one after the other onto a conveying device, where two mold blocks lying close together form cavities corresponding to the model plates, into which liquid metal can then be poured to form castings. A problem that has been known for a long time is that when the molding sand is shot into the Mold chambers and when compressing the molding sand to form blocks, the air contained in the molding chamber and in the molding sand must escape from the molding chamber, but at the same time the sand grains of the molding sand must be retained. Therefore, partial areas of a base plate body of the lining plate are provided with ventilation nozzles, each of which has slots running parallel to one another, through which the air can escape.

EP 0 315 087 A1 describes a lining plate in which a wear plate and a carrier plate, which together form the lining plate, are provided with congruent circular openings in a plurality of partial areas evenly distributed over the plate surface, which openings in the wear plate for receiving nozzle inserts and in serve the carrier plate as air outlet openings. The nozzle inserts are fitted into the openings of the wear plate, taking into account certain tolerance dimensions. They are designed as so-called annular gap nozzles, which are usually made from conventional tool steel, such as 1.2067 or 1.2379. When the venting stream runs along the nozzles, the fine fraction in the molding sand in particular triggers erosion wear, whereby it has a particularly unfavorable effect if the annular gap is formed unevenly, since sand grains of different mass can jam in the gap as a result. The three-point system for fastening the nozzle in the plate, which is present in these nozzles, also causes swirling behind the passage through the gap, which hinders the free outflow of air and fine sand.

The latter disadvantage can be remedied by so-called slot nozzles, which belong to the applicant's production program and which - like the ones described above - can be inserted and fastened as insert parts in corresponding openings in a plate base body, which, however, do not have an annular gap, but rather each have slots running parallel to one another ,

In the known lining panels, there is - as already explained - a further problem in that the inner surfaces of the molding chamber are subject to extremely high wear and tear in some cases due to the pressing and grinding action of the molding sand. This applies not only to the molded rails for the production of molded blocks, which were particularly mentioned at the beginning, but also to the most varied other molding machines in which abrasive material is pressed together. The problems indicated are also described, for example, in EP 0 661 121 B1, which likewise discloses numerous ventilation nozzles which can be distributed in circular areas over the entire surface of a lining plate. According to EP 0 661 121 B1, however, no nozzle inserts are necessary for producing the ventilation nozzles of the lining plate described, since the ventilation nozzles of the lining plate are introduced as slots in a wear plate separated from a carrier plate of the lining plate. The slots are produced using laser beam technology and run parallel to each other in the direction of extension of the mold blocks or molds. They widen slightly conically from the inner surface to the outer surface of the wear plate, the side of the wear plate on which the laser beam strikes during processing forms the inner surface to the cavity of the molding chamber. This design of the venting nozzles has essentially proven itself in practice, but on the one hand it is tied to the two-part design of the lining plate and, on the other hand, as with the other known lining plates, wear in the region of the nozzles is sometimes higher than in the region of the plate surface which is not provided with nozzles.

The invention has for its object to provide a generic lining plate, which is characterized by improved wear behavior with high functionality of the ventilation nozzles.

This object is achieved by a generic lining plate, in which the ventilation nozzles are arranged in the plate base body in such a way that their slots run transversely to the direction of extension of the mold blocks or molds from the mold chamber.

The invention is based on a knowledge derived from damage analyzes, in particular from examinations of traces of wear, that the orientation of the slots of the nozzles has a large influence on the size of the erosion wear occurring in the area of the venting nozzles. From the type and the particular course of wear on lining panels with conventional annular gap and slot nozzles, the conclusion could be drawn that a relative movement of sand particles which in particular promotes wear on the surface of the base plate body in the nozzle area can be effectively prevented by the slot orientation according to the invention. The maximum positive effect occurs when the slots of the ventilation nozzles run at right angles to the direction in which the mold blocks or molds are pushed out of the mold chamber. The free discharge of air and fine sand through and behind the slots ensures high functionality of the nozzle. In contrast to the annular gap of the known nozzles, the slots are dimensionally stable, so that an air quantity that can be removed from the molding chamber per unit of time can be kept constant by a ventilation surface that is essentially unchangeable, apart from sand grains temporarily located in front of the slots.

Jamming of grains of sand can be largely avoided, in particular by a smooth surface in the slots with a surface roughness Rz of at most 2 μm.

The ventilation nozzles can advantageously be designed on the one hand as a one-piece insert body for the base plate body or on the other hand can also be designed as a multi-part body, in particular in two parts. In the second case, the venting nozzles can consist, in particular in a production-technically advantageous manner, of a first, disc-shaped partial body containing the slots and a ring-shaped second partial body connected to the first partial body, in particular glued.

Both one-part and multi-part ventilation nozzles can be glued to the plate base body for fastening, but the slot orientation according to the invention is not dependent on the nozzles being designed as insert parts for the plate base body. In other words, it would also be possible for the nozzles to be more integral, i.e. integral, are part of the base plate body.

The design of the nozzles can be tailored to the properties of the molding sand, in particular from the point of view of reducing wear. From this point of view, it is advantageous, for example, if the slots in the ventilation nozzles are each adapted to a grain size distribution of the molding sand Width, in particular a width in the range from 0.25 mm to 0.55 mm, preferably - corresponding to the grain size distribution of conventional molding sands - of 0.40 mm. Furthermore, it is also advantageous from this aspect if metal carbide or other hard phase particles contained in the structure of the material of the ventilation nozzles and / or the material of the plate base body are at an average distance from one another which is smaller than a predetermined lower limit grain size and / or as one average grain size of the molding sand. In the following it is explained in detail what this advantage is based on.

Further advantageous embodiments of the invention are contained in the subclaims and in the description below.

In the following the invention is explained in more detail using an example with reference to the accompanying drawings. Show it:

1 on a reduced scale, a perspective view of a molding chamber with lining plates according to the invention,

2 also on a reduced scale, a section of a top view of a lining plate according to the invention,

3 shows an illustration of a section of the cross section of a lining plate according to the invention,

4 on an enlarged scale, a front view of a ventilation nozzle used in a lining plate according to the invention,

5 shows a cross section through a ventilation nozzle according to FIG. 4,

6 is a plan view through a vent nozzle according to FIGS. 4 and 5,

7 is a greatly enlarged detail from the cross section through a vent nozzle, 8 shows a cross section through a first material for a lining plate according to the invention,

Fig. 9 shows a cross section through a second material for a lining plate according to the invention.

In the various figures of the drawing, the same parts are always provided with the same reference numerals, so that they are generally only described once.

Fig. 1 illustrates in perspective a simplified drawing mold chamber 1, consisting of a base plate 2, an upper plate 3 and two side plates 4, 5. The upper plate 3 has, for example, a slit-shaped opening 6, above which in practice a feed hopper or Feeder for shooting the molding sand is located. The press plates with model plates located on the open end faces of the molding chamber in practice are not shown for the sake of simplicity. The side plates 4, 5 and optionally the top plate 3 and also the bottom plate 2 consist of the lining plates according to the invention. As described at the beginning, molding sand is introduced into the molding chamber 1 through the feed hopper and then compacted by the action of the press and model plates, not shown. The resulting mold block is pushed out in an extension direction AR after opening one end of the mold chamber 1.

As illustrated in FIG. 1, the side plates 4, 5 and the top plate 3 each consist of a plate base body G, which has partial areas provided with ventilation nozzles 7. As shown in detail in FIGS. 2 and 3, the ventilation nozzles 7 are designed as a one-piece insert body for the plate base body G and are arranged in fastening openings 8 of the plate base body G designed as stepped bores. In particular, the ventilation nozzles 7 are glued to the plate base body G.

The plate base body G can advantageously at least partially consist of a carburized, hardened and optionally tempered case-hardening steel, while the material of the ventilation nozzles 7 is preferably a powder metallurgy material manufactured cold or high speed steel, a hard metal or a ceramic material can be selected. Through a suitable choice of material, it can advantageously be achieved that the ventilation nozzles 7 have a wear resistance that is at least as great as the wear resistance of the plate base body G.

The ventilation nozzles 7 each have parallel slots 9 and are - as can also be seen from FIGS. 2 and 3 - arranged in the plate base G such that the slots 9 transversely, in particular at right angles, to the extension direction AR of the mold blocks or molds from the Mold chamber 1 run.

4 to 7 show further details of the venting nozzles 7. Thus the venting nozzles 7 can have a round, e.g. have a - as shown - circular or an elliptical, as well as a polygonal basic shape. As already mentioned, the slots 9 of the ventilation nozzles 7 can advantageously each have a width B (FIG. 5) adapted to a grain size distribution of the molding sand, in particular a width B in the range from 0.25 mm to 0.55 mm, preferably from 0 , 40 mm. This ensures that only one - e.g. Proportionally small - fine-grained fraction of the molding sand is discharged through the ventilation nozzles 7.

The slots 9 of the ventilation nozzles 7 widen slightly conically from a width B1 to a width B2 from an inner surface IF of the ventilation nozzles 7 lying in the interior of the molding chamber 1 to an outer surface AF of the ventilation nozzle, as shown in FIG. 7. From a fluidic point of view, this conical expansion has the effect of a diffuser, which causes the flow velocity of the particle-laden escaping air to decrease with increasing distance from the molding chamber 1.

The slots 9 can be produced, for example, by sawing in the ventilation nozzles 7. As shown in FIG. 7, when sawing with a saw blade of radius R, a first slot length W1 can result on the inner surface IF of the ventilation nozzles 7, which is in the interior of the molding chamber 1, which then extends to the outer surface AF reduced to a slot length W2. From a fluidic point of view, such a slot formation has the effect that the flow velocity of the particle-laden escaping air increases with increasing distance from the molding chamber 1.

The flow velocity of the escaping air can thus advantageously be adjusted in a controlled manner by a suitable choice of the slot width (s) B, (B1, B2) and slot lengths W1, W2.

In order to prevent sand particles from getting caught and / or jamming in the slots 9 of the ventilation nozzles 7, it is advantageous if the slots 9 have a surface roughness Rz of at most 2 μm.

To further increase the wear resistance of the lining plate according to the invention, it can advantageously be provided that the plate base body G at least on its inner surface lying in the interior of the molding chamber 1, e.g. after carburizing, has a carbon content of> 3%. This makes it possible to produce a structure in the plate base body G, at least on its inner surface IF lying in the interior of the molding chamber 1, which structure consists of metal carbide particles C embedded in a martensitic matrix. The wear-inhibiting role of these metal carbides C is represented by FIGS. 8 and 9.

The base plate body G (and also the nozzle 7) of the lining plate according to FIG. 8 is made of a 12% ledeburitic cold work steel 1.2379, which due to its manufacture as a semi-finished product, for example as a sheet or rod, has a line-like orientation of the metal carbides C contained in it , especially cementite, in its structure. The metal carbides C have a wear-inhibiting effect on the molding sand particles P1, P2 which act under a force F, but they are subject to fluctuations in the material mentioned with regard to their size and their spacing from one another. Because of the linearity that arises during forming, for example during rolling, areas must also be expected that have only a very small number of carbide particles C. These areas are unprotected for abrasive wear with fine sand, since the martensitic structure of the matrix does not have the required hardness to prevent penetration or furrowing Forming sand particles P1, P2 to provide sufficient resistance. In the left side of FIG. 8, the surface is protected by a carbide particle C against attack by the sand particle P1, while in the right half of the figure the particle P2 can penetrate into an unprotected area and furrow. In the material structure shown in Fig. 8, it is - similar to the course of the slots 9 - it is advantageous for increasing the wear resistance of the material if existing line-shaped carbide particles C are arranged transversely to the direction of extension AR of the mold blocks or molds from the Mold chamber 1 run.

FIG. 9 shows the conditions that exist for a component - preferably the ventilation nozzle 7, but also the plate base body G - when using a different material. The drawing first clarifies the existence of an extremely homogeneous distribution of the carbide particles C. Furthermore, it is clear that metal carbide or other hard phase particles C contained in the structure of the material of the ventilation nozzles 7 and / or the material of the plate base body G are at an average distance a from one another, which is smaller than a diameter d of the sand particles P1, P2. Since the sand particles P1, P2 generally do not have a uniform size, but rather a grain size distribution over a certain diameter range, this diameter d can be, for example, a predetermined lower limit grain size and / or an average grain size of the molding sand. Due to the uniform distribution of the carbide C in the material, which is matched to the grain size of the sand particles P1, P2, the material shown offers optimal wear protection.

A material structure, such as that shown, can advantageously be produced in particular by powder metallurgy, for example in a metal injection molding or in a metal powder injection molding process. The material can be made of steel with 2.15 - 2.50% C, 0.30 - 0.50% Si, 0.30 - 0.50% Mn, 11, 5 - 13.5% Cr, 0, 70 - 1, 20% Mo and 3.8 - 4.4% V. Such or similar steels are known in accordance with the relevant German DIN standards under the designation 1.2380, X220 or CrVMo134 and in accordance with the relevant American AISI standards with the designation D7. The invention is not limited to the exemplary embodiment shown, but also encompasses all embodiments having the same effect in the sense of the invention. The described technical design of the ventilation nozzle is also considered to have inventive importance. This includes - as has already been mentioned at the beginning - that the ventilation nozzles 7 can also be designed as multi-part bodies. 4 shows an example of a ventilation nozzle 7, which is broken down by the dash-dotted cross lines into a first disc-shaped part body T1 containing the slots 9 and two ring-shaped further part bodies T2 and T3 connected to the first part body T1. The manufacturing advantages of such an embodiment consist in particular in the fact that only simple geometric shapes have to be observed in a powder-detailed molding process, whereby undercuts, for example, can be avoided. The various partial bodies T1, T2, T3 can be glued together for connection, for example. A one-piece design of ventilation nozzles 7 and plate base body G also falls within the scope of the invention. As an alternative to the sawing mentioned, the slots 9 can also be produced in the ventilation nozzles 7 by laser treatment or in a powder-metallurgical shaping process.

Furthermore, the person skilled in the art can also provide other useful features or technical measures for the structural design of the lining plate according to the invention or the ventilation nozzle 7. For example, the respective flow area of a ventilation nozzle 7 can be optimized by a suitable dimensioning of slot width B and slot length W1 (or also W2) and can also be set in a favorable relation to a non-flowable area of the ventilation nozzles, for which purpose, for example, the corresponding strength requirements Dimensioning of a web width S provided between the slots 9 can be used.

Furthermore, the invention is not limited to the combination of features of claim 1, but can also be defined by any other combination of features from the disclosed features. This means that in principle each individual feature of claim 1 can be omitted or replaced by at least one individual feature disclosed elsewhere. In this respect, claim 1 is only to be understood as a first attempt at formulation for an invention. reference numeral

1 molding chamber

2 base plate of 1

3 top plate of 1

4, 5 side plates of 1

6 opening in 3 for feed hopper for 1

7 vent nozzle

8 mounting hole in G for 7

9 slot in 7

a average distance from C

AF outer surface of 7

AR extension direction

B width of 9, general

B1 first width of 9 (in 1)

B2 second width of 9 (extended part of 9)

C metal carbide particles in 7 / G d diameter of P1, P2

F force on P1. P2

G plate base body of 2, 3, 4, 5

IF inside area of 7 / G

P1, F ° 2 molding sand particles

R radius in 9

Rz medium roughness

S bridge width from 7 to 9

T1 disk-shaped partial body of 7 (FIG. 4)

T2 annular partial body of 7 (FIG. 4)

T3 annular partial body of 7 (Fig. 4)

W1 first slot length of 9

W2 second slot length of 9

Claims

Expectations

1. Lining plate for molding chambers (1) in molding machines for the production of mold blocks or casting molds, which are pressed out of molding sand (P1, P2) and then brought out of the molding chamber (1) in a direction of extension, whereby partial areas of a plate base body (G) with ventilation nozzles ( 7) are provided, each having parallel slots (9), characterized in that the ventilation nozzles (7) are arranged in the plate base body (G) in such a way that their slots (9) transversely to the extension direction (AR) of the mold blocks or Molds run out of the mold chamber (1).

2. Lining plate according to claim 1, characterized in that the slots (9) of the ventilation nozzles (7) run at right angles to the direction of extension (AR) of the mold blocks or molds from the molding chamber (1).

3. Lining plate according to claim 1 or 2, characterized in that the slots (9) of the ventilation nozzles (7) from an inside surface of the molding chamber (1) lying inner surface (IF) of the ventilation nozzles (7) towards an outer surface (AF) Extend the vent nozzle (7) slightly conically.

4. Lining plate according to one of claims 1 to 3, characterized in that the slots (9) of the ventilation nozzles (7) each have a width (B), in particular a width (B), adapted to a grain size distribution of the molding sand (P1, P2) Range from 0.25 mm to 0.55 mm, preferably from 0.40 mm.

5. lining plate according to one of claims 1 to 4, characterized in that the slots (9) of the ventilation nozzles (7) have a surface roughness Rz of at most 2 microns.

6. lining plate according to one of claims 1 to 5, characterized in that the ventilation nozzles (7) are designed as a one-piece insert body for the plate base body (G).

7. lining plate according to one of claims 1 to 5, characterized in that the ventilation nozzles (7) as a multi-part body (T1, T2, T3), in particular in two parts, are formed, the ventilation nozzles (7) at least from one of the slots (9 ) containing first, disc-shaped partial body (T1) and a ring-shaped second partial body (T2) connected, in particular glued, to the first partial body (T1).

8. lining plate according to one of claims 1 to 7, characterized in that the ventilation nozzles (7) are glued to the plate base body (G).

9. lining plate according to one of claims 1 to 8, characterized in that the ventilation nozzles (7) have a round in plan view, such as a circular or elliptical, or a polygonal basic shape.

10. lining plate according to one of claims 1 to 9, d ad u rch ge ke n nze i ch n et that the plate base body (G) and / or the vent nozzle (7) at least partially consists of a carburized, hardened and optionally tempered case hardening steel ,

11. Lining plate according to one of claims 1 to 10, d ad u rc hge ke n nze i ch n et that the plate base body (G) and / or the ventilation nozzle (7) at least on an inner surface in the molding chamber (1) ( IF) has a carbon content of> 3%.

12. lining plate according to one of claims 1 to 11, d ad u rch ge ken nze i ch n et that the plate base body (G) and / or the vent nozzle (7) at least on an inner surface in the molding chamber (1) ( IF) has a structure consisting of metal carbides (C) embedded in a martensitic matrix.

13. Lining panel according to one of claims 1 to 12, characterized in that the ventilation nozzles (7) have a wear resistance that is at least as large as a wear resistance of the base plate body (G).

14. Lining plate according to one of claims 1 to 13, characterized in that the ventilation nozzles (7) and / or the plate base body (G) consist of, in particular powder-metallurgically produced, cold or high-speed steel, hard metal or ceramic.

15. lining plate according to one of claims 1 to 14, characterized in that the ventilation nozzles (7) and / or the plate base body (G) made of a steel with 2.15 - 2.50% C, 0.30 - 0.50% Si, 0.30-0.50% Mn, 11.5-13.5% Cr, 0.70-1.20% Mo and 3.8-4.4% V.

16. Lining plate according to one of claims 1 to 15, characterized in that the ventilation nozzles (7) and / or the plate base body (G) are made in a metal injection molding or in a metal powder injection molding process.

17. lining plate, in particular according to one of claims 1 to 16, characterized in that in the structure of the material of the ventilation nozzles (7) and / or the material of the plate base body (G) contained metal carbide or other hard phase particles (C) an average distance (a ) from each other, which is smaller than a predetermined one Diameter (d), such as a lower limit grain size and / or an average grain size, of the molding sand (P1, P2).

18. lining plate, in particular according to one of claims 1 to 16, characterized in that in the structure of the material of the ventilation nozzles (7) and / or the material of the plate base body (G) contained metal carbide or other hard phase particles (C) are arranged in a cell shape, wherein the lines run transversely to the direction of extension (AR) of the mold blocks or molds from the mold chamber (1).

19. Venting nozzle for a lining plate according to one of claims 1 to 18, characterized by one or more of the features of the characterizing part of claims 3 to 7 and / or 9 to 18.

20. Vent nozzle according to claim 19, g e ke n n ze i ch net d u rch with a one-piece with the plate base body (G) design.