EP0275963A2 - Method and apparatus for compacting granular moulding materials such as moulding foundry sand - Google Patents
Method and apparatus for compacting granular moulding materials such as moulding foundry sand Download PDFInfo
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- EP0275963A2 EP0275963A2 EP88100653A EP88100653A EP0275963A2 EP 0275963 A2 EP0275963 A2 EP 0275963A2 EP 88100653 A EP88100653 A EP 88100653A EP 88100653 A EP88100653 A EP 88100653A EP 0275963 A2 EP0275963 A2 EP 0275963A2
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- molding
- box wall
- molding material
- moulding
- compressed air
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22C—FOUNDRY MOULDING
- B22C15/00—Moulding machines characterised by the compacting mechanism; Accessories therefor
- B22C15/28—Compacting by different means acting simultaneously or successively, e.g. preliminary blowing and finally pressing
- B22C15/30—Compacting by different means acting simultaneously or successively, e.g. preliminary blowing and finally pressing by both pressing and jarring devices
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22C—FOUNDRY MOULDING
- B22C15/00—Moulding machines characterised by the compacting mechanism; Accessories therefor
Definitions
- the invention relates to a method according to the characterizing feature of claim 1 and an apparatus for carrying out the method according to the characterizing features of claims 2 and 3.
- thermodynamic compressed air pulse compression process has brought considerable advantages over the mechanical compression process, difficulties also arise in the form of unsatisfactory compression of the corresponding areas when relatively high mold boxes and / or high model parts have to be compacted at a relatively short distance from the mold box wall.
- bridges (24) can form between the model and the mold box wall if the filling process is carried out very quickly (e.g. in approx. 1.5 seconds). This is often necessary because of the machine performance with very short cycle times.
- the spaces under the bridges (24) that are formed are not adequately filled with loose molding material.
- the bridging is further intensified by the compression, but is also broken again with the appropriate energy supply. However, the energy consumed for the breakthrough is then missing for the compression.
- the formation of bridges is largely avoided, which explains the considerably improved compression results in the critical areas described.
- the bridging (24) between the model and the molding box wall is caused by the poor flowability of the molding material but also by the friction between the molding material and the model or between the molding material and the molding box wall, since a sand bridge can only be formed by abutments on the model and on the molding box wall Abutment can only come about through the friction. Since the models have a very smooth and clean surface, the coefficient of friction on the model surface is significantly lower than on the surface of the mold box walls, which are in an unprocessed raw state and very often still have incrusted old sand. The resulting frictional resistance is destroyed especially in the compressed air pulse process due to the extremely high compression speed a correspondingly high proportion of energy that is lost to the compression energy in the area of the mold box wall.
- the method according to the invention and the device according to the invention can be used both for the mechanical compression methods such as shaking, pressing, vibrating presses, high-pressure multi-punch presses, suction presses and shooting presses and for the thermodynamic compression methods with compressed air pulse or combustion pulse.
- FIG. 1 shows a model plate (1) with model (1a) together with a molding box (2), a filling frame (3) and a compressed air pulse unit (4) arranged above it.
- the molding material (5) is filled in loosely up to the line (7).
- Line (6) marks the surface of the molding material after compression.
- Fig. 2 shows an enlarged section of the filling frame and mold box wall for a clearer representation of the blow-out nozzles.
- the compressed air pulse unit (4) indicated by way of example triggers a frontal pressure wave, which strikes the loose molding material surface (7) at extremely high speed and pushes the molding material together to about line (6) and compresses it.
- a corresponding compressed air pulse unit has been described in DE3327822.
- the compression movement of the molding material (5) causes considerable frictional resistance on the inside of the molding box (2a). This is particularly true for compressed air pulse compression, because the extremely high compression speed means that the frictional resistance is correspondingly high.
- molding material bridges (24) can form, which are further reinforced during compression and thus result in poor shaping of the areas under the molding material bridges.
- a pneumatic sliding film (8) is produced directly on the inside of the molding box (2a), which is basically effective during the compression phase, but which can also become effective during the filling process if necessary.
- the pneumatic sliding film (8) is produced by blowing a flat air flow between the mold box wall (2a) and the molding material (5) through a large number of flat nozzles (9), which are almost completely distributed over the entire circumference of the filling frame inner wall (3a) which flows directly along the inside of the molding box (2a) in the direction of the model plate and there is withdrawn again from the sand filter slot nozzles (10) which are under vacuum and which are arranged without gaps on the entire circumference of the model plate and in the immediate vicinity of the molding box wall. It is important here that the inner blow-out lip of the flat nozzle (9) either ends exactly flush with the inner wall of the molding box (2a) or has a maximum tolerance-related projection of 2mm compared to the inner wall of the molding box (dimension 12).
- blow-out nozzles (9) are arranged at the same angle (26) as the inner wall of the molding box (2a). This is given by the same angular inclination (26) of the mold box inner wall (2a) and the filling frame inner wall (3a).
- the angular inclination (26) or the trough of the inner wall of the molding box (2a) has the task of fixing the bale in the molding box and the angular inclination of the inner wall of the filling frame (3a) is required in order to facilitate detachment of the filling frame from the protruding, compressed molding material (5- 6) enable.
- the pneumatic sliding film (8) produced in this way which flows evenly on the entire inner surface of the molding box in the direction of the outer edge of the model plate and in the direction of compaction, cancels or substantially reduces the friction between the molding material and the molding box wall. There is also a rinsing effect that draws the molding material into the recessed zones between the molding box wall and the model.
- the type of nozzle formation (9-Fig.2) makes it possible that the inner projection (13) from the mold box inner wall to the filling frame inner wall, including the tolerance-related offset (12), does not have to be larger than 12 mm.
- the 45 ° bevel (14) prevents a molding shadow space from forming under the projection (13). The compression path of the molding material can thus run in the vertical direction without transverse movement and unhindered.
- the intensity of the pneumatic sliding film can be adjusted to the practical requirements by continuously adjusting the overpressure and underpressure.
- the circulation The compressed air duct (15) can be divided into several sections (Fig. 3) by the partitions (18), with each section having its own controllable compressed air supply. There is thus the further possibility of setting a different intensity of the pneumatic sliding film in different zones, which corresponds to the practical requirements.
- the friction between the filling frame inner wall and the molding material is to be viewed differently than the friction between the molding material and the molding box inner wall.
- a suitable surface finish e.g. hard chrome-plated with a low roughness depth. Since the filling frame is a single piece of a molding machine, this can also be achieved economically. In the case of mold boxes, which are always required in large numbers, such a measure is not possible in the economic context.
- the problem of molding bridges between the filler frame and the model does not exist with the filler frame. The compression and the side pressure causing the friction is much lower in the filling frame area than in the molding box.
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Abstract
Description
Die Erfindung betrifft ein Verfahren nach dem kennzeichnenden Merkmal des Anspruches 1 sowie eine Vorrichtung zur Durchführung des Verfahrens nach den kennzeichnenden Merkmalen der Ansprüche 2 und 3.The invention relates to a method according to the characterizing feature of
Zur Verdichtung von Gießereiformen, insbesondere solche aus bentonitgebundenen Formstoffen, sind verschiedene Verfahren wie Rütteln, Pressen, Rüttelpressen, Hochdruck-Vielstempel-Pressen, Saugpressen und Schießpressen bekannt. Seit einiger Zeit hat sich im verstärkten Maße das vorteilhafte Druckluftimpuls-Verdichtungsverfahren durchgesetzt. Obwohl das thermodynamische Druckluftimpuls-Verdichtungsverfahren gegenüber dem mechanischen Verdichtungsverfahren erhebliche Vorteile gebracht hat, zeigen sich auch hierbei noch Schwierigkeiten in Form von nicht befriedigender Verdichtung entsprechender Bereiche, wenn relativ hohe Formkästen und/oder hohe Modellpartien mit relativ geringem Abstand zur Formkastenwand verdichtet werden müssen. Bei de'n mechanischen Verdichtungsverfahren wurde bei oft nur mäßigen Erfolg versucht, diesen Problemen mit entsprechendem Rüttlereinsatz und/oder verstärktem Hochdruckpressen am Formkastenwand durch eine Vielstempelpresse oder auch durch schichtweises Sanddosieren in Verbindung mit Rütteln entgegenzutreten. Beim Druckluftimpuls-Verfahren wird versucht, durch höhere Energiezufuhr im Außenbereich in den kritischen Fällen eine bessere Verdichtung zu erzielen. Aber auch hierdurch werden nicht immer befriedigende Ergebnisse erreicht. Ein schichtweises Sanddosieren und Verdichten mit dem Druckluftimpuls-Verfahren bringt zwar wesentlich verbesserte Ergebnisse, jedoch wird hierdurch die Formzeit erheblich verlängert, was zum unwirtschaftlichen Einsatz der Formmaschinen führt. Eine Vergrößerung des Formkastens um eine größere Distanz zwischen Formkastenwand und Modell zu erzielen ist ebenfalls keine wirtschaftliche Lösung.Various methods are known for compacting foundry molds, in particular those made from bentonite-bonded molding materials, such as vibrating, pressing, vibrating presses, high-pressure multi-punch presses, suction presses and shooting presses. For some time now, the advantageous compressed air pulse compression process has become increasingly popular. Although the thermodynamic compressed air pulse compression process has brought considerable advantages over the mechanical compression process, difficulties also arise in the form of unsatisfactory compression of the corresponding areas when relatively high mold boxes and / or high model parts have to be compacted at a relatively short distance from the mold box wall. In mechanical compression processes, with often only moderate success, attempts have been made to counteract these problems with a suitable vibrator and / or increased high-pressure presses on the molding box wall by means of a multi-ram press or by layer-by-layer sand metering in connection with vibrating. The compressed air pulse method tries to achieve better compression in critical cases by using more energy outdoors. But this also does not always lead to satisfactory results. A layered sand dosing and compacting with the compressed air pulse method brings significantly improved results, but will this considerably extends the molding time, which leads to the uneconomical use of the molding machines. Enlarging the molding box to achieve a greater distance between the molding box wall and the model is also not an economical solution.
Die Ursache für die unbefriedigende Verdichtung in den beschriebenen kritischen Bereichen liegt in erster Linie in der schlechten Fließfähigkeit des bentonitgebundenen Formstoffes begründet. Schon beim Einfüllen des losen Formstoffes in die Formeinrichtung kann es zu Brückenbildungen (24) zwischen Modell und Formkastenwand kommen, wenn der Einfüllvorgang sehr schnell (z.B. in ca. 1,5 sek) durchgeführt wird. Dies ist häufig wegen der Maschinenleistung mit sehr kurzen Taktzeiten erforderlich. Die unter den sich gebildeten Brücken (24) liegenden Räume werden nicht ausreichend mit losem Formstoff ausgefüllt. Durch die Verdichtung wird die Brückenbildung weiter verstärkt, aber auch bei entsprechender Energiezufuhr wieder durchbrochen. Die für den Durchbruch verbrauchte Energie fehlt dann jedoch für die Verdichtung. Bei einem langsamen und schichtweisen Einfüllen und Verdichten des Formstoffes wird die Brückenbildung weitgehend vermieden, womit sich die hierbei wesentlich verbesserten Verdichtungsergebnisse in den beschriebenen kritischen Bereichen erklären lassen.The reason for the unsatisfactory compression in the critical areas described lies primarily in the poor flowability of the bentonite-bound molding material. As soon as the loose molding material is poured into the molding device, bridges (24) can form between the model and the mold box wall if the filling process is carried out very quickly (e.g. in approx. 1.5 seconds). This is often necessary because of the machine performance with very short cycle times. The spaces under the bridges (24) that are formed are not adequately filled with loose molding material. The bridging is further intensified by the compression, but is also broken again with the appropriate energy supply. However, the energy consumed for the breakthrough is then missing for the compression. With slow and layer-by-layer filling and compression of the molding material, the formation of bridges is largely avoided, which explains the considerably improved compression results in the critical areas described.
Die Brückenbildung (24) zwischen Modell und Formkastenwand wird neben der schlechten Fließfähigkeit des Formstoffes aber auch von der Reibung zwischen Formstoff und Modell bzw. zwischen Formstoff und Formkastenwand verursacht, da sich eine Sandbrücke nur durch Widerlager am Modell und an der Formkastenwand bilden kann und diese Widerlager nur durch die Reibung zustande kommen können. Da die Modelle sehr glatte und saubere Oberfläche aufweisen, ist der Reibungskoeffizient an der Modelloberfläche wesentlich geringer als an der Oberfläche der Formkastenwände, die sich in einem unbearbeiteten Rohzustand befinden und sehr oft noch mit verkrusteten Altsand behaftet sind. Der hierdurch verursachte Reibungswiderstand vernichtet insbesondere beim Druckluftimpuls-Verfahren wegen der extrem hohen Verdichtungsgeschwin digkeit einen entsprechend hohen Energieanteil, der der Verdichtungsenergie im Bereich der Formkastenwand verloren geht. Es kommt daher im besonderen Maße darauf an, die Reibung zwischen Formkastenwand und Formstoff aufzuheben oder wesentlich zu reduzieren. Auf eine denkbare Aufhebung oder Reduzierung der Reibung zwischen Modell und Formstoff kann dabei verzichtet werden, weil zur Bildung einer Sandbrücke (24) immer zwei Widerlager erforderlich sind und sich das Widerlager (25) an der Formkastenwand nicht mehr bilden kann, wenn hier die Reibung aufgehoben oder wesentlich reduziert wird. Zudem wäre eine entsprechende Vorrichtung für die Modellseite nicht einfach zu realisieren, da sie immer den ständig wechselnden Modellkonturen angeglichen werden müßte.The bridging (24) between the model and the molding box wall is caused by the poor flowability of the molding material but also by the friction between the molding material and the model or between the molding material and the molding box wall, since a sand bridge can only be formed by abutments on the model and on the molding box wall Abutment can only come about through the friction. Since the models have a very smooth and clean surface, the coefficient of friction on the model surface is significantly lower than on the surface of the mold box walls, which are in an unprocessed raw state and very often still have incrusted old sand. The resulting frictional resistance is destroyed especially in the compressed air pulse process due to the extremely high compression speed a correspondingly high proportion of energy that is lost to the compression energy in the area of the mold box wall. It is therefore particularly important to eliminate or significantly reduce the friction between the molding box wall and the molding material. A conceivable abolition or reduction of the friction between the model and the molding material can be dispensed with because two abutments are always required to form a sand bridge (24) and the abutment (25) can no longer form on the wall of the molding box if the friction is eliminated here or is significantly reduced. In addition, a corresponding device for the model side would not be easy to implement, since it would always have to be adapted to the constantly changing model contours.
Es ist daher Aufgabe der Erfindung, ein Verfahren und eine Vorrichtung zu schaffen, womit die Reibung zwischen Formkastenwand und Formstoff durch einen pneumatischen Gleitfilm aufgehoben oder wesentlich reduziert wird, um eine durchgreifende Verbesserung der Verdichtung im Bereich der Formkastenwand bzw. im engräumigen Bereich zwischen Modell und Formkastenwand zu erzielen.It is therefore an object of the invention to provide a method and an apparatus with which the friction between the mold box wall and the molding material is eliminated or substantially reduced by a pneumatic sliding film in order to improve the compression in the area of the mold box wall or in the narrow area between the model and To achieve mold box wall.
Diese Aufgabe wird erfindungsgemäß gelöst durch die kennzeichnenden Merkmale der Ansprüche 1, 2 und 3. Weitere Merkmale und die Ausführungsformen sind in den sonstigen Ansprüchen wiedergegeben.This object is achieved according to the invention by the characterizing features of
Das erfindungsgemäße Verfahren und die erfindungsgemäße Vorrichtung kann sowohl für die mechanischen Verdichtungsverfahren wie Rütteln, Pressen, Rüttelpressen, Hochdruck-Vielstempel-Pressen, Saugpressen und Schießpressen als auch für die thermodynamischen Verdichtungsverfahren mit Druckluftimpuls oder Verbrennungsimpuls eingesetzt werden.The method according to the invention and the device according to the invention can be used both for the mechanical compression methods such as shaking, pressing, vibrating presses, high-pressure multi-punch presses, suction presses and shooting presses and for the thermodynamic compression methods with compressed air pulse or combustion pulse.
Nachstehend wird nun die Erfindung anhand der in den Zeichnungen dargestellten Ausführungsbeispiele beschrieben. Hierbei zeigen:
- Fig.1 einen Vertikalschnitt durch eine Formeinrichtung mit einer angedeuteten Druckluftimpulseinheit.
- Fig.2 einen vergrößerten Querschnitt einer Seitenwand des Füllrahmens und des Formkastens
- Fig.3 einen Horizontalschnitt durch den Füllrahmen.
- Fig.4 einen Horizontalschnitt durch den Formkasten bzw. eine Draufsicht auf die Modellplatte.
- 1 shows a vertical section through a shaping device with an indicated compressed air pulse unit.
- 2 shows an enlarged cross section of a side wall of the filling frame and the molding box
- 3 shows a horizontal section through the filling frame.
- 4 shows a horizontal section through the molding box or a plan view of the model plate.
Fig.1 zeigt eine Modellplatte (1) mit Modell (1a) zusammen mit einem Formkasten (2), einem Füllrahmen (3) und einer darüber angeordneten Druckluftimpuls-Einheit (4). Der Formstoff (5) ist bis zur Linie (7) lose eingefüllt. Die Linie (6) kennzeichnet die Formstoffoberfläche nach der Verdichtung. Fig.2 zeigt einen vergrößerten Ausschnitt der Füllrahmen- und Formkastenwand zur deutlicheren Darstellung der Ausblasdüsen. Zum Verdichten wird von der beispielhaft angedeuteten Druckluftimpuls-Einheit (4) eine frontale Druckwelle ausgelöst, die mit extrem hoher Geschwindigkeit auf die lose Formstoffoberfläche (7) auftrifft und den Formstoff dabei bis etwa zur Linie (6) zusammenschiebt und verdichtet. Eine entsprechende Druckluftimpuls-Einheit wurde u.a. in DE3327822 beschrieben.1 shows a model plate (1) with model (1a) together with a molding box (2), a filling frame (3) and a compressed air pulse unit (4) arranged above it. The molding material (5) is filled in loosely up to the line (7). Line (6) marks the surface of the molding material after compression. Fig. 2 shows an enlarged section of the filling frame and mold box wall for a clearer representation of the blow-out nozzles. For compression, the compressed air pulse unit (4) indicated by way of example triggers a frontal pressure wave, which strikes the loose molding material surface (7) at extremely high speed and pushes the molding material together to about line (6) and compresses it. A corresponding compressed air pulse unit has been described in DE3327822.
Die Verdichtungsbewegung des Formstoffes (5) verursacht an der Formkasteninnenwand (2a) einen erheblichen Reibungswiderstand. Dies trifft im besonderen Maße für die Druckluftimpuls-Verdichtung zu, weil hier durch die extrem hohe Verdichtungsgeschwindigkeit auch der Reibungswiderstand entsprechend hoch ist. Beim Einfüllen des Formstoffes in die Formeinheit können sich Formstoffbrücken (24) bilden, die sich beim Verdichten noch weiter verstärken und dadurch eine schlechte Ausformung der unter den Formstoffbrücken liegenden Bereiche zur Folge haben. Zur Verhinderung dieser Nachteile wird unmittelbar an der Formkasteninnenwand (2a) ein pneumatischer Gleitfilm (8) erzeugt, der grundsätzlich während der Verdichtungsphase wirksam ist, der aber auch im erforderlichen Fall schon während des Einfüllvorganges wirksam werden kann.The compression movement of the molding material (5) causes considerable frictional resistance on the inside of the molding box (2a). This is particularly true for compressed air pulse compression, because the extremely high compression speed means that the frictional resistance is correspondingly high. When the molding material is poured into the molding unit, molding material bridges (24) can form, which are further reinforced during compression and thus result in poor shaping of the areas under the molding material bridges. To prevent these disadvantages, a pneumatic sliding film (8) is produced directly on the inside of the molding box (2a), which is basically effective during the compression phase, but which can also become effective during the filling process if necessary.
Der pneumatische Gleitfilm (8) wird dadurch erzeugt, daß durch eine große Anzahl flacher Düsen (9), die nahezu lückenlos am gesamten Umfang der Füllrahmeninnenwand (3a) verteilt sind, ein flacher Luftstrom zwischen Formkastenwand (2a) und Formstoff (5) eingeblasen wird, der unmittelbar an der Formkasteninnenwand (2a) entlang in Richtung Modellplatte fließt und dort von den unter Unterdruck stehenden Sandfilter-Schlitzdüsen (10), die am gesamten Modellplattenumfang und in unmittelbarer Nähe der Formkastenwand lückenlos angeordnet sind, wieder abgezogen wird. Von Bedeutung ist hierbei, daß die innere Ausblaslippe der Flachdüse (9) entweder genau bündig zur Formkasteninnenwand (2a) abschließt oder gegenüber der Formkasteninnenwand einen maximalen, toleranzbedingten Vorsprung von 2mm hat (Maß 12). Von Bedeutung ist außerdem, daß die Ausblasdüsen (9) im gleichen Winkel (26) angeordnet sind wie die Formkasteninnenwand (2a). Dies ist durch die gleiche Winkelneigung (26) der Formkasteninnenwand (2a) und der Füllrahmeninnenwand (3a) gegeben. Die Winkelneigung (26) bzw. die Muldung der Formkasteninnenwand (2a) hat dabei die Aufgabe, den Formballen im Formkasten zu fixieren und die Winkelneigung der Füllrahmeninnenwand (3a) ist erforderlich, um eine leichtere Ablösung des Füllrahmens vom überstehenden, verdichteten Formstoff (5-6) zu ermöglichen.The pneumatic sliding film (8) is produced by blowing a flat air flow between the mold box wall (2a) and the molding material (5) through a large number of flat nozzles (9), which are almost completely distributed over the entire circumference of the filling frame inner wall (3a) which flows directly along the inside of the molding box (2a) in the direction of the model plate and there is withdrawn again from the sand filter slot nozzles (10) which are under vacuum and which are arranged without gaps on the entire circumference of the model plate and in the immediate vicinity of the molding box wall. It is important here that the inner blow-out lip of the flat nozzle (9) either ends exactly flush with the inner wall of the molding box (2a) or has a maximum tolerance-related projection of 2mm compared to the inner wall of the molding box (dimension 12). It is also important that the blow-out nozzles (9) are arranged at the same angle (26) as the inner wall of the molding box (2a). This is given by the same angular inclination (26) of the mold box inner wall (2a) and the filling frame inner wall (3a). The angular inclination (26) or the trough of the inner wall of the molding box (2a) has the task of fixing the bale in the molding box and the angular inclination of the inner wall of the filling frame (3a) is required in order to facilitate detachment of the filling frame from the protruding, compressed molding material (5- 6) enable.
Der so erzeugte pneumatische Gleitfilm (8), der an der gesamten Innenfläche des Formkastens gleichmäßig in Richtung Modellplattenaußenrand und in Verdichtungsrichtung strömt, hebt die Reibung zwischen Formstoff und Formkastenwand auf oder reduziert sie im wesentlichen Maße. Es entsteht darüber hinaus noch ein Spüleffekt, der den Formstoff in die vertieften Zonen zwischen Formkastenwand und Modell hinein zieht. Das Widerlager (25) welches zur Bildung einer Formstoffbrücke (24) erforderlich wäre, kann nicht entstehen und somit auch nicht die Formstoffbrücke selbst.The pneumatic sliding film (8) produced in this way, which flows evenly on the entire inner surface of the molding box in the direction of the outer edge of the model plate and in the direction of compaction, cancels or substantially reduces the friction between the molding material and the molding box wall. There is also a rinsing effect that draws the molding material into the recessed zones between the molding box wall and the model. The abutment (25), which would be required to form a molding bridge (24), cannot be created, and therefore not the molding bridge itself.
Die Art der Düsenausbildung (9-Fig.2) ermöglicht es, daß der innere Vorsprung (13) von Formkasteninnenwand zur Füllrahmeninnenwand einschließlich des toleranzbedingten Versatzes (12) nicht größer als 12mm ausgeführt werden muß. Durch die 45°-Abschrägung (14) wird verhindert, daß sich ein Formstoff-Schattenraum unter dem Vorsprung (13) bilden kann. Der Verdichtungsweg des Formstoffes kann somit ohne Querbewegung und unbehindert in senkrechter Richtung verlaufen.The type of nozzle formation (9-Fig.2) makes it possible that the inner projection (13) from the mold box inner wall to the filling frame inner wall, including the tolerance-related offset (12), does not have to be larger than 12 mm. The 45 ° bevel (14) prevents a molding shadow space from forming under the projection (13). The compression path of the molding material can thus run in the vertical direction without transverse movement and unhindered.
Die Intensität des pneumatischen Gleitfilms kann durch stufenloses Verstellen der Über- und Unterdrücke den praktischen Erfordernissen entsprechend eingestellt werden. Der umlauf fende Druckluftkanal (15) kann durch die Trennwände (18) in mehrere Sektionen (Fig.3) eingeteilt werden, wobei an jede Sektion eine eigene, regelbare Drucklufteinspeisung angeschlossen werden kann. Es besteht dadurch die weitere Möglichkeit, in verschiedenen Zonen eine unterschiedliche, den praktischen Erfordernissen entsprechende Intensität des pneumatischen Gleitfilms einzustellen.The intensity of the pneumatic sliding film can be adjusted to the practical requirements by continuously adjusting the overpressure and underpressure. The circulation The compressed air duct (15) can be divided into several sections (Fig. 3) by the partitions (18), with each section having its own controllable compressed air supply. There is thus the further possibility of setting a different intensity of the pneumatic sliding film in different zones, which corresponds to the practical requirements.
Die Reibung zwischen Füllrahmeninnenwand und dem Formstoff ist anders zu betrachten als die Reibung zwischen Formstoff und Formkasteninnenwand. Zunächst besteht die Möglichkeit, den Reibungskoeffizienten der Füllrahmeninnenwände durch entsprechende Oberflächenbeschaffenheit (z.B. hartverchromt mit geringer Rauhtiefe) auf einen kleinstmöglichen Wert zu reduzieren. Da es sich beim Füllrahmen um ein Einzelstück einer Formmaschine handelt, ist dies auch wirtschaftlich realisierbar. Bei den Formkästen, die immer in größeren Stückzahlen erforderlich sind, ist eine solche Maßnahme im wirtschaftlichen Rahmen nicht möglich. Das Problem der Formstoff-Brückenbildung zwischen Füllrahmen und Modell ist beim Füllrahmen nicht gegeben. Die Verdichtung und der die Reibung verursachende Seitendruck ist im Füllrahmenbereich wesentlich geringer als im Formkasten. Aus den vorangegangenen Überlegungen resultiert, daß der pneumatische Gleitfilm nur im Formkastenbereich und nicht im Füllrahmenbereich zur Wirkung gebracht werden muß. Bei einem praktischen Erfordernis besteht jedoch auch die Möglichkeit, in das Blech (20) umlaufend kleine Bohrungen (23) als Perforation einzubringen, um einen kleinen Teil des Luftstromes zur Fluidisierung des Formstoffes im Füllrahmenbereich abführen zu können.The friction between the filling frame inner wall and the molding material is to be viewed differently than the friction between the molding material and the molding box inner wall. First of all, there is the possibility of reducing the coefficient of friction of the filling frame inner walls to the lowest possible value by means of a suitable surface finish (e.g. hard chrome-plated with a low roughness depth). Since the filling frame is a single piece of a molding machine, this can also be achieved economically. In the case of mold boxes, which are always required in large numbers, such a measure is not possible in the economic context. The problem of molding bridges between the filler frame and the model does not exist with the filler frame. The compression and the side pressure causing the friction is much lower in the filling frame area than in the molding box. It follows from the above considerations that the pneumatic sliding film only has to be activated in the molding box area and not in the filling frame area. If there is a practical requirement, however, there is also the possibility of making small holes (23) all around the plate as perforations in order to be able to discharge a small part of the air flow for fluidizing the molding material in the filling frame area.
Claims (11)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE3701438 | 1987-01-20 | ||
DE19873701438 DE3701438A1 (en) | 1987-01-20 | 1987-01-20 | METHOD AND DEVICE FOR COMPRESSING GRAIN-MOLDED MOLDING SUBSTANCES e.g. FOUNDRY MOLD SAND |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0275963A2 true EP0275963A2 (en) | 1988-07-27 |
EP0275963A3 EP0275963A3 (en) | 1989-03-15 |
Family
ID=6319105
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP88100653A Withdrawn EP0275963A3 (en) | 1987-01-20 | 1988-01-19 | Method and apparatus for compacting granular moulding materials such as moulding foundry sand |
Country Status (2)
Country | Link |
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EP (1) | EP0275963A3 (en) |
DE (1) | DE3701438A1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0380758A2 (en) * | 1989-01-30 | 1990-08-08 | Rütgerswerke Aktiengesellschaft | Device and method for the dosed filling of stationary moulds |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
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DE19755755A1 (en) * | 1997-12-16 | 1999-06-24 | Wagner Heinrich Sinto Masch | Method and device for compacting molding sand |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR1049962A (en) * | 1951-02-09 | 1954-01-04 | Fischer Ag Georg | Method and apparatus for ensuring the smooth flow of powdery or granular materials from loading hoppers, particularly in core blowing and molding machines |
JPS58125339A (en) * | 1982-01-20 | 1983-07-26 | Mitsubishi Heavy Ind Ltd | Molding method for casting mold |
EP0197388A2 (en) * | 1985-03-28 | 1986-10-15 | Georg Fischer Aktiengesellschaft | Method and apparatus for compacting foundry moulding materials |
WO1987007544A1 (en) * | 1986-06-13 | 1987-12-17 | Georg Fischer Aktiengesellschaft | Process and device for compacting powdery materials |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CH659201A5 (en) * | 1983-03-14 | 1987-01-15 | Fischer Ag Georg | MOLDING MACHINE WITH FILLING FRAME FOR COMPRESSING GRAINY MOLDING MATERIALS. |
DE3507179C1 (en) * | 1985-03-01 | 1985-10-31 | Eugen Dipl.-Ing. 8877 Burtenbach Bühler | Method and device for producing boxless molds |
-
1987
- 1987-01-20 DE DE19873701438 patent/DE3701438A1/en not_active Withdrawn
-
1988
- 1988-01-19 EP EP88100653A patent/EP0275963A3/en not_active Withdrawn
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR1049962A (en) * | 1951-02-09 | 1954-01-04 | Fischer Ag Georg | Method and apparatus for ensuring the smooth flow of powdery or granular materials from loading hoppers, particularly in core blowing and molding machines |
JPS58125339A (en) * | 1982-01-20 | 1983-07-26 | Mitsubishi Heavy Ind Ltd | Molding method for casting mold |
EP0197388A2 (en) * | 1985-03-28 | 1986-10-15 | Georg Fischer Aktiengesellschaft | Method and apparatus for compacting foundry moulding materials |
WO1987007544A1 (en) * | 1986-06-13 | 1987-12-17 | Georg Fischer Aktiengesellschaft | Process and device for compacting powdery materials |
Non-Patent Citations (2)
Title |
---|
GIESSEREI, Band 73, Nr. 22, 27. Oktober 1986, Seiten 643-650, D}sseldorf, DE; D. BOENISCH et al.: "Die Fluid-Impulsverdichtung von Nassgussformen" * |
PATENT ABSTRACTS OF JAPAN, Band 7, Nr. 237 (M-250)[1382], 21. Oktober 1983; & JP-A-58 125 339 (MITSUBISHI JUKOGYO K.K.) 26-07-1983 * |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0380758A2 (en) * | 1989-01-30 | 1990-08-08 | Rütgerswerke Aktiengesellschaft | Device and method for the dosed filling of stationary moulds |
EP0380758A3 (en) * | 1989-01-30 | 1991-10-16 | Rütgerswerke Aktiengesellschaft | Device and method for the dosed filling of stationary moulds |
Also Published As
Publication number | Publication date |
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DE3701438A1 (en) | 1988-07-28 |
EP0275963A3 (en) | 1989-03-15 |
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