EP0432277B1 - Method and device for making single-casting moulds - Google Patents

Method and device for making single-casting moulds Download PDF

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Publication number
EP0432277B1
EP0432277B1 EP90910975A EP90910975A EP0432277B1 EP 0432277 B1 EP0432277 B1 EP 0432277B1 EP 90910975 A EP90910975 A EP 90910975A EP 90910975 A EP90910975 A EP 90910975A EP 0432277 B1 EP0432277 B1 EP 0432277B1
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EP
European Patent Office
Prior art keywords
air
compressed air
chamber
moulding
plate
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Expired - Lifetime
Application number
EP90910975A
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German (de)
French (fr)
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EP0432277A4 (en
EP0432277A1 (en
Inventor
Anatoly Alexandrovich Volkomich
Nikolai Konstantinovich Chernyshev
Gennady Ivanovich Bobryakov
Georgy Mikhailovich Orlov
Boris Panteleimonovich Blagonravov
Garegin Serezhovich Garibian
Nikolai Ivanovich Bekh
Anatoly Iosifovich Yakobson
Vladimir Ivanovich Sivko
Adolf Vladimirovich Korchin
Valentin Fedorovich Mitrofanov
Valery Alexandrovich Svechnikov
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NAUCHNO-PROIZVODSTVENNOE OBIEDINENIE TEKHNOLOGII AVTOMOBILNOI PROMYSHLENNOSTI (NPO "NIITAVTOPROM")
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NAUCHNO-PROIZVODSTVENNOE OBIEDINENIE TEKHNOLOGII AVTOMOBILNOI PROMYSHLENNOSTI (NPO "NIITAVTOPROM")
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Publication of EP0432277A1 publication Critical patent/EP0432277A1/en
Publication of EP0432277A4 publication Critical patent/EP0432277A4/en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C11/00—Moulding machines characterised by the relative arrangement of the parts of same
    • B22C11/10—Moulding machines characterised by the relative arrangement of the parts of same with one or more flasks forming part of the machine, from which only the sand moulds made by compacting are removed
    • 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

Definitions

  • the invention relates to the foundry industry and relates in particular to a method for producing disposable casting molds and an apparatus for carrying it out.
  • a method for producing single-use molds (US, A, 4313486) which consists in feeding a molding material in a direction in a direction parallel to the pattern plate into a molding chamber provided with a pattern plate. Simultaneously with the molding material supply, the molding material is pre-compressed under the action of the compressed air, which is supplied in a direction parallel to the model plate. After filling the molding chamber, the molding material is compressed by pressing.
  • an apparatus (US, A, 431 3486) which comprises a molding chamber which is formed by, arranged in pairs, an upper plate and a lower plate, side plates, a model plate and a press plate, a compressed air source and a means for supplying the Contains compressed air in the mold chamber. Cavities and channels for the passage of air through said cavities are provided in the model plate and in the pressure plates. A channel for feeding the molding material into the molding chamber is embodied in the top plate, the molding material being fed in the air flow in a direction parallel to the model plate. At the same time, from the compressed air source via the supply means
  • Compressed air is fed into the cavity of the press plate and from there passed through the channels of the press plate into the molding chamber.
  • the air from the molding chamber is released into the atmosphere via the channels dissipated in the model plate, in the top and in the bottom plate.
  • the horizontally directed air flows take the molding material particles with them and move them towards the model plate by filling the narrow, deep recesses of the models with molding material.
  • the density of the molding material is not evenly distributed over the volume of the molding chamber: the layers of molding material adjacent to the model plate have the maximum density, while the molding material lying on the press plate has a minimum density, whereby form cavities in the channels of the press plate for the passage of air in the casting mold, because the compressed air jets emerging from the channels prevent these zones of the casting mold from being filled with the molding material.
  • the molding material is compacted in the layers adjacent to the press plate; but it is impossible to find an uneven density distribution of the Completely eliminate molding materials via the volume of the casting mold and the cavities in the zones of the compressed air supply.
  • a process for the production of single-use molds (SU, A, 1060299) is known, which consists in that a molding material is fed into a molding chamber provided with a model plate by means of an air flow in a direction parallel to the model plate. Subsequently, after a period of time which is approximately 8 to 60% of the duration of the molding material supply, the molding material is pre-compressed by the compressed air, which is supplied in a direction parallel to the model plate. The final compression of the molding material is carried out by pressing.
  • the device for carrying out this method contains plates arranged in pairs which form a molding chamber, a compressed air source and a means which ensures a recurrent connection of the compressed air source to the molding chamber.
  • Four side plates, which are opposed to each other in pairs, are fixedly mounted, while two others, an upper plate and a lower plate, which are opposed to each other, are arranged to and fro, each of these plates having a cavity and channels for the passage of air through said Cavity are provided.
  • a slot is provided in one of the side plates for the molding material feed into the molding chamber.
  • a model plate is accommodated in the molding chamber, which is rigidly attached to the movable lower plate and has channels for the passage of air, which run coaxially with the channels of this plate.
  • the top plate is movably arranged over the slot for the molding material feed within the molding chamber and is provided with a means for a recurrent connection of the cavity of the plate with the compressed air source.
  • the molding material is fed via the slot in an air flow in a direction parallel to the model plate.
  • the compressed air is supplied from the air pressure source via the means for recurrently connecting it to the molding chamber into the cavity of the top plate under pressure which is higher than the pressure of the air for supplying the Molding material is in the molding chamber.
  • the compressed air is fed from the cavity of the top plate via the channels of the top plate into the molding chamber in a direction perpendicular to the model plate.
  • a pressure drop in the molding chamber also creates eddy currents as well as air currents that move in the direction of move the model plate perpendicular to it.
  • a certain amount of molding material is fed into the molding chamber, which partially fills the molding chamber on the part of the model plate, the narrow deep recesses of the model being partially filled with a loose molding material.
  • the air streams directed perpendicular to the model plate will take the molding material particles to be fed into the molding chamber and move them in the direction of the model plate.
  • the air streams which are filtered through the layers of the loose molding material that has been brought into the molding chamber before the compressed air supply begins, compress the molding material, the molding material density being distributed unevenly, and the maximum density being the molding material layers adjacent to the model plate, while the layers of molding material that are particularly removed from the model plate have a minimal density.
  • the process of filling the molding chamber with the molding material and compressing the molding material continues until the slot for the molding material feed into the molding chamber is covered by the upper layers of the molding material.
  • the air jets emerging from the channels prevent the nearby zones of the molding chamber from being filled with the molding material, so that cavities are formed in addition to the plate mentioned.
  • the top plate After filling the molding chamber with the molding material, the top plate is moved towards the model plate, whereby the molding material is compressed by pressing. Pressing enables the molding material to be compressed on the top plate and a certain increase in the uniformity of the molding material over the volume of the casting mold; as a result, the cavities in the zone of the casting mold which are arranged opposite the channels for the compressed air supply next to the press plate cannot be eliminated. After pressing, the lower plate with the model plate attached to it is lowered and the model is lifted out of the mold.
  • the present invention has for its object to provide a method for producing disposable casting molds and a device for its implementation, which allow a uniform compression of the molding material over the volume of the casting mold and through the appropriate design of the device, the production of high quality molds difficult to mold .
  • This object is achieved in that, in a method for producing single-use casting molds, which consists in feeding a molding material in a direction in a direction parallel to the model plate into a mold chamber provided with a model plate, only after a period of time which is about 8 accounts for up to 60% of the duration of the molding material feed, the molding material is pre-compressed by means of compressed air supplied, and then the molding material is compressed by pressing, according to the invention the air is removed from the molding chamber before the molding material is fed in and during the feeding thereof in a direction perpendicular to the model plate and ended simultaneously with the termination of the molding material supply, the supply of compressed air into the molding chamber taking place in a direction running parallel to the model plate and being set before the molding material supply is terminated.
  • the molding material While the molding material is being fed into the molding chamber, the molding material is exposed to the horizontal air flows mentioned deflected onto the model plate, which contributes to a better penetration of the molding material into the narrow, deep recesses of the model.
  • the necessity of supplying compressed air to the molding chamber in a direction running parallel to the model plate is due to the fact that the compressed air flows moving in the mentioned direction, by interacting with the air flows moving in the direction towards the model plate, compress the molding material in the narrow, deep recesses of the models and ensure even compression of the molding material over the volume of the casting mold.
  • the stated condition for the air discharge from the molding chamber must be observed in order to ensure a reliable movement of the air flow towards the model plate.
  • the stable air flows directed perpendicular to the model plate do not come about, while the air removal from the molding chamber within a time that is more than 1 s before the molding material is uneconomical.
  • the compressed air is preferably fed into the molding chamber within a time which is 5 to 30% of the duration of the molding material feeding.
  • the limit values mentioned for the duration of the compressed air supply to the molding chamber are optimal, because if the duration of the compressed air supply is less than 5% of the duration of the molding material supply, the effect of the compressed air is not sufficient, while for a duration of more than 30% the molding material cannot fill in the hard-to-reach areas of the model because the required amount of molding material cannot get into the molding chamber during the remaining time of the molding material supply.
  • the condition mentioned for the compressed air supply is preferably used when using large-volume mold chambers.
  • a device for carrying out the method for producing disposable casting molds comprising plates arranged in pairs and forming a mold chamber, two side plates of which are fixedly mounted opposite one another, while two others, opposite one another, back and forth are arranged movably, wherein in each of these plates a cavity and channels for air passage through said cavity are provided, in one of the remaining plates a slot for the molding material feed into the molding chamber is made, in which a rigidly attached to one of the movable plates Model plate is housed, which has channels for the passage of air, which are designed coaxially with the channels of this plate, wherein a compressed air source and a means for a recurring connection of the compressed air source to the mold chamber are provided, according to the invention a system for Air discharge, which is recurrently connected to the mold chamber, and has at least one additional plate, which by is rigidly attached to the outside of the fixed side plate and has a recess on the part of the latter, which forms an air chamber with this fixed plate, a means for
  • Such a structural design of the device for carrying out the method for producing disposable casting molds enables the implementation of a method with which the air as the molding chamber can be discharged thanks to a system for air removal provided in the device, in order in this way to uniformly compress the To ensure molding material over the volume of the mold.
  • At least one additional plate is provided in the device with a means for supplying the compressed air into the air chamber, from which it is then passed into the mold chamber, a compressed air supply is also ensured in the mold chamber in a direction running parallel to the model plate, which leads to an improvement in the filling of the narrow, deep recesses of the models with the molding material and the pre-compression of the molding material.
  • the process for producing disposable casting molds is carried out as follows.
  • the air is removed from a molding chamber provided with a model plate 0.1 to 1.0 s before the start of the molding material feed in order to initiate the formation of horizontally directed air streams in the molding chamber.
  • the air is discharged in a direction perpendicular to the model plate.
  • a molding material is then fed into the molding chamber in the air stream in a direction running parallel to the model plate, and after a period of time which is approximately 8 to 60% of the duration of the molding material supply, the molding material is pre-compressed under the action of the compressed air supplied.
  • the compressed air supply into the molding chamber takes place in a direction running parallel to the model plate and within a time which is approximately 5 to 30% of the duration of the molding material supply, ie the compressed air supply is stopped before the molding material supply is terminated.
  • the air removal from the molding chamber is continued during the molding material supply and is stopped at the same time as the molding material supply is terminated. Then the molding material is compressed by pressing.
  • the device for carrying out the method for producing disposable casting molds contains. plates 1,2 (Fig.1), 3,4 (Fig.2) 5,6 (Fig.1) arranged in pairs, which form a mold chamber 7, a compressed air source 8, a means 9 for the recurrent connection of the compressed air source 8 to the Molding chamber 7 and a system 10 for air discharge from the molding chamber 7.
  • the two side plates 3, 4 (FIG. 2) arranged opposite one another are fixedly mounted.
  • the device is provided with at least one additional plate, the number of which is selected taking into account the main dimensions of the molding chamber 7 and can be four.
  • these additional plates can be placed on the plates 1,2 (Fig.1) 3, 4 (Fig.2) accordingly.
  • the device is provided with two additional plates 11, 12 which are rigidly fastened from the outside to the fixed side plates 3, 4 by means of bolts 13.
  • Each additional plate 11, 12 has a recess on the part of the associated plate 3, 4, which forms an air chamber 14, 15 with the last-mentioned plate 3, 4.
  • Channels 16, 17 are provided in the plates 3, 4 for the compressed air supply via the corresponding air chambers 14, 15 into the molding chamber 7.
  • the two opposing plates 5, 6 are arranged such that they can move back and forth, each of them being connected to a piston rod 18 of a hydraulic cylinder (not shown in FIG. 1).
  • a cavity 19, 20 and channels 21, 22 are provided in each movable plate 5, 6 for the passage of air through the corresponding cavity 19, 20.
  • a slot 23 is provided for the molding material feed into the molding chamber 7, the molding material being fed into the slot 23 from a blow container (not shown in the figures).
  • model plates 24, 25 are accommodated, which are rigidly mounted on the fixed plates 5, 6 by means of bolts 26.
  • Each model plate 24, 25 has channels 27, 28 for the passage of air, which run coaxially with the channels 21, 22.
  • Models 30, 31 are each fastened to the model plates 24, 25 (FIG. 2) by means of bolts 29.
  • a channel 32, 33 is provided coaxially with the associated channel 28, 27 of the corresponding model plate 24, 25.
  • the means 9 (FIG. 1) for a repeatable connection of the compressed air source 8 to the molding chamber 7 is designed as a valve 34 and pipes 35, 36 which are connected to the cavities 19, 20.
  • the system 10 for discharging air from the molding chamber 7 is connected to the tap 34 and is designed in the form of a vacuum pump 37 which is connected to a vacuum container 38.
  • the system 10 for air discharge is repeatedly connected to the tap 34 by means of a pipeline 39.
  • the valve 34 is designed so that it can periodically connect the molding chamber 7 to the compressed air source 8 or to the system 10 for air discharge.
  • Each additional plate 11, 12 (FIG. 2) is provided with a means 40 for supplying compressed air to the corresponding air chamber 14, 15.
  • the means 40 represents a compressed air container 41 which is connected to a valve 42 and by means of a pipe 43 to the corresponding air chambers 14, 15.
  • the device according to the invention for carrying out the method for producing disposable casting molds has the following mode of action.
  • the cavities 19, 20 are connected to the system 10 for air removal via the pipes 35, 36 by means of the cock 34 (FIG. 1); a pressure gradient is generated between the cavities 19, 20 and the mold chamber 7, as a result of which the air is discharged from the mold chamber 7 via the channels 27, 28 and 21, 22 in a direction running perpendicular to the model plates 24, 25.
  • An air discharge in a direction perpendicular to the models 24, 25 is necessary in order to generate stable air flows in the molding chamber 7, which are directed perpendicular to the model plates 24, 25. Since the air here is an inert medium, a period of time is required for the generation of stable air flows of the required orientation, i.e. the air must be removed before the molding material 7 is fed into the molding chamber 7.
  • the air is removed from the molding chamber 0.5 s before the molding material is started.
  • this time period should be in the range of 0.1 to 1 s because it does not occur in a shorter time period than 0.1 s that stable and perpendicular air streams are generated, and because it is uneconomical to keep the air inside of a time of more than 1 s, since the currents have already developed reliably by then and the energy for the air discharge is used uselessly.
  • the overall cycle time for the manufacture of a mold is extended, reducing the performance of the device.
  • a molding material is passed through the slot 23 in the air stream into the molding chamber 7 in after the time period mentioned (0.5 s) in a direction parallel to the model plates 24, 25.
  • the molding material particles moving parallel to the model plates 24, 25 in the air flow become in the direction of the latter under the action of the air flows moving vertically in the direction of the model plates 24, 25 Model plates 24, 25 transported there, filling the narrow deep recesses of the models 30, 31.
  • the molding material is precompressed by the compressed air to be supplied.
  • this time period is selected to be 10% of the duration of the molding material supply.
  • the compressed air is fed into the air chambers 14, 15 via the pipelines 43 (FIG. 2), and from there is then passed on via the channels 16, 17 into the molding chamber 7 in a direction parallel to the model plates 24, 25.
  • the compressed air is supplied at a higher pressure than the air pressure used for the molding material supply, the compressed air supply being carried out in opposite flows via two additional plates 11, 12.
  • the compressed air is supplied in a stream which is directed parallel to the model plates.
  • a two-sided compressed air supply (in opposite flows) in mold chambers of low content as well as a one-sided compressed air supply (in one flow) in large-volume mold chambers are also possible.
  • the cross-sectional areas of the means 40 for the compressed air supply must be increased and the pressure of the compressed air increased.
  • the compressed air is fed into the molding chamber 7 in a direction parallel to the model plates 24, 25, because the compressed air flows moving in the mentioned direction interact with air flows which move in the direction of the model plates 24, 25 perpendicular to them and ensure compression of the molding material in narrow, deep recesses of the models 30, 31 and uniform compression of the molding material over the volume of the casting mold, with the exception of the zones on the plates, over their Channels 16, 17 in the chamber 7 compressed air is supplied.
  • the volume of the molding material decreases, and the air flows leading into the molding chamber 7 prevent the zones of the compressed air supply from being filled with the molding material; In this way, in addition to the plates 3, 4, via the channels 16, 17 of which compressed air is supplied, cavities and loosening occur which can only be filled with the molding material if the compressed air supply is stopped in the molding chamber 7 before the molding material supply has ended.
  • the molding material that is fed into the molding chamber 7 in the period between the termination of the compressed air supply and the cessation of the molding material supply will fill these cavities smoothly and be compressed there, ensuring an even distribution of the density over the volume of the entire casting mold.
  • the compressed air must be fed into the molding chamber 7 within a time which is approximately 5 to 30% of the duration of the molding material supply into the molding chamber 7, ie the duration of the compressed air supply should be shorter than the duration of the molding material supply. If the duration of the compressed air supply is less than 5% of the duration of the molding material supply the effect of the compressed air is not sufficiently strong, and with a duration of the air supply of more than 30%, the molding material cannot fill the cavities because the required amount of molding material will not get into the molding chamber 7 in the remaining time of the molding material supply.
  • the compressed air is fed into the molding chamber 7 within a time which is 20% of the duration of the feeding of the molding material in a direction parallel to the molding plates 24, 25.
  • the molding material feed is set through the slot 23 (FIG. 1), the air discharge from the molding chamber 7 being interrupted at the same time.
  • the cavities 19, 20 are separated from the system 10 for air removal by means of the cock 34.
  • the plates 5 and 6 are moved against each other, final compression of the molding material being achieved by pressing.
  • the cavities 19, 20 are then connected to the compressed air source 8 by means of the cock 34; at the same time the plates 5 and 6 are moved from one another and the models 30, 31 are lifted out of the mold.
  • the compressed air to be supplied via the channels 21, 22, 27, 28 generates air currents which move perpendicularly to the model plates 24, 25 in the direction of the mold and ensure smooth lifting of the models 30, 31 from the mold, without the high fine parts of it.
  • the air is discharged from the molding chamber in a direction perpendicular to the model plates, the air removal also continuing during the molding material supply.
  • the molding material with a composition of (% by weight): Bentonite - 10; Starch (binder) - 0.2; Quartz sand residue is fed in an air stream under a pressure of 0.3 MPa into a molding chamber provided with two model plates in a direction parallel to the model plates.
  • the molding material has the following strength values: compressive strength - 0.15 MPa, tensile strength - 0.015 MPa, moisture - 3 to 3.5%.
  • the molding material is fed for 1 s.
  • the molding material is then pre-compressed under the action of the compressed air to be supplied in a direction running parallel to the model plates.
  • the compressed air is supplied in opposing flows 0.5 s after the molding material supply (this means 50% of the duration of the molding material supply) within 0.2 s (20% of the duration of the molding material supply).
  • the molding material is then compressed by pressing.
  • the hardness number which is determined using a hardness meter, serves as an evaluation criterion for the quality of the compression.
  • the surface hardness of the mold is determined in points 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, which are given on the diagram of the mold shown in FIGS. 3 and 4.
  • the method according to the invention for the production of casting molds and the device for its implementation ensure a high-quality impression of the models on both side surfaces of the casting mold and a high effectiveness of the production, which are achieved in that a mold chamber two-sided molds of complicated shape are produced with a significant expansion of the nomenclature of the castings, which are produced by the process for boxless horizontal stack molds in automatic operation.
  • the present invention can find particular effective application on automated molding lines for boxless molding in the production of difficult-to-shape castings.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Casting Devices For Molds (AREA)
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  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Abstract

PCT No. PCT/SU90/00170 Sec. 371 Date Mar. 29, 1991 Sec. 102(e) Date Mar. 29, 1991 PCT Filed Jun. 28, 1990.A molding chamber (7) accommodating pattern plates (24, 25) is supplied by a steam of air with sand mixture delivered in a direction parallel to the pattern plates (24, 25). After a time delay relative to the start of the sand delivery operation, and sand mixture is preliminarily compacted by delivering a stream of compressed air directly into the molding chamber in a direction parallel to the pattern plates, the delivery of compressed air being continued within a period of time equal to 5 to 30 percent of the duration of the sand mixture delivery operation. As a result of the delivery of compressed air, the delivery of the sand mixture is retarded and even interrupted. The stream of compressed air diverts the sand mixture in the molding chamber towards the pattern plates, thus providing a better filling of narrow deep hollows on pattern surfaces and preliminary compaction of the sand mixture. The sand delivery operation is completed after the end of the preliminary compaction. The sand mixture is finally compacted by mechanical pressing.

Description

Die Erfindung bezieht sich auf das Gießereiwesen und betrifft insbesondere ein Verfahren zur Herstellung von einmalig verwendbaren Gießformen sowie eine Vorrichtung zu seiner Durchführung.The invention relates to the foundry industry and relates in particular to a method for producing disposable casting molds and an apparatus for carrying it out.

Stand der TechnikState of the art

Es ist ein Verfahren zur Herstellung von einmalig verwendbaren Gießformen (US, A, 4313486) bekannt, welches darin besteht, daß in eine mit einer Modellplatte versehene Formkammer im Luftstrom ein Formstoff in einer zu der Modellplatte parallel verlaufenden Richtung zugeführt wird. Gleichzeitig mit der Formstoffzuführung wird der Formstoff unter Einwirkung der Druckluft vorverdichtet, die in einer zu der Modellplatte parallel liegenden Richtung zugeführt wird. Nach dem Ausfüllen der Formkammer wird der Formstoff durch Pressen verdichtet.A method for producing single-use molds (US, A, 4313486) is known which consists in feeding a molding material in a direction in a direction parallel to the pattern plate into a molding chamber provided with a pattern plate. Simultaneously with the molding material supply, the molding material is pre-compressed under the action of the compressed air, which is supplied in a direction parallel to the model plate. After filling the molding chamber, the molding material is compressed by pressing.

Das Verfahren wird mittels einer Vorrichtung (US, A, 431 3486) durchgeführt, die eine Formkammer, welche von, paarweise angeordnet, einer Oberplatte und einer Unterplatte, Seitenplatten, einer Modellplatte und einer Preßplatte gebildet ist, eine Druckluftquelle und ein Mittel zum Zuführen der Druckluft in die Formkammer enthält. In der Modellplatte und in den Preßplatten sind Hohlräume sowie Kanäle für den Durchgang der Luft durch die genannten Hohlräume vorgesehen. In der Oberplatte ist ein Kanal für die Zuführung des Formstoffes in die Formkammer ausgeführt, wobei der Formstoff im Luftstrom in einer zu der Modellplatte parallelliegenden Richtung zugeführt wird. Gleichzeitig wird von der Druckluftquelle über die ZufuhrmittelThe process is carried out by means of an apparatus (US, A, 431 3486) which comprises a molding chamber which is formed by, arranged in pairs, an upper plate and a lower plate, side plates, a model plate and a press plate, a compressed air source and a means for supplying the Contains compressed air in the mold chamber. Cavities and channels for the passage of air through said cavities are provided in the model plate and in the pressure plates. A channel for feeding the molding material into the molding chamber is embodied in the top plate, the molding material being fed in the air flow in a direction parallel to the model plate. At the same time, from the compressed air source via the supply means

Druckluft in den Hohlraum der Preßplatte zugeführt und von da aus über die Kanäle der Preßplatte in die Formkammer weitergeleitet.Compressed air is fed into the cavity of the press plate and from there passed through the channels of the press plate into the molding chamber.

Unter Einwirkung des Druckgefälles wird die Luft aus der Formkammer in die Atmosphäre über die Kanäle in der Modellplatte, in der Ober und in der Unterplatte abgeführt. Auf diese Weise entstehen in der Formkammer nicht nur vertikal gerichtete, sondern auch horizontal gerichtete Luftströme. Die horizontal gerichteten Luftströme nehmen die Formstoffteilchen mit und bewegen diese in Richtung zu der Modellplatte hin, indem sie die schmalen tiefen Aussparungen der Modelle mit Formstoff ausfüllen.Under the influence of the pressure drop, the air from the molding chamber is released into the atmosphere via the channels dissipated in the model plate, in the top and in the bottom plate. In this way, not only vertically directed, but also horizontally directed air flows arise in the molding chamber. The horizontally directed air flows take the molding material particles with them and move them towards the model plate by filling the narrow, deep recesses of the models with molding material.

Für die Erzeugung der genannten horizontal gerichteten Luftströme, welche sich in Richtung zu der Modellplatte hin und senkrecht zu dieser bewegen, wird nur ein Teil der Druckluft verbraucht, die über die Kanäle der Preßplatte zugeführt wird, wobei der Druck dieser Druckluft gleich oder etwas niedriger als der Druck der Luft ist, mit deren Hilfe der Formstoff in die Formkammer zugeführt wird. Aus diesem Grunde reicht die Leistung der horizontal gerichteten Luftströme für ein qualitätsgerechtes Ausfüllen der schmalen tiefen Aussparungen der Modelle mit dem Formstoff und für die Verdichtung des Formstoffes an diesen Stellen nicht aus.For the generation of the above-mentioned horizontally directed air flows, which move in the direction of the model plate and perpendicular to it, only a part of the compressed air which is supplied via the channels of the press plate is used, the pressure of this compressed air being equal to or slightly lower than is the pressure of the air, with the help of which the molding material is fed into the molding chamber. For this reason, the performance of the horizontally directed air flows is not sufficient to fill the narrow, deep recesses of the models with the molding material and to compress the molding material at these points.

Unter Einwirkung der entstandenen Luftströme auf den Formstoff verteilt sich die Dichte des Formstoffes über das Volumen der Formkammer nicht gleichmäßig: die maximale Dichte weisen die an die Modellplatte angrenzenden Schichten des Formstoffes auf, während der an der Preßplatte anliegende Formstoff eine minimale Dichte besitzt, wobei sich den Kanälen der Preßplatte für den Luftdurchgang gegenüber in der Gießform Hohlräume bilden, weil die aus den Kanälen austretenden Druckluftstrahlen ein Ausfüllen dieser Zonen der Gießform mit dem Formstoff verhindern.Under the influence of the resulting air currents on the molding material, the density of the molding material is not evenly distributed over the volume of the molding chamber: the layers of molding material adjacent to the model plate have the maximum density, while the molding material lying on the press plate has a minimum density, whereby form cavities in the channels of the press plate for the passage of air in the casting mold, because the compressed air jets emerging from the channels prevent these zones of the casting mold from being filled with the molding material.

Durch das anschließende Preisen des Formstoffes mittels der Bewegung der Preßplatte in Richtung zu der Modellplatte hin wird der Formstoff in den an die Preßplatte angrenzenden Schichten verdichtet; es ist aber unmöglich, eine ungleichmäßige Dichteverteilung des Formstoffe über das Volumen der Gießform sowie die Hohlräume in den Zonen der Druckluftzuführung völlig zu beseitigen.As a result of the subsequent pricing of the molding material by means of the movement of the press plate in the direction of the model plate, the molding material is compacted in the layers adjacent to the press plate; but it is impossible to find an uneven density distribution of the Completely eliminate molding materials via the volume of the casting mold and the cavities in the zones of the compressed air supply.

Außerdem ist es kompliziert, die hergestellte Form aus der Formkammer auszuheben, ohne daß dabei die feinen herausragenden Formteile, die von den schmalen tiefen Aussparungen des Modells gebildet sind, brechen, weil die Modellplatte starr befestigt ist und die Form aus der Formkammer nicht herausziehen kann.In addition, it is difficult to lift the mold out of the mold chamber without breaking the fine protruding mold parts, which are formed by the narrow deep recesses of the model, because the model plate is rigidly attached and the mold cannot pull out of the mold chamber.

Auf diese Weise können das bekannte Verfahren zur Herstellung von einmalig verwendbaren Gießformen und die Vorrichtung zu seiner Durchführung die Herstellung von qualitätsgerechten formschwierigen Gießformen nicht gewährleisten.In this way, the known method for the production of single-use casting molds and the device for its implementation cannot guarantee the production of high-quality mold-difficult casting molds.

Es ist ein Verfahren zur Herstellung von einmalig verwendbaren Gießformen (SU, A, 1060299) bekannt, welches darin besteht, daß in eine mit einer Modellplatte versehene Formkammer ein Formstoff mittels eines Luftstromes in einer zu der Modellplatte parallelverlaufenden Richtung zugeführt wird. Anschließend wird nach einer Zeitspanne, die etwa 8 bis 60% der Dauer der Formstoffzuführung beträgt, eine Vorverdichtung des Formstoffes durch die Druckluft vorgenommen, welche in einer zu der Modellplatte parallelliegenden Richtung zugeführt wird. Die endgültige Verdichtung des Formstoffes wird durch Pressen durchgeführt.A process for the production of single-use molds (SU, A, 1060299) is known, which consists in that a molding material is fed into a molding chamber provided with a model plate by means of an air flow in a direction parallel to the model plate. Subsequently, after a period of time which is approximately 8 to 60% of the duration of the molding material supply, the molding material is pre-compressed by the compressed air, which is supplied in a direction parallel to the model plate. The final compression of the molding material is carried out by pressing.

Die Vorrichtung zur Durchführung dieses Verfahrens enthält paarweise angeordnete Platten, welche eine Formkammer bilden, eine Druckluftquelle und ein Mittel, das für eine wiederkehrende Verbindung der Druckluftquelle mit der Formkammer sorgt. Vier Seitenplatten, welche paarweise einander gegenüber liegen, sind feststehend montiert, während zwei andere, eine Oberplatte und eine Unterplatte, welche einander gegenüber liegen, hin- und hergehend angeordnet sind, wobei in jeder dieser Platten ein Hohlraum sowie Kanäle für den Luftdurchgang durch den genannten Hohlraum vorgesehen sind. In einer der Seitenplatten ist ein Schlitz für die Formstoffzuführung in die Formkammer vorgesehen. In der Formkammer ist eine Modellplatte untergebracht, die an der bewegbaren Unterplatte starr befestigt ist und Kanäle für den Luftdurchgang aufweist, welche koaxial mit den Kanälen dieser Platte verlaufen. Die Oberplatte ist über dem Schlitz für die Formstoffzuführung innerhalb der Formkammer bewegbar angeordnet und mit einem Mittel für eine wiederkehrende Verbindung des Hohlraumes der Platte mit der Druckluftquelle versehen.The device for carrying out this method contains plates arranged in pairs which form a molding chamber, a compressed air source and a means which ensures a recurrent connection of the compressed air source to the molding chamber. Four side plates, which are opposed to each other in pairs, are fixedly mounted, while two others, an upper plate and a lower plate, which are opposed to each other, are arranged to and fro, each of these plates having a cavity and channels for the passage of air through said Cavity are provided. A slot is provided in one of the side plates for the molding material feed into the molding chamber. A model plate is accommodated in the molding chamber, which is rigidly attached to the movable lower plate and has channels for the passage of air, which run coaxially with the channels of this plate. The top plate is movably arranged over the slot for the molding material feed within the molding chamber and is provided with a means for a recurrent connection of the cavity of the plate with the compressed air source.

Über den Schlitz wird mittels eines Luftstromes der Formstoff in einer zu der Modellplatte parallelverlaufenden Richtung zugeführt.The molding material is fed via the slot in an air flow in a direction parallel to the model plate.

Nach einer Zeitspanne, die 8 bis 60% der Dauer der Formstoffzuführung beträgt, wird die Druckluft von der Luftdruckquelle über das Mittel zum wiederkehrenden Verbinden derselben mit der Formkammer in den Hohlraum der Oberplatte unter Druck zugeführt, der höher als der Druck der Luft zum Zuführen des Formstoffes in die Formkammer ist. Aus dem Hohlraum der Oberplatte wird die Druckluft über die Kanäle der Oberplatte in die Formkammer in einer zur Modellplatte senkrecht verlaufenden Richtung zugeführt.After a period of time which is 8 to 60% of the duration of the molding material supply, the compressed air is supplied from the air pressure source via the means for recurrently connecting it to the molding chamber into the cavity of the top plate under pressure which is higher than the pressure of the air for supplying the Molding material is in the molding chamber. The compressed air is fed from the cavity of the top plate via the channels of the top plate into the molding chamber in a direction perpendicular to the model plate.

Da die Formkammer über die Kanäle der Modellplatte mit der Atmosphäre in Verbindung steht, und die Druckluft in die Formkammer über die im oberen Teil der Kammer vorgesehenen Kanäle zugeführt wird, entstehen infolge eines Druckgefälles in der Formkammer neben Wirbelströmen auch Luftströme, die sich in Richtung zu der Modellplatte senkrecht zu dieser bewegen.Since the molding chamber is connected to the atmosphere via the channels of the model plate, and the compressed air is fed into the molding chamber via the channels provided in the upper part of the chamber, a pressure drop in the molding chamber also creates eddy currents as well as air currents that move in the direction of move the model plate perpendicular to it.

Während der genannten Zeitspanne wird in die Formkammer eine bestimmte Formstoffmenge zugeführt, die teilweise die Formkammer von seiten der Modellplatte ausfüllt, wobei die schmalen tiefen Aussparungen des Modells mit einem lockeren Formstoff teilweise gefüllt sein werden. Die senkrecht zu der Modellplatte gerichteten Luftströme werden die in die Formkammer zuzuführenden Formstoffteilchen mitnehmen und diese in Richtung zu der Modellplatte hin bewegen. Die Luftströme, welche durch die Schichten des lockeren Formstoffes, der in die Formkammer vor Beginn der Druckluftzuführung gebracht worden ist, filtriert werden, verdichten den Formstoff, wobei sich die Formstoffdichte ungleichmäßig verteilt, u.z. die maximale Dichte weisen die an die Modellplatte angrenzenden Formstoffschichten auf, während die besonders von der Modellplatte entfernten Formstoffschichten eine minimale Dichte besitzen.During the period of time mentioned, a certain amount of molding material is fed into the molding chamber, which partially fills the molding chamber on the part of the model plate, the narrow deep recesses of the model being partially filled with a loose molding material. The air streams directed perpendicular to the model plate will take the molding material particles to be fed into the molding chamber and move them in the direction of the model plate. The air streams, which are filtered through the layers of the loose molding material that has been brought into the molding chamber before the compressed air supply begins, compress the molding material, the molding material density being distributed unevenly, and the maximum density being the molding material layers adjacent to the model plate, while the layers of molding material that are particularly removed from the model plate have a minimal density.

So verläuft der Prozeß der Füllung der Formkammer mit dem Formstoff und der Verdichtung des Formstoffes, bis der Schlitz für die Formstoffzuführung in die Formkammer von den oberen Schichten des Formstoffes überdeckt ist. Die aus den Kanälen austretenden Luftstrahlen verhindern dabei ein Ausfüllen der nahe liegenden Zonen der Formkammer mit dem Formstoff, so daß neben der genannten Platte Hohlräume entstehen.The process of filling the molding chamber with the molding material and compressing the molding material continues until the slot for the molding material feed into the molding chamber is covered by the upper layers of the molding material. The air jets emerging from the channels prevent the nearby zones of the molding chamber from being filled with the molding material, so that cavities are formed in addition to the plate mentioned.

Nach dem Ausfüllen der Formkammer mit dem Formstoff bewegt man die Oberplatte in Richtung zu der Modellplatte hin, wodurch man den Formstoff durch Pressen verdichtet. Das Pressen ermöglicht eine Verdichtung des Formstoffes an der Oberplatte und eine bestimmte Erhöhung der Gleichmäßigkeit des Formstoffes über das Volumen der Gießform; dadurch können die Hohlräume in der Zone der Gießform nicht beseitigt werden, die den Kanälen für die Druckluftzuführung gegenüber neben der Preßplatte angeordnet sind. Nach dem Pressen wird die Unterplatte mit der an dieser befestigten Modellplatte gesenkt und das Modell wird aus der Gießform ausgehoben.After filling the molding chamber with the molding material, the top plate is moved towards the model plate, whereby the molding material is compressed by pressing. Pressing enables the molding material to be compressed on the top plate and a certain increase in the uniformity of the molding material over the volume of the casting mold; as a result, the cavities in the zone of the casting mold which are arranged opposite the channels for the compressed air supply next to the press plate cannot be eliminated. After pressing, the lower plate with the model plate attached to it is lowered and the model is lifted out of the mold.

Die bekannten Verfahren und Vorrichtungen zu deren Durchführung gestatten es nicht, qualitätsgerechte formschwierige Gießformen herzustellen.The known methods and devices for their implementation do not make it possible to produce high-quality, difficult-to-shape casting molds.

Beim Ausheben der Modelle aus der Gießform werden außerdem die hochragenden feinen Teile dieser Form öfters infolge einer mangelhaften Dichte dieser Abschnitte der Form abgebrochen.When lifting the models out of the mold, they are also the towering fine parts of this form are often broken off due to insufficient density of these sections of the form.

Der vorliegenden Erfindung liegt die Aufgabe zugrunde, ein Verfahren zur Herstellung von einmalig verwendbaren Gießformen und eine Vorrichtung zu seiner Durchführung zu schaffen, die eine gleichmäßige Verdichtung des Formstoffes über das Volumen der Gießform und durch die entsprechende Konstruktion der Vorrichtung die Herstellung von qualitätsgerechten formschwierigen Gießformen ermöglichen.The present invention has for its object to provide a method for producing disposable casting molds and a device for its implementation, which allow a uniform compression of the molding material over the volume of the casting mold and through the appropriate design of the device, the production of high quality molds difficult to mold .

Diese Aufgabe wird dadurch gelöst, daß bei einen Verfahren zur Herstellung von einmalig verwendbaren Gießformen, welches darin besteht, daß man in eine mit einer Modellplatte versehene Formkammer im Luftstrom einen Formstoff in einer zur Modellplatte parallelverlaufenden Richtung zuführt, erst nach einer Zeitspanne, die etwa 8 bis 60% der Dauer der Formstoffzuführung ausmacht, den Formstoff mittels zugeführter Druckluft vorverdichtet, und anschließend den Formstoff durch Pressen verdichtet, man erfindungsgemäß die Luftabführung aus der Formkammer vor Beginn der Zuführung des Formstoffes und während der Zuführung desselben in einer zur Modellplatte senkrechtverlaufenden Richtung vornimmt und gleichzeitig mit der Beendigung der Formstoffzuführung beendet, wobei die Zuführung der Druckluft in die Formkammer in einer zur Modellplatte parallelverlaufenden Richtung erfolgt und vor der Beendigung der Formstoffzuführung eingestellt wird.This object is achieved in that, in a method for producing single-use casting molds, which consists in feeding a molding material in a direction in a direction parallel to the model plate into a mold chamber provided with a model plate, only after a period of time which is about 8 accounts for up to 60% of the duration of the molding material feed, the molding material is pre-compressed by means of compressed air supplied, and then the molding material is compressed by pressing, according to the invention the air is removed from the molding chamber before the molding material is fed in and during the feeding thereof in a direction perpendicular to the model plate and ended simultaneously with the termination of the molding material supply, the supply of compressed air into the molding chamber taking place in a direction running parallel to the model plate and being set before the molding material supply is terminated.

Es ist notwendig, daß die Luft aus der Formkammer vor der Zuführung des Formstoffes in diese abgeführt wird, um die Bildung intensiver horizontal gerichter Luftströme in der Formkammer einzuleiten, die sich in Richtung zu der Modellplatte hin senkrecht zu dieser bewegen.It is necessary that the air from the molding chamber is discharged into the molding chamber before the molding material is fed in order to initiate the formation of intense horizontally directed air currents in the molding chamber which move in the direction of the model plate perpendicular to the latter.

Während der Formstoffzuführung in die Formkammer wird der Formstoff von den genannten horizontalen Luftströmen auf die Modellplatte abgelenkt, was zu einem besseren Eindringen des Formstoffes in die schmalen tiefen Aussparungen des Modells beiträgt.While the molding material is being fed into the molding chamber, the molding material is exposed to the horizontal air flows mentioned deflected onto the model plate, which contributes to a better penetration of the molding material into the narrow, deep recesses of the model.

Die Notwendigkeit der Druckluftzuführung in die Formkammer in einer zu der Modellplatte parallelverlaufenden Richtung ist darauf zurückzuführen, daß die sich in der genannten Richtung bewegenden Druckluftströme, indem sie mit den sich in Richtung zu der Modellplatte hin senkrecht zu dieser bewegenden Luftströmen zusammenwirken, eine Verdichtung des Formstoffes in schmalen tiefen Aussparungen der Modelle sowie eine gleichmäßige Verdichtung des Formstoffes über das Volumen der Gießform gewährleisten.The necessity of supplying compressed air to the molding chamber in a direction running parallel to the model plate is due to the fact that the compressed air flows moving in the mentioned direction, by interacting with the air flows moving in the direction towards the model plate, compress the molding material in the narrow, deep recesses of the models and ensure even compression of the molding material over the volume of the casting mold.

Es ist vorteilhaft, mit der Luftabführung aus der Formkammer 0,1 bis 1,0 s vor dem Beginn der Formstoffzuführung anzufangen.It is advantageous to start the air discharge from the molding chamber 0.1 to 1.0 s before the start of the molding material feed.

Die genannte Bedingung für die Luftabführung aus der Formkammer ist einzuhalten, um damit eine zuverlässige Bewegung des Luftstromes zu der Modellplatte hin zu gewährleisten. In einer Zeitspanne, die weniger als 0,1 s beträgt, kommen die senkrecht zur Modellplatte gerichteten stabilen Luftströme nicht dazu, sich auszugestalten, während die Luftabführung aus der Formkammer innerhalb einer Zeit, die mehr als 1 s beträgt, vor der Formstoffzuführung unwirtschaftlich ist.The stated condition for the air discharge from the molding chamber must be observed in order to ensure a reliable movement of the air flow towards the model plate. In a period of time that is less than 0.1 s, the stable air flows directed perpendicular to the model plate do not come about, while the air removal from the molding chamber within a time that is more than 1 s before the molding material is uneconomical.

Erfindungsgemäß ist die Zuführung der Druckluft in die Formkammer vorzugsweise innerhalb einer Zeit vorzunehmen, die 5 bis 30% der Dauer der Formstoffzuführung beträgt.According to the invention, the compressed air is preferably fed into the molding chamber within a time which is 5 to 30% of the duration of the molding material feeding.

Infolge der Zuführung der Druckluft in die Formkammer in einer zu der Modellplatte parallelverlaufenden Richtung werden ein besseres Ausfüllen der schmalen tiefen Aussparungen der Modelle mit dem Formstoff sowie eine bessere Vorverdichtung erzielt.As a result of the compressed air being fed into the molding chamber in a direction running parallel to the model plate, better filling of the narrow, deep recesses of the models with the molding material and better pre-compression are achieved.

Gleichzeitig nimmt aber dabei der Druck der Luft in der Formkammer zu, was zu einer Verzögerung oder sogar zu einer Einstellung der Formstoffzuführung führen kann. Deshalb muß man die Druckluftzuführung in die Formkammer vor der Beendigung der Formstoffzuführung einstellen.At the same time, however, the pressure of the air in the molding chamber increases, which can lead to a delay or even to an adjustment of the molding material supply. Therefore you have to pressurize the compressed air into the molding chamber adjust before stopping the molding material feed.

Die genannten Grenzwerte für die Dauer der Druckluftzuführung in die Formkammer sind optimal, weil bei einer Dauer der Druckluftzuführung, die weniger als 5% der Dauer der Formstoffzuführung beträgt, der Effekt der Drucklufteinwirkung nicht ausreichend ist, während bei einer Dauer von über 30% der Formstoff die schwer zugänglichen Stellen des Modells nicht ausfüllen kann, weil in der restlichen Zeit der Formstoffzuführung die erforderliche Formstoffmenge nicht in die Formkammer gelangen kann.The limit values mentioned for the duration of the compressed air supply to the molding chamber are optimal, because if the duration of the compressed air supply is less than 5% of the duration of the molding material supply, the effect of the compressed air is not sufficient, while for a duration of more than 30% the molding material cannot fill in the hard-to-reach areas of the model because the required amount of molding material cannot get into the molding chamber during the remaining time of the molding material supply.

Es ist auch vorteilhaft, die Druckluftzuführung in gegenläufigen Strömen vorzunehmen.It is also advantageous to supply the compressed air in opposite flows.

Die genannten Bedingung für die Druckluftzuführung wird vorzugsweise beim Einsatz großvolumiger Formkammern verwendet.The condition mentioned for the compressed air supply is preferably used when using large-volume mold chambers.

Die Aufgabe wird auch dadurch gelöst, daß eine Vorrichtung zur Durchführung des Verfahrens zur Herstellung von einmalig verwendbaren Gießformen, enthaltend paarweise angeordnete und eine Formkammer bildende Platten, von denen zwei Seitenplatten einander gegenüber feststehend montiert sind, während zwei andere, einander gegenüber liegende hin- und hergehend bewegbar angeordnet sind, wobei in jeder dieser Platten ein Hohlraum sowie Kanäle für den Luftdurchgang durch den genannten Hohlraum vorgesehen sind, in einer der restlichen Platten ein Schlitz für die Formstoffzuführung in die Formkammer ausgeführt ist, in welcher eine starr an einer der bewegbaren Platten befestigte Modellplatte untergebracht ist, die Kanäle für den Luftdurchgang aufweist, welche koaxial mit den Kanälen dieser Platte ausgeführt sind, wobei eine Druckluftquelle und eine Mittel für eine wiederkehrende Verbindung der Druckluftquelle mit der Formkammer vorgesehen sind, erfindungsgemäß ein System zur Luftabführung, das mit der Formkammer wiederkehrend in Verbindung gesetzt wird, sowie mindestens eine zusätzliche Platte hat, welche von außen an der feststehenden Seitenplatte starr befestigt ist und seitens der letzteren eine Aussparung aufweist, welche mit dieser feststehenden Platte eine Luftkammer bildet, wobei in der zusätzlichen Platte ein Mittel zur Zuführung der Druckluft in die Luftkammer vorgesehen ist, das mit der Druckluftquelle in Verbindung steht, während in der feststehenden Seitenplatte Kanäle für die Zuführung der Druckluft durch die Luftkammer in die Formkammer ausgeführt sind.The object is also achieved in that a device for carrying out the method for producing disposable casting molds, comprising plates arranged in pairs and forming a mold chamber, two side plates of which are fixedly mounted opposite one another, while two others, opposite one another, back and forth are arranged movably, wherein in each of these plates a cavity and channels for air passage through said cavity are provided, in one of the remaining plates a slot for the molding material feed into the molding chamber is made, in which a rigidly attached to one of the movable plates Model plate is housed, which has channels for the passage of air, which are designed coaxially with the channels of this plate, wherein a compressed air source and a means for a recurring connection of the compressed air source to the mold chamber are provided, according to the invention a system for Air discharge, which is recurrently connected to the mold chamber, and has at least one additional plate, which by is rigidly attached to the outside of the fixed side plate and has a recess on the part of the latter, which forms an air chamber with this fixed plate, a means for supplying the compressed air into the air chamber being provided in the additional plate, said means being connected to the compressed air source, while channels are provided in the fixed side plate for the supply of compressed air through the air chamber into the molding chamber.

Es ist vorteilhaft, in der Formkammer eine zusätzliche Modellplatte unterzubringen, die an einer anderen bewegbaren Platte starr angeordnet ist und Kanäle aufweist, die koaxial mit den Kanälen dieser bewegbaren Platte verlaufen.It is advantageous to accommodate an additional model plate in the molding chamber, which is rigidly arranged on another movable plate and has channels which run coaxially with the channels of this movable plate.

Eine solche konstruktive Ausführung der Vorrichtung zur Durchführung des Verfahrens zur Herstellung von einmalig verwendbaren Gießformen ermöglicht die Realisierung eine Verfahrens, mit dem die Luft als der Formkammer dank einem in der Vorrichtung vorgesehenen System zur Luftabführung abgeführt werden kann, um auf diese Weise eine gleichmäßige Verdichtung des Formstoffes über das Volumen der Gießform zu gewährleisten.Such a structural design of the device for carrying out the method for producing disposable casting molds enables the implementation of a method with which the air as the molding chamber can be discharged thanks to a system for air removal provided in the device, in order in this way to uniformly compress the To ensure molding material over the volume of the mold.

Dadurch, daß in der Vorrichtung mindestens eine zusätzliche Platte mit einem Mittel zum Zuführen der Druckluft in die Luftkammer vorgesehen ist, aus welcher sie dann in die Formkammer geleitet wird, wird außerdem eine Druckluftzuführung in die Formkammer in einer zu der Modellplatte parallelverlaufenden Richtung gewährleistet, was zu einer Verbesserung des Ausfüllens der schmalen tiefen Aussparungen der Modelle mit dem Formstoff und der Vorverdichtung des Formstoffes führt.Characterized in that at least one additional plate is provided in the device with a means for supplying the compressed air into the air chamber, from which it is then passed into the mold chamber, a compressed air supply is also ensured in the mold chamber in a direction running parallel to the model plate, which leads to an improvement in the filling of the narrow, deep recesses of the models with the molding material and the pre-compression of the molding material.

Durch das Vorhandensein einer zusätzlichen Modellplatte in der Formkammer wird eine Herstellung von qualitätsgerechten, zweiseitigen, formschwierigen Gießformen gewährleistet.The presence of an additional model plate in the molding chamber ensures that high-quality, two-sided, difficult-to-shape casting molds are produced.

Auf diese Weise gewährleisten die oben erwähnten Bedingungen für die Durchführung des Verfahrens zur Herstellung von einmalig verwendbaren Gießformen und die konstruktive Ausführung der Vorrichtung zu seiner Durchführung eine gleichmäßige Verdichtung des Formstoffes beim Ausfüllen von schmalen tiefen Stellen der Form, was zu einer Verbesserung der Qualität der formschwierigen Gießformen führt und die Herstellung von zweiseitigen, einmalig verwendbaren Gießformen ermöglicht.This ensures the conditions mentioned above for the implementation of the process for the production of single-use casting molds and the constructive implementation of the device for its implementation, a uniform compression of the molding material when filling narrow, deep places in the mold, which leads to an improvement in the quality of the mold-difficult casting molds and the production of one-time use molds.

Beschreibung der ZeichnungenDescription of the drawings

Zu einen besseren Verständnis der Erfindung werden konkrete Ausführungsbeispiele unter Bezugnahme auf Zeichnungen angeführt. Es zeigt:

  • Fig. 1 in schematischer Darstellung eine erfindungsgemäße Vorrichtung zur Durchführung des Verfahrens zur Herstellung von einmalig verwendbaren Gießformen, in Frontansicht im Längsschnitt;
  • Fig. 2 - einen Schnitt nach der Linie II-II der Fig. 1;
  • Fig. 3 - in schematischer Darstellung eine Gießform, die nach dem erfindungsgemäßen Verfahren auf der in Fig.1,2 dargestellten Vorrichtung hergestellt wurde, in Frontansicht;
  • Fig. 4 - dieselbe Gießform, die in Fig.3 dargestellt ist, mit einem Teilausschnitt (linke Seitenansicht).
For a better understanding of the invention, specific exemplary embodiments are given with reference to drawings. It shows:
  • Figure 1 is a schematic representation of an inventive device for performing the method for producing disposable casting molds, in front view in longitudinal section.
  • Fig. 2 - a section along the line II-II of Fig. 1;
  • Fig. 3 - a schematic representation of a casting mold, which was produced by the method according to the invention on the device shown in Fig. 1,2, in front view;
  • Fig. 4 - the same mold, which is shown in Fig.3, with a partial section (left side view).

Das Verfahren zur Herstellung von einmalig verwendbaren Gießformen wird wie folgt durchgeführt.The process for producing disposable casting molds is carried out as follows.

Aus einer mit einer Modellplatte versehenen Formkammer wird 0,1 bis 1,0 s vor dem Beginn der Formstoffzuführung die Luft abgeführt, um die Entstehung von horizontal gerichteten Luftströmen in der Formkammer einzuleiten. Die Luftabführung wird in einer zur Modellplatte senkrecht verlaufenden Richtung vorgenommen. Dann wird in die Formkammer im Luftstrom ein Formstoff in einer zur Modellplatte parallel verlaufenden Richtung zugeführt, und nach einer Zeitspanne, die etwa 8 bis 60% der Dauer der Formstoffzuführung beträgt, wird eine Vorverdichtung des Formstoffes unter Einwirkung der zugeführten Druckluft durchgeführt. Die Druckluftzuführung in die Formkammer erfolgt in einer zur Modellplatte parallel verlaufenden Richtung und innerhalb einer Zeit, die etwa 5 bis 30% der Dauer der Formstoffzuführung beträgt, d.h., die Druckluftzuführung wird vor der Beendigung der Formstoffzuführung eingestellt.The air is removed from a molding chamber provided with a model plate 0.1 to 1.0 s before the start of the molding material feed in order to initiate the formation of horizontally directed air streams in the molding chamber. The air is discharged in a direction perpendicular to the model plate. A molding material is then fed into the molding chamber in the air stream in a direction running parallel to the model plate, and after a period of time which is approximately 8 to 60% of the duration of the molding material supply, the molding material is pre-compressed under the action of the compressed air supplied. The compressed air supply into the molding chamber takes place in a direction running parallel to the model plate and within a time which is approximately 5 to 30% of the duration of the molding material supply, ie the compressed air supply is stopped before the molding material supply is terminated.

Die Luftabführung aus der Formkammer wird während der Formstoffzuführung fortgesetzt und gleichzeitig mit der Beendigung der Formstoffzuführung eingestellt. Dann wird der Formstoff durch Pressen verdichtet.The air removal from the molding chamber is continued during the molding material supply and is stopped at the same time as the molding material supply is terminated. Then the molding material is compressed by pressing.

Die Vorrichtung zur Durchführung des Verfahrens zur Herstellung von einmalig verwendbaren Gießformen enthält. paarweise angeordnete Platten 1,2 (Fig.1), 3,4 (Fig.2) 5,6 (Fig.1), welche eine Formkammer 7 bilden, eine Druckluftquelle 8, ein Mittel 9 zum wiederkehrenden Verbinden der Druckluftquelle 8 mit der Formkammer 7 sowie ein System 10 zur Luftabführung aus der Formkammer 7. Die zwei einander gegenüber angeordneten Seitenplatten 3,4 (Fig.2) sind feststehend montiert.The device for carrying out the method for producing disposable casting molds contains. plates 1,2 (Fig.1), 3,4 (Fig.2) 5,6 (Fig.1) arranged in pairs, which form a mold chamber 7, a compressed air source 8, a means 9 for the recurrent connection of the compressed air source 8 to the Molding chamber 7 and a system 10 for air discharge from the molding chamber 7. The two side plates 3, 4 (FIG. 2) arranged opposite one another are fixedly mounted.

Die Vorrichtung ist mindestens mit einer zusätzlichen Platte versehen, wobei deren Anzahl unter Berücksichtigung der Hauptabmessungen der Formkammer 7 gewählt wird und gleich vier sein kann. In diesem Fall können diese zusätzlichen Platten dementsprechend auf die Platten 1,2 (Fig.1) 3, 4 (Fig.2) aufgestellt werden.The device is provided with at least one additional plate, the number of which is selected taking into account the main dimensions of the molding chamber 7 and can be four. In this case, these additional plates can be placed on the plates 1,2 (Fig.1) 3, 4 (Fig.2) accordingly.

Im vorliegenden Ausführungsbeispiel ist die Vorrichtung mit zwei zusätzlichen Platten 11, 12 versehen, die von außen an den feststehenden Seitenplatten 3,4 mittels Bolzen 13 starr befestigt sind. Jede zusätzliche Platte 11, 12 weist seitens der zugehörigen Platte 3,4 eine Aussparung auf, die mit der zuletzt genannten Platte 3,4 eine Luftkammer 14,15 bildet. In den Platten 3,4 sind Kanäle 16, 17 für die Druckluftzuführung über die entsprechenden Luftkammern 14, 15 in die Formkammer 7 vorgesehen.In the present exemplary embodiment, the device is provided with two additional plates 11, 12 which are rigidly fastened from the outside to the fixed side plates 3, 4 by means of bolts 13. Each additional plate 11, 12 has a recess on the part of the associated plate 3, 4, which forms an air chamber 14, 15 with the last-mentioned plate 3, 4. Channels 16, 17 are provided in the plates 3, 4 for the compressed air supply via the corresponding air chambers 14, 15 into the molding chamber 7.

Die zwei einander gegenüberliegenden Platten 5,6 (Fig.1) sind hin- und hergehend bewegbar angeordnet, wobei jede von ihnen mit eine Kolbenstange 18 eines Hydraulikzylinders (in Fig. nicht dargestellt ) verbunden ist.The two opposing plates 5, 6 (FIG. 1) are arranged such that they can move back and forth, each of them being connected to a piston rod 18 of a hydraulic cylinder (not shown in FIG. 1).

In jeder bewegbaren Platte 5,6 sind jeweils ein Hohlraum 19,20 und Kanäle 21, 22 für den Luftdurchgang über den entsprechenden Hohlraum 19,20 ausgeführt. In der Platte 2, welche gegenüber der Platte 1 feststehend angeordnet ist, ist ein Schlitz 23 für die Formstoffzuführung in die Formkammer 7 vorgesehen, wobei der Formstoff in den Schlitz 23 aus einem Blasbehälter (in den Fig. nicht dargestellt ) zugeführt wird.A cavity 19, 20 and channels 21, 22 are provided in each movable plate 5, 6 for the passage of air through the corresponding cavity 19, 20. In the plate 2, which is arranged fixedly opposite the plate 1, a slot 23 is provided for the molding material feed into the molding chamber 7, the molding material being fed into the slot 23 from a blow container (not shown in the figures).

In der Formkammer 7 sind zwei Modellplatten 24, 25 untergebracht, die mittels Bolzen 26 an den feststehenden Platten 5,6 starr montiert sind. Jede Modellplatte 24, 25 weist jeweils Kanäle 27, 28 für den Luftdurchgang auf, die koaxial mit den Kanälen 21, 22 verlaufen. An den Modellplatten 24, 25 (Fig.2) sind mittels Bolzen 29 jeweils Modelle 30, 31 befestigt. In jedem Modell 30,31 ist jeweils ein Kanal 32, 33 koaxial mit dem zugehörigen Kanal 28,27 der entsprechenden Modellplatte 24, 25 vorgesehen.In the molding chamber 7, two model plates 24, 25 are accommodated, which are rigidly mounted on the fixed plates 5, 6 by means of bolts 26. Each model plate 24, 25 has channels 27, 28 for the passage of air, which run coaxially with the channels 21, 22. Models 30, 31 are each fastened to the model plates 24, 25 (FIG. 2) by means of bolts 29. In each model 30, 31 a channel 32, 33 is provided coaxially with the associated channel 28, 27 of the corresponding model plate 24, 25.

Das Mittel 9 (Fig.1) für eine wiederholbare Verbindung der Druckluftquelle 8 mit der Formkammer 7 ist als ein Hahn 34 und Rohrleitungen 35, 36 ausgeführt, die mit den Hohlräumen 19, 20 in Verbindung stehen. An den Hahn 34 ist das System 10 zur Luftabführung aus der Formkammer 7 angeschlossen, das in Form einer Vakuumpumpe 37 ausgebildet ist, welche mit einem Vakuumbehälter 38 verbunden ist. Das System 10 zur Luftabführung ist mittels einer Rohrleitung 39 mit dem Hahn 34 wiederholbar verbunden. Der Hahn 34 ist so ausgeführt, daß er die Formkammer 7 mit der Druckluftquelle 8 oder mit dem System 10 zur Luftabführung periodisch verbinden kann. Jede zusätzliche Platte 11, 12 (Fig.2) ist mit einem Mittel 40 zur Druckluftzuführung in die entsprechende Luftkammer 14, 15 versehen. Das Mittel 40 stellt einen Druckluftbehälter 41 dar, der mit einem Ventil 42 und mittels einer Rohrleitung 43 mit den entsprechenden Luftkammern 14, 15 verbunden ist.The means 9 (FIG. 1) for a repeatable connection of the compressed air source 8 to the molding chamber 7 is designed as a valve 34 and pipes 35, 36 which are connected to the cavities 19, 20. The system 10 for discharging air from the molding chamber 7 is connected to the tap 34 and is designed in the form of a vacuum pump 37 which is connected to a vacuum container 38. The system 10 for air discharge is repeatedly connected to the tap 34 by means of a pipeline 39. The valve 34 is designed so that it can periodically connect the molding chamber 7 to the compressed air source 8 or to the system 10 for air discharge. Each additional plate 11, 12 (FIG. 2) is provided with a means 40 for supplying compressed air to the corresponding air chamber 14, 15. The means 40 represents a compressed air container 41 which is connected to a valve 42 and by means of a pipe 43 to the corresponding air chambers 14, 15.

Die erfindungsgemäße Vorrichtung zur Durchführung des Verfahrens zur Herstellung von einmalig verwendbaren Gießformen hat folgende Wirkungsweise.The device according to the invention for carrying out the method for producing disposable casting molds has the following mode of action.

Mittels des Hahnes 34 (Fig.1) werden die Hohlräume 19, 20 über die Rohrleitungen 35, 36 mit dem System 10 zur Luftabführung in Verbindung gesetzt; dabei wird ein Druckgefälle zwischen den Hohlräumen 19, 20 und der Formkammer 7 erzeugt, wodurch die Luft aus der Formkammer 7 über die Kanäle 27, 28 und 21, 22 in einer zu den Modellplatten 24, 25 senkrecht verlaufenden Richtung abgeführt wird. Eine Luftabführung in einer zu den Modellen 24, 25 senkrecht verlaufenden Richtung ist notwendig, um in der Formkammer 7 stabile Luftströme zu erzeugen, die senkrecht zu den Modellplatten 24, 25 gerichtet sind. Da die Luft hier ein träges Medium darstellt, ist für die Erzeugung von stabilen Luftströmen der erforderlichen Ausrichtung eine Zeitspanne erforderlich, d.h., mit der Luftabführung muß man vor der Formstoffzuführung in die Formkammer 7 beginnen. Im vorliegenden Beispiel wird die Luftabführung aus der Formkammer 0,5 s vor dem Beginn der Formstoffzuführung durchgeführt. Im allgemeinen soll diese Zeitspanne in einem Bereich von 0,1 bis 1 s liegen weil es in einer kürzeren Zeitspanne als 0,l s nicht dazu kommt, daß stabile und senkrecht zu den Modellplatten gerichtete Luftströme entstehen, und weil es unwirtschaftlich ist, die Luft innerhalb einer Zeit von mehr als 1 s abzuführen, da sich die Strome bis dann bereits zuverlässig ausgestaltet haben und die Energie für die Luftabführung unnütz verbraucht wird. Außerdem verlängert sich die Gesamtdauer des Zyklus für die Herstellung einer Gießform, wodurch die Leistung der Vorrichtung herabgesetzt wird.The cavities 19, 20 are connected to the system 10 for air removal via the pipes 35, 36 by means of the cock 34 (FIG. 1); a pressure gradient is generated between the cavities 19, 20 and the mold chamber 7, as a result of which the air is discharged from the mold chamber 7 via the channels 27, 28 and 21, 22 in a direction running perpendicular to the model plates 24, 25. An air discharge in a direction perpendicular to the models 24, 25 is necessary in order to generate stable air flows in the molding chamber 7, which are directed perpendicular to the model plates 24, 25. Since the air here is an inert medium, a period of time is required for the generation of stable air flows of the required orientation, i.e. the air must be removed before the molding material 7 is fed into the molding chamber 7. In the present example, the air is removed from the molding chamber 0.5 s before the molding material is started. In general, this time period should be in the range of 0.1 to 1 s because it does not occur in a shorter time period than 0.1 s that stable and perpendicular air streams are generated, and because it is uneconomical to keep the air inside of a time of more than 1 s, since the currents have already developed reliably by then and the energy for the air discharge is used uselessly. In addition, the overall cycle time for the manufacture of a mold is extended, reducing the performance of the device.

Nachdem sich die Luftströme, die sich in Richtung zu den Modellplatten 24, 25 hin senkrecht zu diesen bewegen, zuverlässig ausgestaltet haben, wird nach Verlauf der genannten Zeitspanne (0,5 s) durch den Schlitz 23 im Luftstrom ein Formstoff in die Formkammer 7 in einer zu den Modellplatten 24, 25 parallelverlaufenden Richtung zugeführt. Die sich im Luftstrom parallel zu den Modellplatten 24, 25 bewegenden Formstoffteilchen werden unter Einwirkung der sich in Richtung zu den Modellplatten 24, 25 hin senkrecht bewegenden Luftströme in Richtung zu diesen Modellplatten 24, 25 hin befördert, wobei sie die schmalen tiefen Aussparungen der Modelle 30, 31 ausfüllen. Um eine solche Bewegung der Formstoffteilchen während des gesamten Prozesses des Ausfüllens der Formkammer 7 zu gewährleisten, muß man die Luftabführung in der genannten Richtung vor der Beendigung der Formstoffzuführung in die Formkammer 7 vornehmen.After the air streams, which move in the direction of the model plates 24, 25 perpendicular to them, have been reliably configured, a molding material is passed through the slot 23 in the air stream into the molding chamber 7 in after the time period mentioned (0.5 s) in a direction parallel to the model plates 24, 25. The molding material particles moving parallel to the model plates 24, 25 in the air flow become in the direction of the latter under the action of the air flows moving vertically in the direction of the model plates 24, 25 Model plates 24, 25 transported there, filling the narrow deep recesses of the models 30, 31. In order to ensure such a movement of the molding material particles during the entire process of filling the molding chamber 7, one has to carry out the air discharge in the mentioned direction before the molding material supply into the molding chamber 7 is terminated.

Nach einer Zeitspanne, welche etwa 8 bis 60% der Dauer der Formstoffzuführung beträgt, wird eine Vorverdichtung des Formstoffes durch die zuzuführende Druckluft durchgeführt. Im vorliegenden Fall wird diese Zeitspanne gleich 10% der Dauer der Formstoffzuführung gewählt. Die Druckluft wird über die Rohrleitungen 43 (Fig.2) in die Luftkammern 14, 15 zugeführt, und aus diesen dann über die Kanäle 16, 17 in die Formkammer 7 in einer zu den Modellplatten 24, 25 parallelliegenden Richtung weitergeleitet. Die Druckluft wird unter einem höheren Druck als der für die Formstoffzuführung verwendete Luftdruck zugeführt, wobei die Druckluftzuführung in gegenläufigen Strömen über zwei zusätzliche Platten 11, 12 vorgenommen wird.After a period of time which is approximately 8 to 60% of the duration of the molding material supply, the molding material is precompressed by the compressed air to be supplied. In the present case, this time period is selected to be 10% of the duration of the molding material supply. The compressed air is fed into the air chambers 14, 15 via the pipelines 43 (FIG. 2), and from there is then passed on via the channels 16, 17 into the molding chamber 7 in a direction parallel to the model plates 24, 25. The compressed air is supplied at a higher pressure than the air pressure used for the molding material supply, the compressed air supply being carried out in opposite flows via two additional plates 11, 12.

Ist nur eine zusätzliche Platte in der Vorrichtung vorhanden, was vorteilhaft ist, wenn die Formkammer einen geringen Inhalt hat, wird die Druckluft in einem Strom zugeführt, der parallel zu den Modellplatten gerichtet ist.If there is only one additional plate in the device, which is advantageous if the molding chamber has a low content, the compressed air is supplied in a stream which is directed parallel to the model plates.

Es ist auch eine zweiseitige Druckluftzuführung (in gegenläufigen Strömen) in Formkammern eines geringen Inhaltes wie auch eine einseitige Druckluftzuführung (in einem Strom) in großvolumige Formkammern möglich. Im letzten Fall müssen die Querschnittsflächen der Mittel 40 für die Druckluftzuführung vergrößert und der Druck der Druckluft erhöht werden.A two-sided compressed air supply (in opposite flows) in mold chambers of low content as well as a one-sided compressed air supply (in one flow) in large-volume mold chambers are also possible. In the latter case, the cross-sectional areas of the means 40 for the compressed air supply must be increased and the pressure of the compressed air increased.

Die Druckluft wird in die Formkammer 7 in einer zu den Modellplatten 24, 25 parallelliegenden Richtung zugeführt, weil die sich in der genannten Richtung bewegenden Druckluftströme mit Luftströmen zusammenwirken, welche sich in Richtung zu den Modellplatten 24, 25 hin senkrecht zu diesen bewegen und eine Verdichtung des Formstoffes in schmalen tiefen Aussparungen der Modelle 30, 31 sowie eine gleichmäßige Verdichtung des Formstoffes über das Volumen der Gießform mit Ausnahme der Zonen an den Platten gewährleisten, über deren Kanäle 16, 17 in die Kammer 7 Druckluft zugeführt wird.The compressed air is fed into the molding chamber 7 in a direction parallel to the model plates 24, 25, because the compressed air flows moving in the mentioned direction interact with air flows which move in the direction of the model plates 24, 25 perpendicular to them and ensure compression of the molding material in narrow, deep recesses of the models 30, 31 and uniform compression of the molding material over the volume of the casting mold, with the exception of the zones on the plates, over their Channels 16, 17 in the chamber 7 compressed air is supplied.

Bei einer anderen beliebigen Richtung der Druckluftzuführung entstehen in der Kammer 7 Luftströme, die den Luftströmen, welche den Formstoff in Richtung zu den Modellplatten 24, 25 hin bewegen, entgegen gerichtet sind, und folglich das Ausfüllen der schmalen tiefen Aussparungen der Modelle 30,31 mit dem Formstoff verhindern und dadurch die Qualität der Gießformen verschlechtern.In any other direction of the compressed air supply, air flows occur in the chamber 7, which are directed in the opposite direction to the air flows which move the molding material in the direction of the model plates 24, 25, and consequently also the filling in of the narrow deep recesses of the models 30, 31 prevent the molding material and thereby deteriorate the quality of the molds.

Bei der Verdichtung nimmt das Volumen des Formstoffes ab, und die in die Formkammer 7 zuführenden Luftströme verhindern das Ausfüllen der Zonen der Druckluftzuführung mit dem Formstoff; auf diese Weise entstehen neben den Platten 3,4, über deren Kanäle 16, 17 Druckluft zugeführt wird, Hohlräume und Auflockerungen, die mit dem Formstoff nur dann ausgefüllte werden können, wenn die Druckluftzuführung vor Beendigung der Formstoffzuführung in die Formkammer 7 eingestellt wird. Der Formstoff, der in die Formkammer 7 in der Zeitspanne zwischen der Beendigung der Druckluftzuführung und der Einstellung der Formstoffzuführung zugeführt wird, wird diese Hohlräume reibungslos ausfüllen und dort verdichtet werden, wobei eine gleichmäßige Verteilung der Dichte über das Volumen der gesamten Gießform gewährleistet wird. Auf diese Weise muß die Druckluft in die Formkammer 7 innerhalb einer Zeit zugeführt werden, die etwa 5 bis 30% der Dauer der Formstoffzuführung in die Formkammer 7 beträgt, d.h., die Dauer der Druckluftzuführung soll kürzer als die Dauer der Formstoffzuführung sein. Bei einer Dauer der Druckluftzuführung von weniger als 5% der Dauer der Formstoffzuführung ist der Einwirkungseffekt der Druckluft nicht ausreichend stark, und bei einer Dauer der Luftzuführung von über 30% kann der Formstoff die Hohlräume nicht ausfüllen, weil in der restlichen Zeit der Formstoffzuführung die erforderliche Formstoffmenge in die Formkammer 7 nicht gelangen wird.During the compression, the volume of the molding material decreases, and the air flows leading into the molding chamber 7 prevent the zones of the compressed air supply from being filled with the molding material; In this way, in addition to the plates 3, 4, via the channels 16, 17 of which compressed air is supplied, cavities and loosening occur which can only be filled with the molding material if the compressed air supply is stopped in the molding chamber 7 before the molding material supply has ended. The molding material that is fed into the molding chamber 7 in the period between the termination of the compressed air supply and the cessation of the molding material supply will fill these cavities smoothly and be compressed there, ensuring an even distribution of the density over the volume of the entire casting mold. In this way, the compressed air must be fed into the molding chamber 7 within a time which is approximately 5 to 30% of the duration of the molding material supply into the molding chamber 7, ie the duration of the compressed air supply should be shorter than the duration of the molding material supply. If the duration of the compressed air supply is less than 5% of the duration of the molding material supply the effect of the compressed air is not sufficiently strong, and with a duration of the air supply of more than 30%, the molding material cannot fill the cavities because the required amount of molding material will not get into the molding chamber 7 in the remaining time of the molding material supply.

Bei dem vorliegenden konkreten Ausführungsbeispiel wird die Druckluft in die Formkammer 7 innerhalb einer Zeit zugeführt, die 20% der Dauer der Zuführung des Formstoffes in einer zu den Formplatten 24, 25 parallelliegenden Richtung beträgt.In the present specific exemplary embodiment, the compressed air is fed into the molding chamber 7 within a time which is 20% of the duration of the feeding of the molding material in a direction parallel to the molding plates 24, 25.

Nachdem die Formkammer 7 mit dem Formstoff gefüllt ist, wird die Formstoffzuführung durch den Schlitz 23 (Fig.1) eingestellt, wobei gleichzeitig die Luftabführung aus der Formkammer 7 unterbrochen wird. Zu diesem Zweck werden die Hohlräume 19, 20 mittels des Hahnes 34 vom System 10 zur Luftabführung getrennt. Die Platten 5 und 6 werden gegeneinander gerückt, wobei eine endgültige Verdichtung des Formstoffes durch Pressen verwirklicht wird. Anschließend werden die Hohlräume 19, 20 mittels des Hahnes 34 mit der Druckluftquelle 8 in Verbindung gesetzt; gleichzeitig werden die Platten 5 und 6 voneinander bewegt, und die Modelle 30, 31 werden aus der Form gehoben. Die über die Kanäle 21, 22, 27, 28 zuzuführende Druckluft erzeugt Luftströme, welche sich senkrecht zu den Modellplatten 24, 25 in Richtung zu der Form hin bewegen und ein reibungsloses Ausheben der Modelle 30, 31 aus der Form gewährleisten, ohne daß dabei die hohen feinen Teile derselben brechen.After the molding chamber 7 is filled with the molding material, the molding material feed is set through the slot 23 (FIG. 1), the air discharge from the molding chamber 7 being interrupted at the same time. For this purpose, the cavities 19, 20 are separated from the system 10 for air removal by means of the cock 34. The plates 5 and 6 are moved against each other, final compression of the molding material being achieved by pressing. The cavities 19, 20 are then connected to the compressed air source 8 by means of the cock 34; at the same time the plates 5 and 6 are moved from one another and the models 30, 31 are lifted out of the mold. The compressed air to be supplied via the channels 21, 22, 27, 28 generates air currents which move perpendicularly to the model plates 24, 25 in the direction of the mold and ensure smooth lifting of the models 30, 31 from the mold, without the high fine parts of it.

Beispiel 1example 1

0,1 s vor dem Beginn der Formstoffzuführung wird die Luft aus der Formkammer in einer zu den Modellplatten senkrecht verlaufenden Richtung abgeführt, wobei die Luftabführung auch während der Formstoffzuführung fortgesetzt wird.0.1 s before the start of the molding material supply, the air is discharged from the molding chamber in a direction perpendicular to the model plates, the air removal also continuing during the molding material supply.

Der Formstoff mit einer Zusammensetzung von (Gew.%): Bentonit - 10; Stärke (Bindemittel) - 0,2; Quarzsand - -Rest, wird im Luftstrom unter einem Druck von 0,3 MPa in eine mit zwei Modellplatten versehene Formkammer in einer zu den Modellplatten parallelverlaufenden Richtung zugeführt. Der Formstoff hat folgende Festigkeitswerte: Druckfestigkeit - 0,15 MPa, Zugfestigkeit - 0,015 MPa, Feuchtigkeit - 3 bis 3,5%.The molding material with a composition of (% by weight): Bentonite - 10; Starch (binder) - 0.2; Quartz sand residue is fed in an air stream under a pressure of 0.3 MPa into a molding chamber provided with two model plates in a direction parallel to the model plates. The molding material has the following strength values: compressive strength - 0.15 MPa, tensile strength - 0.015 MPa, moisture - 3 to 3.5%.

Die Dauer der Formstoffzuführung beträgt 1 s. Dann wird eine Vorverdichtung des Formstoffes unter Einwirkung der zuzuführenden Druckluft in einer zu den Modellplatten parallel verlaufenden Richtung vorgenommen. Die Druckluft wird in gegenläufigen Strömen 0,5 s nach der Formstoffzuführung (das bedeutet 50% der Dauer der Formstoffzuführung) innerhalb von 0,2 s (20% der Dauer der Formkstoffzuführung) zugeführt.The molding material is fed for 1 s. The molding material is then pre-compressed under the action of the compressed air to be supplied in a direction running parallel to the model plates. The compressed air is supplied in opposing flows 0.5 s after the molding material supply (this means 50% of the duration of the molding material supply) within 0.2 s (20% of the duration of the molding material supply).

Anschließend wird der Formstoff durch Pressen verdichtet. Die Preßkraft beträgt 10 kp/cm² (= 98 N/cm²).The molding material is then compressed by pressing. The pressing force is 10 kp / cm² (= 98 N / cm²).

Dann wird über die Modellplatten Druckluft zugeführt, und gleichzeitig werden die Platten von der Form abgeführt und die Modelle ausgehoben.Then compressed air is supplied via the model plates, and at the same time the plates are removed from the mold and the models are lifted out.

Unter ähnlichen Bedingungen wurden 22 Versuche durchgeführt. Die Ergebnisse der Versuche sind in der Tabelle 1 zusammengefaßt.22 experiments were carried out under similar conditions. The results of the tests are summarized in Table 1.

Als Bewertungskriterium der Qualität der Verdichtung dient die Härtezahl, die mittels eines Härtemessers ermittelt wird. Die Oberflächenhärte der Form wird in Punkten 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 bestimmt, die auf dem in Fig. 3 und 4 dargestellten Schema der Gießform angegeben sind.The hardness number, which is determined using a hardness meter, serves as an evaluation criterion for the quality of the compression. The surface hardness of the mold is determined in points 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, which are given on the diagram of the mold shown in FIGS. 3 and 4.

Die Ergebnisse der Versuche werden in der Tabelle 2 angeführt.The results of the tests are shown in Table 2.

Das erfindungsgemäße Verfahren zur Herstellung von Gießformen und die Vorrichtung zu seiner Durchführung gewährleisten einen qualitätsgerechten Abdruck der Modelle an beiden Seitenflächen der Gießform und eine hohe Wirksamkeit der Produktion, welche dadurch erzielt werden, daß in einer Formkammer zweiseitige Gießformen komplizierter Gestalt bei einer bedeutenden Erweiterung der Nomenklatur der Gußteile hergestellt werden, die nach dem Verfahren zum kastenlosen horizontalen Stapelformen im automatischen Betrieb produziert werden.The method according to the invention for the production of casting molds and the device for its implementation ensure a high-quality impression of the models on both side surfaces of the casting mold and a high effectiveness of the production, which are achieved in that a mold chamber two-sided molds of complicated shape are produced with a significant expansion of the nomenclature of the castings, which are produced by the process for boxless horizontal stack molds in automatic operation.

Industrielle AnwendbarkeitIndustrial applicability

Eine besondere wirksame Anwendung kann die vorliegende Erfindung auf automatisierten Formließlinien zum kastenlosen Formen bei der Produktion von formschwierigen Gußteilen finden.

Figure imgb0001
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 The present invention can find particular effective application on automated molding lines for boxless molding in the production of difficult-to-shape castings.
Figure imgb0001
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Figure imgb0006

Claims (6)

  1. Process for the manufacture of casting moulds which can be used once, which process consists in the fact that a moulding material is fed into a moulding chamber (7), provided with a pattern plate (24), in the air flow in a direction running parallel to the pattern plate (24), the moulding material is preformed by means of supplied compressed air only after a period lasting about 8 to 60% of the duration of the moulding-material supply, and the moulding material is subsequently compacted by pressing, characterized in that the conducting-away of air from the moulding chamber (7) is carried out prior to the onset of the supply of the moulding material and during the supply thereof in a direction running perpendicular to the pattern plate (24) and is ended simultaneously with the completion of the moulding-material supply, the supply of the compressed air into the moulding chamber (7) taking place in a direction running parallel to the pattern plate (24) and being stopped prior to the completion of the moulding-material supply.
  2. Process according to Claim 1, characterized in that the conducting-away of air from the moulding chamber begins 0.1 to 1.0 s prior to the onset of the moulding-material supply.
  3. Process according to Claim 1 or 2, characterized in that the supply of the compressed air into the moulding chamber is carried out within a time amounting to 5 to 30% of the duration of the moulding-material supply.
  4. Process according to Claim 1, characterized in that the supply of the compressed air is carried out in opposing flows.
  5. Apparatus for carrying out the process for the manufacture of casting moulds which can be used once according to Claim 1, containing plates (1, 2, 3, 4, 5, 6) which are arranged in pairs, form a moulding chamber (7), and of which two side plates (3, 4) are mounted fixedly opposite one another, while two other plates (5, 6) located opposite one another are arranged so that they can be moved back and forth, there being provided in each of these plates a cavity (19, 20) and channels (21, 22) for the passage of air through the said cavity (19, 20), a slot (23) being formed in one of the further plates (1 or 2) for feeding the moulding material into the moulding chamber (7) in which a pattern plate (24) is accommodated, which is rigidly attached to one of the movable plates and has channels (28) for the passage of air, which channels are formed coaxially with the channels (22) of the said plate (6), a source of compressed air (8) and a means (9) being provided for a recurrent connection of the source of compressed air (8) to the moulding chamber (7), characterized in that the said apparatus has a system (10) for conducting air away, which system can be repeatedly connected to the moulding chamber (7), and at least one additional plate (11) which is rigidly attached externally to the fixed side plate (3) and has, on the side of the latter, a cutout which forms an air chamber (14) with the fixed plate (3), a means (40) being provided in the additional plate (11) for feeding compressed air into the air chamber (14), which means is connected to the source of compressed air (8), and channels (16) for feeding the compressed air through the air chamber (14) into the moulding chamber (7) being formed in the fixed side plate (3).
  6. Apparatus for carrying out the process for the manufacture of casting moulds which can be used once according to Claim 5, characterized in that an additional pattern plate (25) is accommodated in the moulding chamber (7), which additional pattern plate is rigidly arranged on a different movable plate (5) and has channels (27) which run coaxially with the channels (21) of the said movable plate (5).
EP90910975A 1989-06-29 1990-06-28 Method and device for making single-casting moulds Expired - Lifetime EP0432277B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
SU4705358 1989-06-29
SU894705358A RU1780917C (en) 1989-06-29 1989-06-29 Method and device for manufacturing one-time casting molds
PCT/SU1990/000170 WO1991000156A1 (en) 1989-06-29 1990-06-28 Method and device for making single-casting moulds

Publications (3)

Publication Number Publication Date
EP0432277A1 EP0432277A1 (en) 1991-06-19
EP0432277A4 EP0432277A4 (en) 1993-07-07
EP0432277B1 true EP0432277B1 (en) 1996-05-08

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EP90910975A Expired - Lifetime EP0432277B1 (en) 1989-06-29 1990-06-28 Method and device for making single-casting moulds

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US (1) US5161603A (en)
EP (1) EP0432277B1 (en)
JP (1) JPH07506296A (en)
AT (1) ATE137694T1 (en)
DE (1) DE59010317D1 (en)
DK (1) DK33891A (en)
ES (1) ES2091245T3 (en)
RU (1) RU1780917C (en)
WO (1) WO1991000156A1 (en)

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Publication number Priority date Publication date Assignee Title
DK170988B1 (en) * 1992-06-10 1996-04-15 Dansk Ind Syndikat Process and molding machine for making molds or mold parts of mold sand
US6705382B1 (en) * 1999-12-27 2004-03-16 Disa Industries A/S Method of improving the mould quality of mould-forming machine
US6668904B1 (en) * 2000-02-04 2003-12-30 Disa Industries A/S Method and apparatus for producing casting moulds or mould parts
AT413949B (en) * 2003-06-17 2006-07-15 Boehler Bleche Multilayer Gmbh DEVICE FOR CREATING MOLDING
US10589347B2 (en) * 2015-06-12 2020-03-17 Disa Industries A/S Sand moulding machine and method of producing moulds

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3293703A (en) * 1962-11-13 1966-12-27 Arthur R Taccone Vacuum molding apparatus
BE788716A (en) * 1971-09-23 1973-01-02 Dansk Ind Syndikat PROCESS FOR OPERATING AUTOMATIC MACHINES FOR MANUFACTURING MOLD PARTS AND INSTALLATION FOR IMPLEMENTING THIS PROCESS
JPS6048261B2 (en) * 1979-07-11 1985-10-26 株式会社豊田自動織機製作所 Mold making method
SU975184A1 (en) * 1981-05-26 1982-11-23 Московский автомеханический институт Method of producing single-use casting moulds
SU1060299A1 (en) * 1982-10-19 1983-12-15 Московский автомеханический институт Method of producing temporary moulds
DK294584D0 (en) * 1984-06-15 1984-06-15 Dansk Ind Syndikat PROCEDURE FOR MANUFACTURING FORM PARTS
JPS6127145A (en) * 1984-07-18 1986-02-06 Taiyo Chuki Kk High-packing molding method of drag mold in blow type automatic flaskless molding machine
DE3511283A1 (en) * 1985-03-28 1986-10-09 Dietmar Prof. Dr.-Ing. 5100 Aachen Boenisch METHOD AND DEVICE FOR COMPRESSING FOUNDRY MOLDING MATERIALS
US4620584A (en) * 1985-05-24 1986-11-04 Witt Raymond H Green sand mold filling system
US4791974A (en) * 1987-05-18 1988-12-20 Dansk Industri Syndikat A/S Method and an apparatus for producing shaped bodies from particulate material

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RU1780917C (en) 1992-12-15
DE59010317D1 (en) 1996-06-13
JPH07506296A (en) 1995-07-13
EP0432277A4 (en) 1993-07-07
US5161603A (en) 1992-11-10
WO1991000156A1 (en) 1991-01-10
ES2091245T3 (en) 1996-11-01
EP0432277A1 (en) 1991-06-19
DK33891D0 (en) 1991-02-27
DK33891A (en) 1991-04-29
ATE137694T1 (en) 1996-05-15

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