EP0650787A1 - Method for compacting foundry mould material - Google Patents

Method for compacting foundry mould material Download PDF

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Publication number
EP0650787A1
EP0650787A1 EP94116287A EP94116287A EP0650787A1 EP 0650787 A1 EP0650787 A1 EP 0650787A1 EP 94116287 A EP94116287 A EP 94116287A EP 94116287 A EP94116287 A EP 94116287A EP 0650787 A1 EP0650787 A1 EP 0650787A1
Authority
EP
European Patent Office
Prior art keywords
pressure
pressure gradient
molding
compression
sec
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP94116287A
Other languages
German (de)
French (fr)
Other versions
EP0650787B1 (en
Inventor
Kurt Fischer
Hans Riester
Hans Leutwiler
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Georg Fischer Giessereianlagen AG
Original Assignee
Georg Fischer Giessereianlagen AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Georg Fischer Giessereianlagen AG filed Critical Georg Fischer Giessereianlagen AG
Publication of EP0650787A1 publication Critical patent/EP0650787A1/en
Application granted granted Critical
Publication of EP0650787B1 publication Critical patent/EP0650787B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C9/00—Moulds or cores; Moulding processes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C15/00—Moulding machines characterised by the compacting mechanism; Accessories therefor
    • 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 present invention relates to a method for compressing foundry molding material, the molding material being introduced into a molding device with a model plate with a model and a molding and filling frame arranged thereon, by means of a compressed gas, the compressed gas being used at least for precompression.
  • the present invention is based on the object of proposing a method for compacting foundry molding material which ensures homogeneously compacted molds with high hardness, even in the case of models which are difficult in terms of shape, with significant differences in height of the model contour or with a small edge distance.
  • This object is achieved according to the invention in that the pre-compression surge is generated with two differently high pressure gradients.
  • a pressure curve according to the invention during the compression process is described and explained in more detail.
  • the pressure in the molding space is controlled with a low pressure gradient of approximately 3 bar / sec. elevated.
  • This first pressure section merges seamlessly into a much steeper pressure section which has a pressure gradient of 30 bar / sec. having.
  • the subsequent printing section leads to the final compression and can e.g. pneumatically mechanically etc.
  • the pressure increase preceding the known two-stage compression process causes the filled molding material to be fluidized.
  • the fluidity of the sand is improved by fluidization, so that the pre-compression of the molding material is improved in the subsequent second pressure increase. Since the increase in pressure immediately adjoins the increase in pressure, the flowability generated in the pressure section fully benefits the compression phase in the pressure section.
  • the molding material in the model plate area is in a state of fluidization. This significantly improves the compaction ability, especially in the narrow areas between model parts or molding boxes, so that after compaction has taken place, the root strength is increased significantly.
  • the pressure curve according to the invention is therefore particularly suitable for complicated shapes, particularly with deep bales.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Casting Devices For Molds (AREA)
  • Moulds For Moulding Plastics Or The Like (AREA)
  • Casting Or Compression Moulding Of Plastics Or The Like (AREA)

Abstract

The proposal is for a method of compacting foundry mould material by means of a pressurised gas, the mould material being introduced into a moulding device with a pattern plate with a pattern frame and a mould and filling frame, the pressurised gas being used at least for precompaction, the pressure surge used for precompaction being released into the mould cavity with a low and then a higher pressure gradient.

Description

Die vorliegende Erfindung betrifft ein Verfahren zum Verdichten von Giessereiformstoff, wobei der Formstoff in eine Formeinrichtung mit einer Modellplatte mit darauf angeordnete Modell- und einem Form- und Füll-Rahmen eingebracht wird, mittels eines Druckgases, wobei das Druckgas mindestens zur Vorverdichtung verwendet wird.The present invention relates to a method for compressing foundry molding material, the molding material being introduced into a molding device with a model plate with a model and a molding and filling frame arranged thereon, by means of a compressed gas, the compressed gas being used at least for precompression.

Das sogenannte Luftimpulsverfahren ist aus verschiedenen Veröffentlichungen bekannt.The so-called air pulse method is known from various publications.

Bei den heute bekannten Verfahren zum Verdichten von körnigen Formstoffen mittels eines Gasdruckstosses wird in der Regel mindestens ein Durchlass zwischen dem Druckraum und dem Formraum mittels eines Ventils schlagartig geöffnet.In the methods known today for compressing granular molding materials by means of a gas pressure surge, at least one passage between the pressure chamber and the molding chamber is opened abruptly by means of a valve.

Aus der DE-OS 37 40 775 ist es bekannt, eine Endverdichtung mit zwei aufeinander folgenden Druckstössen herbeizuführen, wobei der Druckgradient des ersten Druckstosses kleiner als der des zweiten Druckstosses ist.From DE-OS 37 40 775 it is known to bring about a final compression with two successive pressure surges, the pressure gradient of the first pressure surge being smaller than that of the second pressure surge.

Ausgehend von diesem Stand der Technik liegt der vorliegenden Erfindung die Aufgabe zugrunde, ein Verfahren vorzuschlagen zur Verdichtung von Giessereiformstoff, das homogen verdichtete Formen mit hoher Härte auch bei formtechnisch schwierigen Modellen mit wesentlichen Höhendifferenzen der Modellkontur oder mit geringem Randabstand sicherstellt.On the basis of this prior art, the present invention is based on the object of proposing a method for compacting foundry molding material which ensures homogeneously compacted molds with high hardness, even in the case of models which are difficult in terms of shape, with significant differences in height of the model contour or with a small edge distance.

Diese Aufgabe wird erfindungsgemäss dadurch gelöst, dass der Vorverdichtungsdruckstoss mit zwei unterschiedlich hohen Druckgradienten erzeugt wird.This object is achieved according to the invention in that the pre-compression surge is generated with two differently high pressure gradients.

Weitere vorteilhafte Modifikationen des Verfahrens ergeben sich aus den abhängigen Ansprüchen.Further advantageous modifications of the method result from the dependent claims.

Untersuchungen haben überraschenderweise ergeben, dass ein erfindungsgemäss gesteuerter Druckstoss wesentlich bessere Verdichtungswerte liefert als die bekannten Druckimpulse.Surprisingly, investigations have shown that a pressure surge controlled according to the invention delivers significantly better compression values than the known pressure pulses.

Ein erfindungsgemässer Druckverlauf während des Verdichtungsvorganges wird näher beschrieben und erklärt.A pressure curve according to the invention during the compression process is described and explained in more detail.

Erfindungsgemäss wird der Druck im Formraum mit einem niedrigen Druckgradient von ca. 3 bar/sec. erhöht. Dieser erste Druckabschnitt geht lückenlos über in einen wesentlich steileren Druckabschnitt, der einen Druckgradient von 30 bar/sec. aufweist. Der danach anschliessende Druckabschnitt führt zur Endverdichtung und kann beliebig z.B. pneumatisch mechanisch etc. erfolgen.According to the invention, the pressure in the molding space is controlled with a low pressure gradient of approximately 3 bar / sec. elevated. This first pressure section merges seamlessly into a much steeper pressure section which has a pressure gradient of 30 bar / sec. having. The subsequent printing section leads to the final compression and can e.g. pneumatically mechanically etc.

Der dem bekannten Zweistufen-Verdichtungsverfahren vorgeschaltete Druckanstieg bewirkt eine Fluidisierung des eingefüllten Formstoffes. Bekannterweise wird durch Fluidisierung die Fliessfähigkeit des Sandes verbessert, so dass beim anschliessenden zweiten Druckanstieg die Vorverdichtung des Formstoffes verbessert wird. Da der Druckanstieg sich unmittelbar an den Druckanstieg anschliesst, kommt die im Druckabschnitt erzeugte Fliessfähigkeit der Verdichtungsphase im Druckabschnitt voll zugute.The pressure increase preceding the known two-stage compression process causes the filled molding material to be fluidized. As is known, the fluidity of the sand is improved by fluidization, so that the pre-compression of the molding material is improved in the subsequent second pressure increase. Since the increase in pressure immediately adjoins the increase in pressure, the flowability generated in the pressure section fully benefits the compression phase in the pressure section.

Dies erklärt sich folgendermassen: Da die Verdichtungsfähigkeit mit der Fliessfähigkeit in direktem Zusammenhang steht, ist es erwünscht, den Verdichtungsstoss auf eine Formstoffmasse einwirken zu lassen, die sich im optimalen Fliesszustand befindet.This can be explained as follows: Since the compressibility is directly related to the flowability, it is desirable to allow the compression shock to act on a molding material that is in the optimal flow state.

Da im vorliegenden Fall der zweite Druckabschnitt des Vorverdichtungssdruckstosses sich unmittelbar dem Druckabschnitt anschliesst bevor die Luft, die aus der Druckeinwirkung im ersten Druckabschnitt stammt, den Formraum verlassen hat, befindet sich der Formstoff im Modellplattenbereich in einem Zustand der Fluidisierung. Dadurch wird die Verdichtungsfähigkeit gerade in den engen Bereichen zwischen Modellteilen bzw. Formkasten bedeutend verbessert, so dass nach erfolgter Verdichtung eine bedeutend erhöhte optimale Wurzelfestigkeit erhalten wird.Since, in the present case, the second pressure section of the pre-compression pressure surge immediately adjoins the pressure section before the air that comes from the pressure in the first pressure section has left the molding space, the molding material in the model plate area is in a state of fluidization. This significantly improves the compaction ability, especially in the narrow areas between model parts or molding boxes, so that after compaction has taken place, the root strength is increased significantly.

Der erfindungsgemässe Druckverlauf ist daher besonders für komplizierte Formen insbesondere mit tiefen Ballen geeignet.The pressure curve according to the invention is therefore particularly suitable for complicated shapes, particularly with deep bales.

Mit dem Einsatz dieses Verfahrens kann die Ausformbarkeit der Formen wesentlich verbessert sowie der Formen-Transport innerhalb der Formanlagen erleichtert werden.With the use of this method, the formability of the molds can be significantly improved and the mold transport within the molding systems can be facilitated.

Claims (5)

Verfahren zum Verdichten von Giessereiformstoff, wobei der Formstoff in eine Formeinrichtung mit einer Modellplatte mit darauf angeordnete Modell- und einem Form- und Füll-Rahmen eingebracht wird, mittels eines Druckgases, wobei das Druckgas mindestens zur Vorverdichtung verwendet wird, dadurch gekennzeichnet, dass der zur Vorverdichtung verwendete Druckstoss mit einem niedrigen, danach mit einem höheren Druckgradienten in den Formraum entspannt wird.Method for compressing foundry molding material, the molding material being introduced into a molding device with a model plate with a model frame and a molding and filling frame arranged thereon, by means of a compressed gas, the compressed gas being used at least for pre-compression, characterized in that the Pre-compression used pressure surge is relaxed with a low, then with a higher pressure gradient into the mold space. Verfahren nach Anspruch 1, dadurch gekennzeichnet, dass der mit höherem Druckgradient erzeugte Teil der Druckkurve lückenlos an den niedrigen Druckgradientenbereich anschliesst.A method according to claim 1, characterized in that the part of the pressure curve generated with a higher pressure gradient connects seamlessly to the low pressure gradient area. Verfahren nach Anspruch 1, dadurch gekennzeichnet, dass der Druckanstieg mit einem niedrigen Druckgradient (1a) in einem Bereich von 0,1 bis 10 bar/sec. erfolgt.A method according to claim 1, characterized in that the pressure increase with a low pressure gradient (1a) in a range from 0.1 to 10 bar / sec. he follows. Verfahren nach Anspruch 1, dadurch gekennzeichnet, dass der Druckgradient (2a) in einem Bereich von 1 bis 80 bar/sec. zur Einwirkung gebracht wird.A method according to claim 1, characterized in that the pressure gradient (2a) in a range from 1 to 80 bar / sec. is brought into effect. Verfahren nach Anspruch 4, dadurch gekennzeichnet, dass der Druckgradient (2a) in einem Bereich von 1 bis 50 bar/sec. zur Einwirkung gebracht wird.A method according to claim 4, characterized in that the pressure gradient (2a) in a range from 1 to 50 bar / sec. is brought into effect.
EP94116287A 1993-10-27 1994-10-15 Method for compacting foundry mould material Expired - Lifetime EP0650787B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CH323693 1993-10-27
CH3236/93 1993-10-27

Publications (2)

Publication Number Publication Date
EP0650787A1 true EP0650787A1 (en) 1995-05-03
EP0650787B1 EP0650787B1 (en) 1998-05-27

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EP94116287A Expired - Lifetime EP0650787B1 (en) 1993-10-27 1994-10-15 Method for compacting foundry mould material

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US (1) US5601777A (en)
EP (1) EP0650787B1 (en)
JP (1) JPH07164105A (en)
KR (1) KR950011003A (en)
BR (1) BR9404258A (en)
CZ (1) CZ238594A3 (en)
DE (1) DE59406076D1 (en)
DK (1) DK0650787T3 (en)
ES (1) ES2119044T3 (en)
HU (1) HUT69252A (en)
RU (1) RU94039291A (en)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE29925010U1 (en) * 1999-10-26 2008-09-04 Mincelco Gmbh Water glass bonded core molding material
DE60127231T2 (en) * 2000-04-13 2007-07-05 Sintokogio, Ltd., Nagoya COMPRESSION METHOD FOR GIESS SAND AND DEVICE THEREFOR
BR0106085A (en) * 2000-04-21 2002-03-05 Sintokogio Ltd Molding machine and mold conveyor used for the same

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3740775A1 (en) * 1986-12-17 1988-07-07 Fischer Ag Georg METHOD FOR COMPRESSING GRAINY MOLDS
EP0560116A1 (en) * 1992-03-10 1993-09-15 Georg Fischer Giessereianlagen Ag Process for compacting foundry moulding sand

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH666426A5 (en) * 1984-06-25 1988-07-29 Fischer Ag Georg MOLDING PLANT.
DE3836876C2 (en) * 1988-10-29 1994-06-09 Badische Maschf Gmbh Method and device for compacting foundry molding material
CH682547A5 (en) * 1990-04-20 1993-10-15 Fischer Ag Georg Method and apparatus for compressing granular molding materials.

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3740775A1 (en) * 1986-12-17 1988-07-07 Fischer Ag Georg METHOD FOR COMPRESSING GRAINY MOLDS
EP0560116A1 (en) * 1992-03-10 1993-09-15 Georg Fischer Giessereianlagen Ag Process for compacting foundry moulding sand

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
HANS RIESTER: "Eine neue Generation der Impuls-Formtechnologie", GIESSEREI 76 (1989) 15 MAI, N0. 10/11, SEITE 342-349, DüSSELDORF *

Also Published As

Publication number Publication date
HU9403103D0 (en) 1994-12-28
HUT69252A (en) 1995-08-28
RU94039291A (en) 1996-08-27
BR9404258A (en) 1995-07-04
DK0650787T3 (en) 1999-03-22
EP0650787B1 (en) 1998-05-27
ES2119044T3 (en) 1998-10-01
KR950011003A (en) 1995-05-15
DE59406076D1 (en) 1998-07-02
US5601777A (en) 1997-02-11
JPH07164105A (en) 1995-06-27
CZ238594A3 (en) 1995-08-16

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