EP0650787B1 - Method for compacting foundry mould material - Google Patents

Method for compacting foundry mould material Download PDF

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Publication number
EP0650787B1
EP0650787B1 EP94116287A EP94116287A EP0650787B1 EP 0650787 B1 EP0650787 B1 EP 0650787B1 EP 94116287 A EP94116287 A EP 94116287A EP 94116287 A EP94116287 A EP 94116287A EP 0650787 B1 EP0650787 B1 EP 0650787B1
Authority
EP
European Patent Office
Prior art keywords
pressure
pressure gradient
compression
process according
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.)
Expired - Lifetime
Application number
EP94116287A
Other languages
German (de)
French (fr)
Other versions
EP0650787A1 (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
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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 compression of foundry molding material, the molding material in a molding device with a model plate with model and arranged on it a form and fill frame is introduced by means of a Pressurized gas, the pressurized gas at least for pre-compression is used.
  • EP-A-0 560 116 describes a method in which a push is divided into two successive areas is, the first area for precompression and the second is used for final compression.
  • the pressure gradient of the the first pressure surge area is smaller than that of the second and the two areas are directly connected.
  • the present Invention the object of proposing a method for Compression of foundry molding material that compacted homogeneously Molds with high hardness even with difficult models with significant differences in height of the model contour or ensures with a small edge distance.
  • 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 low Pressure gradient of approx. 3 bar / sec. elevated.
  • This first printing section merges seamlessly into a much steeper one Pressure section that has a pressure gradient of 30 bar / sec. having.
  • the subsequent printing section leads to final compression and can be e.g. pneumatic mechanical etc. respectively.
  • the first section of the Pressure increase in pre-compression improves fluidization of the filled molding material.
  • the flowability of the sand improves, so that when Subsequent second section of the pressure increase the pre-compression the molding material is improved. Since the two sections connect the pressure increase directly to one another, comes the flowability generated in the first pressure section fully benefit from the compression phase in the second printing section.
  • the molding material is in one in the model plate area State of fluidization. This makes the compaction ability especially in the narrow areas between model parts or Molding box significantly improved so that after compression obtain a significantly increased optimal root strength becomes.
  • the pressure curve according to the invention is therefore particularly for complicated ones Forms particularly suitable 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)

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 compression of foundry molding material, the molding material in a molding device with a model plate with model and arranged on it a form and fill frame is introduced by means of a Pressurized gas, the pressurized gas at least for pre-compression is used.

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

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 compacting granular Molding materials using a gas pressure surge is usually used at least one passage between the pressure space and the molding space opened suddenly by means of a valve.

Aus der DE-OS 37 40 775 ist es bekannt, eine Verdichtung mit zwei aufeinander folgenden Druckstössen herbeizuführen, wobei der erste Druckstoss der Vorverdichtung dient, und der zweite der Endverdichtung. Der Druckgradient des ersten Druckstosses ist kleiner als der des zweiten Druckstosses. Die zwei Druckstösse schliesen sich nicht unmittelbar aneinander an, sondern zwischen den beiden Stössen wird der Druck erniedrigt. From DE-OS 37 40 775 it is known to use compression bring about two successive pressure surges, whereby the first pressure surge serves for pre-compression, and the second the final compression. The pressure gradient of the first pressure surge is smaller than that of the second pressure surge. The two pressure surges do not immediately follow one another, but the pressure is reduced between the two impacts.

In der EP-A-0 560 116 wird ein Verfahren beschrieben, bei welchem ein Durckstoss in zwei aufeinanderfolgende Bereiche eingeteilt ist, wobei der erste Bereich zur Vorverdichtung und der zweite zur Endverdichtung verwendet wird. Der Druckgradient des ersten Druckstossbereiches ist kleiner als der des zweiten und die zwei Bereiche schliessen sich unmittelbar aneinander an.EP-A-0 560 116 describes a method in which a push is divided into two successive areas is, the first area for precompression and the second is used for final compression. The pressure gradient of the the first pressure surge area is smaller than that of the second and the two areas are directly connected.

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.Based on this prior art, the present Invention, the object of proposing a method for Compression of foundry molding material that compacted homogeneously Molds with high hardness even with difficult models with significant differences in height of the model contour or ensures with a small edge distance.

Diese Aufgabe wird bei einem Verfahren der eingangs genannten Art entsprechend dem kennzeichnenden Teil des Anspruchs 1 gelöst.This task will in a procedure of the type mentioned at the beginning according to the characteristic part of the Claim 1 solved.

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, studies have shown that an inventive controlled pressure surge significantly better compression values delivers than the known pressure impulses.

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 low Pressure gradient of approx. 3 bar / sec. elevated. This first printing section merges seamlessly into a much steeper one Pressure section that has a pressure gradient of 30 bar / sec. having. The subsequent printing section leads to final compression and can be e.g. pneumatic mechanical etc. respectively.

Gegenüber dem bekannten Zweistufen-Verdichtungsverfahren bestehend aus Vor-und Endverdichtung bewirkt der erste Abschnitt des Druckanstieg der Vorverdichtung eine verbesserte Fluidisierung des eingefüllten Formstoffes. Bekannterweise wird durch Fluidisierung die Fliessfähigkeit des Sandes verbessert, so dass beim anschliessenden zweiten Abschnitt des Druckanstieg die Vorverdichtung des Formstoffes verbessert wird. Da sich die zwei Abschnitte des Druckanstieges unmittelbar aneinander anschliessen, kommt die im ersten Druckabschnitt erzeugte Fliessfähigkeit der Verdichtungsphase im zweiten Druckabschnitt voll zugute.Compared to the known two-stage compression process the first section of the Pressure increase in pre-compression improves fluidization of the filled molding material. As is known through fluidization the flowability of the sand improves, so that when Subsequent second section of the pressure increase the pre-compression the molding material is improved. Since the two sections connect the pressure increase directly to one another, comes the flowability generated in the first pressure section fully benefit from the compression phase in the second printing 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 fluidity, it is desired to impact the compression on a molding material to let, which is in the optimal flow state.

Da im vorliegenden Fall der zweite Druckabschnitt des Vorverdichtungssdruckstosses sich unmittelbar dem ersten 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 precompression surge immediately the first printing section before the air comes out from the pressure in the first printing section, has left the mold space, the molding material is in one in the model plate area State of fluidization. This makes the compaction ability especially in the narrow areas between model parts or Molding box significantly improved so that after compression obtain a significantly increased optimal root strength becomes.

Der erfindungsgemässe Druckverlauf ist daher besonders für komplizierte Formen insbesondere mit tiefen Ballen geeignet.The pressure curve according to the invention is therefore particularly for complicated ones Forms particularly suitable 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 significantly improved as well as the mold transport within of the molding plants are facilitated.

Claims (5)

  1. A process for compressing foundry moulding material, where the moulding material is introduced into a moulding device with a pattern plate with a pattern frame and a forming and filling frame arranged thereon, by means of a compressed gas, the compressed gas being used at least for preliminary compression, characterised in that the pressure surge used for preliminary compression is released with a low and than with a higher pressure gradient into the moulding chamber.
  2. A process according to claim 1, characterised in that the portion of the pressure curve produced with the higher pressure gradient follows on without interruption from the low pressure gradient phase.
  3. A process according to claim 1, characterised in that the pressure increase with a low pressure gradient is effected in a range of from 0.1 to 10 bar/sec.
  4. A process according to claim 1, characterised in that the higher pressure gradient is in a range of from 1 to 80 bar/sec.
  5. A process according to claim 4, characterised in that the higher pressure gradient is in a range of from 1 to 50 bar/sec.
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
CH3236/93 1993-10-27
CH323693 1993-10-27

Publications (2)

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

Family

ID=4251600

Family Applications (1)

Application Number Title Priority Date Filing Date
EP94116287A Expired - Lifetime EP0650787B1 (en) 1993-10-27 1994-10-15 Method for compacting foundry mould material

Country Status (11)

Country Link
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
ATE356679T1 (en) * 2000-04-13 2007-04-15 Sintokogio Ltd COMPRESSION METHOD FOR CASTING SAND AND DEVICE THEREOF
CN1214880C (en) * 2000-04-21 2005-08-17 新东工业株式会社 Die molding machine and pattern carrier

Family Cites Families (5)

* 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.
CH672270A5 (en) * 1986-12-17 1989-11-15 Fischer Ag Georg
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.
CH686412A5 (en) * 1992-03-10 1996-03-29 Fischer Georg Giessereianlagen A method of compacting molding sand for molds.

Also Published As

Publication number Publication date
HU9403103D0 (en) 1994-12-28
ES2119044T3 (en) 1998-10-01
DE59406076D1 (en) 1998-07-02
KR950011003A (en) 1995-05-15
JPH07164105A (en) 1995-06-27
BR9404258A (en) 1995-07-04
RU94039291A (en) 1996-08-27
CZ238594A3 (en) 1995-08-16
US5601777A (en) 1997-02-11
EP0650787A1 (en) 1995-05-03
DK0650787T3 (en) 1999-03-22
HUT69252A (en) 1995-08-28

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