EP0344225B1 - Process for manufacturing a casting mould - Google Patents
Process for manufacturing a casting mould Download PDFInfo
- Publication number
- EP0344225B1 EP0344225B1 EP88907601A EP88907601A EP0344225B1 EP 0344225 B1 EP0344225 B1 EP 0344225B1 EP 88907601 A EP88907601 A EP 88907601A EP 88907601 A EP88907601 A EP 88907601A EP 0344225 B1 EP0344225 B1 EP 0344225B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- material mixture
- casting
- water
- moulding material
- casting mould
- 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
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Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22C—FOUNDRY MOULDING
- B22C1/00—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds
- B22C1/16—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by the use of binding agents; Mixtures of binding agents
- B22C1/162—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by the use of binding agents; Mixtures of binding agents use of a gaseous treating agent for hardening the binder
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22C—FOUNDRY MOULDING
- B22C9/00—Moulds or cores; Moulding processes
- B22C9/12—Treating moulds or cores, e.g. drying, hardening
Definitions
- the invention relates to a method for producing a casting mold in the manner of a block mold from a granular molding material mixture for pouring preferably coreless castings, a molding material mixture containing quartz sand and a predetermined amount of water glass being introduced into a molding box containing the model and the molding material mixture being introduced during a certain time with CO2 gas is applied.
- the known molding processes such as Shaking, pressing, blowing, shooting or high pressure pressing have in common that molding materials with additives such as e.g. Bentonite can be used. Since the old sand accumulated when the castings are emptied is reused and must therefore be processed accordingly, any type of additive in the molding material - for the process of reprocessing - is problematic.
- a method of the type mentioned is known from GB-A-745 402. According to this, in order to shorten the hardening time or to accelerate the removal of water, a water-soluble, emulsifiable or saponifiable substance, which serves to bind the water formed during hardening, is additionally added to the molding material mixture. This addition of this substance can increase the strength of the casting mold in accordance with the removal of water, which, however, is only comparatively small.
- FR-A-1 322 512 is also next to quartz sand only used as a binder water glass in casting mold manufacture, however, no CO2 exposure is intended here, but only a heat exposure by dielectric high-frequency exposure by practically insulating, ie made of plastic, the green mold-containing mold boxes are guided between two capacitor plates connected to a high-frequency generator.
- the object of the present invention is to propose a method for producing a casting mold from a granular molding material mixture, in which there are no reactive additives to the liquid metal.
- the casting mold produced by the process should be environmentally friendly and easy to process.
- quartz sand is first mixed with water glass, the water glass serving as a binder. Fumigation with carbonic acid rapidly solidifies the molding material. Silica gels are formed with the elimination of water, which firmly bind the quartz sand.
- the bonding introduced by the carbon dioxide allows the mold to be separated from the model without damage.
- the pourable final hardness is adjusted by exposure to microwaves.
- a casting mold 1 according to the invention has molded parts 2 and 3 modeled on both sides with cavities already molded. Several such molds are produced for series production, two of them each be pushed together in a block so that a complete casting cavity is created. This not only brings optimal use of the shape, but also leads to economical series production.
- Directional solidification can be achieved by providing cooling bores 4 which can be supplied with air as the cooling medium.
- Sand with the designation M36 and 5% was used for the mold production.
- Water glass e.g. Kernex
- the molds were placed in the microwave oven. The oven was operated at a power level corresponding to an energy output of about 700 watts for 5 minutes. Loss of water has increased the dimensional stability.
- the mold After the casting and solidification of the metal in the mold, the mold can be dissolved in water. The castings are then cleaned by blasting. The lowering of the mold in the water can be carried out in various stages, which means that a change in the structure of the casting can be avoided or set in a targeted manner.
- the sand detached in the water is fed to the reprocessing after drying, whereby this reprocessing can be carried out in an environmentally friendly process without additional manipulations, since no additives are used, e.g. Bentonite, coal dust or other additives.
- the casting mold produced in the proposed manner has a very high strength, there is no feeder for gray-rigid materials.
- the cast body cast in this form has a good surface due to the low penetration.
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Materials Engineering (AREA)
- Mold Materials And Core Materials (AREA)
- Molds, Cores, And Manufacturing Methods Thereof (AREA)
- Moulds For Moulding Plastics Or The Like (AREA)
Abstract
Description
Die Erfindung betrifft ein Verfahren zur Herstellung einer Gießform in der Art einer Blockform aus einer körnigen Formstoffmischung zum Abgießen von vorzugsweise kernlosen Gußstücken, wobei eine Formstoffmischung enthaltend Quarzsand und eine vorbestimmte Menge Wasserglas in einen Formkasten, der das Modell enthält, eingebracht und die Formstoffmischung während einer bestimmten Zeit mit CO₂-Gas beaufschlagt wird.The invention relates to a method for producing a casting mold in the manner of a block mold from a granular molding material mixture for pouring preferably coreless castings, a molding material mixture containing quartz sand and a predetermined amount of water glass being introduced into a molding box containing the model and the molding material mixture being introduced during a certain time with CO₂ gas is applied.
Es gibt verschiedene Verfahren zur Herstellung von Gießformen aus einem körnigen Formstoffgemisch. Um eine Formstoffmasse zum Abgießen von flüssigem Metall verwendbar zu machen, muß zunächst eine Verdichtung der Formstoffmasse erfolgen. Die Gießform muß ausreichende Festigkeitswerte aufweisen, um dem ferrostatischen Druck der flüssigen Metallschmelze standzuhalten.There are various methods for producing casting molds from a granular molding material mixture. In order to make a molding material usable for pouring liquid metal, the molding material must first be compressed. The mold must have sufficient strength values to withstand the ferrostatic pressure of the molten metal.
Den bekannten Formverfahren wie z.B. Rütteln, Pressen, Blasen, Schießen oder Hochdruckpressen ist gemeinsam, daß Formstoffe mit Zusatzstoffen wie z.B. Bentonit verwendet werden. Da der beim Ausleeren der Gußstücke anfallende Altsand wieder verwendet wird und deshalb entsprechend aufbereitet werden muß, ist jede Art von Zusatz im Formstoff - für den Vorgang der Wiederaufbereitung - problematisch.The known molding processes such as Shaking, pressing, blowing, shooting or high pressure pressing have in common that molding materials with additives such as e.g. Bentonite can be used. Since the old sand accumulated when the castings are emptied is reused and must therefore be processed accordingly, any type of additive in the molding material - for the process of reprocessing - is problematic.
Ein Verfahren der eingangs genannten Art ist aus der GB-A-745 402 bekannt. Hiernach ist zur Verkürzung der Aushärtungszeit bzw. zur Beschleunigung des Wasserentzugs vorgesehen, zusätzlich eine wasserlösliche, emulgier- oder verseifbare Substanz, die zum Binden des beim Aushärten entstehenden Wassers dient, der Formstoffmischung zuzufügen. Dieser Zusatz dieser Substanz kann die Festigkeit der Gießform entsprechend dem Wasserentzug, der jedoch nur vergleichsmäßig gering ausfällt, erhöhen.A method of the type mentioned is known from GB-A-745 402. According to this, in order to shorten the hardening time or to accelerate the removal of water, a water-soluble, emulsifiable or saponifiable substance, which serves to bind the water formed during hardening, is additionally added to the molding material mixture. This addition of this substance can increase the strength of the casting mold in accordance with the removal of water, which, however, is only comparatively small.
Außerdem wird nach der FR-A-1 322 512 ebenfalls neben Quarzsand nur als Bindemittel dienendes Wasserglas bei der Gießformherstellung verwendet, jedoch ist hierbei keine CO₂-Beaufschlagung beabsichtigt, sondern lediglich eine Wärmebeaufschlagung durch dielektrische Hochfrequenzbeaufschlagung, indem praktisch isolierende, d.h. aus Kunststoff bestehende, die Grünform enthaltende Formkästen zwischen zwei an einen Hochfrequenzgenerator angeschlossene Kondensatorplatten geführt werden.In addition, according to FR-A-1 322 512 is also next to quartz sand only used as a binder water glass in casting mold manufacture, however, no CO₂ exposure is intended here, but only a heat exposure by dielectric high-frequency exposure by practically insulating, ie made of plastic, the green mold-containing mold boxes are guided between two capacitor plates connected to a high-frequency generator.
Aufgabe der vorliegenden Erfindung ist es, ein Verfahren zur Herstellung einer Giessform aus einer körnigen Formstoffmischung vorzuschlagen, bei dem keine reaktiven Zusätze gegenüber dem flüssigen Metall vorhanden sind. Die nach dem Verfahren hergestellte Giessform soll umweltschonend und auf einfache Art und Weise aufbereitet werden können.The object of the present invention is to propose a method for producing a casting mold from a granular molding material mixture, in which there are no reactive additives to the liquid metal. The casting mold produced by the process should be environmentally friendly and easy to process.
Diese Aufgabe wird erfindungsgemäss durch den kennzeichnenden Teil des Anspruches 1 gelöst.According to the invention, this object is achieved by the characterizing part of
Weitere vorteilhafte Ausgestaltungen gehen aus den abhängigen Ansprüchen 2 und 3 hervor.Further advantageous embodiments emerge from the
Zur Herstellung einer Giessform in der Art einer Blockform aus einer körnigen Formstoffmasse wird zunächst einmal feinkörniger Quarzsand mit Wasserglas gemischt, wobei das Wasserglas als Binder dient. Durch Begasung mit Kohlensäure erfolgt eine rasche Erstarrung der Formstoffmasse. Es bilden sich unter Wasserabspaltung Kieselsäuregele, die den Quarzsand fest abbinden.To produce a casting mold in the manner of a block mold from a granular molding material mixture, fine-grained quartz sand is first mixed with water glass, the water glass serving as a binder. Fumigation with carbonic acid rapidly solidifies the molding material. Silica gels are formed with the elimination of water, which firmly bind the quartz sand.
Die durch die Kohlensäure eingeleitete Abbindung gestattet die Form vom Modell beschädigungsfrei zu trennen.The bonding introduced by the carbon dioxide allows the mold to be separated from the model without damage.
Die giessfähige Endhärte wird durch Mikrowelleneinwirkung eingestellt.The pourable final hardness is adjusted by exposure to microwaves.
Anhand der Figur wird eine bevorzugte Ausführungsform näher beschrieben.A preferred embodiment is described in more detail with reference to the figure.
Eine erfindungsgemässe Giessform 1 weist zweiseitig modellierte Formteile 2 und 3 auf mit bereits eingeformten Hohlräumen. Für die Serienfertigung werden mehrere solche Giessformen hergestellt, von denen jeweils je zwei zu einem Block zusammengeschoben werden, so dass ein kompletter Giesshohlraum entsteht. Dies bringt nicht nur eine optimale Ausnützung der Form mit sich, sondern führt auch zu einer wirtschaftlichen Serienfertigung.A
Durch Anbringung von Kühlbohrungen 4, die mit Luft als Kühlmedium beaufschlagt werden können, kann eine gerichtete Erstarrung bewerkstelligt werden.Directional solidification can be achieved by providing
Für die Formherstellung wurde Sand mit der Bezeichnung M36 und 5 %. Wasserglas (z. B. Kernex) verwendet. Nach Begasung mit Kohlensäure wurden die Formen in den Mikrowellenofen gelegt. Während 5 Min. wurde der Ofen mit einer Leistungsstufe gefahren, die einer Energieabgabe von etwa 700 Watt entspricht. Durch Wasserverlust ist eine Erhöhung der Formfestigkeit eingetreten.Sand with the designation M36 and 5% was used for the mold production. Water glass (e.g. Kernex) is used. After carbonation, the molds were placed in the microwave oven. The oven was operated at a power level corresponding to an energy output of about 700 watts for 5 minutes. Loss of water has increased the dimensional stability.
Nach dem Abguss und dem Erstarren des Metalls in der Form kann die Form im Wasser aufgelöst werden. Die Gussstücke werden dann durch Strahlen fertiggeputzt. Das Absenken der Form im Wasser kann in verschiedenen Stufen gesteuert erfolgen, womit eine Gefügeveränderung im Gussstück sicher vermieden oder auch gezielt eingestellt werden kann.After the casting and solidification of the metal in the mold, the mold can be dissolved in water. The castings are then cleaned by blasting. The lowering of the mold in the water can be carried out in various stages, which means that a change in the structure of the casting can be avoided or set in a targeted manner.
Der im Wasser abgelöste Sand wird nach dem Trocknen der erneuten Aufbereitung zugeführt, wobei diese Aufbereitung ohne zusätzliche Manipulationen in einem umweltschonenden Verfahren erfolgen kann, da keine Zusatzstoffe verwendet werden wie z.B. Bentonit, Kohlenstaub oder andere Additiven.The sand detached in the water is fed to the reprocessing after drying, whereby this reprocessing can be carried out in an environmentally friendly process without additional manipulations, since no additives are used, e.g. Bentonite, coal dust or other additives.
Da die auf die vorgeschlagene Art und Weise hergestellte Giessform eine sehr hohe Festigkeit aufweist, ist ein speiserloses Giessen für grauerstarrende Werkstoffe gegeben. Der in dieser Form abgegossene Gusskörper weist eine gute Oberfläche als Folge der geringen Penetration auf.Since the casting mold produced in the proposed manner has a very high strength, there is no feeder for gray-rigid materials. The cast body cast in this form has a good surface due to the low penetration.
Die erhaltenen genauen Abgüsse erfordern keine wesentliche Nachbehandlung.The exact casts obtained do not require any significant post-treatment.
Die Vorteile der nach dem beschriebenen Verfahren hergestellten Form sind vielfältig:
- Verfahren ist voll automatisierbar.
- Da nur anorganische Stoffe, CO₂, Wasserglas, SiO₂ (Quarzsand verwendet werden, ist das Verfahren physiologisch unbedenklich. Während und nach Abguss entstehen keine störenden Geruchsentwicklungen.
- Das Auspacken erfolgt im Wasser. Dadurch werden Staubbelästigungen vermieden.
- Umweltschonende, verlustarme Sandaufbereitung.
- Geringer Energieaufwand.
- The process can be fully automated.
- Since only inorganic substances, CO₂, water glass, SiO₂ (quartz sand are used), the process is physiologically harmless.
- Unpacking is done in water. This avoids dust nuisance.
- Environmentally friendly, low-loss sand preparation.
- Low energy consumption.
Claims (3)
- Process for producing a casting mould in the manner of an ingot mould from a granular moulding material mixture, for casting preferably coreless pieces, wherein a moulding material mixture containing quartz sand and a specific amount of water glass is introduced into a moulding box which contains the pattern, and the moulding material mixture is subjected to CO₂ gas action, characterized in that the moulding material mixture consists only of quartz sand and water glass and after the CO₂ action the casting mould formed from the moulding material mixture is hardened in a microwave oven under the effect of microwaves.
- Casting mould produced according to the process of claim 1, characterized in that it is soluble in water.
- Use of the casting mould according to claim 2 for casting crankshafts, piston rods and flywheels.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CH3608/87 | 1987-09-18 | ||
| CH3608/87A CH675973A5 (en) | 1987-09-18 | 1987-09-18 | |
| PCT/CH1988/000161 WO1989002325A1 (en) | 1987-09-18 | 1988-09-15 | Process for manufacturing a casting mould |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0344225A1 EP0344225A1 (en) | 1989-12-06 |
| EP0344225B1 true EP0344225B1 (en) | 1994-08-17 |
Family
ID=4259648
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP88907601A Expired - Lifetime EP0344225B1 (en) | 1987-09-18 | 1988-09-15 | Process for manufacturing a casting mould |
Country Status (6)
| Country | Link |
|---|---|
| EP (1) | EP0344225B1 (en) |
| JP (1) | JPH02501204A (en) |
| AT (1) | ATE110016T1 (en) |
| CH (1) | CH675973A5 (en) |
| DE (1) | DE3851143D1 (en) |
| WO (1) | WO1989002325A1 (en) |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB745402A (en) * | 1952-07-09 | 1956-02-22 | Wilhelm Schmidt | Improvements in or relating to a process for the production of moulds and cores for foundry purposes |
| DE1030525B (en) * | 1952-11-13 | 1958-05-22 | Gutehoffnungshuette Sterkrade | Process for the production of molded masks |
| FR1322512A (en) * | 1962-05-02 | 1963-03-29 | Siemens Ag | Method and apparatus for constructing dimensionally stable foundry molds and cores from molding sands and binders |
| FR1517167A (en) * | 1967-03-09 | 1968-03-15 | Usines Belges Vynckier Freres | Process for curing a sand-based composition and installation for carrying out this process |
| JPS58100938A (en) * | 1981-12-11 | 1983-06-15 | Sintokogio Ltd | Molding method for mold |
-
1987
- 1987-09-18 CH CH3608/87A patent/CH675973A5/de not_active IP Right Cessation
-
1988
- 1988-09-15 JP JP63507037A patent/JPH02501204A/en active Pending
- 1988-09-15 AT AT88907601T patent/ATE110016T1/en not_active IP Right Cessation
- 1988-09-15 EP EP88907601A patent/EP0344225B1/en not_active Expired - Lifetime
- 1988-09-15 WO PCT/CH1988/000161 patent/WO1989002325A1/en active IP Right Grant
- 1988-09-15 DE DE3851143T patent/DE3851143D1/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH02501204A (en) | 1990-04-26 |
| ATE110016T1 (en) | 1994-09-15 |
| WO1989002325A1 (en) | 1989-03-23 |
| CH675973A5 (en) | 1990-11-30 |
| DE3851143D1 (en) | 1994-09-22 |
| EP0344225A1 (en) | 1989-12-06 |
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