EP0143954A2 - Procédé de fabrication de parties de moule, selon le procédé en boîte froide et appareil de moulage utilisé - Google Patents

Procédé de fabrication de parties de moule, selon le procédé en boîte froide et appareil de moulage utilisé Download PDF

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Publication number
EP0143954A2
EP0143954A2 EP84112344A EP84112344A EP0143954A2 EP 0143954 A2 EP0143954 A2 EP 0143954A2 EP 84112344 A EP84112344 A EP 84112344A EP 84112344 A EP84112344 A EP 84112344A EP 0143954 A2 EP0143954 A2 EP 0143954A2
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EP
European Patent Office
Prior art keywords
molding
molded part
mold
cold box
molding tool
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
EP84112344A
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German (de)
English (en)
Other versions
EP0143954A3 (en
EP0143954B1 (fr
Inventor
Dietmar Prof. Dr.-Ing. Boenisch
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.)
Rheinische Maschinenfabrik & Eisengiesserei Anton
Original Assignee
Rheinische Maschinenfabrik & Eisengiesserei Anton Roper & Co GmbH KG
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.)
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Publication date
Application filed by Rheinische Maschinenfabrik & Eisengiesserei Anton Roper & Co GmbH KG filed Critical Rheinische Maschinenfabrik & Eisengiesserei Anton Roper & Co GmbH KG
Publication of EP0143954A2 publication Critical patent/EP0143954A2/fr
Publication of EP0143954A3 publication Critical patent/EP0143954A3/de
Application granted granted Critical
Publication of EP0143954B1 publication Critical patent/EP0143954B1/fr
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
    • B22C9/12—Treating moulds or cores, e.g. drying, hardening
    • B22C9/123—Gas-hardening

Definitions

  • Molded parts made of synthetic resin-bonded quartz sands including the casting molds, including those with cores in them, are an important basis for the mass production of high-quality castings.
  • the different manufacturing processes differ according to the type of synthetic resin used and its catalytic hardening.
  • the catalysis is carried out either by heating or at room temperature by adding a catalyst.
  • the thermosetting manufacturing processes are known under the names of hot box, warm box and thermal shock processes. However, they are increasingly being replaced by cold hardening processes, because saving energy and facilitating workplace conditions are important advantages. Molded parts can also be produced in plastic molds.
  • Coldbox binders contain about 30 to 40% of different solvents, which are necessary for the thin liquid, a high reactivity of the binder, good moldability of the molding material mixture and sufficient strength. These high amounts of solvent lead to considerable environmental pollution during processing and casting. However, less than the amounts mentioned impair the strength, in particular of the surfaces of the molded parts. The edge strength is impaired and the molded parts become huge and crumbly overall. As a result, the coldbox process loses its usefulness. With a sufficient solvent and binder content, polyurethane-bonded molded parts have good strength immediately after their manufacture. However, they are very sensitive to moisture and lose strength in a short time at higher air humidity. However, high humidity levels are unavoidable in foundries.
  • Coldbox cores are also often treated with water sizing and also placed in wet casting molds and are therefore subject to severe moisture damage. It is particularly detrimental to the quality of the molded part that this damage progresses from the outside inwards and thus affects the particularly important molded surface first and foremost. The result is a highly undesirable strength gradient with low external but high internal strength.
  • the present invention is based on the object of improving the strength properties and the core disintegration in molded parts by the cold box process with a reduced binder content.
  • the moisture In the measure according to the invention. to refine the molding surface with a thickness of a few millimeters, the moisture However, maintaining or even strengthening the sensitivity inside the core so that the strength in the course of core storage is reduced at these points means that strength and resistance to moisture in the surface layer are increased, but are reduced in the core inside, in order in this way at the same time Improve core decay. As a result of the surface refinement, the binder content can be reduced. This measure lowers costs, reduces environmental pollution and improves core decay.
  • the process according to the invention is based on the idea that the disadvantages of the coldbox process described are due to a weakness in the crosslinking of the polyurethane molecules due to the weft and the immediately subsequent very rapid cold curing. Then the weak bonds between the molecular chains can easily be destroyed by water and the strength of the molded parts can be irreparably weakened.
  • the method according to the invention therefore aims to convert the polyurethane in the molded part surface into a highly crosslinked state and thereby to increase the strength and in particular the moisture resistance in the surface layer, but to leave the underlying sand layers in a weakly crosslinked state.
  • the surface refinement either by a slight heat shock or by a superficial increase in the Solvent content or by both measures at the same time or in close succession. Both measures improve the surface quality of cold box molded parts to a surprising extent.
  • the process according to the invention can be carried out with the greatest effectiveness after the shot and shortly before the gas hardening because the molded part has already been designed at this point in time, but the molecular mobility in the still soft molding material is still great.
  • the method according to the invention thus intervenes in a manufacturing step of the cold box method which has so far been ignored without care and as quickly as possible. Finishing measures only after hardening on the finished molded part are far less effective owing to the largely fixed fixing of the binder structures and in particular cannot be achieved with the low temperatures which characterize the process according to the invention.
  • the method according to the invention works with heated molds. Relatively low temperatures below 100 C can be used. The uniformity of heating is also of minor importance. So the same mold, e.g. B. 50 ° in places and 80 ° elsewhere, without serious quality differences become clear.
  • Metallic molds can be heated in a known manner by electrical or gas heating. More options are given by the application of hot air or by the fact that the necessary shooting, gassing and flushing air are passed through preheaters beforehand.
  • the method according to the invention is not to be confused with the conventional hotbox and warmbox methods and differs fundamentally from these.
  • These conventional processes use the heat for curing and therefore require the entire cross-section of the molded part to be warmed through. They work at significantly higher temperatures between around 150 0 and 250 ° C and require high temperature uniformity with thermostatic control.
  • the heat of the method according to the invention does not lead to hardening even in the heated surface layer.
  • the molding material remains soft and would not allow handling.
  • the process according to the invention remains a cold process in which the molding hardening is achieved unchanged by a gaseous catalyst. The method serves only to greatly improve the effectiveness of gas hardening.
  • the method according to the invention requires a holding time of approximately 20 to 90 seconds between the shot and the gas hardening. As a result, there may be a need to extend the procedure somewhat. This waiting time can, however, be shortened considerably in a further embodiment of the invention if required, if, as mentioned above, the solvent content in the molded part surface is increased. In order to achieve this, it is proposed in a further embodiment according to the invention to provide the molding tool with a thin film of solvent shortly before the shot by spraying. The injected molding material takes over the solvent and the desired surface finishing can be achieved in a shorter time.
  • the resistant and moisture-resistant molded part surfaces that can be achieved by the methods and devices according to the invention enable the use of low-solvent binders, which can now be offered for coldbox production. They are particularly recommended for light metal casting. Low-solvent coldbox binders tend to soften during storage of the parts and are also particularly sensitive to moisture. For these reasons, they could not previously be used. According to the method according to the invention, these previous disadvantages are now limited to the interior of the molded part and have an advantageous effect there because the core disintegration and also the reusability of the used sand are thereby facilitated. These advantages and the considerable advantages already offered by the possibility of lowering the binder content are offset by a slightly longer cold box process and the need to heat the molding tools.
  • the comparatively low temperatures in the method according to the invention allow the use of plastic tools.
  • To the plant Tool tempering is suitable for hot water, which can greatly simplify the process.
  • 1 denotes the upper and 2 the lower tool half. 3 indicates the division. 4 denotes the bullet, 5 the mold cavity.
  • the sharply defined synthetic resin layer is designated by 6. With 7 pipes for hot water are designated. 8 indicates the water inlet and 9 the water outlet.
  • the flexible hose connection between the two tool halves is indicated by 10.
  • 11 means the aluminum grit, which is compacted in the sand bound by synthetic resin.
  • At 12 is a heat insulating outer jacket, for. B. made of quartz sand bonded with synthetic resin.
  • 13 means the tool frame. With the molding tool according to FIG. 1, the core 14 is created, which, according to the illustration in FIG. With 19 the gate is designated. There may also be a stone through which Jon the casting melt exits after the mold cavity 21 has been filled.
  • FIG. 2 shows that not only the surface 23 of the core 14 is finished with the molding tool according to FIG. 1. This refinement in a certain layer thickness is shown by hatching 24.
  • Figure 2 shows that the molded parts 17 and 18 of the lower box and upper box are each provided with a finish, which are shown by hatching 25 and 26. It should be noted that the finishing achieved according to the invention need only be present on the surfaces of the mold parts which delimit the mold cavity 21.
EP84112344A 1983-11-23 1984-10-13 Procédé de fabrication de parties de moule, selon le procédé en boîte froide et appareil de moulage utilisé Expired - Lifetime EP0143954B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19833342225 DE3342225A1 (de) 1983-11-23 1983-11-23 Verfahren zum herstellen von formteilen nach dem coldboxverfahren sowie formteil und formwerkzeug
DE3342225 1983-11-23

Publications (3)

Publication Number Publication Date
EP0143954A2 true EP0143954A2 (fr) 1985-06-12
EP0143954A3 EP0143954A3 (en) 1988-01-20
EP0143954B1 EP0143954B1 (fr) 1990-08-01

Family

ID=6214974

Family Applications (1)

Application Number Title Priority Date Filing Date
EP84112344A Expired - Lifetime EP0143954B1 (fr) 1983-11-23 1984-10-13 Procédé de fabrication de parties de moule, selon le procédé en boîte froide et appareil de moulage utilisé

Country Status (5)

Country Link
US (1) US4664171A (fr)
EP (1) EP0143954B1 (fr)
JP (1) JPS60133948A (fr)
DE (2) DE3342225A1 (fr)
ES (1) ES8603305A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102018114700B3 (de) 2018-06-19 2019-10-24 Römheld & Moelle Eisengießerei GmbH Verwendung eines Verfahrens zur Herstellung eines Werkzeugs für die Aluminiumblech-Umformung

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH07107404B2 (ja) * 1991-04-22 1995-11-15 上西鉄工株式会社 シリンダ装置
US7001546B2 (en) * 2001-08-09 2006-02-21 G H. Tool & Mold, Inc. Method for thermostatically controlling mold temperatures
CN100453205C (zh) * 2005-07-04 2009-01-21 上海市机械制造工艺研究所有限公司 一种co2吹气硬化砂型的方法
CA2690579C (fr) * 2009-01-21 2015-06-02 Alchemy Group Of Companies Inc. Methode et appareillage de coulage a froid

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2882569A (en) * 1957-03-29 1959-04-21 Ram Inc Method and apparatus for molding and hardening articles
US4051886A (en) * 1973-08-27 1977-10-04 Liquid Carbonic Canada Ltd. Saturated liquid/vapor generating and dispensing
US4068703A (en) * 1975-09-10 1978-01-17 The Quaker Oats Company Apparatus for catalytic gassing in the manufacture of foundry cores and molds

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2619702A (en) * 1948-11-12 1952-12-02 Ram Inc Mold
US2887741A (en) * 1954-10-11 1959-05-26 Flexonics Corp Shell molding apparatus
US3550673A (en) * 1968-06-10 1970-12-29 Foundry Allied Ind Inc Polyurethane mold articles

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2882569A (en) * 1957-03-29 1959-04-21 Ram Inc Method and apparatus for molding and hardening articles
US4051886A (en) * 1973-08-27 1977-10-04 Liquid Carbonic Canada Ltd. Saturated liquid/vapor generating and dispensing
US4068703A (en) * 1975-09-10 1978-01-17 The Quaker Oats Company Apparatus for catalytic gassing in the manufacture of foundry cores and molds

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102018114700B3 (de) 2018-06-19 2019-10-24 Römheld & Moelle Eisengießerei GmbH Verwendung eines Verfahrens zur Herstellung eines Werkzeugs für die Aluminiumblech-Umformung

Also Published As

Publication number Publication date
US4664171A (en) 1987-05-12
EP0143954A3 (en) 1988-01-20
ES537860A0 (es) 1985-12-16
EP0143954B1 (fr) 1990-08-01
DE3342225A1 (de) 1985-05-30
DE3482868D1 (de) 1990-09-06
JPS60133948A (ja) 1985-07-17
ES8603305A1 (es) 1985-12-16

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