EP2432606A2 - Noyaux a base de sel dotés d'une surface traitée - Google Patents

Noyaux a base de sel dotés d'une surface traitée

Info

Publication number
EP2432606A2
EP2432606A2 EP10722051A EP10722051A EP2432606A2 EP 2432606 A2 EP2432606 A2 EP 2432606A2 EP 10722051 A EP10722051 A EP 10722051A EP 10722051 A EP10722051 A EP 10722051A EP 2432606 A2 EP2432606 A2 EP 2432606A2
Authority
EP
European Patent Office
Prior art keywords
salt
cores
water
core
layer
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.)
Withdrawn
Application number
EP10722051A
Other languages
German (de)
English (en)
Inventor
Peter Stingl
Dieter Käfer
Harald Hudler
Hans-Jürgen SCHREINER
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.)
Ceramtec GmbH
Original Assignee
Ceramtec GmbH
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 Ceramtec GmbH filed Critical Ceramtec GmbH
Publication of EP2432606A2 publication Critical patent/EP2432606A2/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C3/00—Selection of compositions for coating the surfaces of moulds, cores, or patterns
    • 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
    • B22C1/02—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by additives for special purposes, e.g. indicators, breakdown additives
    • B22C1/14—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by additives for special purposes, e.g. indicators, breakdown additives for separating the pattern from the mould
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C9/00—Moulds or cores; Moulding processes
    • B22C9/10—Cores; Manufacture or installation of cores
    • B22C9/105—Salt cores
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C33/00—Moulds or cores; Details thereof or accessories therefor
    • B29C33/44—Moulds or cores; Details thereof or accessories therefor with means for, or specially constructed to facilitate, the removal of articles, e.g. of undercut articles
    • B29C33/52—Moulds or cores; Details thereof or accessories therefor with means for, or specially constructed to facilitate, the removal of articles, e.g. of undercut articles soluble or fusible
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
    • B29C45/17—Component parts, details or accessories; Auxiliary operations
    • B29C45/40—Removing or ejecting moulded articles
    • B29C45/44—Removing or ejecting moulded articles for undercut articles
    • B29C45/4457—Removing or ejecting moulded articles for undercut articles using fusible, soluble or destructible cores

Definitions

  • the invention relates to cores and to a process for forming a layer on the surface of salt-based cores for use as cavity locators in the manufacture of metallic castings and plastic injection molded parts which have a stable and smooth surface and which are firmer without remaining Residues completely dissolve in a solvent and can therefore be completely and easily removed from the workpieces.
  • a single salt or a mixture of different salts can be used for the preparation of the cores.
  • the surface of the cores must be particularly smooth and contour-accurate.
  • the cast material must not react with the surface of a core, do not penetrate the surface and do not unclog it.
  • the cores must dissolve completely in a suitable solvent and can be easily removed without leaving any solid residue from the cavities of the workpieces.
  • the materials used for the production of the cores and the dissolving solvents should not affect the casting quality, the environment or cause any health hazards.
  • Material in the form of fibers, grains, whiskers or platelets can be added.
  • the dry-pressed core is covered with a thin layer of a ceramic slip.
  • the structure of such a core may be dissolved by the addition of a solvent, such as water, but the core only breaks down and due to the ceramic materials in the layer, the insoluble matter must be flushed out with the solvent become. With insufficient cleaning residues may remain in the cavity of the casting.
  • the object of the present invention is to produce cores of salt, each of which has a smooth surface, with which the casting material does not react and in which it does not penetrate, which have a strength required for the casting process and whose constituents are in a solvent without a residue dissolve solids.
  • the cores according to the invention consist of a salt or of a mixture of salts, to which optionally optionally completely soluble auxiliaries in the form of binders, fillers, additives and catalysts, individually or jointly, can be admixed.
  • These cores are also particularly suitable for the production of workpieces made of nonferrous metals by the die casting process, for example, aluminum, brass or copper.
  • the cores can also be used in the injection molding of plastic parts.
  • the cores can be produced, for example, by pressing, core shooting or pouring from the molten salt.
  • the cores according to the invention are composed of substances which dissolve completely in water as a preferred solvent for reasons of environmental protection and can thus be removed from the cavities of the workpieces without any residue from solids.
  • the selected grain size distribution of the core materials in particular affects the surface properties of the cores. The smaller the grain size, the smoother the surface. In general, the highest possible degree of filling is sought, which can be achieved by mixing different salts and optionally the additional substances with different distribution curves, for example by a bi- or trimodal grain distribution of the mixture.
  • the particle sizes range from 0.01 mm to 2 mm, depending on the material, the desired surface quality and contour accuracy of the workpiece to be cast.
  • a structure may appear on the surface of the cores that allows the melt to penetrate into the surface.
  • the surface of the cores is treated according to the invention completely or only on the surface exposed to the casting material such that the melt does not affect the surface of the cores and thereby also the surface of the castings.
  • a thin layer is formed on the cores. This layer is so thin that it does not change the contour of the cores and therefore their dimensions.
  • the layer is formed according to the invention in two steps.
  • a surface activation is carried out by which the surface of the cores is prepared to receive a substance to be applied in the second step, by which the pores and cavities are closed and by which the surface is smoothed and solidified.
  • Possibilities of surface activation and formation of the layer 1.
  • the salt core is sprayed with water or moistened by a mist. - A -
  • the salt core is sprayed with a mixture of water and alcohol or moistened with a mist (all proportions possible).
  • the salt core is sprayed with a mixture of water and water glass or moistened with a mist (all
  • the salt core is sprayed with a mixture of water, water glass and alcohol or moistened with a mist (all proportions possible).
  • a binder and further additives known from the prior art and suitable for admixing with the salt such as, for example, hardening agents, wetting agents and surface-activating substances, may be applied to the surface of the core individually or in any suitable composition. The application can be done together with the humectant.
  • Second step The moistened core surface becomes drier
  • the moistening and / or application can be carried out in suitable devices in a continuous process.
  • the moisture can be dosed so that it is "self-consuming". That is, only the top layer of the salt crystals of the core is dissolved in the water. This prepares the surface of the core for bonding the impinging solid salt crystals. These dissolve completely or partially in the saline solution on the core surface and thereby become bound to the core surface. After drying, the pores in the surface are closed and the surface is smoothed and solidified.
  • Another possible method of forming a layer on the core surface is electrostatic coating.
  • a potential difference must be created, which can be achieved by establishing an electric field between the core surface and the device with which the salt crystals are emitted towards the core surface.
  • a high-voltage electrode may be provided on a spray nozzle for salt crystals, with which the charging of the salt crystals to be applied takes place.
  • the surface of the core may be grounded, for example.
  • the charged salt crystals are bound by the Coulomb attraction forces on the core surface.
  • the film formation is comparable to the industrially applied powder coating.
  • the electrical charge can be carried out on a core with a dry surface or even on a core with moistened surface.
  • the salt crystals accumulate in a thin layer on the surface of the core until the different electrical charges are balanced.
  • a fixation on the surface of the core can be carried out by a subsequent careful humidification, for example by air supersaturated with air, for example through fog.
  • a subsequent careful humidification for example by air supersaturated with air, for example through fog.
  • air supersaturated with air for example through fog.
  • a thermal treatment of the core surface can be performed.
  • This thermal aftertreatment can be carried out exclusively for drying the core surface.
  • the thermal treatment can also be carried out at temperatures which cause the layer to melt, as a result of which a particularly good adhesion and surface finish of the layer is achieved.
  • Such a thermal treatment can be carried out, for example, in the case of a layer formation of dry salt crystals on a dry surface for fixing the salt crystals and for smoothing the surface.
  • the achievable layer thickness on the surface of the cores depends on the chosen application method and the grain size of the applied salt crystals. Common layer thicknesses are around 300 ⁇ m. By appropriate control of the application process can also be achieved that only the pores and holes are sealed on the surface of the core.
  • the layer on the core surface can be formed over the entire surface or only in selected subregions.
  • the unintended areas can be covered, for example.
  • the surface treatment of the cores according to the invention significantly improves the stability of the surface.
  • the melt does not attack the surface of a core and does not leach out, thereby achieving a smooth and contoured surface of the casting.
  • the cores having the layer applied to them by the surface treatment according to the invention have the advantage that they are composed of substances which, when handled properly, do not show any reactions which pollute the environment, neither during their production nor during the casting process. When removing the cores from the workpieces, there are no residues that require special disposal.
  • the present invention is a core based on salt or a mixture of salts:
  • Preferred is a core based on salt or a mixture of salts:
  • the subject of the present invention is a core based on salt or a mixture of salts:
  • Core-forming salt or the mixture of salts optionally optionally completely soluble excipients in the form of binders, fillers,
  • Additives and catalysts individually or jointly admixed, wherein the surface of the core in at least a portion with a
  • Salts optionally additionally mixed with completely water-soluble excipients, is covered, and that the substances forming the layer are bonded to the surface of the cores prepared for the formation of the layer.
  • the subject of the present invention is furthermore a method:
  • Salts which optionally optionally completely soluble excipients in the form of binders, fillers, additives and catalysts, individually or together, can be admixed, their surface in at least a portion with a layer of water-soluble salt or mixtures of water-soluble salts, optionally in addition Water completely soluble excipients is mixed, covered and that the layer is formed in two steps, wherein in the first step at least in a partial region of the surface of the cores surface activation takes place for receiving the substances to be applied and in a second step, the substances are applied to the intended surface area and these substances are bound to the surface of the salt cores.
  • the surface of the salt cores is moistened.
  • the surface of the salt cores is sprayed with a mixture of water, water glass and alcohol or moistened by a mist of it.
  • xi. according to (v) to (x), individually or in any combination, that on the surface of the salt cores additionally a binder and other, known from the prior art and suitable for admixing with salt additives, such as solidifying agents, wetting agents and / or the surface activating substances are applied.
  • salt additives such as solidifying agents, wetting agents and / or the surface activating substances
  • the present invention furthermore relates to the use of the core according to the invention according to (i) to (iv), in each case individually or in any combination, as a cavity locator in the production of metallic castings as well as plastic injection molded parts which are completely complete without leaving solid residues in a solvent dissolve and remove completely from the castings.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Materials Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Molds, Cores, And Manufacturing Methods Thereof (AREA)

Abstract

Lorsque les cavités des pièces coulées doivent satisfaire à des critères particuliers en ce qui concerne leur surface et la précision de leurs contours, les noyaux doivent présenter une surface lisse, aux contours exacts. La matière de la pièce coulée ne doit pas réagir avec la surface du noyau, ni pénétrer sa surface, ni la cratériser. A cet effet, l'invention prévoit que la surface des noyaux est revêtue, au moins en partie, d'une couche de sel soluble dans l'eau ou de mélanges de sels solubles dans l'eau, éventuellement avec ajout supplémentaire de matières auxiliaires totalement solubles dans l'eau, la couche étant formée en deux temps, une activation de surface permettant la réception des matières à appliquer étant effectuée au moins sur une zone partielle de la surface des noyaux au cours de la première étape, les matières étant ensuite appliquées sur la partie de surface prévue et liées à la surface des noyaux de sel dans une seconde étape.
EP10722051A 2009-05-18 2010-05-18 Noyaux a base de sel dotés d'une surface traitée Withdrawn EP2432606A2 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102009003184 2009-05-18
PCT/EP2010/056819 WO2010133596A2 (fr) 2009-05-18 2010-05-18 Noyaux a base de sel dotés d'une surface traitée

Publications (1)

Publication Number Publication Date
EP2432606A2 true EP2432606A2 (fr) 2012-03-28

Family

ID=42583976

Family Applications (1)

Application Number Title Priority Date Filing Date
EP10722051A Withdrawn EP2432606A2 (fr) 2009-05-18 2010-05-18 Noyaux a base de sel dotés d'une surface traitée

Country Status (3)

Country Link
EP (1) EP2432606A2 (fr)
DE (1) DE102010029077A1 (fr)
WO (1) WO2010133596A2 (fr)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102013007735B4 (de) * 2012-05-08 2015-10-15 Audi Ag Verfahren zum Herstellen eines gussgeeigneten Salzkerns
DE102012108079B3 (de) * 2012-08-31 2013-11-14 Hochschule Aalen Verfahren zur Herstellung hohler Salzkerne
DE102012022631B3 (de) * 2012-11-20 2014-04-03 Audi Ag Verfahren zur Herstellung eines Salzkerns für das Druckgießen mit einer zuvor abgepackten Salzmenge
EP3024610B1 (fr) 2013-07-24 2018-11-21 Emil Müller GmbH Noyaux de sel et procédés de fabrication additive pour réaliser des noyaux de sel
DE102014017091A1 (de) 2014-11-20 2016-05-25 Mahle International Gmbh Verfahren zum Herstellen eines Kühlkanalkolbens sowie nach einem derartigen Verfahren hergestellter Kühlkanalkolben
DE102021200812A1 (de) 2021-01-29 2022-08-04 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung eingetragener Verein Verfahren zur Herstellung von Formelementen für Tauch- und Laminierverfahren, Kernen oder Modellen, die zum Abbilden von Hinterschneidungen in Metall-, Keramik-, Kunststoff- oder Compositebauteilen einsetzbar sind

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1934787A1 (de) * 1969-07-09 1971-01-14 Schmidt Gmbh Karl Salzkern fuer Giessereizwecke
US3692551A (en) * 1970-02-24 1972-09-19 Libbey Owens Ford Co Core for use in pressure molding
US5803151A (en) 1996-07-01 1998-09-08 Alyn Corporation Soluble core method of manufacturing metal cast products
DE10305612B4 (de) * 2003-02-11 2005-04-07 Ashland-Südchemie-Kernfest GmbH Beschichtungsmassen für Gusskerne
DE102006046792A1 (de) * 2005-09-30 2007-04-05 Ceramtec Ag Innovative Ceramic Engineering Kerne sowie ein Verfahren zur Herstellung von Kernen
EP1934002B1 (fr) * 2005-09-30 2019-07-31 CeramTec GmbH Noyaux et procédé de production de noyaux
JP2008036702A (ja) * 2006-08-10 2008-02-21 Toyota Motor Corp 金属鋳物用鋳造型

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
None *

Also Published As

Publication number Publication date
WO2010133596A2 (fr) 2010-11-25
DE102010029077A1 (de) 2010-11-25
WO2010133596A3 (fr) 2011-02-03

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