EP0664172A2 - Procédé pour la production d'un moule négatif - Google Patents

Procédé pour la production d'un moule négatif Download PDF

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Publication number
EP0664172A2
EP0664172A2 EP95890005A EP95890005A EP0664172A2 EP 0664172 A2 EP0664172 A2 EP 0664172A2 EP 95890005 A EP95890005 A EP 95890005A EP 95890005 A EP95890005 A EP 95890005A EP 0664172 A2 EP0664172 A2 EP 0664172A2
Authority
EP
European Patent Office
Prior art keywords
model
mold
negative
parts
negative mold
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Withdrawn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
EP95890005A
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German (de)
English (en)
Other versions
EP0664172A3 (fr
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.)
Gmundner Keramik Hohenberg GesmbH
Original Assignee
Gmundner Keramik Hohenberg GesmbH
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 Gmundner Keramik Hohenberg GesmbH filed Critical Gmundner Keramik Hohenberg GesmbH
Publication of EP0664172A2 publication Critical patent/EP0664172A2/fr
Publication of EP0664172A3 publication Critical patent/EP0664172A3/fr
Withdrawn legal-status Critical Current

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B28—WORKING CEMENT, CLAY, OR STONE
    • B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
    • B28B7/00—Moulds; Cores; Mandrels
    • B28B7/0064—Moulds characterised by special surfaces for producing a desired surface of a moulded article, e.g. profiled or polished moulding surfaces
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B28—WORKING CEMENT, CLAY, OR STONE
    • B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
    • B28B7/00—Moulds; Cores; Mandrels
    • B28B7/34—Moulds, cores, or mandrels of special material, e.g. destructible materials
    • B28B7/346—Manufacture of moulds

Definitions

  • the invention relates to a method for producing a, in particular two-part, negative mold, for example plaster mold for coreless casting, from a model with an outer shape which cannot be demolded by simple mold separation.
  • Negative molds are used in a wide variety of casting processes, for example as a plaster mold for coreless casting of ceramics.
  • the coreless casting process is preferred for the production of series of identical ceramic objects and in particular of non-rotationally symmetrical ceramic hollow bodies, such as cans with a beak and handle or the like. applied.
  • Liquid clay slip is poured into a negative mold made of plaster or water-absorbing plastic and the mold is left to stand for a certain time. During this time, the gypsum mold sucks some of the water out of the poured slip, causing a ceramic layer to deposit on the inner wall of the mold. After the molding has reached the desired wall thickness, the excess slip is poured out of the negative mold and the molding is cured in the mold until it can be removed from the mold without damage.
  • the negative mold is usually produced in such a way that a model of the molded piece to be produced is worked out from a plaster block, this model is then poured into the flowable material of the negative mold, typically plaster or liquid-absorbing plastic, the hardened negative mold is hardened and the model can be removed from the mold.
  • the model is usually coated with a release agent before pouring in order to prevent the model from sticking to the negative mold.
  • This type of negative mold production requires, however, that the molded part has an external shape that can be removed from the mold, because in contrast to the molded part itself, which shrinks when hardened, which means that profiles that cannot be removed from the mold can also be removed from the mold, the model can absorb water when poured into the mold Swell the negative form.
  • the present invention avoids the disadvantages mentioned and discloses a method for producing a, in particular two-part, negative mold from a model with an outer shape which cannot be demolded by mold separation.
  • the method according to the invention is characterized by the removal of the model parts which prevent the demolding by mold separation from the model body, the replication of the removed model parts by applying and modeling a moldable, preferably not too quickly curing, molding compound on the model body, the molding compound, for example plasticine, putty or Like.
  • model prefferably coated with a release agent before it is poured into the material for producing the negative mold, that prevents the model and negative form from sticking together.
  • the invention also encompasses a negative casting mold, in particular a two-part casting mold produced by the method according to the invention, with a molding profile which cannot be demolded by mold separation.
  • This negative mold is characterized in that the negative mold profile has an internal width which is at least enlarged by the shrinkage of the molded part to be produced plus a possible swelling dimension of the negative mold compared to the outer profile of the molded part to be produced, for example approx. 5% for clay.
  • FIG. 1 schematically shows a two-part casting mold for coreless casting in longitudinal section
  • FIG. 2 shows an enlarged cross section along the line II-II in FIG. 1 through the casting mold and the ceramic vessel produced
  • FIGS. 3 to 5 the individual, on 6 a side view of the manufactured vessel
  • FIGS. 7 to 10 a jug, which was manufactured in a negative form according to the invention, in side view, view from the handle side, top view and view from the beak side, and 11 to 14 a model of the jug when carrying out the method according to the invention.
  • FIG. 1 and 2 show a casting mold 1 which can be divided along the separating surface 2, the two casting mold halves being movable in the direction of the arrows L, R.
  • the mold is usually made of gypsum, but liquid-absorbent plastic can also be used.
  • the mold is then left to stand for a predetermined time.
  • the mold 1 made of plaster or plastic absorbs water from the clay slip 3, whereby a layer 4 of the solid components of the slip is deposited on the inner wall of the casting mold, which layer grows with continuous duration and has a substantially constant thickness. Only in the area of the edge 5 of the layer 4 does its thickness gradually decrease, as can be seen in FIG. 1. This is due to the lowering of the liquid level of the clay slip in the course of the deposition process.
  • a layer thickness of 4-6 mm is obtained after a standing time of 2-2.5 hours. After the desired layer thickness has been reached, the excess clay slip is emptied from the mold and layer 4 is dried and thereby hardened. Layer 4 shrinks considerably, for example by 5% for the given clay slip mixture.
  • Form 1 swells due to water absorption, if only in the alcohol range. Due to the effect of the shrinkage of the layer 4 and the swelling of the mold 1, the layer 4 detaches from the inner wall of the mold 1 and the intermediate space 6 is formed can be seen in Fig. 2. After a further drying time of 2-4 hours, the ceramic body has hardened to such an extent that it can be removed from the negative mold without damage.
  • a cylindrical vase with a corrugated wall was first selected as the molding to be produced, as shown in cross-section in FIG. 2 with reference numeral 4. This vase is also shown in side view in FIG. 6.
  • a model 7 is worked out from a blank, for example a gypsum block, the external shape of which corresponds to the external shape of the molded piece to be produced, taking into account the shrinkage of the mixture used, as shown in FIG. 3.
  • a separation plane (s) 8 is / are defined, at which the separation of the negative form is to take place later.
  • the movement is determined according to which the negative molded parts are to be separated.
  • linear movement of two, separated in plane 8 Mold halves selected in the direction of arrows L, R; for example, a pivoting movement of the mold halves could also be expedient.
  • the removed model parts are reproduced by applying and modeling a moldable molding compound 13, 14, 15, 16, which preferably does not harden too quickly.
  • a moldable molding compound 13, 14, 15, 16 which preferably does not harden too quickly.
  • the replicas were only designated in a quarter circle, with the other three quadrants one must proceed symmetrically. It can be seen from FIG. 5 that the model body 7 ', together with the replicas from the molding compound, has exactly the same shape as the original model 7 shown in FIG. 3.
  • the molding compound must be such that, on the one hand, it is neither deformed nor detached from the model body when the model is subsequently poured into a material for producing a negative mold and, on the other hand, is soft enough at the time the model is detached from the negative mold so as not to damage it.
  • Suitable molding compounds are e.g. Plasticine or putty.
  • the model reconstructed by the molding compound is usually coated with a release agent.
  • the next step is to cast the model in a flowable and hardenable material, such as plaster, to produce a negative mold.
  • a flowable and hardenable material such as plaster
  • the model does not stick to the negative mold.
  • 5 shows the process state in which the already hardened negative mold 1 is along the parting surface 2, which coincides with the parting plane 8, is divided into two halves.
  • the model parts 13-16 formed by the molding compound which are much softer than the negative mold 1 and the model body 7', are detached from the model body and remain in the Negative mold halves from which they can be easily removed by hand or with a blunt scraper.
  • the method according to the invention is explained on the basis of the production of a negative shape for a can 20 with a bulbous, almost spherical body with helical ribs 21 with a triangular cross section and running on the outside thereof.
  • a can 20 is shown in FIGS. 7-10 in a side view, as well as a view from the handle side, from above and from the beak side.
  • a model is constructed from a plaster block with the external shape of the jug to be produced (taking into account the shrinkage of the plaster mixture used) and then the ribs are removed in all areas that would prevent demolding.
  • the demoulding separation plane is expediently defined as the vertical plane lying in the longitudinal axis of the can.
  • the plaster model 22 is shown in FIGS. 11-14 in side view, view from the handle side, top view and view from the beak side. The size of the areas to be removed depends on the height and shape of the ribs. You can either remove exactly those rib parts that prevent demolding or also remove the ribs entirely in these areas 23, 24, as shown by way of example in FIGS. 11-14.
  • the removed material is applied and modeled in the areas 23, 24 Reconstructed ribs, so that the model has its original exterior shape again.
  • This is followed, as already explained with reference to the first example, by coating the model with a release agent, pouring the model into a curable agent, curing this agent, demolding the model from the negative mold thus obtained and removing the mold from the mold The remaining molding compound.

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Chemical & Material Sciences (AREA)
  • Ceramic Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Moulds For Moulding Plastics Or The Like (AREA)
EP95890005A 1994-01-25 1995-01-10 Procédé pour la production d'un moule négatif. Withdrawn EP0664172A3 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
AT13194A ATA13194A (de) 1994-01-25 1994-01-25 Verfahren zur herstellung von saugfähigen giessformen
AT131/94 1994-01-25

Publications (2)

Publication Number Publication Date
EP0664172A2 true EP0664172A2 (fr) 1995-07-26
EP0664172A3 EP0664172A3 (fr) 1997-07-30

Family

ID=3482355

Family Applications (1)

Application Number Title Priority Date Filing Date
EP95890005A Withdrawn EP0664172A3 (fr) 1994-01-25 1995-01-10 Procédé pour la production d'un moule négatif.

Country Status (2)

Country Link
EP (1) EP0664172A3 (fr)
AT (1) ATA13194A (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2006005002A3 (fr) * 2004-06-30 2006-02-23 Cheryl R P Kull Recipient isole

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1538607A (en) * 1924-06-30 1925-05-19 Anderson Andrew Method of making molds for ornamental flowerpots
GB320519A (en) * 1928-10-08 1929-10-17 William Coulter Improvements relating to the manufacture of teapots and like articles
GB722062A (en) * 1952-07-07 1955-01-19 Booths And Colcloughs Ltd Improvements relating to the manufacture of ceramic hollow-ware and moulds for use in such manufacture
US2941277A (en) * 1956-04-30 1960-06-21 Rudolph V Ganz Method of making casting molds for ceramic forms
FR1517144A (fr) * 1967-02-28 1968-03-15 Système de moulage d'éléments préfabriqués en béton
DE3226793A1 (de) * 1982-07-17 1984-01-19 Gummi-Jäger KG GmbH & Cie, 3000 Hannover Form zur herstellung von faltenbaelgen
JPH0195840A (ja) * 1987-10-06 1989-04-13 Ngk Insulators Ltd 鋳造金型の製造方法
US4923672A (en) * 1987-12-16 1990-05-08 Eta Sa Fabriques D'ebauches Method of obtaining a mould intended for the manufacture of very small parts
JPH02243703A (ja) * 1989-03-17 1990-09-27 Onoda Cement Co Ltd 金属、セラミックス等の粉末の成形方法
DE4217100A1 (de) * 1991-12-17 1993-06-24 Dennert Kg Veit Verfahren und vorrichtung zum herstellen von fertigkaminen

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1538607A (en) * 1924-06-30 1925-05-19 Anderson Andrew Method of making molds for ornamental flowerpots
GB320519A (en) * 1928-10-08 1929-10-17 William Coulter Improvements relating to the manufacture of teapots and like articles
GB722062A (en) * 1952-07-07 1955-01-19 Booths And Colcloughs Ltd Improvements relating to the manufacture of ceramic hollow-ware and moulds for use in such manufacture
US2941277A (en) * 1956-04-30 1960-06-21 Rudolph V Ganz Method of making casting molds for ceramic forms
FR1517144A (fr) * 1967-02-28 1968-03-15 Système de moulage d'éléments préfabriqués en béton
DE3226793A1 (de) * 1982-07-17 1984-01-19 Gummi-Jäger KG GmbH & Cie, 3000 Hannover Form zur herstellung von faltenbaelgen
JPH0195840A (ja) * 1987-10-06 1989-04-13 Ngk Insulators Ltd 鋳造金型の製造方法
US4923672A (en) * 1987-12-16 1990-05-08 Eta Sa Fabriques D'ebauches Method of obtaining a mould intended for the manufacture of very small parts
JPH02243703A (ja) * 1989-03-17 1990-09-27 Onoda Cement Co Ltd 金属、セラミックス等の粉末の成形方法
DE4217100A1 (de) * 1991-12-17 1993-06-24 Dennert Kg Veit Verfahren und vorrichtung zum herstellen von fertigkaminen

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 013, no. 305 (M-849), 13.Juli 1989 & JP 01 095840 A (NGK INSULATORS LTD), 13.April 1989, *
PATENT ABSTRACTS OF JAPAN vol. 014, no. 570 (M-1060), 18.Dezember 1990 & JP 02 243703 A (ONODA CEMENT CO LTD), 27.September 1990, *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2006005002A3 (fr) * 2004-06-30 2006-02-23 Cheryl R P Kull Recipient isole

Also Published As

Publication number Publication date
ATA13194A (de) 1997-02-15
EP0664172A3 (fr) 1997-07-30

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