WO1993019692A1 - Procede et moule ceramique pour la fabrication de pieces coulees dentaires en titane et composition ceramisable pour la fabrication d'un tel moule - Google Patents

Procede et moule ceramique pour la fabrication de pieces coulees dentaires en titane et composition ceramisable pour la fabrication d'un tel moule Download PDF

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Publication number
WO1993019692A1
WO1993019692A1 PCT/DE1993/000293 DE9300293W WO9319692A1 WO 1993019692 A1 WO1993019692 A1 WO 1993019692A1 DE 9300293 W DE9300293 W DE 9300293W WO 9319692 A1 WO9319692 A1 WO 9319692A1
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WIPO (PCT)
Prior art keywords
casting
titanium
ceramic
solid
composition
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Application number
PCT/DE1993/000293
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German (de)
English (en)
Inventor
Joachim Pajenkamp
Original Assignee
Joachim Pajenkamp
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 Joachim Pajenkamp filed Critical Joachim Pajenkamp
Publication of WO1993019692A1 publication Critical patent/WO1993019692A1/fr

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C9/00—Moulds or cores; Moulding processes
    • B22C9/02—Sand moulds or like moulds for shaped castings
    • B22C9/04—Use of lost patterns
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61C—DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE
    • A61C13/00—Dental prostheses; Making same
    • A61C13/20—Methods or devices for soldering, casting, moulding or melting
    • 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

Definitions

  • a key problem in the production of dental casting workpieces made of titanium are the molding or investment materials used for the production of the casting molds.
  • the investment materials based on metal oxides and mostly ohosphate-bound react chemically with the extremely aggressive titanium melt, which in the cubic body-centered / 5-phase above a temperature of 882.5
  • C has a high affinity for oxygen, carbon, nitrogen and hydrogen.
  • the consequence of the oxidation is embrittlement of the edge zones of the cast object with penetration depths of 0.05 to 0.3 mm and thus an increase in the material hardness up to 10 times (measured according to Brinell) compared to the starting material. While, for example, the increased material hardness present in the edge zones of the casting can be a welcome effect in certain areas of application, for example in the aerospace industry, this embrittled outer skin, which is the result of oxidation and which is the alpha-case form of the Titans is said to be completely removed.
  • the oxidation in the edge zones of the casting also leads to inaccuracies in fit, in addition, voids, gas inclusions and even non-flown modeling parts in complicated castings, as are customary in model casting technology, are caused by the chemical reactions.
  • the invention has for its object to provide measures which enable an alpha-case-free, dental titanium casting.
  • the method according to the invention for producing dental cast workpieces made of titanium is characterized by the measures according to patent claim 1.
  • An essential measure in the production of the casting mold is to produce a gas-permeable ceramic shell which is inert to the titanium melt, in particular according to the so-called slip method, and to embed the ceramic shell produced in this way in a likewise gas-permeable, ceramic support mass, both with during the manufacture of the casting mold and also during the titanium casting, it must be ensured that the ceramic shell embedded in the supporting mass is kept under compressive stress during its sintering process and during the casting process. The following must be taken into account:
  • the total expansion (ie: setting expansion and thermal expansion) must be between 0.30% and 0.50%; the contraction shrinkage of unalloyed titanium is approx. 0.36%.
  • the investment casting slip In order to avoid crack formation in the ceramic shell, the investment casting slip must always be under slight compressive stress. The expansion behavior of the shell support mass must run linearly slightly below that of the slip.
  • the total expansion must be reached at temperatures around 1000 ° C (750 ° C - 1050 ° C).
  • the ceramic shell needs this temperature for the sintering process.
  • the casting temperature must not be lowered; because otherwise the shell will be under tension (cracks would result).
  • the shell support mass must be gas-permeable in order to completely degas the interior of the muffle and to achieve the highest possible vacuum (at least: 76 cm / Hg).
  • the shell supporting mass must have a high mechanical strength at final temperatures in order to be able to withstand the process-related pressures in the casting machine.
  • a wax model that can be melted out is immersed in a corresponding binder solution, and the binder solution layer is then dusted with ceramic material. This process is repeated several times until there is sufficient wall thickness to achieve sufficient strength for the metal casting.
  • the material used for the support mass preferably has the composition described in the patent claim.
  • the materials used for the construction of the ceramic shell which is inert towards the liquid titanium melt are described in claims 6 to 10.
  • the binder used is of essential importance for the production of the ceramic shell.
  • methyl acetate mixed with acrylic resins can be used, provided that these do not dissolve the cast waxes used in dental technology.
  • Methylaceto ⁇ ate dissolved in about 70% n-propanol or corresponding alcohols are more complex but, as a result, cheaper.
  • In this liquid preferably about 20% of the Oxyds to be used.
  • Binders which have such a consistency harden by taking up H 0. The duration of this curing process depends on the relative humidity and can be completed in about 2 hours in air enriched with ammonia. The relative air humidity should be at least 80%. Subsequent sanding under pressure is extremely advantageous for both binding liquids or binders.
  • the method according to the invention is described in the following by way of example in connection with the dental model casting technique and on the other hand with the dental crown and bridge technique.
  • a fully prepared master model is duplicated with an addition-cross-linked silicone material. After the silicone material has hardened, the master model is removed from the duplicating mold. Since, according to the invention, the titanium melt should not come into contact with the molding compound at any point, the basal surface of the model cast to be produced must first be provided with the ceramic shell in the investment casting slip technique used according to the invention.
  • an insulating or separating agent is, for example, the white form of a paraffin sold by Chesebrough Pond's Inc. under the trademark "Vaseline".
  • the praffin oil is distributed evenly thin in the silicone mold.
  • the completely mixed and well-leveled liquid slip material based on lanthanum oxyfluoride (LaOF), stabilized zirconium oxide (ZrO p ) or precipitated yttrium oxide (Y 2 ° 3) is filled into the mold, which is then rotated so that excess slip liquid can flow out. After approximately 30 seconds, the duplicating mold is rotated again by 180 °.
  • LaOF lanthanum oxyfluoride
  • ZrO p stabilized zirconium oxide
  • Y 2 ° 3 precipitated yttrium oxide
  • the slip material is produced in such a way that powdered LaOF, ZrO "or Y 9 O 3 ⁇ ne ⁇ ner
  • Grain size 0 - 50 ⁇ m is mixed in a binding liquid which either consists of methyl acetate mixed with acrylic resins which do not dissolve the modeling waxes used in dental technology, or consists of methyl acetonate dissolved in alcohol, especially 70% n-propanol.
  • a binding liquid which either consists of methyl acetate mixed with acrylic resins which do not dissolve the modeling waxes used in dental technology, or consists of methyl acetonate dissolved in alcohol, especially 70% n-propanol.
  • Preferably 18-25% by weight, preferably about 20% by weight of the respective solid is dissolved in the binding liquid used.
  • Zr0 " is used as the solid, this preferably contains an addition of 3 to 30% by weight; preferably about 5% by weight Y" 0 ".
  • ZrÜ 2 is used, it is preferably a fully stabilized, cubic zirconium oxide with a CaO content in the range of about 4.4% by weight.
  • slip material layer is off
  • the duplicating mold is placed in a pressure compressor which is set to a minimum pressure of 5 bar. The coarse powder material penetrates evenly into the soft layer of slip material.
  • the duplicating mold is removed from the pressure compressor and the excess powder material is removed by rotating the duplicating mold.
  • the investment casting slip must be dried in this state. The duration of this drying process depends on the relative air humidity and can be completed in about 2 hours in air enriched with ammonia. The relative humidity should be at least 80%.
  • the relatively coarse powder used for sanding or sprinkling is said to be a clinging or
  • This investment or support compound is mixed with a conventional ceramic binder, in particular based on silica sol.
  • a material of the following composition is used as an investment or support mass:
  • the ceramic agent has a silica sol content of 10-100% by weight, the rest.
  • an organic binder based on zirconic acid ether can also be used.
  • the duplicating mold After filling with this molding or supporting material, the duplicating mold is placed in a pressure compressor (minimum pressure: 5 bar) for about 15 minutes, and after removal from the pressure compressor, the duplicate model can be used after about another 30 minutes can be removed from the duplicating mold.
  • a pressure compressor minimum pressure: 5 bar
  • the model Since the investment casting slip is not very stable at room temperature, the model must be hardened before modeling. For this purpose, it is placed in a preheating oven at room temperature, which then opens
  • the hardened model is then removed from the oven.
  • the casting slip layer is then sprayed with a hardening liquid which preferably consists of n-butyl acetate and 1-prooanol.
  • the model is then placed back in the hot oven for about 5 minutes and then air-cooled to room temperature.
  • the modeling process with wax or another meltable material can then be carried out in the customary manner on this cast cast slip layer.
  • the entire waxed-up area must again be covered with the investment casting slip, although initially about 2/3 of the pouring channel and the entire pouring funnel former must be supplied.
  • the pouring channel is placed on the model and bent into its final shape without being waxed with the model.
  • the casting funnel former is waxed with the channel and aligned in such a way that the upper edge of the casting funnel former ends with the upper side of the muffle and is located as centrally as possible in the muffle.
  • the pouring channel thus prefabricated (with waxed pouring funnel former) is removed from the model, thinly coated with white petroleum jelly oil and then immersed in the liquid slip material mass. It is important to ensure that the end of the pouring channel, which will later be waxed on the model with the wax, does not come into contact with the slip material. Subsequently, depending on the respective slip material composition, z. B. Lanthanium oxyfluoride powder in a grain size of 0.12 - 0.25 mm sprinkled and compressed. Then the hardened pouring channel including pouring funnel former can be waxed with the wax-up.
  • the framework model is again provided with an investment casting slip layer by applying the liquid slip material and then is sanded or sprinkled with the appropriate powder. The mixture is then pressure-compressed in the manner described above and the slip is left to dry.
  • the mold can then be over-bedded or embedded in the support composition in accordance with Table 1 above.
  • the muffle is placed in a cold preheating furnace and then heated to the casting temperature of the titanium, so that the casting can finally take place.
  • the wax object is lifted off the master model and waxed up on the usual rubber funnel former.
  • the cast object in dental titanium casting should lie in the muffle center. Otherwise there is a risk that the titanium melt, which is hotter than 1700 C, will thin Penetrating molding compound. Direct channel attachment or beam casting have proven themselves and lead to optimal results.
  • the rubber cone is also covered with a wax layer.
  • the slip slides can e.g. the lanthanium oxyfluoride slip can be created entirely in the immersion process.
  • the rubber plate is completely immersed in the slip liquid with the modeling downward. After 5 seconds it is pulled out. Now it has to drain for another 5 seconds.
  • the plate is now rotated 180 degrees, the metal ring is attached and filled with lanthanium oxyfluoride powder with a grain size of 0.12 - 0.25 mm beyond the upper edge of the model.
  • the metal ring is now lined with a 2 mm thick, fire-resistant expansion fleece.
  • the prepared muffle is then filled with the same support or molding compound as in the model casting technique.
  • smaller expansions are required for crown and bridge work. This is achieved by thermal control of the support or investment material.
  • the pouring takes place again in the usual way. Do not quench in cold water. After devestment, if properly processed, there will be metallic bare, i.e. alpha-case-free, peripheral zones in the investment casting slip process. The process of blasting with metal oxides is completely eliminated, so that fits with optimal values can be achieved.

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  • Health & Medical Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Dentistry (AREA)
  • Materials Engineering (AREA)
  • Oral & Maxillofacial Surgery (AREA)
  • Chemical & Material Sciences (AREA)
  • Epidemiology (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
  • Public Health (AREA)
  • Veterinary Medicine (AREA)
  • Dental Prosthetics (AREA)
  • Mold Materials And Core Materials (AREA)

Abstract

Pour empêcher la fragilisation des faces externes de pièces dentaires coulées en titane, fragilisation provoquée par la formation alpha case, la présente invention propose un procédé et un moule céramique caractérisés par la garniture des surfaces du moule qui viennent en contact avec le titane en fusion, y compris de celles de l'entonnoir de coulée et du chenal de coulée, avec une coquille céramique perméable aux gaz et inerte par rapport au titane en fusion. Cette coquille est noyée dans une masse stabilisante céramique ou céramisable de composition telle que la coquille noyée dans la masse stabilisante soit maintenue sous contrainte de compression pendant son frittage et pendant l'opération de coulée.
PCT/DE1993/000293 1992-03-27 1993-03-25 Procede et moule ceramique pour la fabrication de pieces coulees dentaires en titane et composition ceramisable pour la fabrication d'un tel moule WO1993019692A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19924210004 DE4210004A1 (de) 1992-03-27 1992-03-27 Verfahren und keramische Gußform zur Herstellung von dentalen Gußwerkstücken aus Titan und keramisierbare Zusammensetzung für die Herstellung einer keramischen Gußform zur Herstellung von dentalen Gußwerkstücken aus Titan
DEP4210004.6 1992-03-27

Publications (1)

Publication Number Publication Date
WO1993019692A1 true WO1993019692A1 (fr) 1993-10-14

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PCT/DE1993/000293 WO1993019692A1 (fr) 1992-03-27 1993-03-25 Procede et moule ceramique pour la fabrication de pieces coulees dentaires en titane et composition ceramisable pour la fabrication d'un tel moule

Country Status (2)

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DE (1) DE4210004A1 (fr)
WO (1) WO1993019692A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111189322A (zh) * 2020-01-07 2020-05-22 合肥华特义齿加工有限公司 一种义齿铸造电阻炉

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JPH10277061A (ja) * 1997-04-04 1998-10-20 Injietsukusu:Kk 支台歯模型および歯冠修復物の製造方法
DE59713010D1 (de) * 1997-11-14 2009-08-06 Shera Werkstofftechnologie Gmb Verfahren zur Steuerung und Einstellung der Expansion von keramischen Einbettmassen
DE59914938D1 (de) * 1999-04-09 2009-02-05 Shera Werkstofftechnologie Gmb Verfahren zur Herstellung von Gusswerkstücken
US6494250B1 (en) * 2001-05-14 2002-12-17 Howmet Research Corporation Impregnated alumina-based core and method
ATE297277T1 (de) * 2001-12-07 2005-06-15 Schuetz Dental Gmbh Giessformstoff für die herstellung von gussformen zum giessen von werkstoffen mit hohem schmelzpunkt

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US1499132A (en) * 1920-07-27 1924-06-24 Chris S Van Horn Electric pneumatic casting machine
DE945717C (de) * 1943-11-14 1956-07-12 Siemens Ag Verfahren zur Herstellung von Giessformen fuer Metallguss, Eisenguss od. dgl.
GB2168060A (en) * 1984-12-04 1986-06-11 Ohara Kk Mold material and process for casting of pure titanium or titanium alloy
FR2606688A1 (fr) * 1986-11-17 1988-05-20 Pechiney Aluminium Procede de moulage a mousse perdue de pieces metalliques
EP0372180A2 (fr) * 1988-12-03 1990-06-13 Shera-Werkstofftechnologie Gmbh Système céramique

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1499132A (en) * 1920-07-27 1924-06-24 Chris S Van Horn Electric pneumatic casting machine
DE945717C (de) * 1943-11-14 1956-07-12 Siemens Ag Verfahren zur Herstellung von Giessformen fuer Metallguss, Eisenguss od. dgl.
GB2168060A (en) * 1984-12-04 1986-06-11 Ohara Kk Mold material and process for casting of pure titanium or titanium alloy
FR2606688A1 (fr) * 1986-11-17 1988-05-20 Pechiney Aluminium Procede de moulage a mousse perdue de pieces metalliques
EP0372180A2 (fr) * 1988-12-03 1990-06-13 Shera-Werkstofftechnologie Gmbh Système céramique

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OTT D.: "GIESSEN VON TITAN IM DENTALLABOR. ENTWICKLUNG EINES VERFAHRENS.", ZWR DAS DEUTSCHE ZAHNARZTEBLATT., GEORG THIEME VERLAG, STUTTGART., DE, vol. 100., no. 02., 1 February 1991 (1991-02-01), DE, pages 106 - 109., XP000175044, ISSN: 0044-166X *

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111189322A (zh) * 2020-01-07 2020-05-22 合肥华特义齿加工有限公司 一种义齿铸造电阻炉

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Publication number Publication date
DE4210004A1 (de) 1993-09-30

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