Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F5/00—Manufacture of workpieces or articles from metallic powder characterised by the special shape of the product
  • B22F5/007—Manufacture of workpieces or articles from metallic powder characterised by the special shape of the product of moulds
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
  • B22F3/12—Both compacting and sintering
  • B22F3/1208—Containers or coating used therefor
  • B22F3/1258—Container manufacturing
  • B22F3/1275—Container manufacturing by coating a model and eliminating the model before consolidation

Definitions

• materials such as stainless steel or Cr-Mo-Co alloys are used for biomedical castings whose reactivity to gases in the atmosphere and molding materials, such as. B. ceramics, is relatively low.
• Such materials can accordingly z. B. in the centrifugal casting process with the aid of individual ceramic shapes, which were created by using a wax model.
• these materials have the disadvantage that they are not sufficiently biologically compatible.
• the metals titanium, tantalum, niobium or zirconium and their alloys are known as particularly good biocompatible materials, these materials also having very advantageous mechanical properties for exhibit biotechnical applications.
• alpha case oxygen-stabilized alpha phase
• the object of the invention Reasons to further develop such a method and in particular to enable the production of castings with advantageous surface properties while minimizing the effort for post-processing of the finished casting and at the same time to achieve an increase in shape accuracy.
• This object is achieved in that the wax model is provided with a metal coating before embedding in the metallic investment material.
• the modeling wax can either be made conductive by adding an electrically conductive additive, such as metal powder, carbon powder or the like, or by dipping, applying, spraying or the like of an electrically conductive coating. It was particularly good experience that a silver conductive varnish was applied to the wax model with a brush.
• an electrically conductive additive such as metal powder, carbon powder or the like
• the galvanic production of the metal coating it can also be provided that it is applied by PVD (Physical Vapor Deposition) or CVD (Chemical Vapor Deposition).
• PVD Physical Vapor Deposition
• CVD Chemical Vapor Deposition
• a copper or silver layer is preferably provided as the metal coating.
• the thickness of the metal coating is advantageously between 10 and 10 ⁇ , but depending on the requirement, even higher layer thicknesses can be achieved.
• the metallic investment material consists of a metal powder, a metal powder mixture or a mixture with the addition of metal oxides.
• the metallic investment After embedding the wax model provided with a metal coating, the metallic investment is solidified in a manner known per se by sintering, the modeling wax being melted out, organic residues in the casting cavity then being evaporated out by applying a vacuum.
• the invention also relates to a casting mold which was produced by the method described above.
• the dentist creates a plaster cast of the tooth to be veneered in a conventional manner.
• a wax model is created in a well-known manner using a modeling wax that is customary on the market.
• This wax model is now made conductive by applying a commercially available silver conductive lacquer using a brush.
• the electrically conductive coating layer of the wax model is used as the cathode of a galvanic bath.
• a platinized titanium anode in a copper electrolyte is used as the counter electrode.
• a voltage By applying a voltage, an approximately 100 ⁇ thick copper coating layer is deposited on the rendered wax model within approximately 2 hours.
• the wax model with the metal layer produced in this way is embedded in a container in a metal powder.
• the metal powder consists of a mixture of copper and tin powder in a ratio of 10: 1.
• the sintering process is initiated by the added tin with its relatively low melting point. The entire arrangement is then exposed to a temperature of about 500 ° C. in a vacuum, the sintering process progressing and at the same time the wax of the wax model melting and organic vapors being drawn off due to the vacuum applied.
• the sintered metal powder can be easily removed by scraping.
• the remaining core area around the casting with the copper coating is placed in a nitric acid bath, whereby the remaining mold residues and in particular also the copper layer are completely removed, but the titanium casting itself is not attacked at all.

Landscapes

• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Mechanical Engineering (AREA)
• Dental Prosthetics (AREA)
• Molds, Cores, And Manufacturing Methods Thereof (AREA)
• Powder Metallurgy (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=6384008

Family Applications (1)

Country Status (3)

Cited By (1)

Families Citing this family (4)

Citations (3)

Family Cites Families (1)

• 1989
  • 1989-06-30 DE DE19893921514 patent/DE3921514A1/de active Granted
• 1990
  • 1990-05-19 EP EP90109551A patent/EP0405131A1/de not_active Withdrawn
  • 1990-06-29 JP JP17434390A patent/JPH0335840A/ja active Pending

Patent Citations (3)

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