Method for the production of a molded blank from metal powder

Abstract

Disclosed is a method for producing a molded blank from metal powder using a gel-casting process, wherein a starting mixture for the gel-based process is made by mixing the metal powder with a liquid and a binder, the starting mixture being thoroughly mixed in a vacuum.

1 . A method for producing a molded blank from metal powder using a gel-casting process, wherein a starting mixture for the gel-casting process is made by mixing the metal powder with a liquid and a binder, wherein the starting mixture is thoroughly mixed in a vacuum. 
     
     
         2 . The method according to  claim 1 , wherein the relationship of the weight percentage of liquid to binder in the starting mixture is between 95 to 5 and 99.9 to 0.1. 
     
     
         3 . The method according to  claim 1 , wherein the relationship of the weight percentage of liquid and binder to metal powder in the starting mixture is between 5 to 95 and 20 to 80. 
     
     
         4 . The method according to  claim 1 , wherein the binder is blended with the liquid to a liquid-binder mixture before this liquid-binder mixture is blended with the metal powder. 
     
     
         5 . The method according to  claim 1 , wherein metal powder is used which is based on cobalt, chrome, molybdenum, wolfram, carbide, beryllium, stainless steel, titanium, aluminum, copper, tin or mixtures thereof. 
     
     
         6 . The method according to  claim 1 , wherein, preferably distilled, water is used as liquid. 
     
     
         7 . The method according to  claim 1 , wherein the binder contains cellulose, preferably methyl cellulose. 
     
     
         8 . The method according to  claim 1 , wherein a chemical auxiliary means for the mixing, preferably a dispersant, is admixed to the starting mixture. 
     
     
         9 . The method according to  claim 1 , wherein the thoroughly mixing in a vacuum is effected in a vacuum chamber, wherein a low pressure, preferably between 25 and 40 millibar, prevails in the vacuum chamber. 
     
     
         10 . The method according to  claim 1 , wherein the starting mixture thoroughly mixed in a vacuum is poured, preferably in a vacuum, into a mold. 
     
     
         11 . The method according to  claim 10 , wherein the mold is treated with a release agent before the starting mixture is poured into the mold. 
     
     
         12 . The method according to  claim 1 , wherein the starting mixture, preferably located in the mold closed with a cover, is warmed, preferably in a heating cabinet, whereby the gelation starts in the starting mixture and the starting mixture is solidified to a gel-solidified green body. 
     
     
         13 . The method according to  claim 12 , wherein for the gelation the starting mixture is warmed in the heating cabinet for 20 minutes to 70 minutes, preferably for 35 minutes to 55 minutes, to a temperature between 50° C. and 95° C., preferably to 60° C. to 85° C. 
     
     
         14 . The method according to  claim 12 , wherein the gel-solidified green body, preferably located in an opened mold, is dried to a dried green body in a drying cabinet for 10 to 20 hours at a temperature between 50° C. and 95° C. 
     
     
         15 . The method according to  claim 12 , wherein the gel-solidified green body or the dried green body is taken out of the mold. 
     
     
         16 . The method according to  claim 15 , wherein after the demolding the surface of the dried green body is machined by a machining device. 
     
     
         17 . The method according to  claim 12 , wherein the dried green body is compressed in a cold isostatic pressing process. 
     
     
         18 . The method according to  claim 17 , wherein the cold isostatic pressing process of the dried green body arranged in a watertight packaging is carried out in pressure vessel filled with a liquid at a pressure of at least 1000 bar, preferably at 2000 to 5000 bar, for at least 10 seconds, preferably for 20 to 40 seconds. 
     
     
         19 . The method according to  claim 12 , wherein the dried green body is debinded and sintered in a sintering oven to a pre-sintering body. 
     
     
         20 . The method according to  claim 19 , wherein in the event of sintering of the dried green body in the sintering oven a debinding is initially effected, in which the temperature in the sintering oven increases in about 10 to 20 hours to 400° C. to 550° C. 
     
     
         21 . The method according to  claim 19 , wherein after the debinding a pre-sintering of the dried green body to a pre-sintering body is carried out, in which the temperature in the sintering oven remains for 25 to 180 minutes in a range between 650° C. and 900° C. 
     
     
         22 . The method according to  claim 19 , wherein in a machining device, preferably in a CNC milling device, the pre-sintering bode is machined to the molded blank. 
     
     
         23 . A molded blank produced in a method according to  claim 1 . 
     
     
         24 . Use of the molded blank according to  claim 23  for the production of a denture.