Rounded-Particle Plastic Powder in Particular for Application in Laser Sintering, Method for Production of Such a Powder and Laser Sintering Process Using Such a Powder

Abstract

In a laser sintering method for producing a three-dimensional object wherein subsequent layers of the object to be formed are subsequently solidified on positions corresponding to the object, as a build-up material, a powder is used wherein the upper grain limit of the powder particles is below 100 μm, the D 0.5 -value is below 55 μm, the BET-surface is smaller than 5 m 2 /g and the grains of the powder basically have a spherical shape.

1 . A polyamide powder consisting of a single component comprising a surface which is compact and not jagged wherein said polyamide powder is suited to be used as building material in the production of a three-dimensional object by selective solidification of the powder by electromagnetic radiation. 
     
     
         2 . A polyamide powder consisting essentially of a single component comprising a surface which is compact and not jagged wherein said polyamide powder is suited to be used as building material in the production of a three-dimensional object by selective solidification of the powder by electromagnetic radiation, wherein the powder comprises a BET-surface which is smaller than 5 m 2 /g and at the same time the upper grain limit is below 100 μm, the D 0.9 -value is below 80 μm, and the D 0.5 -value is below 55 μm and the particles comprise a basically spherical shape. 
     
     
         3 . A powder according to  claim 1 , wherein the powder has a BET-surface having a value smaller than or equal to 4 m 2 /g. 
     
     
         4 . A powder according to  claim 1 , wherein the powder has a BET-surface having a value smaller than or equal to 3 m 2 /g. 
     
     
         5 . A powder according to  claim 1 , wherein the powder has a BET-surface having a value smaller than or equal to 2 m 2 /g. 
     
     
         6 . A powder for manufacturing a three-dimensional object by means of laser sintering  claim 1 , wherein a laser sintering refreshing factor is less than 50 percent. 
     
     
         7 . A powder according to  claim 6 , wherein the refreshing factor is less than 30 percent. 
     
     
         8 . A powder according to  claim 1 , wherein the powder is a polyamide powder. 
     
     
         9 . A powder according to  claim 1 , wherein the powder consists of polyamide 11 or polyamide 12. 
     
     
         10 . A powder according to  claim 8 , wherein the powder is a precipitated PA12 powder. 
     
     
         11 . A method for producing a powder according to  claim 1 , wherein as a base material a plastic powder attained by means of precipitation or milling is used which is mechanically or mechanically-thermally mixed for at least one minute in an appropriate aggregate. 
     
     
         12 . A method for manufacturing a three-dimensional object by means of laser sintering wherein subsequent layers of the object to be formed are subsequently solidified from solidifiable powder material in positions corresponding to the object and a powder according to  claim 1  is used as powder material. 
     
     
         13 . A method according to  claim 12  wherein the powder base material has at least one further powder component. 
     
     
         14 . A method according to  claim 13  wherein a further powder component is a polymer powder or an additive. 
     
     
         15 . A powder according to  claim 1  for producing a three-dimensional object by laser sintering, wherein the powder comprises a BET-surface which is smaller than 5 m 2 /g and at the same time the upper grain limit is below 100 μm, the D 0.9 -value is below 80 μm, and the D 0.5 -value is below 55 μm and the particles comprise a basically spherical shape.