Method And Apparatus For Making Products By Sintering And/Or Melting

Abstract

The invention relates to a method for making metallic and/or non-metallic products 2, in particular dental products, by freeform sintering and/or melting, in which the products 2 are fabricated layer by layer from a material 5 that is applied layer by layer by means of a computer-controlled high-energy beam 7, in particular a laser or electron beam. In order to reduce production times, beam 7 irradiates predetermined positions P 1 to P 6 of a layer of a material 5 a plurality of time, namely m times, where m is a whole integer greater than 1. Each of said positions P 1 to P 6 is initially heated during the first irradiation to a temperature below the melting point T melt of the material 5, and during the mth irradiation to a temperature above said melting point and is completely melted over the entire thickness of the layer in such a way that the material ( 5 ) fuses at said position to the layer thereunder. The invention also relates to an apparatus for performing said method.

1 . The invention relates to a method for making metallic and/or nonmetallic products, in particular dental products, by freeform sintering and/or melting, in which the products are fabricated layer by layer from a material that is applied layer by layer by means of a computer-controlled high-energy beam, in particular a laser or electron beam, wherein the beam irradiates predetermined positions of a material a plurality of times in each case, namely m times, where m is a whole integer greater than 1, wherein each of said positions is initially heated during the first irradiation to a temperature below the melting point (T melt ) of the material and during the m-th irradiation to a temperature above said melting point (T melt ) and is completely melted over the entire thickness of the layer in such a way that the material fuses at said position to a layer thereunder. 
     
     
         2 . Method according to  claim 1 , wherein m equals 2. 
     
     
         3 . A method according to  claim 2 , wherein each of said positions is irradiated for a first duration (Δt on ), then not irradiated during a second duration (Δt off ), wherein the second duration (Δt off ) is at least exactly as long or twice as long as the first duration (Δt on ). 
     
     
         4 . Method according to  claim 1 , wherein m equals 3. 
     
     
         5 . Method according to  claim 4 , wherein each of said positions is irradiated for a first duration (Δt on ), then not irradiated during a second duration (Δt off ), wherein the second duration ((Δt off ) is at least exactly as long, twice as long or four times as long as the first duration (Δt on ). 
     
     
         6 . Method according to  claim 5 , wherein the beam is guided backward and forward with a first substantially linear movement, the forward movement extending over a longer path than the backward movement. 
     
     
         7 . Method according to  claim 6 , wherein a second, meandering movement is superimposed upon said first movement. 
     
     
         8 . Method according to  claim 7 , wherein a powdery material is used. 
     
     
         9 . Method according to  claim 8 , wherein during and/or after a layer is irradiated an ensuing or completed contour of the product is optically measured, and the measuring data thus obtained are compared with specified data and if a deviation is discovered the beam is adjusted to take account of the deviation thus identified. 
     
     
         10 . An apparatus for making metallic and/or non-metallic products, in particular dental products, by freeform sintering and/or melting using a high-energy beam, in particular a laser or electron beam, and for performing a method according to  claim 9 , wherein the apparatus comprises:
 a beam source for generating said beam,   a platform for receiving a material that can be applied in layers and a controller for controlling the beam, by means of which the beam can be guided by computer in order to fabricate the products layer by layer from the material, wherein the controller is configured in such a way that, by means of said controller, the beam irradiates predetermined positions of a material a plurality of times in each case, namely m times, where m is a whole integer greater than 1, wherein each of said positions is initially heated during the first irradiation to a temperature below the melting point (T melt ) of the material and during the mth irradiation to a temperature above said melting point (T melt ) and is completely melted over the entire thickness of the layer in such a way that the material fuses at said position to the layer thereunder.