Process and apparatus for producing 3d moldings comprising a radiation filter

Abstract

A process and an apparatus for producing 3D moldings, wherein a spectrum converter is used. Said converter is defined as a means which absorbs a radiation, for example electromagnetic thermal radiation, and radiates or emits one or more defined wavelength ranges; the spectrum converter is here irradiated by an emitter of an electromagnetic thermal radiation (shortwave or longwave radiation), i.e. by a lamp or an emitter, for example an overhead emitter or a sintering unit, and then emits a defined electromagnetic thermal radiation

What is claimed is: 
     
         1 . A device for producing 3D molded parts using a powder-based printing process comprising:
 i) a construction platform;   ii) a coater for applying particulate construction material in layers over the construction platform;   iii) a print head for selectively applying an absorber on the particulate construction material; and   iv) a sintering unit including a first sintering radiator and a second sintering radiator, wherein the second sintering radiator includes a radiation filter;   wherein the sintering unit passes over the construction platform after the print head selectively applies the absorber.   
     
     
         5 - 26 . (canceled) 
     
     
         27 . The device of  claim 1 , wherein the device includes a third sintering radiator that passes over the construction platform after the coater applies the particulate construction material and before the print head selectively applies the absorber. 
     
     
         28 . The device of  claim 1 , wherein the first sintering radiator moves with the second sintering radiator. 
     
     
         29 . The device of  claim 27 , wherein the first and second sintering radiators move together over the construction platform. 
     
     
         30 . The device of  claim 29 , wherein the third sintering radiator moves with the coater. 
     
     
         31 . The device of  claim 29 , wherein the coater, the sintering unit, the print head, and the third sintering radiator each operate while moving in a same horizontal direction over the construction platform. 
     
     
         32 . The device of  claim 1 , wherein the sintering unit causes a temperature of a printed area, printed with the absorber, to increase from a temperature within a sintering window and causes a temperature of an unprinted area, without the absorber, to increase from a temperature within the sintering window to a higher temperature within the sintering window;
 wherein the sintering window is from a liquidus temperature of the particulate material to a solidus temperature of the particulate material.   
     
     
         33 . The device of  claim 1 , wherein the device includes a controller for adjusting a power of a radiator. 
     
     
         34 . The device of  claim 1 , wherein the device includes at least two overhead radiators. 
     
     
         35 . A method for manufacturing a molded part with the device of  claim 1 , the method comprising steps of:
 i) applying a layer of the particulate material over the building platform with the coater;   ii) heating the entire layer of particulate material to a base temperature within the sintering window;   iii) selectively printing the absorber on the particulate material;   iv) heating the particulate material after printing with the absorber with the sintering unit wherein the particulate material with the absorber is heated to a temperature above the sintering window and the particulate material without the absorber is increased to a second temperature within the sintering window; and   v) lowering the building platform;   wherein steps (i), (ii), (iii), (iv), (v) are repeated.   
     
     
         36 . The method of  claim 35 , wherein the first and second sintering radiators are attached. 
     
     
         37 . The method of  claim 36 , wherein the step of heating to a base temperature includes heating with a third sintering radiator, prior to selectively applying the absorber. 
     
     
         38 . The method of  claim 37 , wherein the third sintering radiator is attached to the coater. 
     
     
         39 . The method of  claim 38 , wherein a radiation from the third sintering radiators arrives at the particulate material without passing through a radiation filter. 
     
     
         40 . The method of  claim 35 , wherein the applied absorber is selected to absorb the wavelengths of a radiation of the second sintering radiator that passes through the radiation filter. 
     
     
         41 . The method of  claim 35 , wherein the method includes a step of adjusting a power output of a radiator. 
     
     
         42 . The method of  claim 35 , wherein the heating of the particulate material is controlled by a traversing speed of the radiators, optionally wherein the second temperature and the base temperature are about the same. 
     
     
         43 . The method of  claim 36 , wherein the second temperature is greater than the base temperature. 
     
     
         44 . The method of  claim 35 , wherein the first and second sintering units have different spectra. 
     
     
         45 . The method of  claim 35 , wherein the method is free of heating the particulate material with a stationary overhead radiator.