Process for melting/sintering powder particles for layer-by-layer production of three-dimensional objects
A process for melting/sintering powder particles for layer-by-layer production of three-dimensional objects is performed by a)applying a layer of a powder material solidifiable under the action of electromagnetic radiation, b) heating the powder material to not more than 10 K below the melting point according to DIN 53765 by a radiation from a heat-radiating element whose maximum radiation intensity is at a wavelength of 5000 nm or at longer wavelengths, c) selective melting/sintering of at least a region of the powder material which corresponds to the cross section of the three-dimensional object, d)repeating steps a) to c) until the three-dimensional object is obtained.
1. A process for layer-by-layer production of three-dimensional objects, said process comprising:
a) applying a layer of a powder material solidifiable under the action of electromagnetic radiation,
b) heating the powder material to not more than 10 K below the melting point according to DIN 53765 by simultaneous radiation from high surface area heat-radiating elements from different directions whose maximum radiation intensity is at a wavelength of 5000 nm or at longer wavelengths,
c) selective melting/sintering of at least a region of the powder material which corresponds to the cross section of the three-dimensional object,
d) repeating steps a) to e) until the three-dimensional object is obtained, wherein the high surface area heat-radiating elements are not used to conduct the selective melting/sintering.
2. The process according to claim 1 , wherein an irradiation power of the heat-radiating element is at least 2000 W/m 2 based on a vertically projected area of a powder bed that is to be heated.
3. The process according to claim 1 , wherein an area of the heat-radiating elements is altogether at least 100% of a vertically projected area of a powder bed that is to be heated.
4. The process according to claim 1 , wherein the powder material has an absorptivity at wavelengths above 5000 nm of at least 0.8.