PROCESS FOR LAYER-BY-LAYER PRODUCTION OF THREE-DIMENTIONAL OBJECTS

1 . A process for layer-by-layer production of a three-dimensional object, the process comprising:

applying a layer of a powder material comprising polyamide PA613 onto a vertically moveable construction platform in a construction chamber to obtain a planar layer;

focusing a beam of electromagnetic radiation through a lens on a plane of the material layer;

traversing the focused beam across the plane of the material layer as directed by a control unit;

selectively melting the powder material under the focus of the beam according to the control unit to obtain a layer having a completed melt pattern;

lowering the vertically moveable construction platform; and

adding a layer of the powder material onto the layer having a completed melt pattern;

repeating the controlled melting; and

continuously adding a further layer of the powder material over the previous completed layer and repeating the controlled melting until the melt pattern of the three dimensional object is formed;

cooling the melt pattern to harden to the three dimensional shape; and

removing the three dimensional object from adhering powder material not melted by the focused beam.

2 . The process according to claim 1 , wherein a content of the polyamide PA613 in the powder material is at least 47 wt %, based on the total weight of the powder material.

3 . The process according to claim 2 wherein the content of the polyamide PA613 is at least 75 wt %, based on the total weight of the powder material.

4 . The process according to claim 1 , wherein a number-average molecular weight of the polyamide PA613 is from 8000 to 50 000 g/mol.

5 . The process according to claim 1 , wherein a bulk density of the polyamide PA613 is from 0.35 to 0.55 g/cm 3 .

6 . The process according to claim 1 , wherein a d50 particle size of the polyamide PA613 is from 30 to 80 μm.

7 . The process according to claim 1 , wherein a pourability of the polyamide PA613 is not more than 70 s.

8 . The process according to claim 1 , wherein a solution viscosity of the polyamide PA613 is from 1.5 to 2.2.

9 . The process according to claim 1 , wherein a BET surface area of the polyamide PA613 is not more than 30 m 2 /g.

10 . The process according to claim 1 , wherein a melting point of the polyamide PA613 is from 205 to 215° C.

11 . The process according to claim 1 , wherein a processing temperature of the construction chamber is at least 190° C.

12 . A three dimensional object obtained according to the process of claim 1 .

13 . The three dimensional object of claim 12 , wherein a modulus of elasticity of the three dimensional object is greater than 2000 MPa.

14 . The three dimensional object of claim 12 , wherein an elongation at break of the three dimensional object is greater than 30%.

15 . A layer-by-layer construction device for the process of claim 1 , comprising:

a construction chamber having an adjustable-height construction platform;

an apparatus for applying a layer of the powder material comprising polyamide PA613 to the construction platform;

an irradiation device comprising a radiation source which emits electromagnetic radiation;

a control unit; and

a lens which is located in the beam path of the electromagnetic radiation.