Method for analysing a build layer
Described is a method for analyzing a build layer ( 1; 11 ) in an additive manufacturing machine when forming a three-dimensional article layer by layer by successive fusion of selected areas of powder layers, which selected areas correspond to successive layers of the three-dimensional article. The method comprises the steps of radiating a portion ( 4; 14 ) of the build layer ( 1; 11 ) by an energy beam and detecting particles emitted, backscattered or reflected from the radiated portion of the build layer, and scanning the portion ( 4; 14 ) of the build layer by moving the energy beam along a main path ( 5; 15 ) and simultaneously moving the energy beam back-and-forth across the main path in a meandering pattern ( 6; 16 ).
1. A method for analyzing a build layer ( 1 ; 11 ) in an additive manufacturing machine when forming a three-dimensional article layer by layer by successive fusion of selected areas of powder layers, which selected areas correspond to successive layers of the three-dimensional article, the method comprising the steps of:
radiating a portion ( 4 ; 14 ) of the build layer ( 1 ; 11 ) by an energy beam,
detecting particles emitted, backscattered or reflected from the radiated portion of the build layer, and
scanning the portion ( 4 ; 14 ) of the build layer by moving the energy beam along a main path ( 5 ; 15 ) and simultaneously moving the energy beam back-and-forth across the main path in a meandering pattern ( 6 ; 16 ) having alternating peaks ( 9 ) and valleys ( 10 ), such that a distance in a direction orthogonal to the direction ( 8 ) of the main path ( 5 ) between a peak and a subsequent valley of the meandering pattern is y, where 1<y<100 mm, and a distance in parallel with the direction of the main path between two consecutive peaks of the meandering pattern is x, where 2<x<1000 μm.
2. The method according to claim 1 , wherein the moving of the energy beam along the main path ( 15 ) is selected on the basis of a boundary ( 20 ) between a previously melted section and a non-melted section of the build layer ( 11 ).
3. The method according to claim 1 , wherein the moving of the energy beam along the main path ( 15 ) occurs substantially following a boundary ( 20 ) between a previously melted section and a non-melted section of the build layer ( 11 ).
4. The method according to claim 1 , wherein the moving of the energy beam along the main path ( 5 ; 15 ) is selected on the basis of a path along which an electron beam or a laser beam has been previously moved for melting the build layer ( 1 ; 11 ).
5. The method according to claim 1 , wherein the moving of the energy beam along the main path ( 5 ; 15 ) occurs substantially following a path along which an electron beam or a laser beam has been previously moved for melting the build layer ( 1 ; 11 ).
6. The method according to claim 1 , wherein the moving of the energy beam occurs in a continuous meandering pattern ( 6 ; 16 ).
7. The method according to claim 1 , wherein the moving of the energy beam occurs such that a non-melted section ( 12 ) of the build layer is radiated for detecting particles emitted, backscattered or reflected from the non-melted section.
8. The method according to claim 1 , wherein the moving of the energy beam occurs such that a previously melted and solidified section ( 3 ; 13 ) of the build layer is radiated for detecting particles emitted, backscattered or reflected from the previously melted and solidified section.
9. The method according to claim 1 , wherein y is 2<y<50 mm and x is 5<x<500 μm.
10. The method according to claim 1 , wherein y is 4<y<10 mm and x is 10<x<100 μm.
11. The method according to claim 1 , wherein the moving of the energy beam occurs in alternating directions in parallel vectors (V 1 , V 2 ) crossing the main path ( 5 ; 15 ).
12. The method according to claim 11 , wherein the moving of the energy beam in the parallel vectors (V 1 , V 2 ) is orthogonal to the direction of the main path ( 5 ).
13. The method according to claim 11 , wherein the moving of the energy beam in the meandering pattern ( 6 ; 16 ) is substantially square wave shaped.
14. The method according to claim 1 , wherein the energy beam is an electron beam ( 33 ).
15. The method according to claim 14 , further comprising the step of detecting at least one of back-scattered electrons or secondary electrons emitted from the build layer ( 1 ; 11 ).
16. The method according to claim 14 , further comprising the step of radiating the portion ( 4 ; 14 ) of the build layer by the electron beam ( 33 ), wherein the electron beam ( 33 ) has a beam current I B in the range 1<I B <1000 μA.
17. The method according to claim 16 , wherein the beam current is 5<I B <500 μA.
18. The method according to claim 16 , wherein the beam current is 10<I B <100 μA.
19. An arrangement ( 50 ; 150 ) for an additive manufacturing machine, the arrangement comprising:
an energy beam ( 33 ; 133 ) configured to radiate a portion ( 4 ; 14 ) of a build layer ( 1 ; 11 ; 34 ; 134 );
a particle detector device ( 31 ; 131 ) for detecting particles emitted, backscattered or reflected from the build layer ( 1 ; 11 ; 34 ; 134 ) in the additive manufacturing machine; and
a control unit ( 32 ; 132 ),
wherein the control unit ( 32 ; 132 ) is configured to:
detect particles emitted, backscattered or reflected from the radiated portion of the build layer, and
move the energy beam ( 33 ; 133 ) along a main path ( 5 ; 15 ) and simultaneously back-and-forth across the main path in a meandering pattern ( 6 ; 16 ) having alternating peaks ( 9 ) and valleys ( 10 ), such that a distance in a direction orthogonal to the direction ( 8 ) of the main path ( 5 ) between a peak and a subsequent valley of the meandering pattern is y, where 1<y<100 mm, and a distance in parallel with the direction of the main path between two consecutive peaks of the meandering pattern is x, where 2<x<1000 μm.
20. A computer program product comprising at least one non-transitory computer-readable storage medium having computer-readable program code portions embodied therein, the computer-readable program code portions comprising one or more executable portions configured for performing the method according to claim 1 .
21. A method for analyzing a build layer ( 1 ; 11 ) in an additive manufacturing machine when forming a three-dimensional article layer by layer by successive fusion of selected areas of powder layers, which selected areas correspond to successive layers of the three-dimensional article, the method comprising the steps of:
radiating a portion ( 4 ; 14 ) of the build layer ( 1 ; 11 ) by an energy beam,
detecting particles emitted, backscattered or reflected from the radiated portion of the build layer, and
scanning the portion ( 4 ; 14 ) of the build layer by moving the energy beam along a main path ( 5 ; 15 ) and simultaneously moving the energy beam back-and-forth in alternating directions in parallel vectors (V 1 , V 2 ) crossing the main path ( 5 ; 15 ) in a meandering pattern ( 6 ; 16 ) having a substantially square shape.