Melt pool control in additive manufacturing systems
Systems and methods for additive manufacturing are described. In some embodiments, a method of controlling a weld height in an additive manufacturing process includes determining a desired melt pool width based, at least in part, on a desired weld height; selectively activating one or more laser energy sources based, at least in part, on the desired melt pool width; and melting a portion of a layer of material on a build surface via exposure to laser energy from the one or more activated laser energy sources to form a melt pool on the build surface having the desired melt pool width. Systems and methods to the use of staggered laser energy sources are also described.
1 . An additive manufacturing system comprising:
a build surface;
a plurality of laser energy sources;
an optics assembly optically coupled to the plurality of laser energy sources and configured to direct laser energy from the plurality of laser energy sources toward the build surface; and
a processor operatively coupled to the plurality of laser energy sources, the processor configured to determine one or more operating parameters for the plurality of laser energy sources and/or the optics assembly predicted to produce a desired weld height for a portion of a fused layer of a part to be built by the additive manufacturing system, the processor configured to determine the one or more operating parameters by:
using the desired weld height and a desired melt pool height to determine a desired melt pool width predicted to produce the desired weld height and the desired melt pool height, wherein the desired weld height is different from the desired melt pool height; and
determining the one or more operating parameters such that exposure of a portion of a layer of material on the build surface to the laser energy from one or more laser energy sources of the plurality of laser energy sources activated according to the one or more operating parameters is predicted to form the portion of the fused layer having the desired weld height by melting the portion of the layer of material to form one or more melt pools having the desired melt pool width and/or the desired melt pool height; and wherein
the processor is further configured to control the optics assembly and/or the one or more laser energy sources of the plurality of laser energy sources according to the one or more operating parameters.
2 . The additive manufacturing system of claim 1 , wherein the one or more operating parameters comprises a number of laser energy sources to be activated, a laser power density, a laser scan speed, a laser spot size, a laser focus, and/or a laser pulse rate.
3 . The additive manufacturing system of claim 1 , wherein the one or more melt pools forms one or more liquid menisci on the build surface.
4 . The additive manufacturing system of claim 3 , wherein a maximum height of the one or more liquid menisci is less than the desired weld height.
5 . The additive manufacturing system of claim 3 , wherein a maximum height of the one or more liquid menisci is equal to the desired weld height.
6 . The additive manufacturing system of claim 1 , wherein the plurality of laser energy sources are configured as an array of laser energy sources, and wherein the processor is configured to selectively activate two or more adjacent laser energy sources of the array to form the one or more melt pools.
7 . The additive manufacturing system of claim 1 , wherein the one or more melt pools includes a first melt pool, and wherein the processor is further configured to form a second melt pool on the build surface via exposure of a second portion of the layer of material on the build surface to the laser energy from the activated laser energy sources.
8 . The additive manufacturing system of claim 7 , wherein the second melt pool is physically spaced from the first melt pool on the build surface.
9 . The additive manufacturing system of claim 8 , wherein a spacing between the first and second melt pools is between 25 μm and 100 mm.
10 . The additive manufacturing system of claim 8 , wherein a spacing between the first and second melt pools is based, at least in part, on a material property of the layer of material on the build surface.
11 . The additive manufacturing system of claim 10 , wherein the material property is a surface tension of the layer of material when the layer of material is melted.
12 . The additive manufacturing system of claim 7 , wherein the second melt pool is formed after the first melt pool is solidified to form a first portion of a fused layer.
13 . The additive manufacturing system of claim 12 , wherein a position of the second melt pool is adjacent a position of the first melt pool.
14 . The additive manufacturing system of claim 1 , wherein the desired melt pool width is between 50 μm and 5 mm.
15 . The additive manufacturing system of claim 1 , wherein the desired weld height is between 20 μm and 5 mm.
16 . The additive manufacturing system of claim 1 , wherein the processor is further configured to control a width of the one or more melt pools by adjusting a focus of one or more of the activated laser energy sources.
17 . The additive manufacturing system of claim 1 , wherein forming the one or more melt pools includes forming a plurality of melt pools including at least one leading melt pool and at least one trailing melt pool, wherein the at least one leading melt pool solidifies prior to the at least one trailing melt pool contacting the at least one leading melt pool.
18 . An additive manufacturing system comprising:
a build surface;
a plurality of laser energy sources;
an optics assembly optically coupled to the plurality of laser energy sources and configured to direct laser energy from the plurality of laser energy sources toward the build surface; and
a processor operatively coupled to the plurality of laser energy sources, the processor configured to:
determine a desired weld height and/or a desired melt pool height;
determine a desired melt pool width based on the desired weld height and/or the desired melt pool height;
determine one or more operating parameters of at least one of the plurality of laser energy sources and/or the optics assembly based on the desired melt pool width, such that exposure of a portion of a layer of material on the build surface to the laser energy from the at least one of the plurality of laser energy sources activated according to the one or more operating parameters fuses a portion of the layer having the desired weld height by melting the portion of the layer to form one or more melt pools having the desired melt pool height and/or the desired melt pool width; and
control the optics assembly and/or the at least one of the plurality of laser energy sources according to the one or more operating parameters.
19 . The additive manufacturing system of claim 18 , wherein the desired melt pool width is only determined by the desired weld height.
20 . The additive manufacturing system of claim 18 , wherein the desired melt pool width is only determined by the desired melt pool height.
21 . The additive manufacturing system of claim 18 , wherein the plurality of laser energy sources are configured as an array of laser energy sources, and wherein the processor is configured to selectively activate two or more adjacent laser energy sources of the array to form the one or more melt pools.
22 . The additive manufacturing system of claim 18 , wherein the one or more melt pools include a first melt pool, and wherein the processor is configured to form a second melt pool on the build surface via exposure of a second portion of the layer of material on the build surface to the laser energy from the activated laser energy sources according to the one or more operating parameters.
23 . The additive manufacturing system of claim 18 , wherein the processor is configured to cause adjustment of a focus of one or more of the activated laser energy sources to control a width of the one or more melt pools.
24 . The additive manufacturing system of claim 18 , wherein the one or more operating parameters comprises a number of laser energy sources to be activated, a laser power density, a laser scan speed, a laser spot size, a laser focus, and/or a laser pulse rate.
25 . The additive manufacturing system of claim 18 , wherein the one or more melt pools forms one or more liquid menisci on the build surface.
26 . The additive manufacturing system of claim 25 , wherein a maximum height of the one or more liquid menisci is less than the desired weld height.
27 . The additive manufacturing system of claim 25 , wherein a maximum height of the one or more liquid menisci is equal to the desired weld height.
28 . The additive manufacturing system of claim 18 , wherein the plurality of laser energy sources is configured as an array of laser energy sources, and wherein the processor is configured to selectively activate two or more adjacent laser energy sources of the array to form the one or more melt pools.
29 . The additive manufacturing system of claim 18 , wherein the one or more melt pools includes a first melt pool, and wherein the processor is further configured to form a second melt pool on the build surface via exposure of a second portion of the layer of material on the build surface to the laser energy from the activated laser energy sources.
30 . The additive manufacturing system of claim 29 , wherein the second melt pool is physically spaced from the first melt pool on the build surface.
31 . The additive manufacturing system of claim 30 , wherein a spacing between the first and second melt pools is between 25 μm and 100 mm.
32 . The additive manufacturing system of claim 30 , wherein a spacing between the first and second melt pools is based, at least in part, on a material property of the layer of material on the build surface.
33 . The additive manufacturing system of claim 32 , wherein the material property is a surface tension of the layer of material when the layer of material is melted.
34 . The additive manufacturing system of claim 29 , wherein the second melt pool is formed after the first melt pool is solidified to form a first portion of a fused layer.
35 . The additive manufacturing system of claim 34 , wherein a position of the second melt pool is adjacent a position of the first melt pool.
36 . The additive manufacturing system of claim 18 , wherein the desired melt pool width is between 50 μm and 5 mm.
37 . The additive manufacturing system of claim 18 , wherein the desired weld height is between 20 μm and 5 mm.
38 . The additive manufacturing system of claim 18 , wherein the processor is further configured to control a width of the one or more melt pools by adjusting a focus of one or more of the activated laser energy sources.
39 . The additive manufacturing system of claim 18 , wherein forming the one or more melt pools includes forming a plurality of melt pools including at least one leading melt pool and at least one trailing melt pool, wherein the at least one leading melt pool solidifies prior to the at least one trailing melt pool contacting the at least one leading melt pool.