Processes, compositions and systems for 2D and 3D printing
The present disclosure is directed to 3D printing and other additive manufacturing, in aspects including aqueous dispersion precipitation, exothermic metal conductor processing, foaming, seeding, thermosensitive polymers, build material crosslinking.
1. A method for additive 3D manufacturing of a designed object based on a 3D digital data model of said object characterized in shape and structure by a plurality of adjacent object layers of build material, by sequential application of a plurality of geometrically designed object layer patterns of build material characterizing the shape and structure of said object, comprising the steps of
providing an aqueous dispersion of an object build material dispersed in an aqueous solution of a thermosensitive polymer in water to form an aqueous amphiphilic dispersion which undergoes phase separation from the water component of said aqueous dispersion upon heating to a phase change temperature at which said thermosensitive polymer precipitates from aqueous solution together with said build material above the lower critical solution temperature, LCST, of said aqueous amphiphilic dispersion,
selectively extruding said aqueous amphiphilic dispersion at a temperature below its LCST precipitation phase change temperature onto a suitable substrate corresponding to a geometrically defined pattern of the first of said object layers,
heating said extruded aqueous dispersion above its LCST to congeal and aggregate said build material of said extruded aqueous dispersion together with said thermosensitive polymer while separating and expelling liquid water to deposit the build material in the first of said object layer patterns, said heating being carried out by application of thermal energy to the extruded amphiphilic dispersion by directed laser light,
subsequently repeating said extrusion and heating steps to form each of said adjacent layers of build material on the preceding object layer as a substrate, to form the shape and structure of said object.
2. The method of claim 1 wherein said congealed and aggregated build material of said extruded aqueous dispersion does not re-emulsify or re-disperse when the temperature of the formed object is cooled below the LCST.
3. The method of claim 1 wherein the substrate is maintained at a temperature higher than the LCST of the applied aqueous suspension.
4. The method of claim 1 wherein said aqueous amphiphilic dispersion comprises a conductive or semiconductive material for fabricating conductor or semiconductor patterns, devices, electrodes, capacitors and other electronic components.
5. The method of claim 1 wherein said aqueous amphiphilic dispersion comprises silver or copper acetylides or —C≡C—CH3 precipitates deposited on silicon nanoparticles for manufacture of lithium battery electrodes by 3D printing.
6. The method of claim 1 wherein said aqueous amphiphilic dispersion comprises from about 10 wt % to about 85 wt % water, from about 1 wt % to about 15 wt % of an amphiphilic thermosensitive polymer, and from about 5 wt % to about 80 wt % of a build material based on the total weight of said aqueous amphiphilic dispersion, and wherein said build material has an average particle size in the range of from about 0.1 micron to about 500 microns.
7. The method of claim 1 wherein said build material comprises low alloy high carbon ferrous metal powder for metal product manufacture, and wherein said aqueous amphiphilic dispersion further comprises short hBN nanotube, short carbon nanotube, and/or cBN seeds having an individual particle volume of less than about 3 million cubic nanometers and wherein the carbon nanotube or hBN nanotube seeds have a length less than about 1000 microns, and wherein the average distance between said seed particles in said congealed and aggregated build material is less than 50 microns.
8. The method of claim 7 wherein said aqueous amphiphilic dispersion comprises Fe or Ni or acetylide coated particles as internal-heat generating particles.
9. The method of claim 7 wherein said congealed and aggregated layer of said build material is dried to form a metal particle layer from about 5 to about 200 μm thick, wherein said dried metal particle layer is scanned by laser at high temperature to melt through and re-solidify one or more previously-deposited layers, and wherein carbon is grown onto said seeds at temperatures in the range of 700° C. to 900° C.
10. The method of claim 1 wherein said formed and structured object is dried and sintered.