3D PRINTING METHODS
This disclosure describes a method of printing a 3D printed object. The method comprises: selectively applying a fusing agent onto a portion of a build material, wherein the fusing agent comprises a radiation-absorbing dye dissolved in an aqueous liquid carrier; exposing the selectively applied fusing agent to radiation to produce heat energy to fuse the portion of build material to form a layer of the 3D printed object; and thermally treating the 3D printed object at a temperature of above 70° C.
1 . A method of printing a 3D printed object, said method comprising:
selectively applying a fusing agent onto a portion of a build material, wherein the fusing agent comprises a radiation-absorbing dye dissolved in an aqueous liquid carrier;
exposing the selectively applied fusing agent to radiation to produce heat energy to fuse the portion of build material to form a layer of the 3D printed object; and
thermally treating the 3D printed object at a temperature of above 70° C.
2 . The method of claim 1 , wherein, prior to thermal treatment, the 3D printed object comprises a first region and a second region, wherein the concentration of radiation-absorbing dye in the first region is higher than the concentration of radiation-absorbing dye in the second region, and
wherein, during thermal treatment, migration of radiation-absorbing dye occurs between the first region and the second region to decrease the difference in concentration in radiation-absorbing dye between the first region and the second region.
3 . The method of claim 2 , wherein, prior to thermal treatment, there is an alternating concentration of radiation-absorbing dye within the structure of the 3D printed object, whereby first regions of high concentration of radiation-absorbing dye alternate with second regions of low concentration of radiation-absorbing dye.
4 . The method of claim 1 , wherein the 3D printed object is thermally treated at a temperature that is within 100 degrees C. below the melting temperature of the build material.
5 . The method of claim 1 , wherein the build material comprises a polymer having a melting temperature of above 140° C.
6 . The method of claim 1 , wherein the fusing agent comprises less than 1 weight % of a radiation-absorbing pigment.
7 . The method of claim 1 , wherein the aqueous liquid carrier comprises water and an organic solvent.
8 . The method of claim 7 , wherein the organic solvent comprises a first organic solvent and a second organic solvent.
9 . The method of claim 8 , wherein the first organic solvent is a plasticizer.
10 . The method of claim 8 , wherein the second organic solvent is a solubilizer for solubilizing the radiation-absorbing dye and/or the first organic solvent in the liquid aqueous carrier.
11 . The method of claim 7 , wherein the first organic solvent is selected from benzyl alcohol and diethylene glycol butyl ether (DEGBE), and the second organic solvent is selected from diethylene glycol butyl ether (DEGBE), 1,2-hexanediol, hydroxyethyl-2-pyrrolidone (HE2P), glycerol, propylene glycol, ethylene glycol and 1,5-pentane diol.
12 . The method as claimed in claim 7 , wherein the weight ratio of the first organic solvent to the second organic solvent is 1:8 to 1:1.
13 . The method of claim 1 , wherein the radiation-absorbing dye absorbs radiation in the infrared or visible region of the electromagnetic spectrum.
14 . The method of claim 1 , wherein, after thermal treatment, the elongation at break perpendicular to the layers of the 3D printed object is at least 60% of the elongation at break along the layers of the 3D printed object.
15 . A 3D printed object obtainable by the method of claim 1 .