System and method for dispensing composite filaments for additive manufacturing

An assembly for 3D printing, the assembly comprising:

• a nozzle with an orifice through which can be dispensed a composite filament;
• and
• a steered light source comprising at least one light source for UV radiation positioned adjacent the nozzle;
• wherein the steered light source comprises a controller and a motor;
• wherein the motor controls a relative position of the at least one light source in order to direct UV radiation onto the dispensed composite filament;
• wherein the steered light source is advanced as the nozzle is advanced to dispense the composite filament;
• and
• wherein the controller directs a direction and intensity of the UV radiation from the at least one light source in response to instructions provided to the controller.

A method for 3D printing comprising:

• dispensing through an orifice in a nozzle a composite filament comprising a curable polymer matrix portion wherein the curable polymer matrix has dispersed therein a plurality of fibers or particles, wherein the fibers or particles do not react with the curable polymer matrix;
• wherein the curable polymer matrix comprises a UV curable polymer and a heat curable polymer, wherein the curable polymer matrix comprises at least one of monomers or oligomers or both and wherein the composite filament is at least about 30 volume percent to about 70 volume percent curable polymer matrix of which at least 80 volume percent is thermoset polymer and at least 4 volume percent is UV-curable polymer and the composite filament is about 30 volume percent to about 70 volume percent carbon fibers or particles;
• upon dispense, flowing the composite filament past a UV radiation source, wherein the UV radiation source is positioned to direct UV radiation toward the dispensed composite filament, at least partially curing the UV curable polymer in the composite filament;
• dispensing the composite filament onto a surface;
• forming a 3D printed article;
• and
• heating the 3D printed article to cure the heat curable polymer in the curable polymer matrix.