System and method for dispensing composite filaments for additive manufacturing

Abstract

A method and apparatus for forming a 3D article. According to the method, a composite filament material is formed from a UV curable material, a thermoset polymer material and at least one of filaments or fibers. After the composite is formed, the filament is dispensed to form the 3D article. Dispense is typically through a nozzle or other orifice that delivers the composite filament material as a bead of material. As the composite is dispensed, at least a portion of the composite material is exposed to UV radiation thereby curing a portion of the dispensed composite filament. The UV radiation is provided by a light source than can target discrete portions of the dispensed composite filament. For this purpose, the UV radiation source can be a light source integrated with the nozzle or a steered light source. As the composite filament is dispensed, UV radiation is directed onto the composite filament. If a steered light source is used, the composite filament is dispensed and light from the steered UV radiation source is directed to targeted regions of the composite filament, introducing cured zones or regions into the composite filament.

1 . An assembly for 3D printing, the assembly comprising:
 a nozzle with a first channel through which can pass a composite filament; and   a lighting apparatus adjacent the channel, wherein the lighting apparatus comprises a support and at least one light source positioned on the support and wherein the at least one light source is positioned to direct at least a portion of the composite filament to UV radiation as the composite filament is dispensed past the light source;   wherein the first channel terminates in an orifice wherein the composite filament is dispensed from the nozzle through the orifice;   wherein the at least one light source is a source for ultraviolet (UV) radiation; and   wherein the at least one light source is positioned on the support to direct the UV radiation onto at least a portion of the composite filament as it is dispensed past the light source.   
     
     
         2 . The assembly of  claim 1  wherein the lighting apparatus comprises a plurality of light sources wherein the plurality of light sources are placed on the support such that each light source of the plurality of light sources is about a same distance from the composite filament as the composite filament passes through the lighting apparatus. 
     
     
         3 . The assembly of  claim 2  wherein the plurality of light sources are integrated with the nozzle and direct the UV radiation toward the first channel. 
     
     
         4 . The assembly of  claim 1  further comprising at least one of light baffles, light filters or light reflectors to direct UV radiation from the UV radiation source onto the composite filament in a predetermined location at a predetermined dose. 
     
     
         5 . The assembly of  claim 2  wherein the support is configured such that each light source is positioned on the support approximately equidistantly from the composite filament as it passes through the lighting apparatus. 
     
     
         6 . The assembly of  claim 1  wherein the light source is configured such that a surface of the composite filament on which the UV radiation is incident is approximately equidistantly spaced from one of the light source or a reflector in a light path from the light source. 
     
     
         7 . The assembly of  claim 1  wherein the support has one of a circular configuration, a hexagonal configuration, or an octagonal configuration. 
     
     
         8 . The assembly of  claim 2  wherein the plurality of light sources is at least two. 
     
     
         9 . The assembly of  claim 2  wherein the plurality of light sources is at least four. 
     
     
         10 . The assembly of  claim 1  wherein the nozzle has a second channel, the second channel and the first channel having a common central axis, the second channel configured as an annular ring around the first channel, such that a material dispensed through the second channel forms a coating on the material dispensed through the first channel. 
     
     
         11 . The assembly of  claim 1  further comprising a roller, the roller configured to exert a smoothing force onto the composite filament dispensed by the nozzle. 
     
     
         12 . The assembly of  claim 11  further comprising an independently moveable UV radiation source, wherein the independently moveable UV radiation source is positioned to direct UV radiation onto the composite filament dispensed by the nozzle after the roller has passed over the composite filament dispensed by the nozzle. 
     
     
         13 . The assembly of  claim 12  further comprising a steering mechanism for the independently moveable UV radiation source, the steering mechanism comprising a motor and a controller, the controller configured to determine an amount and duration of the UV radiation to be directed toward the composite filament dispensed by the nozzle and the motor is configured to adjust a position of at least one of the UV radiation source. 
     
     
         14 . The assembly of  claim 13  wherein the steering mechanism further comprises at least one mirror disposed in a light path from at least one of the UV radiation sources, wherein a position of the at least one mirror is controlled by the motor in response to a signal from the controller. 
     
     
         15 . The assembly of  claim 1  wherein the at least one light source is adjacent the orifice and the orifice is configured to direct UV radiation onto the composite filament dispensed through the orifice. 
     
     
         16 . The assembly of  claim 15  further comprising a second UV radiation source wherein the second UV radiation source is positioned in a downstream direction in the nozzle relative to a first UV radiation source such that the composite filament is exposed to the UV radiation from the first UV radiation source as it is dispensed therethrough before it is exposed to the UV radiation from the second UV radiation source as it is dispensed therethrough. 
     
     
         17 . The assembly of  claim 1  wherein the nozzle and lighting apparatus form a unitary rotatable assembly. 
     
     
         18 . 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.   
     
     
         19 . The assembly of  claim 18  wherein the steered light source comprises a plurality of light sources wherein the plurality of light sources are placed on a support such that each light source of the plurality of light sources is about a same distance from the composite filament as the composite filament is dispensed from the nozzle. 
     
     
         20 . The assembly of  claim 18  further comprising at least one of light baffles, light filters or light reflectors to direct UV radiation from the UV radiation source onto the composite filament in a predetermined location at a predetermined dose. 
     
     
         21 . The assembly of  claim 19  wherein the support is configured such that each light source is positioned on the support approximately equidistantly from the composite filament as it passes the steered light source. 
     
     
         22 . The assembly of  claim 18  wherein the light source is configured such that a surface of the composite filament on which the UV radiation is incident is approximately equidistantly spaced from the light source. 
     
     
         23 . The assembly of  claim 19  wherein the plurality of light sources is at least two. 
     
     
         24 . The assembly of  claim 19  wherein the plurality of light sources is at least four. 
     
     
         25 . The assembly of  claim 18  wherein the nozzle has a first and a second channel, the second channel and the first channel having a common central axis, the second channel configured as an annular ring around the first channel, such that a material dispensed through the second channel forms a coating on the material dispensed through the first channel. 
     
     
         26 . The assembly of  claim 18  further comprising a roller, the roller configured to exert a smoothing force onto the composite filament dispensed by the nozzle. 
     
     
         27 . The assembly of  claim 18  wherein the nozzle further comprises a first lighting apparatus comprising at least one source for UV radiation and a support therefore wherein the at least one source for UV radiation is positioned on the support to direct UV radiation onto the composite filament as it is dispensed from the nozzle. 
     
     
         28 . The assembly of  claim 27  wherein the first lighting apparatus comprises a plurality of sources for UV radiation wherein the plurality of sources for UV radiation are placed on the support such that each light source of the plurality of sources for UV radiation is about a same distance from the composite filament as the composite filament passes through the first lighting apparatus. 
     
     
         29 . The assembly of  claim 28  further comprising a second lighting apparatus comprising at least one source for UV radiation and a support therefore wherein the second lighting apparatus positioned to direct UV radiation onto the composite filament after the first light apparatus has directed UV radiation onto the composite filament. 
     
     
         30 . The assembly of  claim 18  wherein the controller is configured to determine an amount and duration of the UV radiation to be directed toward the dispensed composite filament and the motor is configured to adjust a position of the at least one light source. 
     
     
         31 . The assembly of  claim 18  further comprising at least one mirror disposed in a light path from the at least one light source, wherein a position of the at least one mirror is controlled by the motor in response to a signal from the controller. 
     
     
         32 . The assembly of  claim 27  wherein the first light apparatus is adjacent the orifice and the first light apparatus is configured to direct UV radiation onto the composite filament dispensed through the orifice. 
     
     
         33 . The assembly of  claim 29  wherein the second lighting apparatus is positioned in a downstream direction in the nozzle relative to the first lighting apparatus such that the composite filament is exposed to the UV radiation from the first lighting apparatus as it is dispensed therethrough before it is exposed to the UV radiation from the second lighting apparatus as it is dispensed therethrough.