Additive fabrication methods and devices for manufacture of objects having preform reinforcements

Abstract

Additive fabrication methods for 3D composite objects having preform fiber reinforcements embedded in a matrix material include providing local heat and mechanical energy to at least partially melt, impregnate and solidify the matrix material forming at least one reinforced composite layer of the object. Successive layers are added in accordance to a computer generated tool path to form a three dimensional object with useful features.

What is claimed is: 
     
         1 . A method of forming a reinforced composite layer comprising:
 disposing a fiber preform on a target platform;   applying an electrical voltage through a pair of electrodes and the fiber preform;   disposing a layer of powder onto at least a portion of the fiber preform; and   impregnating the powder into the fiber preform, thereby forming a reinforced composite layer.   
     
     
         2 . The method of  claim 1 , wherein impregnating the powder further comprises projecting a directed energy beam onto the powder to at least partially melt the powder. 
     
     
         3 . The method of  claim 2 , wherein the directed energy beam is produced by a laser, an electron beam, a plasma jet, or combinations thereof. 
     
     
         4 . The method of  claim 1 , further comprising providing ultrasonic waves to the at least a portion of the fiber preform. 
     
     
         5 . The method of  claim 1 , wherein the electrical voltage is applied at a current of 1 Ampere to 100 Amperes. 
     
     
         6 . The method of  claim 1 , wherein the fiber preform comprises a non-conductive fiber, wherein applying the electrical voltage generates a surface plasma on the fiber preform. 
     
     
         7 . A device configured to impregnate a powder into a fiber preform according to the method of  claim 1 , said device comprising:
 a pair of electrodes operable to apply a voltage across at least a portion of a fiber preform;   a powder delivery channel; and   a powder delivery roll coupled to the pair of electrodes, the powder delivery roll in communication with the powder delivery channel and configured to dispose a layer of a powder onto a portion of the fiber preform exposed to said voltage an optional enclosure configured to maintain a process atmosphere around the portion of the fiber preform exposed to said voltage, the enclosure optionally coupled to the pair of electrodes and the powder delivery roll.   
     
     
         8 . The device of  claim 7 , further comprising an ultrasonic transducer optionally coupled to the pair of electrode rolls, the ultrasonic transducer configured to provide an ultrasonic wave to the portion of the fiber preform exposed to said voltage. 
     
     
         9 . The device of  claim 8 , wherein the ultrasonic transducer comprises a pair of ultrasonic transducers. 
     
     
         10 . The device of  claim 9 , wherein a first ultrasonic transducer roll of the pair of ultrasonic transducers is configured to transmit the ultrasonic wave and a second ultrasonic transducer of the pair of ultrasonic transducers is configured to receive the ultrasonic wave. 
     
     
         11 . The device of  claim 10 , wherein each ultrasonic transducer roll in the pair of ultrasonic transducer rolls is configured to induce ultrasonic waves. 
     
     
         12 . The device of  claim 9 , wherein the pair of ultrasonic transducers are positioned adjacent to the pair of electrodes. 
     
     
         13 . The device of  claim 7 , further comprising an enclosure configured to maintain a process atmosphere around the heated portion of the fiber preform. 
     
     
         14 . The device of  claim 13 , further comprising a gas delivery channel for providing a cover gas to the enclosure. 
     
     
         15 . The device of  claim 14 , further comprising a gas release passage. 
     
     
         16 . The device of  claim 7 , wherein a first electrode of the pair of electrodes is parallel to a second electrode of the pair of electrodes. 
     
     
         17 . The device of  claim 7 , further comprising a directed energy delivery system configured to deliver energy in the form of an energy beam to a layer of powder disposed on the fiber preform effective to at least partially melt the layer of powder. 
     
     
         18 . A method for identifying one or more flaws during or following additive fabrication, the method comprising:
 introducing a first ultrasonic wave into a part;   detecting a second ultrasonic wave emanating from the part, the second ultrasonic wave being associated with the first ultrasonic wave;   comparing the second ultrasonic wave with a reference signal, the reference signal derived from a signal associated with a known part in a complete impregnated state; and   determining the presence of one or more flaws based on the step of comparing.   
     
     
         19 . The method of  claim 18 , further comprising:
 generating a reference signal for the known part; and   storing the reference signal in a database.   
     
     
         20 . The method of  claim 19 , wherein identifying the presence of one or more flaws results from the second ultrasonic wave not matching the reference signal.