Optical-coherence-tomography guided additive manufacturing and laser ablation of 3d-printed parts

Patent metadata

Field	Value
Publication number	US-2018143147-A1
Application number	US-201615571957-A
Country	US
Kind code	A1
Filing date	May 11, 2016
Priority date	May 11, 2015
Publication date	May 24, 2018
Grant date	—

Abstract

An apparatus and method for detecting defects in an additive manufacturing process is provided. An example method may include depositing a first layer of material, depositing a second layer of material in at least partial contact with the first layer of material, and inducing a phase change between the first and second layers of material via an energy beam. Further, the method may include directing an electromagnetic radiation beam to at least a portion of a subsurface interface between the first and second layers, measuring radiation returned from the material, and based on the measured radiation, determining a location of a refractive index gradient within the material.

First claim

1 . A method of detecting defects in an additive manufacturing process, comprising:
depositing a first layer of material; depositing a second layer of material in at least partial contact with the first layer of material; inducing a phase change between the first layer of material and the second layer of material via an energy beam; directing an electromagnetic radiation beam to at least a portion of a subsurface interface between the first and second layers; measuring radiation returned from the material; and based on the measured radiation, determining a location of a refractive index gradient within the material.

2 . The method of claim 1 , further comprising determining whether the first and second layers are bonded to one another.

3 . The method of claim 1 , further comprising determining if the material contains voids, defects, or imperfections.

4 . The method of claim 1 , wherein inducing a phase change comprises fusing the second layer of material to the first layer of material.

5 . The method of claim 1 , comprising determining the refractive index gradient, wherein the refractive index gradient provides an indication of whether voids or imperfections exist within the second layer.

6 . The method of claim 1 , further comprising determining measurements characterizing a surface topography of the second layer based on the measured radiation.

7 . The method of claim 1 , further comprising correcting a void or imperfection by directing the energy beam or a second energy beam to at least a portion of the second layer based on the measured radiation.

8 . The method of claim 7 , wherein correcting the void or imperfection further comprises depositing a corrective layer of material.

9 . The method of claim 7 , wherein correcting a surface defect comprises removing material by ablation.

10 . The method of claim 1 , wherein the measured radiation provides an indication of backscattered light intensity from the material.

11 . The method of claim 1 , wherein the measured radiation provides an indication of the Doppler shift of a moving phase boundary.

12 . The method of claim 1 , wherein an operating parameter of the additive manufacturing process is changed based on a comparison of the measured radiation to a reference control signal.

13 . An apparatus for producing a part via additive manufacturing, comprising:
a print head configured to deposit material onto a build surface of a part; an energy source that directs energy into the deposited material; an optical source comprising an emitter for emitting an electromagnetic radiation beam and a receiver for receiving return radiation, wherein the optical source directs the electromagnetic radiation beam toward the deposited material; and a controller that receives measurements of the returned radiation indicating the existence of refractive index gradients within the fused material.

14 . The apparatus of claim 13 , wherein the energy source and optical source are contained within a housing.

15 . The apparatus of claim 13 , wherein the controller compares the deposited material with a reference control signal to determine the existence of deviations.

16 . The apparatus of claim 13 , wherein the measurements provide a surface topography of the deposited material.

17 . The apparatus of claim 13 , wherein the controller adapts process parameters in response to received measurements.

18 . A method of detecting and correcting defects in an additive manufacturing process, comprising:
depositing material to a working surface; directing an electromagnetic radiation beam to at least a portion of the material; measuring radiation returned from the material; based on the measured radiation, determining a portion of the material to be removed; and removing the portion of the material via an energy beam.

19 . The method of claim 18 , wherein the portion of the material to be removed comprises a refractive index gradient.

20 . The method of claim 18 , wherein the energy beam is a spatially chirped beam.

21 . The method of claim 18 , wherein the portion of the material to be removed comprises a protrusion on the surface of the material.

Assignees

• Univ Texas

Inventors

• Milner Thomas
• Mcelroy Austin
• Beaman Joseph
• Fish Scott

Classifications

• B22F3/105 Primary

  by using electric current {other than for infrared radiant energy}, laser radiation or plasma (B22F3/11 takes precedence){; by ultrasonic bonding (B22F3/115 takes precedence)} · CPC title

• B33Y99/00

  Subject matter not provided for in other groups of this subclass · CPC title

• B33Y30/00

  Apparatus for additive manufacturing; Details thereof or accessories therefor · CPC title

• B22F2999/00

  Aspects linked to processes or compositions used in powder metallurgy · CPC title

• B33Y50/02

  for controlling or regulating additive manufacturing processes · CPC title