System and method for high power diode based additive manufacturing

• US 9,308,583 B2
• Filed: 03/05/2013
• Issued: 04/12/2016
• Est. Priority Date: 03/05/2013
• Status: Active Grant

• Current Assignee: Lawrence Livermore National Security LLC (Government of the United States of America)
• Original Assignee: Lawrence Livermore National Security LLC (Government of the United States of America)
• Inventors: El-Dasher, Bassem S., Farmer, Joseph C., Bayramian, Andrew, Demuth, James A., Torres, Sharon G.
• Primary Examiner(s): Sanders, James
• Application Number:
  US13/785,484
• Publication Number:
  US 20140252687A1
• Time in Patent Office: 1,134 Days
• US Class Current: 1/1
• CPC Class Codes: B22F 10/20 Direct sintering or melting
• CPC Class Codes: B22F 10/28 Powder bed fusion, e.g. selective laser melting [SLM] or electron beam melting [EBM]
• CPC Class Codes: B22F 10/30 Process control
• CPC Class Codes: B22F 10/36 of energy beam parameters
• CPC Class Codes: B22F 12/43 pulsed; frequency modulated
• CPC Class Codes: B22F 12/44 characterised by the configuration of the radiation means
• CPC Class Codes: B22F 12/55 Two or more means for feeding material
• CPC Class Codes: B23K 26/042 Automatically aligning the laser beam
• CPC Class Codes: B23K 26/0622 by shaping pulses
• CPC Class Codes: B23K 26/0643 comprising mirrors
• CPC Class Codes: B23K 26/066 by using masks
• CPC Class Codes: B23K 26/144 the fluid stream containing particles, e.g. powder
• CPC Class Codes: B23K 26/342 Build-up welding
• CPC Class Codes: B29C 64/153 using layers of powder being selectively joined, e.g. by selective laser sintering or melting
• CPC Class Codes: B33Y 30/00 Apparatus for additive manufacturing; Details thereof or accessories therefor
• CPC Class Codes: B33Y 50/02 for controlling or regulating additive manufacturing processes
• CPC Class Codes: B33Y 80/00 Products made by additive manufacturing
• CPC Class Codes: C22C 32/0026 Matrix based on Ni, Co, Cr or alloys thereof
• CPC Class Codes: Y02P 10/25 Process efficiency

Abstract

A system is disclosed for performing an Additive Manufacturing (AM) fabrication process on a powdered material forming a substrate. The system may make use of a diode array for generating an optical signal sufficient to melt a powdered material of the substrate. A mask may be used for preventing a first predetermined portion of the optical signal from reaching the substrate, while allowing a second predetermined portion to reach the substrate. At least one processor may be used for controlling an output of the diode array.

Claims

1. A system for performing an Additive Manufacturing (AM) fabrication process on a powdered material forming a substrate, the system comprising:

a diode array for generating an optical signal sufficient to melt or sinter a powdered material of the substrate;

a mask for receiving the optical signal generated by the diode array, the mask forming a liquid crystal polarization rotator, the liquid crystal polarization rotator including a liquid crystal module and a polarizer, wherein the liquid crystal module operates to receive and to rotate a first portion of the optical signal passing therethrough while allowing a second portion of the optical signal to pass therethrough without being rotated, and wherein the polarizer operates to reject one of the first or second portions of the optical signal received from the liquid crystal module, and thus to prevent the one of the first or second portions from reaching the substrate, while the polarizer allows the other one of the first or second portions of the optical signal to reach the substrate, the liquid crystal module of the mask having a plurality of pixels arranged in a two dimensional pattern that are individually controlled to enable the mask to mask off one or more selected areas of a specific layer of the powdered material of the substrate, and wherein the mask absorbs substantially no optical energy from the optical signal; and

at least one processor controlling an output of the diode array and assisting in controlling operation of the mask such that only selected one of the pixels are controlled to enable portions of the optical signal passing through the liquid crystal polarization rotator to be rotated to thus form the first portion of the optical signal.

2. The system of claim 1, wherein the diode array comprises a plurality of diode bars.

3. The system of claim 2, wherein the diode array is configured to provide a power density of at least about 10 kW/cm² at a two percent duty cycle.

4. The system of claim 1, wherein the liquid crystal module comprises a computer controllable liquid crystal module configured to be digitally controlled by the processor.

5. The system of claim 1, wherein the polarizer comprises a polarizing mirror.

6. A system for performing an Additive Manufacturing (AM) fabrication process on a powdered material forming a substrate, the system comprising:

a diode array for generating a pulsed optical signal sufficient in optical intensity to melt a powdered material of the substrate;

a mask forming a liquid crystal polarization rotator having a liquid crystal module and a polarizer interposed between the diode array and the substrate, the liquid crystal polarization rotator operating to rotate a first portion of the pulsed optical signal passing therethrough while allowing a second portion of the pulsed optical signal to pass therethrough without being rotated, and the polarizer operating to reject one of the first or second portions of the pulsed optical signal, thus preventing the one of the first or second portions from reaching the substrate, while allowing the other one of the first or second portions of the pulsed optical signal to reach the substrate, the liquid crystal module of the mask including a plurality of pixels arranged in a two dimensional pattern that are individually controlled to enable the mask to simultaneously mask off one or more selected areas of a specific layer of the powdered material of the substrate, and wherein the mask absorbs substantially no optical energy from the pulsed optical signal; and

a processor for determining which one or more pixels of the mask need to be controlled in a manner such that only select portions of the optical signal are rotated to form the first portion of the optical signal, the mask thus operating to pass the optical signal from the diode array to melt only one or more specific, desired portions of the powdered material.

7. The system of claim 6, wherein:

the diode array is configured to be electronically controlled; and

wherein the processor is configured to electronically control the diode array to control on and off operation of the diode array.

8. The system of claim 6, wherein the mask is electronically addressable by the processor to prevent selected areas of the substrate from being exposed to the pulsed optical signal from the diode array.

9. The system of claim 6, wherein the polarizer comprises a polarizing mirror disposed at a 45 degree angle from a plane that the pulsed optical signal from the diode array travels in.

10. The system of claim 6, wherein the diode array is configured to generate a power output of at least about 10 kW/cm² at a duty cycle of about two percent.