Apparatus and method for forming three-dimensional objects using linear solidification

• US 9,981,425 B2
• Filed: 05/14/2015
• Issued: 05/29/2018
• Est. Priority Date: 06/28/2011
• Status: Active Grant

• Current Assignee: Gulf Filtration Systems Inc. (Desktop Metal, Inc.)
• Original Assignee: Gulf Filtration Systems Inc. (Desktop Metal, Inc.)
• Inventors: El-Siblani, Ali, Shkolnik, Alexandr
• Primary Examiner(s): Hindenlang, Alison L
• Application Number:
  US14/712,386
• Publication Number:
  US 20150246482A1
• Time in Patent Office: 1,111 Days
• CPC Class Codes: B29C 64/106 using only liquids or viscous materials, e.g. depositing a continuous bead of viscous material
• CPC Class Codes: B29C 64/124 using layers of liquid which are selectively solidified
• CPC Class Codes: B29C 64/236 for motion in a direction within the plane of a layer
• CPC Class Codes: B29C 64/241 for rotary motion
• CPC Class Codes: B29C 64/245 Platforms or substrates support structures intended to be sacrificed after manufacture B29C64/40
• CPC Class Codes: B29C 64/264 Arrangements for irradiation
• CPC Class Codes: B29C 64/268 using laser beams; using electron beams [EB]
• CPC Class Codes: B29L 2031/772 Articles characterised by their shape and not otherwise provided for closed loop B29L2031/709; ring-like B29L2031/7096; corrugated B29L2016/00, flat B29L2007/00; hollow B29L2022/00; screw-threaded B29L2001/00; toothed B29L2031/775; corrugated tubes B29L2023/18
• CPC Class Codes: B33Y 10/00 Processes of additive manufacturing
• CPC Class Codes: B33Y 30/00 Apparatus for additive manufacturing; Details thereof or accessories therefor

Abstract

An apparatus and method for making a three-dimensional object from a solidifiable material using a linear solidification device is shown and described. In certain examples, the linear solidification device includes a laser diode that projects light onto a scanning device, such as a rotating polygonal mirror or a laser scanning micromirror, which then deflects the light onto a photohardenable resin. As a result, the linear solidification device scans a line of solidification energy in a direction that is substantially orthogonal to the direction of travel of the laser diode. In other examples, the linear solidification device is a laser device array or light emitting diode array that extends in a direction substantially orthogonal to the direction of travel of the array.

Claims

1. A method of making a three-dimensional object from a solidifiable material, comprising:

moving a source of solidification energy in a first direction;

progressively exposing portions of the solidifiable material to solidification energy in a second direction along an exposed surface of the solidifiable material as the source of solidification energy moves in the first direction.

2. The method of claim 1, wherein the first direction is substantially perpendicular to the second direction.

3. The method of claim 1, wherein the step of progressively exposing portions of the solidifiable material to solidification energy in a second direction along an exposed surface of the solidifiable material as the source of solidification energy moves in the first direction comprises performing a series of line scanning operations, and the method further comprises synchronizing a timer to the beginning of each line scanning operation.

4. The method of claim 3, further comprising providing a solidification energy sensor in optical communication with a source of the solidification energy, wherein the step of synchronizing a timer to the beginning of a line scanning operation comprises setting the timer to a specified time value in response to the solidification energy sensor'"'"'s sensing of solidification energy.

5. The method of claim 3, wherein the step of progressively exposing a portion of the solidifiable material to solidification energy along the second direction comprises selectively exposing a portion of the solidifiable material to solidification energy along the second direction in accordance with object data comprising a plurality of string data sets, wherein each string data set comprises a plurality of time values that define a solidification source energization state switching event, and each time value equals an elapsed time following the beginning of a line scanning operation.

6. The method of claim 5, wherein each string data set further comprises a string number, and each string number corresponds to a location within a build envelope portion of a source of solidifiable material.

7. The method of claim 3, wherein the step of synchronizing a timer to the beginning of a line scanning operation comprises projecting solidification energy toward a rotating energy deflector driven by a motor energized by constant frequency energy pulses at a specified time relative to the occurrence of each pulse.

8. The method of claim 7, wherein the step of synchronizing a timer to the beginning of a line scanning operation comprises projecting solidification energy toward a rotating energy deflector for a detection pulse of from about 2 to about 6 milliseconds.

9. The method of claim 8, wherein the step of synchronizing a timer to the beginning of a line scanning operation comprises ceasing to project solidification energy toward the rotating energy detector within a lag time after a synchronization sensor detects solidification energy.

10. The method of claim 9, wherein the lag time is no more than about 400 nanoseconds.

11. The method of claim 1, further comprising:

providing first and second identical three-dimensional object layer data corresponding to adjacent layers of solidifiable material used to form the three-dimensional object;

subdividing the first and second identical three-dimensional object layer data into respective first and second pluralities of object cross-section strips, wherein each object cross-section strip in the first plurality of object cross-section strips has a set of strip data and a corresponding computer memory index value m(0) ranging from 0 to one less than the total number of strips in the first plurality of object cross-section strips (M_total), each strip in the second plurality of object cross-section strips has a set of strip data and a corresponding computer memory index value m(1), and the strip data corresponding to each respective value of m(1) for the second plurality of object cross-section strips equals the strip data for the first plurality of object cross-section strips that corresponds to the computer memory index value m(0) equal to one less than M_total minus the respective value of m(1).

12. The method of claim 1, further comprising:

providing three-dimensional object data representative of the three-dimensional object;

slicing the three-dimensional object data to define a plurality of three-dimensional object layer data sets;

providing a build envelope distance in the first direction, wherein the build envelope distance in the first direction corresponds to a value of a motor movement parameter of a motor that is energizable to move the source of solidification energy source in the first direction;

adjusting the value of the motor movement parameter to which the build envelope distance corresponds based on test part measurement data.

13. The method of claim 12, further comprising:

forming a first series of layers of the test part, wherein each layer in the first series of layers is formed by moving the source of solidification energy in the first test direction and progressively exposing portions of the solidifiable material to solidification energy in the second direction along an exposed surface of the solidifiable material as the source of solidification energy moves in the first direction;

forming a second series of layers of a test part, wherein each layer in the second series of layers is formed by moving the source of solidification energy in a third direction opposite the first test direction and progressively exposing portions of the solidifiable material to solidification energy in the second direction along an exposed surface of the solidifiable material as the source of solidification energy moves in the third direction;

measuring an offset distance between the first series of layers and the second series of layers; and

adjusting the value of the motor movement parameter to which the build envelope distance corresponds based on the measured offset distance between the first series of layers and the second series of layers.

14. The method of claim 1, wherein:

the step of progressively exposing portions of the solidifiable material to solidification energy in the second direction along an exposed surface of the solidifiable material as the source of solidification energy moves in the first direction comprises deflecting solidification energy from a rotating energy deflector having a number of facets F toward the solidifiable material,

the three-dimensional object has a desired length L along the first direction at a specified build axis position,

the step of progressively exposing portions of the solidifiable material to solidification energy in a second direction along an exposed surface of the solidifiable material as the source of solidification energy moves in the first direction comprises performing a number of line scanning operations corresponding to the specified build axis position, and each line scanning operation corresponds to a location along the first direction, and the number of line scanning operations is represented by the following formula;

n=(L/S)*(RPM/60)*F

where, n=number of line scanning operations;

L=desired length of object at the specified build axis position (mm);

S=speed of movement of solidification energy source in the first direction (mm/sec);

RPM=rotational frequency of rotating energy deflector (revolutions/minute); and

F=number of facets on the rotating energy deflector.

15. The method of claim 14, wherein each line scanning operation comprises selectively changing the energization state of the source of solidification energy in accordance with a set of string data that comprises one or more time values, each time value defines a solidification source energization state switching event, and each time value equals an elapsed time following the receipt of a synchronization signal by a solidification energy sensor.

16. The method of claim 1, wherein the step of progressively exposing portions of the solidifiable material to solidification energy in a second direction along an exposed surface of the solidifiable material as the source of solidification energy moves in a first direction is controlled by a microcontroller having an interrupt feature, and the interrupt feature is disabled during the progressively exposing step.