APPARATUS AND METHOD FOR FORMING THREE-DIMENSIONAL OBJECTS USING LINEAR SOLIDIFICATION WITH TRAVEL AXIS CORRECTION AND POWER CONTROL

• US 20140306380A1
• Filed: 04/03/2014
• Published: 10/16/2014
• Est. Priority Date: 04/04/2013
• 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, Zhou, Chi
• Granted Patent: US 10,112,345 B2
• Time in Patent Office: Days
• US Class Current: 264/401
• CPC Class Codes: B29C 64/135 the energy source being concentrated, e.g. scanning lasers or focused light sources
• CPC Class Codes: B29C 64/393 for controlling or regulating additive manufacturing processes
• CPC Class Codes: B33Y 10/00 Processes of additive manufacturing
• CPC Class Codes: B33Y 50/02 for controlling or regulating additive manufacturing processes

Abstract

An apparatus and method for making a three-dimensional object from a solidifiable material using a linear solidification device is shown and described. The apparatus and method compensate for a non-orthogonal angle between the travel axis and scanning axis of a linear scanning device and also provide a substantially constant solidification depth along the scanning axis. In certain examples, a solidification energy control system is also provided to regulate the solidification power supplied to the solidifiable material by modulating the power supplied to the linear solidification device'"'"'s solidification energy source, examples of which include laser diodes.

Claims

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

moving a solidification energy source along a first direction;

progressively projecting solidification energy from the solidification energy source onto selected portions of the solidifiable material along a second direction while the solidification energy source moves along the first direction, wherein the power of the solidification energy received by the selected portions of the solidifiable material onto which the solidification energy is projected is substantially constant along the second direction.

2. The method of claim 1, further comprising modulating the power provided to the solidification energy source to control the solidification power received by the selected portions of the solidifiable material along the second direction.

3. The method of claim 2, wherein the step of modulating the power provided to the solidification energy source comprises providing a selectively switchable, variable amplitude analog voltage signal to a solidification energy source modulator.

4. The method of claim 3, wherein the step of modulating the power provided to the solidification energy source comprises varying the amplitude of the selectively switchable, variable amplitude analog voltage signal based on an elapsed time from the receipt of a sensor synchronization signal.

5. The method of claim 4, further comprising providing a power compensation database comprising a plurality of power compensation data entries, wherein each power compensation data entry corresponds to an elapsed time from the receipt of the sensor synchronization signal and defines the amplitude of the selectively switchable, analog voltage signal at the elapsed time.

6. The method of claim 5, further comprising sensing a solidification power received by a solidification energy sensor and adjusting the plurality of power compensation data entries based on the sensed solidification power.

7. The method of claim 6, wherein the step of moving a solidification energy source along a first direction comprises moving the solidification energy source along the first direction across a build envelope, and the step of adjusting the plurality of power compensation data entries based on the sensed solidification power occurs following each traversal of the solidification energy source across the build envelope.

8. The method of claim 5, further comprising the step of generating the power compensation data entries by projecting test solidification energy onto a surface at a plurality of locations along the second direction while maintaining a substantially constant supply power to the solidification energy source and measuring received test solidification power at the plurality of locations.

9. The method of claim 8, further comprising identifying a location among the plurality of locations having the smallest measured received test solidification power, wherein the step of generating the power compensation data entries further comprises adjusting the supply power to the solidification energy source for the plurality of locations until the received solidification power at each location equals the smallest measured received test solidification power.

10. The method of claim 3, further comprising generating a digital signal based on solidification energy source event data corresponding to the three-dimensional object, wherein the digital signal determines whether the analog voltage signal is in electrical communication with the solidification energy source.

11. The method of claim 2, wherein the step of modulating the power provided to the solidification energy source comprises providing a selectively switchable, analog voltage signal to a solidification energy source modulator, the selectively switchable, analog voltage signal has an amplitude that varies to vary the power provided to the solidification energy source, the selectively switchable analog voltage signal is switched based on a digital signal corresponding to solidification energy source event data, and the selectively switchable analog voltage signal and digital signal are synchronized to a common solidification energy sensor signal.

12. An apparatus for making a three-dimensional object from a solidifiable material, comprising:

a linear solidification device comprising a solidification energy source in optical communication with a scanning device, wherein during an object solidification operation, the linear solidification device projects solidification energy on to selected locations of the solidifiable material along a scanning axis, and the solidification power received at the selected locations is substantially constant.

13. The apparatus of claim 12, wherein when the linear solidification device projects solidification energy on to selected locations of the solidifiable material along the scanning axis, the selected locations of the solidifiable material are solidified to a substantially constant solidification depth.

14. The apparatus of claim 12, further comprising at least one controller, wherein the at least one controller adjusts the solidification power provided to the solidification energy source based on solidification energy source event data and solidification power compensation data, and each item of solidification energy source event data and each item of power compensation data corresponds to an elapsed time from the receipt of a sensor synchronization signal.

15. The apparatus of claim 14, further comprising a solidification energy modulator connected to the source of solidification energy and a switch connected the solidification energy modulator, wherein the switch receives an analog input signal based on the solidification power compensation data and a digital input signal based on the solidification energy source event data, and the switch provides a selectively switchable, variable amplitude analog output signal to the solidification energy source modulator.

16. The apparatus of claim 14, further comprising a solidification energy sensor, wherein the solidification energy source is selectively activatable to transmit solidification energy to the solidification energy sensor, and when the solidification energy sensor receives solidification energy from the solidification energy source it generates a solidification power signal corresponding to the solidification power received by the solidification energy sensor.

17. The apparatus of claim 16, wherein the at least one controller is operatively connected to the solidification energy sensor.

18. The apparatus of claim 14, wherein the solidification power compensation data comprises a database of power compensated voltage values, and the at least one controller is programmed to adjust the solidification power provided to the solidification energy source based on the power compensated voltage values.

19. The apparatus of claim 18, wherein each of the power compensated voltage values corresponds to a location along the scanning axis.

20. The apparatus of claim 18, wherein each of the power compensated voltage values corresponds to an elapsed time from the receipt of a sensor synchronization signal by the at least one controller.

21. A method of making a three-dimensional object, comprising:

providing a linear scanning device;

supplying power to a source of solidification energy, wherein the source of solidification energy projects solidification energy on to a solidifiable material at selected locations along a scanning axis;

sensing a solidification power provided by the solidification energy device; and

adjusting the power supplied to the source of solidification energy to control the sensed solidification power.

22. The method of claim 21, wherein the step of adjusting the power supplied to the source of solidification energy comprises adjusting power compensation data values, wherein each power compensation data value corresponds to a position along the scanning axis and to a value of solidification power received by the solidifiable material that is the same at each position along the scanning axis.

23. The method of claim 22, wherein the power compensation data values are voltage values.

24. The method of claim 22, wherein each power compensation value corresponds to a respective elapsed scanning time.

25. The method of claim 21, wherein the step of adjusting the power supplied to the source of solidification energy comprises adjusting the amplitude of a selectively switchable, variable amplitude analog signal.

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

providing three-dimensional object data representative of a three-dimensional object, wherein the three-dimensional object data corresponds to a build envelope comprising a linear solidification travel axis and an axis perpendicular to the travel axis;

modifying the three-dimensional object data to compensate for a non-orthogonal angle between a travel axis direction of a linear solidification device and a scanning axis direction of the linear solidification device; and

solidifying the solidifiable material by progressively solidifying selected regions of the solidifiable material along the scanning axis direction in accordance with the modified three-dimensional object data as the linear solidification device moves in the travel axis direction.

27. The method of claim 26, wherein the three-dimensional object data comprises a plurality of object layer data sets, wherein each object layer data set corresponds to a position along a build axis and includes a plurality of coordinates along the travel axis and the axis perpendicular to the travel axis, and the step of modifying the three-dimension object data to compensate for the non-orthogonal angle further comprises shifting the coordinates in the plurality of coordinates along the travel axis direction based on the non-orthogonal angle.

28. The method of claim 27, wherein the step of shifting the coordinates along the travel axis direction is performed by calculating a shifted coordinate along the travel axis direction for each coordinate in accordance with the following relationship:

x′

=x+(y−

y₀)(tan(−

α

))

wherein,

x=object layer data coordinate along the travel axis direction;

y=object layer data coordinate along the axis perpendicular to the travel axis;

y₀=reference coordinate along the axis perpendicular to the travel axis

α

=the non-orthogonal angle between the travel axis direction and the scanning axis direction of the linear solidification device; and

x′

=shifted coordinate along the travel axis direction.

29. The method of claim 26, further comprising:

subdividing the modified object data into a plurality of strips, wherein each strip has a length along the axis perpendicular to the travel axis and corresponds to a position along the travel axis; and

defining a plurality of data strings, wherein each data string corresponds to a strip and comprises solidification energy source state event data indicative of a change in the energization state of the solidification energy source, and the step of solidifying the solidifiable material by progressively solidifying selected regions of the solidifiable material along the scanning axis direction in accordance with the modified three-dimensional object data comprises solidifying the solidifiable material in accordance with the data strings.

30. The method of claim 29, wherein the solidification energy source state event data comprises time values at which the energization state of the solidification energy source changes.

31. The method of claim 30, wherein the time values are CPU tick values.

32. The method of claim 26, further comprising:

providing three-dimensional test object data;

mapping the three-dimensional test object data onto a build envelope comprising a travel axis direction and a direction perpendicular to the travel axis direction;

progressively solidifying a solidifiable material in a scanning axis direction with a linear solidification device as the linear solidification device moves in the travel direction;

measuring a plurality of dimensions on the test part; and

determining the non-orthogonal angle based on the measured dimensions.

33. The method of claim 26, wherein the three-dimensional object data comprises a plurality of object layer data sets, each object layer data set corresponds to a position along a build axis, and the step of modifying the three-dimensional object data to compensate for the non-orthogonal angle further comprises subdividing the modified object data into a plurality of strips, wherein each strip has a length that is parallel to the scanning axis direction.

34. A non-transitory, computer readable medium having computer executable instructions stored thereon which perform the following steps when executed by a computer processor:

receiving three-dimensional object data representative of a three-dimensional object, wherein the three-dimensional object data corresponds to a build envelope comprising a linear solidification travel axis and an axis perpendicular to the travel axis; and

modifying the three-dimensional object data to compensate for a non-orthogonal angle between a travel axis direction of a linear solidification device and a scanning axis direction of the linear solidification device.

35. The computer readable medium of claim 34, wherein the three-dimensional object data comprises a plurality of object layer data sets, each object layer data set corresponds to a position along a build axis and includes a plurality of coordinates along the travel axis and the axis perpendicular to the travel axis, and the step of modifying the three-dimension object data to compensate for the non-orthogonal angle further comprises shifting the coordinates along the travel axis direction based on the non-orthogonal angle.

36. The computer readable medium of claim 35, wherein the step of shifting the coordinates along the travel axis direction comprises calculating a shifted coordinate along the travel axis direction for each coordinate in accordance with the following relationship:

x′

=x+(y−

y₀)(tan(−

α

))

wherein,

x=object layer data coordinate along the travel axis direction;

y=object layer data coordinate along the axis perpendicular to the travel axis;

y₀=reference coordinate along the axis perpendicular to the travel axis;

α

=the non-orthogonal angle between the travel axis direction and the scanning axis direction of the linear solidification device; and

x′

=shifted coordinate along the travel axis direction.

37. The computer readable medium of claim 34, wherein when executed by a computer processor, the computer executable instructions further perform the following steps:

subdividing the modified object data into a plurality of strips, wherein each strip has a length along the axis perpendicular to the travel axis and corresponds to a position along the travel axis; and

defining a plurality of data strings, wherein each data string corresponds to a strip and comprises solidification energy source energization state event data indicative of a change in the energization state of the solidification energy source.

38. The computer readable medium of claim 37, wherein the solidification energy source state event data comprises time values at which the energization state of the solidification energy source changes.

39. The computer readable medium of claim 38, wherein the time values are CPU tick values.

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

providing three-dimensional object data representative of a three-dimensional object, wherein the three-dimensional object data corresponds to a build envelope comprising a linear solidification device travel axis and an axis perpendicular to the travel axis;

modifying the three-dimensional object data to compensate for a non-orthogonal angle between a travel axis direction of a linear solidification device and a scanning axis direction of the linear solidification device;

moving the linear solidification device along the linear solidification device travel axis; and

progressively projecting solidification energy from the linear solidification device onto selected portions of the solidifiable material along the scanning axis direction in accordance with the modified three-dimensional object data while the linear solidification device moves along the first direction, wherein the power of the solidification energy received by the selected portions of the solidifiable material onto which the solidification energy is projected is substantially constant along the scanning axis direction.

41. The method of claim 40, wherein the step of modifying the three-dimensional object data further comprises modifying the three-dimensional object data to compensate for variations in scanning speed of the linear solidification device along the scanning axis direction.

42. A method of making a three-dimensional object, comprising:

providing three-dimensional object data representative of a three-dimensional object, wherein the three-dimensional object data corresponds to a build envelope comprising a linear solidification travel axis and an axis perpendicular to the travel axis;

modifying the three-dimensional object data to compensate for a non-orthogonal angle between a travel axis direction of a linear solidification device and a scanning axis direction of the linear solidification device; and

supplying power to a linear solidification device, wherein the linear solidification device projects solidification energy on to a solidifiable material at selected locations along the scanning axis in accordance with the modified three-dimensional object data;

sensing a solidification power provided by the linear solidification device; and

adjusting the power supplied to the linear solidification device to control the sensed solidification power.

43. The method of claim 42, wherein the step of modifying the three-dimensional object data further comprises modifying the three-dimensional object data to compensate for variations in scanning speed of the linear solidification device along the scanning axis direction.