Patent US5430666A successfully refreshed from Google Patents.
US5430666A
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Automated method and apparatus for calibration of laser scanning in a selective laser sintering apparatus
Assignee: 3D Systems Inc
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Filing: 1992-12-18
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Granted: 1995-07-04
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Expires: 2012-12-18
Abstract
Abstract A method and apparatus for calibrating the scan of a laser over a planar surface that includes defining an error table having x-dimension and y-dimension correction factors, and also a scale factor, for each of a plurality of regions of the planar target surface. The scale factor is initially set to a value to account for differences in the size of the image field to be scanned and the overall scan field in the CAD data base. Adjustment is performed to each scale factor to account for theoretical differences due to the use of a perpendicular galvanometer-driven mirror scanning system. A sheet with a large number of square cells is then placed over the target surface, after rotational alignment, and the laser marks each cell. The sheet is then converted into digital form by scanning, and the location of the laser mark relative to the centroid of the cell is used to update the correction factors for that cell.
Inventors
- 👤 Francesco E. DeAngelis
- 👤 Michael R. Davison
- 👤 David K. Leigh
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 06:02
CPC Classifications
G; G05; G05B; G05B19/00; G05B19/02; G05B19/18; G05B19/401; G05B19/4015; B; B29; B29C; B29C64/00; B29C64/10; B29C64/141; B29C64/153; B33; B33Y; B33Y10/00; B33Y30/00; Y; Y02; Y02P; Y02P90/00; Y02P90/02
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
178 words
A method of calibrating a system for scanning a directed energy beam over a planar surface, comprising the steps of: defining an error table corresponding to an image field, said image field being a portion of the planar surface, said error table including a plurality of values, each value associated with one of a plurality of regions of said image field; placing a sheet over the planar surface, said sheet having a plurality of cells defined thereupon, each cell corresponding to one of the plurality of regions of said image field; directing the energy beam in such a manner as to burn a mark in each of said plurality of cells on said sheet; converting the image of said sheet to a computer-readable form; determining a distance of each mark relative to a selected location in its associated cell by operating a computer on the converted image of said sheet; and adjusting each of said plurality of values in said error table according to the distance of each mark relative to the selected location in its associated cell.
Claim 2
Independent Claim
178 words
A method of calibrating a system for scanning a directed energy beam over a planar surface, comprising the steps of: defining an error table corresponding to an image field, said image field being a portion of the planar surface, said error table including a plurality of values, each value associated with one of a plurality of regions of said image field; placing a sheet over the planar surface, said sheet having a plurality of cells defined thereupon, each cell corresponding to one of the plurality of regions of said image field; directing the energy beam in such a manner as to burn a mark in each of said plurality of cells on said sheet; converting the image of said sheet to a computer-readable form; determining a distance of each mark relative to a selected location in its associated cell by operating a computer on the converted image of said sheet; and adjusting each of said plurality of values in said error table according to the distance of each mark relative to the selected location in its associated cell.
Claim 3
Dependent Claim
30 words
The method of claim 1, wherein said defining step comprises determining a scale factor for each of said plurality of values corresponding to its associated region of said image field.
Claim 4
Dependent Claim
50 words
The method of claim 2, wherein said system comprises: a laser; first and second scanning mirrors; and wherein said defining step uses a distance between said first mirror and said planar surface, and a distance between said first and second scanning mirrors, in defining each of said plurality of values.
Claim 5
Dependent Claim
35 words
The method of claim 3, wherein said defining step comprises defining each of said plurality of values using a ratio of a projected arc across its associated region to a length of its associated region.
Claim 6
Dependent Claim
28 words
The method of claim 1, wherein said plurality of values include a x-dimension correction factor and a y-dimension correction factor corresponding to each region of said image field.
Claim 7
Dependent Claim
23 words
The method of claim 5, wherein said plurality of values also include a scale factor corresponding to each region of said image field.
Claim 8
Dependent Claim
24 words
The method of claim 1, further comprising: after said adjusting step, repeating said placing, directing, converting, determining and adjusting steps for a second sheet.
Claim 9
Dependent Claim
51 words
The method of claim 7, further comprising: after each adjusting step, comparing a statistic of the distances of the marks relative to the selected location in its associated cell to a limit; wherein the repeating of said placing, directing, converting, determining and adjusting steps is performed responsive to said comparing step.
Claim 10
Dependent Claim
17 words
The method of claim 1, wherein the selected location in each of said cells is its centroid.
Claim 11
Independent Claim
143 words
A system for fabricating an article by scanning a directed energy beam over a planar surface, comprising: a source of an energy beam; first and second mirrors for controlling the scanning of the energy beam over the planar surface in first and second perpendicular directions, respectively; a sheet disposed over the planar surface, said sheet having a plurality of cells defined thereupon, each of said cells markable by the energy beam; means for controlling said source and said first and second mirrors; and a computer for: defining an error table having a plurality of values, each of said plurality of values associated with one of said plurality of cells of said sheet; and for adjusting said plurality of values in said error table responsive to the distance between a mark in each of said cells and a selected location in its associated cell.
Claim 12
Independent Claim
143 words
A system for fabricating an article by scanning a directed energy beam over a planar surface, comprising: a source of an energy beam; first and second mirrors for controlling the scanning of the energy beam over the planar surface in first and second perpendicular directions, respectively; a sheet disposed over the planar surface, said sheet having a plurality of cells defined thereupon, each of said cells markable by the energy beam; means for controlling said source and said first and second mirrors; and a computer for: defining an error table having a plurality of values, each of said plurality of values associated with one of said plurality of cells of said sheet; and for adjusting said plurality of values in said error table responsive to the distance between a mark in each of said cells and a selected location in its associated cell.
Claim 13
Dependent Claim
18 words
The system of claim 10, further comprising: a mounting disk for holding said sheet at the planar surface.
Claim 14
Dependent Claim
22 words
The system of claim 11, wherein said mounting disk comprises alignment pins, said alignment pins mating with alignment holes in said sheet.
Claim 15
Dependent Claim
27 words
The system of claim 11, wherein each of said plurality of values comprises first and second correction factors, corresponding to the first and second perpendicular directions, respectively.
Claim 16
Dependent Claim
44 words
The system of claim 11, wherein said computer is also for measuring a statistic, over all of said plurality of values in said error table, of the distance between the mark in each of said cells and the selected location in the associated cell.
Claim 17
Dependent Claim
18 words
The system of claim 11, wherein the selected location in each cell is the centroid of the cell.
Claim 18
Dependent Claim
14 words
The system of claim 11, wherein the orientation of said mounting disk is adjustable.
Claim 19
Dependent Claim
11 words
The system of claim 10, wherein said source comprises a laser.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1998-07-03 | 1999-01-02 | 1999-07-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-07-03 | 2003-01-02 | 2003-07-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-07-03 | 2007-01-02 | 2007-07-04 | $7700.00 | Window Closed / Lapsed |