Energy beam size verification

Patent metadata

Field	Value
Publication number	US-2016202042-A1
Application number	US-201615077155-A
Country	US
Kind code	A1
Filing date	Mar 22, 2016
Priority date	Aug 20, 2014
Publication date	Jul 14, 2016
Grant date	—

Abstract

A method for verifying a size of an energy beam spot, said method comprising the steps of providing a first beam spot having a predetermined size and power at a first position on a work piece, varying a focus and/or astigmatism lens setting for said first beam spot until max intensity for the beam spot is detected, comparing the detected settings of said focus lens and/or astigmatism lens for said maximum intensity of the beam spot with stored settings of said focus lens and/or astigmatism lens for the beam spot with said predetermined size and power, repeating step a-c for different predetermined beam powers, repeating step a-d for different positions on said work piece, wherein said beam spot size is verified if each detected settings of said focus lens and/or astigmatism lens are deviating less than a predetermined value from corresponding stored settings of said focus lens and/or astigmatism lens.

First claim

That which is claimed:

1 . A computer-implemented method for automatically verifying a size of at least one energy beam spot, said method comprising the steps of:
(a) generating a first energy beam spot from a first energy beam source having a predetermined size and power at a first position on a work piece, wherein said first position is detected by at least one of an IR-camera, a CCD-camera, a digital camera, a CMOS camera, or a NIR-camera, (b) varying, via at least one control unit, at least one of a focus lens setting or an astigmatism lens setting for said first energy beam spot until max intensity for the first beam spot is detected, (c) comparing, via said at least one control unit, at least one setting of said focus lens and/or astigmatism lens for said detected maximum intensity of the first energy beam spot with corresponding stored settings of said focus lens and/or astigmatism lens for the first energy beam spot with said predetermined size and power, (d) repeating, via said at least one control unit, steps a-c for different predetermined beam powers, and (e) repeating, via said at least one control unit, steps a-d for different positions on said work piece, wherein said first energy beam spot size is verified if each detected settings of said focus lens and/or astigmatism lens are deviating less than a predetermined value from corresponding stored settings of said focus lens and/or astigmatism lens.

2 . The method according to claim 1 , wherein said predetermined beam spot size is a minimum spot size.

3 . The method according to claim 1 , wherein the repeating step for different positions is performed before the repeating step for different predetermined beam powers.

4 . The method according to claim 1 , wherein the first energy beam spot is an electron beam spot.

5 . The method according to claim 4 , wherein said astigmatism lens and/or focus lens setting is a coil current setting to at least one astigmatism coil and/or at least one focus coil respectively.

6 . The method according to claim 1 , wherein the first energy beam spot is a laser beam spot.

7 . The method according to claim 6 , wherein said astigmatism lens and/or focus lens setting is a positioning along the optical axis of at least one astigmatism lens and/or at least one focus lens respectively.

8 . The method according to claim 1 , further comprising a step of sending out a warning signal/message if any one of said detected settings of said focus lens and/or astigmatism lens are deviating more than a predetermined value from corresponding stored settings of said focus lens and/or astigmatism lens.

9 . The method according to according to claim 1 , further comprising the steps of:
providing a second energy beam spot from a second energy beam source having a predetermined size and power at said first position on said work piece, varying a focus and/or astigmatism lens setting for said second energy beam spot until max intensity for said second energy beam spot is detected, and comparing said detected max intensity for said first energy beam spot with said detected max intensity for said second energy beam spot, wherein said first and second energy beam spot sizes are verified if said detected max intensity of said first energy beam spot is deviating less than a predetermined value from said detected max intensity of said second energy beam spot.

10 . The method according to claim 9 , wherein said first and second energy beam spots have equal maximum beam spot power.

11 . The method according to according to claim 1 , further comprising the steps of:
providing said first energy beam spot at said first position during a first predetermined time duration where a first intensity is detected, providing said first energy beam spot at said first position during a second predetermined time duration where a second intensity is detected, and calculating a ratio between said first and second intensities, wherein said first energy beam spot size and/or beam spot power is verified if said calculated ratio between said first and second intensities is deviating less than a predetermined value from a corresponding calibrated ratio of said first beam with said first and second time durations.

12 . The method according to claim 11 , wherein steps therein are repeated for different beam powers and/or time durations.

13 . The method according to claim 1 , wherein:
the method further comprises the step of receiving and storing, within one or more memory storage areas, a model of at least one three-dimensional article; and at least one of the varying, comparing, or repeating steps is performed via execution of one or more computer processors.

14 . The method according to claim 1 , wherein:
the method is further configured for verifying a deflection speed of the at least one energy beam spot; and
the method further comprises the steps of:
generating a predetermined pattern on a work table with said energy beam spot while deflecting said energy beam spot with a first deflection speed;
detecting first positions of said energy beam spot on said work table created with said first deflection speed;
generating said predetermined pattern on a work table with said energy beam spot while deflecting said energy beam spot with a second deflection speed;
detecting second positions of said energy beam spot on said work table created with said second deflection speed; and
comparing said first and second positions, wherein said deflection speed is verified if each one of said first positions are deviating less than a predetermined distance from corresponding ones of said second positions.

15 . A non-transitory computer readable medium having stored thereon a program element configured and arranged when executed on a computer to implement a method for automatically verifying a size of at least one energy beam spot, said method comprising the steps of:
(a) generating a first energy beam spot from a first energy beam source having a predetermined size and power at a first position on a work piece, (b) varying at least one of a focus lens setting or an astigmatism lens setting for said first energy beam spot until max intensity for the first beam spot is detected, (c) comparing, via an executable portion of the program element, at least one setting of said focus lens and/or astigmatism lens for said detected maximum intensity of the first energy beam spot with corresponding stored settings of said focus lens and/or astigmatism lens for the first energy beam spot with said predetermined size and power, (d) repeating steps a-c for different predetermined beam powers, and (e) repeating steps a-d for different positions on said work piece, wherein said first energy beam spot size is verified if each detected settings of said focus lens and/or astigmatism lens are deviating less than a predetermined value from corresponding stored settings of said focus lens and/or astigmatism lens.

Assignees

• Arcam Ab

Inventors

• Snis Anders

Classifications

• G01M11/02

  Testing optical properties · CPC title

• B23K15/02 Primary

  Control circuits therefor · CPC title

• B22F12/90

  Means for process control, e.g. cameras or sensors · CPC title

• B22F12/52

  Hoppers · CPC title

• B22F10/31

  Calibration of process steps or apparatus settings, e.g. before or during manufacturing · CPC title