# US 11,027,494 B2 · Device and method for calibrating an irradiation system of an apparatus for producing a three-dimensional work piece

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- Number: US 11,027,494 B2
- Document ID: US11027494B2
- Status: Granted
- Kind: B2
- Application number: 16/189,562
- Filed: 2018-11-13
- Published: 2019-03-14
- Granted: 2021-06-08
- Earliest claimed: 2016-05-13
- Assignees: SLM Solutions Group AG
- Applicants: SLM Solutions Group AG
- Inventors: Christopher Stengel; Daniel Alberts; Dieter Schwarze; Toni Adam Krol
- Web page: https://patentgrep.com/patent/US11027494B2

## CPC

- G01B 11/24: for measuring contours or curvatures
- B22F 10/28: Powder bed fusion, e.g. selective laser melting [SLM] or electron beam melting [EBM]
- B22F 10/31: Calibration of process steps or apparatus settings, e.g. before or during manufacturing
- B22F 12/49: Scanners
- B22F 12/90: Means for process control, e.g. cameras or sensors
- B29C 64/153: using layers of powder being selectively joined, e.g. by selective laser sintering or melting
- B29C 64/20: Apparatus for additive manufacturing; Details thereof or accessories therefor
- B29C 64/268: using laser beams; using electron beams [EB]
- B29C 64/371: using an environment other than air, e.g. inert gas
- B29C 64/386: Data acquisition or data processing for additive manufacturing
- B29C 64/393: for controlling or regulating additive manufacturing processes
- B33Y 10/00: Processes of additive manufacturing
- B33Y 30/00: Apparatus for additive manufacturing; Details thereof or accessories therefor
- B33Y 50/00: Data acquisition or data processing for additive manufacturing
- G05B 19/4097: characterised by using design data to control NC machines, e.g. CAD/CAM (G05B19/4093 takes precedence)
- G06T 7/13: Edge detection
- G06T 7/73: using feature-based methods
- B22F 7/008: {characterised by the composition}
- B22F 7/02: of composite layers {(B22F7/002 takes precedence)}
- B22F 10/322: of the gas flow, e.g. rate or direction
- B22F 10/77: of gas
- B22F 12/41: characterised by the type, e.g. laser or electron beam
- B22F 12/45: Two or more
- B22F 12/70: Gas flow means
- B22F 2203/03: for feed-back
- B22F 2203/11: temperature, temperature profile
- B22F 2207/20: Cooperating components
- B33Y 50/02: for controlling or regulating additive manufacturing processes
- Y02P 10/25: Process efficiency
- G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- B22F: WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER (making alloys by powder metallurgy C22C); APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00)
- B33Y: ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
- G05B: CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS (systems for controlling or regulating non-electric variables G05D; systems for regulating electric or magnetic variables G05F; control devices or systems insofar as characterised by mechanical features only G05G)
- G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

A device (48) for calibrating an irradiation system (18) of an apparatus (10) for producing a three-dimensional work piece comprises a control unit (50) adapted to control the irradiation system (18) so as to irradiate a radiation beam (22; 22a, 22b) onto an irradiation plane (52) according to a calibration pattern. The device (48) further comprises a sensor arrangement (56) adapted to be arranged in the irradiation plane (52) and to output signals to the control unit (50) in response to being irradiated with the radiation beam (22; 22a, 22b) according to the calibration pattern. The control unit (50) further is adapted to generate a digital image of an actual irradiation pattern produced by the radiation beans (22; 22a, 22b) incident on the sensor arrangement (56) based on the signals output by the sensor arrangement (56), to compare the digital image of the actual irradiation pattern with a digital image of a reference pattern so as to determine a deviation between the actual irradiation pattern and the reference pattern, and to calibrate the irradiation system (18) based on the determined deviation between the actual irradiation pattern and the reference pattern.

## Claims

### Claim 1

An apparatus for associating a position in a construction data set with a position in a building section of the apparatus, comprising:
a building section for generating a three-dimensional work piece, configured to receive a base element comprising a boundary surface;
an irradiation unit configured to generate a radiation beam and to scan the radiation beam over a predefined scanning field, wherein the predefined scanning field comprises at least part of the boundary surface of the base element;
a detecting unit configured to detect time-dependent electromagnetic radiation intensity of electromagnetic radiation emitted at a spot position of the radiation beam while the radiation beam is scanned over the scanning field; and
a controller configured to:
associate the detected electromagnetic radiation intensity with position information indicative of a current position of the radiation beam;
determine a position of the boundary surface of the base element with regard to the scanning field, based on intensity variations of the detected time-dependent electromagnetic radiation intensity and based on the position information, such that abrupt intensity variations over time are identified as corresponding to edges of the boundary surface;
associate a position in a construction data set with a position in the building section, based on the determined position of the boundary surface; and
associate a position of an additive boundary surface of an additive element defined by the construction data set with the determined position of the boundary surface of the base element.

### Claim 2 (depends on 1)

The apparatus of claim 1, wherein the detecting unit is configured to detect the electromagnetic radiation intensity in dependence of the spot position of the radiation beam and to output the position information.

### Claim 3 (depends on 2)

The apparatus of claim 2, wherein the apparatus is configured to produce the additive element onto the base element, the additive boundary surface of the additive element matching the boundary surface of the base element by considering an association between the position in the construction data set and the position in the building section.

### Claim 4 (depends on 3)

The apparatus of claim 3, wherein the controller is configured to generate a two-dimensional image, based on the detected electromagnetic radiation intensity and the associated position information;
identify edges of the boundary surface of the base element in the two-dimensional image by using image processing; and
determine the position of the boundary surface of the base element with regard to the scanning field, based on the identified edges.

### Claim 5 (depends on 1)

The apparatus of claim 1, wherein the controller is configured to determine the position information based on radiation position information input into the irradiation unit.

### Claim 6 (depends on 1)

The apparatus of claim 1, wherein the apparatus is configured to produce the additive element onto the base element, the additive boundary surface of the additive element matching the boundary surface of the base element by considering an association between the position in the construction data set and the position in the building section.

### Claim 7 (depends on 6)

The apparatus of claim 6, wherein the apparatus is configured to generate the additive element onto the base element by powder bed fusion using the irradiation unit.

### Claim 8 (depends on 1)

The apparatus of claim 1, wherein the controller is configured to generate a two-dimensional image, based on the detected electromagnetic radiation intensity and the associated position information;
identify edges of the boundary surface of the base element in the two-dimensional image by using image processing; and
determine the position of the boundary surface of the base element with regard to the scanning field, based on the identified edges.

### Claim 9

A method for associating a position in a construction data set with a position in a building section of an apparatus, comprising:
positioning a base element in a building section for generating a three-dimensional work piece, the base element comprising a boundary surface;
generating a radiation beam and scanning the radiation beam over a predefined scanning field, wherein the predefined scanning field comprises at least part of the boundary surface of the base element;
detecting time-dependent electromagnetic radiation intensity of electromagnetic radiation emitted at a spot position of the radiation beam while the radiation beam is scanned over the scanning field;
associating the detected electromagnetic radiation intensity with position information indicative of a current position of the radiation beam;
determining a position of the boundary surface of the base element with regard to the scanning field, based on intensity variations of the detected time-dependent electromagnetic radiation intensity and based on the position information, such that abrupt intensity variations over time are identified as corresponding to edges of the boundary surface;
associating a position in a construction data set with a position in the building section, based on the determined position of the boundary surface; and
associating a position of an additive boundary surface of an additive element defined by the construction data set with the determined position of the boundary surface of the base element.

### Claim 10 (depends on 9)

The method of claim 9, wherein the radiation beam has an intensity so low that a material structure of the base element is not affected.

### Claim 11 (depends on 10)

The method of claim 10, wherein the radiation beam is scanned over the predefined scanning field in a pattern comprising a plurality of irradiation vectors parallel to each other.

### Claim 12 (depends on 11)

The method of claim 11, further comprising:
producing the additive element onto the base element, the additive boundary surface of the additive element matching the boundary surface of the base element by considering an association between the position in the construction data set and the position in the building section.

### Claim 13 (depends on 12)

The method of claim 12, wherein the additive element is generated onto the base element by powder bed fusion using the irradiation unit.

### Claim 14 (depends on 10)

The method of claim 10, further comprising:
producing the additive element onto the base element, the additive boundary surface of the additive element matching the boundary surface of the base element by considering an association between the position in the construction data set and the position in the building section.

### Claim 15 (depends on 10)

The method of claim 10, wherein the additive element is generated onto the base element by powder bed fusion using the irradiation unit.

### Claim 16 (depends on 9)

The method of claim 9, wherein the radiation beam is scanned over the predefined scanning field in a pattern comprising a plurality of irradiation vectors parallel to each other.

### Claim 17 (depends on 16)

The method of claim 16, further comprising:
producing the additive element onto the base element, the additive boundary surface of the additive element matching the boundary surface of the base element by considering an association between the position in the construction data set and the position in the building section.

### Claim 18 (depends on 16)

The method of claim 16, wherein the additive element is generated onto the base element by powder bed fusion using the irradiation unit.

### Claim 19 (depends on 9)

The method of claim 9, further comprising:
producing the additive element onto the base element, the additive boundary surface of the additive element matching the boundary surface of the base element by considering an association between the position in the construction data set and the position in the building section.

### Claim 20 (depends on 9)

The method of claim 9, wherein the additive element is generated onto the base element by powder bed fusion using the irradiation unit.