# US 10,500,792 B2 · System and method for roll alignment of a multi-nozzle extruder in three-dimensional object printers using cross-process measurements

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- Number: US 10,500,792 B2
- Document ID: US10500792B2
- Status: Granted
- Kind: B2
- Application number: 15/661,711
- Filed: 2017-07-27
- Published: 2019-01-31
- Granted: 2019-12-10
- Earliest claimed: 2017-07-27
- Assignees: Xerox Corporation
- Applicants: Xerox Corporation
- Inventors: David A. Mantell; Christopher G. Lynn; Mark A. Cellura; Peter J. Nystrom
- Web page: https://patentgrep.com/patent/US10500792B2

## CPC

- B29C 64/393: for controlling or regulating additive manufacturing processes
- B29C 48/02: Small extruding apparatus, e.g. handheld, toy or laboratory extruders
- B29C 48/05: Filamentary, e.g. strands
- B29C 48/2528: {Drive or actuation means for non-plasticising purposes, e.g. dosing unit}
- B29C 48/265: Support structures or bases for apparatus, e.g. frames
- B29C 48/302: {being adjustable, i.e. having adjustable exit sections}
- B29C 48/345: Extrusion nozzles comprising two or more adjacently arranged ports, for simultaneously extruding multiple strands, e.g. for pelletising
- B29C 48/92: Measuring, controlling or regulating
- B29C 64/106: using only liquids or viscous materials, e.g. depositing a continuous bead of viscous material
- B29C 64/209: Heads; Nozzles
- G05B 19/4099: Surface or curve machining, making three-dimensional [3D] objects, e.g. desktop manufacturing
- B29C 2948/92076: Position, e.g. linear or angular
- B29C 2948/92409: Die; Nozzle zone
- B29C 2948/92571: Position, e.g. linear or angular
- B29C 2948/92904: Die; Nozzle zone
- B33Y 10/00: Processes of additive manufacturing
- B33Y 30/00: Apparatus for additive manufacturing; Details thereof or accessories therefor
- B33Y 50/02: for controlling or regulating additive manufacturing processes
- G05B 2219/49007: Making, forming 3-D object, model, surface
- 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)
- 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)
- 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

## Abstract

A method for identifying an angle of roll for a multi-nozzle extruder includes moving the extruder in a first process direction to form a first set of swaths of extrusion material using two nozzles in the extruder and moving the extruder in a second process direction to form a second set of swaths of extrusion material. The method further includes identifying a location of one nozzle relative to the other nozzle in two dimensions based on cross-process direction distances between the first and second sets of swaths and identifying the angle of extruder roll for the extruder based on the location of the one nozzle and a predetermined geometry of the extruder.

## Claims

### Claim 1

A method operating a three-dimensional object printer comprising:
moving, with a first actuator, a multi-nozzle extruder in a first process direction within a print zone of the three-dimensional object printer;
operating at least a first nozzle and a second nozzle in a plurality of nozzles in the multi-nozzle extruder to emit a first swath and a second swath, respectively, of an extrusion material onto a surface of a receiving member in the print zone during the moving of the multi-nozzle extruder in the first process direction;
moving, with the first actuator, the multi-nozzle extruder in a second process direction within the print zone of the three-dimensional object printer, the second process direction being different than the first process direction;
operating at least the first nozzle and the second nozzle in the plurality of nozzles in the multi-nozzle extruder to emit a third swath and a fourth swath, respectively, of the extrusion material onto the surface of the receiving member in the print zone during the moving of the multi-nozzle extruder in the second process direction;
generating, with an optical sensor, scanned image data of the first swath, the second swath, the third swath, and the fourth swath;
identifying, with a controller, a measured two-dimensional location of the second nozzle relative to the first nozzle with reference to a first location of the second nozzle in a first cross-process direction corresponding to a location of the second swath relative to the first swath in the scanned image data, the first cross-process direction being perpendicular to the first process direction, and a second location of the second nozzle in a second cross-process direction corresponding to a location of the fourth swath relative to the third swath in the scanned image data, the second cross-process direction being perpendicular to the second process direction; and
identifying, with the controller, an angle of roll for the multi-nozzle extruder with reference to the measured two-dimensional location of the second nozzle relative to the first nozzle and a predetermined geometric arrangement of the first nozzle and the second nozzle in the multi-nozzle extruder.

### Claim 2 (depends on 1)

The method of claim 1 further comprising:
operating, with the controller, a second actuator operatively connected to the multi-nozzle extruder to rotate the multi-nozzle extruder by an angle corresponding to the angle of roll for the multi-nozzle extruder to reduce or eliminate the angle of roll.

### Claim 3 (depends on 2)

The method of claim 2 further comprising:
operating, with the controller, the second actuator operatively connected to the multi-nozzle extruder to rotate the multi-nozzle extruder in a direction opposite of the angle of roll to reduce or eliminate the angle of roll.

### Claim 4 (depends on 1)

The method of claim 1, the identifying of the angle of roll further comprising:
identifying, with the controller, a plurality of two-dimensional locations for the second nozzle relative to the first nozzle that correspond to a plurality of angles of roll for the multi-nozzle extruder within a predetermined range of angles;
identifying, with the controller, a plurality of errors, each error in the plurality of errors corresponding to a distance between one two-dimensional location in the plurality of locations for the second nozzle and the measured two-dimensional location of the second nozzle; and
identifying the angle of roll for the multi-nozzle extruder with reference to one angle of roll in the plurality of angle of rolls that corresponds a minimum error in the plurality of errors.

### Claim 5 (depends on 4)

The method of claim 4, the identifying of the angle of roll further comprising a non-linear least-squares minimization process to identify the one angle of roll in the plurality of angle of rolls that corresponds to a minimum error in the plurality of errors.

### Claim 6 (depends on 4)

The method of claim 4, the identifying of the angle of roll further comprising a sum-of-squares minimization process to minimize a sum-of-squares of a first component of each error corresponding to the first cross-process direction and a second component of each error corresponding to the second cross-process direction.

### Claim 7 (depends on 4)

The method of claim 4, the identifying of the angle of roll further comprising a curve-fitting process to identify the one angle of roll in the plurality of angle of rolls that corresponds a minimum error in the plurality of errors.

### Claim 8 (depends on 1)

The method of claim 1, the identifying of the measured two-dimensional location of the second nozzle further comprising:
identifying, with the controller, a first relative location of the first swath in the first cross-process direction corresponding to a location in a height profile in the scanned image data of a maximum height of the first swath; and
identifying, with the controller, a second relative location of the second swath in the first cross-process direction corresponding to another location in the height profile in the scanned image data of a maximum height of the second swath.

### Claim 9 (depends on 1)

The method of claim 1, the moving of the multi-nozzle extruder in the second process direction further comprising:
moving, with the first actuator, the multi-nozzle extruder in the second process direction at a 90° angle relative to the first process direction.

### Claim 10

A three-dimensional object printer comprising:
a multi-nozzle extruder including a plurality of nozzles;
a first actuator configured to move the multi-nozzle extruder in a first process direction and a second process direction within a print zone of the three-dimensional object printer, the second process direction being different than the first process direction;
an optical sensor; and
a controller operatively connected to the multi-nozzle extruder, the first actuator, and the optical sensor, the controller being configured to:
move the multi-nozzle extruder in the first process direction using the first actuator;
operate at least a first nozzle and a second nozzle in the plurality of nozzles in the multi-nozzle extruder to emit a first swath and a second swath, respectively, of an extrusion material onto a surface of a receiving member in the print zone during the moving of the multi-nozzle extruder in the first process direction;
move the multi-nozzle extruder in the second process direction using the first actuator;
operate at least the first nozzle and the second nozzle in the plurality of nozzles in the multi-nozzle extruder to emit a third swath and a fourth swath, respectively, of the extrusion material onto the surface of the receiving member in the print zone during the moving of the multi-nozzle extruder in the second process direction;
generate scanned image data of the first swath, the second swath, the third swath, and the fourth swath using the optical sensor;
identify a measured two-dimensional location of the second nozzle relative to the first nozzle with reference to a first location of the second nozzle in a first cross-process direction corresponding to a location of the second swath relative to the first swath in the scanned image data, the first cross-process direction being perpendicular to the first process direction, and a second location of the second nozzle in a second cross-process direction corresponding to a location of the fourth swath relative to the third swath in the scanned image data, the second cross-process direction being perpendicular to the second process direction; and
identify an angle of roll for the multi-nozzle extruder with reference to the measured two-dimensional location of the second nozzle relative to the first nozzle and a predetermined geometric arrangement of the first nozzle and the second nozzle in the multi-nozzle extruder.

### Claim 11 (depends on 10)

The three-dimensional object printer of claim 10 further comprising:
a second actuator operatively connected to the multi-nozzle extruder; and
the controller being operatively connected to the second actuator and further configured to:
rotate the multi-nozzle extruder by an angle corresponding to the angle of roll for the multi-nozzle extruder using the second actuator to reduce or eliminate the angle of roll.

### Claim 12 (depends on 11)

The three-dimensional object printer of claim 11, the controller being further configured to:
rotate the multi-nozzle extruder in a direction opposite of the angle of roll using the second actuator to reduce or eliminate the angle of roll.

### Claim 13 (depends on 10)

The three-dimensional object printer of claim 10, the controller being further configured to:
identify a plurality of two-dimensional locations for the second nozzle relative to the first nozzle that correspond to a plurality of angles of roll for the multi-nozzle extruder within a predetermined range of angles;
identify a plurality of errors, each error in the plurality of errors corresponding to a distance between one two-dimensional location in the plurality of locations for the second nozzle and the measured two-dimensional location of the second nozzle; and
identify the angle of roll for the multi-nozzle extruder with reference to one angle of roll in the plurality of angle of rolls that corresponds a minimum error in the plurality of errors.

### Claim 14 (depends on 13)

The three-dimensional object printer of claim 13, the controller being further configured to:
identify the angle of roll using a non-linear least-squares minimization process to identify the one angle of roll in the plurality of angle of rolls that corresponds a minimum error in the plurality of errors.

### Claim 15 (depends on 13)

The three-dimensional object printer of claim 13, the controller being further configured to:
identify the angle of roll using a sum-of-squares minimization process to minimize a sum-of-squares of a first component of each error corresponding to the first cross-process direction and a second component of each error corresponding to the second cross-process direction.

### Claim 16 (depends on 13)

The three-dimensional object printer of claim 13, the controller being further configured to:
identify the angle of roll using a curve-fitting process to identify the one angle of roll in the plurality of angle of rolls that corresponds a minimum error in the plurality of errors.

### Claim 17 (depends on 10)

The three-dimensional object printer of claim 10, the controller being further configured to:
identify a first relative location of the first swath in the first cross-process direction corresponding to a location in a height profile in the scanned image data of a maximum height of the first swath; and
identify a second relative location of the second swath in the first cross-process direction corresponding to another location in the height profile in the scanned image data of a maximum height of the second swath.

### Claim 18 (depends on 10)

The three-dimensional object printer of claim 10, the controller being further configured to:
move the multi-nozzle extruder using the actuator in the second process direction at a 90° angle relative to the first process direction.