APPARATUS AND METHOD FOR PRINTING THREE DIMENSIONAL ARTICLES

• US 20130314460A1
• Filed: 08/01/2013
• Published: 11/28/2013
• Est. Priority Date: 12/31/2007
• Status: Active Grant

• Current Assignee: SABIC Global Technologies BV (Government of Saudi Arabia)
• Original Assignee: Exatec, LLC (Government of Saudi Arabia)
• Inventors: Orr, Craig
• Granted Patent: US 9,630,396 B2
• Time in Patent Office: Days
• US Class Current: 347/2
• CPC Class Codes: B05B 12/124 responsive to distance between spray apparatus and target
• CPC Class Codes: B29C 64/106 using only liquids or viscous materials, e.g. depositing a continuous bead of viscous material
• CPC Class Codes: B29C 70/78 Moulding material on one side only of the preformed part
• CPC Class Codes: B33Y 10/00 Processes of additive manufacturing
• CPC Class Codes: B33Y 30/00 Apparatus for additive manufacturing; Details thereof or accessories therefor
• CPC Class Codes: B33Y 50/02 for controlling or regulating additive manufacturing processes
• CPC Class Codes: B41F 17/00 Printing apparatus or machines of special types or for particular purposes, not otherwise provided for
• CPC Class Codes: B41F 17/006 for printing on curved surfaces not otherwise provided for
• CPC Class Codes: B41J 23/00 Power drives for actions or mechanisms B41J9/00 , B41J19/305 take precedence
• CPC Class Codes: B41J 29/38 Drives, motors, controls or automatic cut-off devices for the entire printing mechanism
• CPC Class Codes: B41J 3/4073 Printing on three-dimensional objects not being in sheet or web form, e.g. spherical or cubic objects B41J3/283, B41J3/286 take precedence; building up a 3D object using individual droplets from jetting heads B29C64/112
• CPC Class Codes: B41M 5/0047 by ink-jet printing
• CPC Class Codes: B41M 5/0064 on plastics, horn, rubber, or other organic polymers
• CPC Class Codes: B41M 5/0088 by ink-jet printing

Abstract

An apparatus for printing an image onto a curved surface of a three dimensional article. The apparatus principally includes a support fixture, an ink jet print head having a plurality of nozzles, and an articulatable robotic arm. One of the support fixture and the print head are mounted to and carried by the robotic arm. The robotic arm is moveable so as to cause relative movement of the print head along a series of scanning paths that follow the surface contour of the curved surface of the article. A controller is coupled to the robotic arm and is configured to cause articulation of the robotic arm. The controller causes the robotic arm to continuously locate the print head relative to the curved surface and to cause the plurality of nozzles to eject printing medium at predetermined locations along the scanning paths so as to form the image.

Claims

1. An apparatus for printing an image onto a curved surface of a three dimensional article, the apparatus comprising:

a support fixture adapted to support the article;

an ink jet print head having a plurality of nozzles coupled to a source of printing medium;

an articulatable robotic arm, one of the print head and the support fixture being mounted to and carried by the robotic arm, the robotic arm having more than three degrees of freedom of movement and being moveable so as to cause relative movement of the print head along a series of scanning paths following surface contour of the curved surface of the article;

a controller coupled to the robotic arm and being configured to cause articulation of the robotic arm so as to cause relative movement of the print head along the series of scanning paths, the controller causing the robotic arm to continuously locate the print head relative to the curved surface of the article in a position suitable for printing as the print head is moved along the series of scanning paths, the controller coupled to the print head and further configured to cause the plurality of nozzles to eject printing medium at predetermined locations along the scanning paths so as to form the image on the curved surface of the substrate; and

a sensor configured to sense part features on the curved surface of the part, wherein the controller is configured to cause the plurality of nozzles to eject printing medium based on the sensing of part features by the sensor;

wherein the controller is configured to cause articulation of the robotic arm to position the print head at an orientation normal to the curved surface of the article.

2. The apparatus of claim 1 wherein the scanning paths are linear.

3. The apparatus of claim 1 wherein the plurality of nozzles are provided in one of a linear array and a two-dimensional array.

4. The apparatus of claim 1 wherein the controller is configured to cause the plurality of nozzles to eject printing medium based on a distance from a known point on the scanning paths correlated to image location data stored in memory of the controller.

5. The apparatus of claim 4 wherein the controller is configured to receive a start signal at a starting point of travel along the scanning paths and additional distance signals at additional distances along the scanning path and relative to the starting point.

6. The apparatus of claim 5 wherein the controller is configured to correct errors based on an actual scanning path relative to a desired scanning path, the controlling of the ejection of printing medium from the plurality of nozzles being corrected to correspond to the actual scanning path.

7. The apparatus of claim 1 where in the sensor is an optical sensor.

8. The apparatus of claim 1 wherein the sensor is a laser sensor.

9. The apparatus of claim 1 wherein the controller is configured to have stored in memory a set of values for the ejection of printing medium from each of the plurality of nozzles, the sets of values corresponding to each location of the part features.

10. The apparatus of claim 1 wherein the controller is configured to compare an actual position of the print head to stored image data corresponding to a three dimensional image on the surface of the article and control the ejection of printing medium from the plurality of nozzles based thereon.

11. The apparatus of claim 1 wherein the sensor is a print head height sensor configured to measure the height of the print head relative to the curved surface of the article.

12. The apparatus of claim 11 further comprising an actuator configured to move one of the print head and surface of the article either toward or away from one another based on the monitored height of the print head.

13. The apparatus of claim 11 wherein the print head height sensor includes a laser.

14. The apparatus of claim 1, wherein the sensor is mounted to and carried by the robotic arm.

15. A method for printing an image onto a curved surface of a three dimensional article, the method comprising:

locating an ink jet print head having a plurality of nozzles proximate to a curved surface of a three dimensional article;

causing relative movement of the ink jet print head along a scanning path across the surface of the article while positioning the ink jet print head at an orientation normal to curvature exhibited by the surface of the article;

sensing the height of the print head relative to the actual surface of the article and adjusting the height of the print head to an off-set height relative to the actual surface of the article; and

ejecting ink from the plurality of nozzles according to the position of the print head relative to the article based on location of the sensed part features correlated with image data stored in memory of a controller and correlated to the surface of the article.

16. The method of claim 15 wherein the step of ejecting ink further comprises the step of determining a starting location for relative movement of the ink jet print head and ejecting ink from the ink jet print head based on distance from the starting point that the print head has moved along the scanning path.

17. The method of claim 15 wherein the step of ejecting ink further comprises the step of determining a time of initial ejection of ink and ejecting ink from the ink jet print head based on elapsed time from the starting of ejecting of ink and the velocity of the print head moving along the scanning path.

18. The method of claim 15 wherein the step of ejecting ink further comprises the step of determining absolute coordinates of the print head relative to the surface of the article and correlating the coordinates with image data stored in memory of a controller.

19. The method of claim 15 further comprising the step of sensing the height of the print head relative to the actual surface of the article and adjusting the height of the print head to an off-set height relative to the actual surface of the article.