THREE-DIMENSIONAL PRINTER WITH FORCE DETECTION

• US 20140117575A1
• Filed: 10/29/2013
• Published: 05/01/2014
• Est. Priority Date: 10/29/2012
• Status: Active Grant

• Current Assignee: Stratasys Incorporated
• Original Assignee: MakerBot Industries, LLC (Ultimaker BV)
• Inventors: Schmehl, Peter Joseph, Kemperle, Aljosa, Gelman, Filipp
• Granted Patent: US 9,168,698 B2
• Time in Patent Office: Days
• US Class Current: 264/40.7
• CPC Class Codes: B29C 2948/9258 Velocity
• CPC Class Codes: B29C 2948/92704 Temperature
• CPC Class Codes: B29C 48/02 Small extruding apparatus, e.g. handheld, toy or laboratory extruders
• CPC Class Codes: B29C 48/154 Coating solid articles, i.e. non-hollow articles
• CPC Class Codes: B29C 48/265 Support structures or bases for apparatus, e.g. frames
• CPC Class Codes: B29C 48/266 Means for allowing relative movements between the apparatus parts, e.g. for twisting the extruded article or for moving the die along a surface to be coated
• CPC Class Codes: B29C 48/92 Measuring, controlling or regulating
• 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 64/118 using filamentary material being melted, e.g. fused deposition modelling [FDM]
• CPC Class Codes: B29C 64/205 Means for applying layers
• CPC Class Codes: B29C 64/209 Heads; Nozzles
• CPC Class Codes: B29C 64/386 Data acquisition or data processing for additive manufacturing
• CPC Class Codes: B29C 64/393 for controlling or regulating additive manufacturing processes
• CPC Class Codes: B29C 64/40 Structures for supporting 3D objects during manufacture and intended to be sacrificed after completion thereof
• CPC Class Codes: B29K 2101/12 Thermoplastic materials
• CPC Class Codes: B29K 2105/0067 Melt
• 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 40/00 Auxiliary operations or equipment, e.g. for material handling
• CPC Class Codes: B33Y 50/00 Data acquisition or data processing for additive manufacturing
• CPC Class Codes: B33Y 50/02 : for controlling or regulating additive manufacturing processes
• CPC Class Codes: B33Y 70/00 : Materials specially adapted for additive manufacturing
• CPC Class Codes: B33Y 80/00 : Products made by additive manufacturing

Abstract

An extruder or other tool head of a three-dimensional printer is instrumented to detect contact force against the extruder, such as by a build platform or an object being fabricated. The tool head may also be instrumented to detect deflection forces and the like acting on the tool that might indicate an operating error. The resulting feedback data can be used in a variety of ways to control operation of the three-dimensional printer during fabrication or diagnostics.

Claims

1. A three-dimensional printer comprising:

a fabrication tool; and

one or more sensors mechanically coupled to the fabrication tool, wherein the one or more sensors are collectively operable to sense a contact force between the fabrication tool and a separate structure.

2. The three-dimensional printer of claim 1, wherein the fabrication tool includes an extruder.

3. The three-dimensional printer of claim 2, wherein the contact force is a force along an extrusion axis of the extruder.

4. The three-dimensional printer of claim 2 wherein the contact force includes a deflection force exerted by the separate structure on a tip of the extruder.

5. The three-dimensional printer of claim 1, wherein the separate structure includes an object being fabricated by the three-dimensional printer.

6. The three-dimensional printer of claim 1, wherein the separate structure includes a build platform of the three-dimensional printer.

7. The three-dimensional printer of claim 1, wherein the contact force is a force normal to a surface of the separate structure.

8. The three-dimensional printer of claim 1, wherein the one or more sensors are collectively operable to sense a force between the fabrication tool and the separate structure along two or more non-parallel axes.

9. The three-dimensional printer of claim 8, wherein the one or more sensors are collectively operable to sense a force between the fabrication tool and the separate structure along three or more non-parallel axes.

10. The three-dimensional printer of claim 1, wherein each of the one or more sensors are selected from the group consisting of:

capacitive sensors, electromagnetic sensors, optical sensors, potentiometric sensors, and piezoelectric sensors.

11. The three-dimensional printer of claim 1, wherein the one or more sensors include one or more strain gauges.

12. The three-dimensional printer of claim 1 further comprising a controller configured to receive a signal from the one or more sensors and to calculate the contact force.

13. The three-dimensional printer of claim 1, further comprising:

one or more actuators mechanically coupled to the fabrication tool, and

a control circuit in data communication with the one or more actuators and the one or more sensors, the control circuit configured to control the one or more actuators to achieve a specified contact force between the one or more sensors and the separate structure.

14. A method comprising:

identifying build instructions for fabricating an object;

initiating a build using a three-dimensional printer comprising a fabrication tool and one or more sensors mechanically coupled to the fabrication tool, the one or more sensors configured to detect a current contact force between the fabrication tool and a separate structure;

detecting the current contact force; and

responsively creating a control signal to control at least one component of the three-dimensional printer during the build.

15. The method of claim 14, wherein the fabrication tool includes an extruder.

16. The method of claim 15, wherein the at least one component of the three-dimensional printer controls a feed rate for a build material used in the build.

17. The method of claim 15, wherein the at least one component of the three-dimensional printer controls a z-distance between the extruder and a build platform of the three-dimensional printer.

18. The method of claim 15 further comprising comparing the current contact force to an expected contact force.

19. The method of claim 18 further comprising adjusting at least one parameter of the three-dimensional printer to reduce a difference between the current contact force and the expected contact force.

20. The method of claim 18 further comprising terminating the build when a difference between the current contact force and the expected contact force indicates a fabrication error.

21. The method of claim 14 wherein the control signal includes a signal to the three-dimensional printer to change a distance between the fabrication tool and the separate structure.

22. The method of claim 15 wherein the control signal includes a signal to the three-dimensional printer to change a feed rate of build material extruded by the extruder.

23. The method of claim 15 further comprising detecting a planarity of the separate structure based upon a number of contact force measurements across a surface of the separate structure.

24. The method of claim 23 further comprising fabricating a layer on the surface of the separate structure that decreases one or more irregularities in the surface of the separate structure.

25. The method of claim 14, wherein the build instructions include at least one instruction for achieving a specified contact force between the fabrication tool and a separate structure, and wherein the control signal controls the at least one component of the three-dimensional printer to achieve the specified contact force.