Method of Reducing and Optimising Printed Support Structures in 3D Printing Processes

• US 20160200051A1
• Filed: 01/12/2016
• Published: 07/14/2016
• Est. Priority Date: 01/13/2015
• Status: Active Grant

• Current Assignee: University of Windsor
• Original Assignee: University of Windsor
• Inventors: URBANIC, Jill
• Granted Patent: US 10,052,812 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• 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 64/393 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 2001/00 Use of cellulose, modified cellulose or cellulose derivatives, e.g. viscose, as moulding material
• CPC Class Codes: B29K 2105/0058 Liquid or visquous
• CPC Class Codes: B29K 2995/0037 Other properties
• CPC Class Codes: B33Y 10/00 Processes of additive manufacturing
• CPC Class Codes: B33Y 50/02 for controlling or regulating additive manufacturing processes

Abstract

A printed target model is formed by 3D printing by inputting target model data, and based on target model data, identifying surface portions requiring support. The surface portions are projected onto a virtual printer table, and one or more virtual support structures having a V-shaped cap portion and optionally a generally planar web are created therefore. The virtual model is then used to control a 3D printer to integrally print-form the target model and support structures.

Claims

1. A process for producing a printed target model formed from a model material using a 3D printer assembly, the 3D printer assembly including a 3D printer having a printer table and a processor having memory actuable to control said 3D printer, wherein the process comprising,

inputting in said memory target model data representative of the printed target model to be formed,

using said target model data, identifying target model surface portions of the printed target model requiring support and which orient at an angle exceeding a predetermined threshold angle,

converting a selected one of said surface portions to an associated planar image in a direction normal to a surface of the printer table,

identifying a long axis of said associated planar image,

generating at least one virtual, model support structure for said selected surface portion relative to said printer table, the support structure including a generally V-shaped cap portion, said cap portion including a pair of longitudinally extending planar sidewalls which extend upwardly outward from a lower vertex to an underside of the selected surface portion of the target model requiring support, each of said sidewalls extending laterally at an angel selected at or upto leas than 10°

from the predetermined threshold angle,

and activating with said 3D printer to form by model material layer build-up said target model and said support structures based on said input target model data and said generated virtual model support structures, and separating said target model from said model support structures.

2. The process as claimed in claim 1, wherein following said step of identifying said long axis, identifying a lateral axis normal to said long axis at a widest portion of said associated planar image, and

wherein generating said virtual model support structure further comprises selecting a symmetrical or asymmetrical configuration for said cap portion side-walls, whereby at a mid-point of said lateral axis identifying a center support axis, parallel to said long axis,

projecting downwardly inwardly towards the center support axis from each lateral edge of the selected surface portion, a virtual line oriented at an angle selected at or upto 10°

less than the predetermined threshold angle,

measuring the relative spacing between respective points of intersection of the virtual lines along a center support axis vertical plane and the selected surface portion, and

selecting said sidewall configuration based on the measured relative spacing.

3. The process as claimed in claim 1, wherein at least one said generated virtual model support structure further includes a longitudinally oriented generally planar support web and/or a plurality of longitudinally spaced support pillars extending vertically from the lower vertex of said cap portion to said printer table.

4. The process as claimed in claim 2, further wherein,

where the spacing between the respective points of intersection of the vertical lines is greater than a spacing between the selected surface portion and a closest one of said points of intersection,

said process comprising identifying at least one secondary support axis parallel to said long axis interposed between said center support axis and each end of said lateral axis, and

virtually modelling said V-shaped cap portion in substantially longitudinal alignment with a selected said secondary support axis by projecting a first said cap portion side laterally downwardly from one lateral edge of the selected surface portion to said selected secondary support axis, and

from the intersection of the first cap portion side and selected secondary axis projecting said second cap portion side laterally upward to contact the selected surface portion along the central support axis.

5. The process as claimed in claim 2, further wherein,

where the spacing between the respective points of intersection of the vertical lines is greater than a spacing between the selected surface portion and a closest one of said points of intersection,

virtually modelling said V-shaped cap portion in substantially longitudinal alignment with said center support axis by projecting a first said cap portion side laterally downward from a first lateral edge of the selected surface portion to intersect a vertical plane of said center support axis, and

from the intersection point of the first cap portion side and center support axis vertical plane, projecting said second cap portion side laterally upward to contact the selected surface portion.

6. The process as claimed in claim 3, wherein said support structure further includes at least one reinforcing web spanning between and integral with at least one associated pair of spaced supporting pillars.

7. The process as claimed in claim 1, wherein said predetermined threshold angle is selected as a departure angle from vertical selected at between about 40°

and 50°

±

1.

8. The process as claimed in claim 7, wherein the predetermined threshold angle is selected at least in part on the basis of at least one of the caring properties of the model material and the binding properties of the model material.

9. The process as claimed in claim 1, wherein said step of forming said support structure comprises depositing by said 3D printer successive layers of said model material to provide said support structure as a built up construction integrally formed with said target model.

10. The process as claimed in claim 9, wherein said model material is selected from the group consisting of a ceramic, a polymer, a cellulose-based and a plastic.

11. The process as claimed in claim 1, wherein said surface portions requiring support are identified on the basis of both the target model geometry and it least one of the curing properties of the model material and the binding properties of the model material.

12. The process as claimed in claim 7, wherein said model material is recyclable, and preferably comprises a recyclable polymer.

13. A process for producing a printed target model formed from a model material using a 3D printer assembly, the 3D pricier assembly including a 3D printer having a printer table and processor having memory actuable to control said 3D printer, wherein the process comprising,

inputting in said memory target model data representative of a virtual target model to be formed,

using said target model data, identifying target model surface portions of the printed target model which are oriented relative to vertical in n position exceeding a predetermined threshold angle as requiring support, projecting a selected said surface portion us a planar image relative to said printer table, and identifying a long axis of said planar image,

generating at least one a virtual support structure configured to provide support to said selected surface portion, and said virtual support structure extending longitudinally in the direction of said long axis and comprising a generally vertically elongated base portion extending from a lower end portion to an upper edge portion spaced a distance therefrom, and a cap portion having V-shaped sidewalls disposed at said upper edge portion,

wherein generating said virtual model support structure including selecting a symmetrical or asymmetrical configuration for said cap portion sidewalls, whereby following said step of identifying said long axis, identifying a lateral axis normal to said long axis at a widest portion of said associated planar image, at a mid-point of said lateral axis, identifying a center support axis, parallel to said long axis,

projecting downwardly inwardly towards a vertical place at the center support axis from each lateral edge of the selected surface portion, a virtual line oriented at an angle selected at or upto 10°

less than the predetermined threshold angle,

measuring the relative spacing between the respective points of intersection of the virtual lines along the center support axis vertical plane and the selected surface portion, and

selecting said sidewall configuration based on the measured relative spacing,

actuating said 3D printer to concurrently integrally form said target model and said support structure on said printer table corresponding to said virtual target model and virtual support structure.

14. The process is claimed in claim 13, further wherein

where the spacing between the respective points of intersection of the vertical lines is less than a spacing between the selected surface portion and a closest one of said points of intersection,

said process comprising identifying at least one secondary support axis parallel to said long axis interposed between said center support axis and each end of said lateral axis, and

virtually modelling said V-shaped cap portion in substantially longitudinal alignment with a selected said secondary support axis by projecting a first said cap portion side laterally downwardly from one lateral edge of the selected surface portion to said selected secondary support axis, and

from the intersection of the first cap portion side and selected secondary axis projecting said second cap portion side laterally upward to contact the selected surface portion along the central support axis.

15. The process as claimed in claim 13, further wherein

where the spacing between the respective points of intersection of the vertical lines is greater than a spacing between the selected surface portion and a closest one of said points of intersection,

virtually modelling said V-shaped cap portion in substantially longitudinal alignment with said center support axis by projecting a first said cap portion side laterally downward from a first lateral edge of the selected surface portion to intersect a vertical plane of said center support axis, and

from the intersection point of the first cap portion side and center support axis vertical plane, projecting said second cap portion side Intensify upward to contact the selected surface portion.

16. The process as claimed in claim 13, wherein said support structure further includes at least one reinforcing web spanning between and integral with said sidewalls.

17. The process as claimed in claim 13, wherein said predetermined threshold is selected as a departure angle from vertical selected at between about 40°

and 50°

±

1.

18. The process as claimed in claim 17, wherein the predetermined threshold angle is selected at least in part on the basis of at least one of the curing properties of the model material and the binding properties of the model material.

19. The process as claimed in claim 18, wherein said step of forming said support structure comprises depositing by said 3D printer successive layers of said model material to provide said support structure as a built up construction.

20. The process as claimed in claim 19, wherein said model material is selected from the group consisting of a ceramic, a polymer, a cellulose-based material and a plastic.

21. The process as claimed in claim 15, wherein said surface portions requiring support are identified on the basis of both the target model geometry and at least one of the curing properties of the model material and the binding properties of the model material.

22. The process as claimed in claim 13, wherein the 3D printer includes a plurality of printer heads, a first said printer head being operable to print form the target model from a first print material, a second said printer head being operable to print form said support structure from a material different from said first print material.