Mold lock remediation

Patent metadata

Field	Value
Publication number	US-11718038-B2
Application number	US-202117474216-A
Country	US
Kind code	B2
Filing date	Sep 14, 2021
Priority date	Apr 24, 2017
Publication date	Aug 8, 2023
Grant date	Aug 8, 2023

Abstract

Mold lock is remediated by performing a layer-by-layer, two-dimensional analysis to identify unconstrained removal paths for any support structure or material within each two-dimensional layer, and then ensuring that aligned draw paths are present for all adjacent layers, all as more specifically described herein. Where locking conditions are identified, a sequence of modification rules are then applied, such as by breaking support structures into multiple, independently removable pieces. By addressing mold lock as a series of interrelated two-dimensional geometric problems, and reserving three-dimensional remediation strategies for more challenging, complex mold lock conditions, substantial advantages can accrue in terms of computational speed and efficiency.

First claim

What is claimed is:

1. A method comprising:
receiving a digital model including a raft, an object for fabrication on the raft, and a support for fabrication with the object to provide physical support according to one or more design rules;
dividing the digital model into a number of layers formed by planar, horizontal cross sections through the digital model;
for each layer, identifying one or more draw paths for separating a layer of support formed by a cross section of the support from a layer of the object formed by a cross section of the object within the layer of the digital model;
identifying one of the number of layers as a locked layer when the layer of support has no draw path for separating the layer of support from the layer of the object, or when the layer of support is vertically coupled to a second layer of the support having no draw path in common with the layer of support;
identifying a mold locked region of the support including the locked layer and any vertically contiguous support layers;
dividing the mold locked region with one or more vertical planes into one or more subregions;
if the one or more subregions can be horizontally removed, processing a remaining digital model, excluding the one or more subregions, for mold lock remediation; and
if the one or more subregions cannot be horizontally removed, employing one or more three-dimensional remediation strategies to address the mold locked region.

2. The method of claim 1 wherein dividing the mold locked region includes iteratively attempting an increasing number of planar slices until the one or more subregions can be horizontally removed or a threshold is reached.

3. The method of claim 1 wherein the one or more three-dimensional remediation strategies includes vertically moving the mold locked region after a second mold locked region is removed from a vertically adjacent volume.

4. The method of claim 1 wherein the one or more three-dimensional remediation strategies includes subdividing the mold locked region into a number of volumetric subregions and searching for three-dimensional draw paths for removing the volumetric subregions from the object.

5. The method of claim 4 wherein the volumetric subregions are sized for removal through an opening in the object.

6. The method of claim 1 further comprising, if the one or more three-dimensional remediation strategies fail to remediate the mold lock, providing a notification to a user of an unremediated mold lock condition.

7. The method of claim 1 wherein the draw path includes a range of angles over which a first rigid shape of the cross section of the support can be separated in a straight line from a second rigid shape of the object.

8. The method of claim 1 wherein identifying one or more draw paths includes testing for linear separation in a straight line at a number of discrete angles over a predetermined range of angles.

9. The method of claim 1 further comprising performing an initial check to determine whether the object can be separated from the support along a vertical axis.

10. The method of claim 1 further comprising separating regions of the support touching the raft from regions of the support not touching the raft along a vertical axis and performing a check to determine whether the object can be separated from the support along the vertical axis.

11. The method of claim 1 further comprising fabricating the object and the support based on the digital model.

12. The method of claim 11 wherein fabricating includes fabricating an interface layer between the one or more subregions of the mold locked region.

13. The method of claim 11 wherein fabricating the object includes fabricating an interface layer between the support and the object.

14. The method of claim 1 wherein the design rules include fabrication design rules.

15. The method of claim 1 wherein the design rules include sintering design rules.

16. The method of claim 1 wherein the number of layers correspond to material deposition layers for an additive fabrication process.

17. A computer program product comprising computer executable code embodied in a non-transitory computer readable medium that, when executing on one or more computing devices, performs the steps of:
receiving a digital model including a raft, an object for fabrication on the raft, and a support for fabrication with the object to provide physical support according to one or more design rules;
dividing the digital model into a number of layers formed by planar, horizontal cross sections through the digital model;
for each layer, identifying one or more draw paths for separating a layer of support formed by a cross section of the support from a layer of the object formed by a cross section of the object within the layer of the digital model;
identifying one of the number of layers as a locked layer when the layer of support has no draw path for separating the layer of support from the layer of the object, or when the layer of support is vertically coupled to a second layer of the support having no draw path in common with the layer of support;
identifying a mold locked region of the support including the locked layer and any vertically contiguous support layers;
dividing the mold locked region with one or more vertical planes into one or more subregions;
if the one or more subregions can be horizontally removed, processing a remaining digital model, excluding the one or more subregions, for mold lock remediation; and
if the one or more subregions cannot be horizontally removed, employing one or more three-dimensional remediation strategies to address the mold locked region.

18. The computer program product of claim 17 further comprising code that performs the step of performing an initial check to determine whether the object can be separated from the support along a vertical axis.

19. The computer program product of claim 17 further comprising code that performs the step of separating regions of the support touching the raft from regions of the support not touching the raft along a vertical axis and performing a check to determine whether the object can be separated from the support along the vertical axis.

20. The computer program product of claim 17 further comprising generating instructions executable by a three-dimensional printer to fabricate the object and the support, including fabricating an interface layer between the object and the support and a second interface layer between the one or more subregions of the mold locked region.

Assignees

• Desktop Metal Inc

Inventors

• Chin Ricardo
• Reeves Blake Z

Classifications

• B29C64/386 Primary

  Data acquisition or data processing for additive manufacturing · CPC title

• B22F10/20

  Direct sintering or melting · CPC title

• B22F10/40

  Structures for supporting workpieces or articles during manufacture and removed afterwards · CPC title

• B22F10/64

  by thermal means (control of energy beam parameters for post heating B22F10/364) · CPC title

• B28B1/001

  Rapid manufacturing of 3D objects by additive depositing, agglomerating or laminating of material (selective deposition modelling of metallic powder B22F10/00; rapid manufacturing of 3D objects in general and in particular of plastics B29C64/00) · CPC title