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CA-3148230-C - A METHOD OF DETERMINING A TOOL PATH FOR CONTROLLING A PRINTING TOOL

CA3148230CCA 3148230 CCA3148230 CCA 3148230CCA-3148230-C

Abstract

A method of determining a tool path for controlling a printing tool, including step (401) of receiving an input file containing data indicative of a three-dimensional structure to be formed. At step (404) the structure is divided into a plurality of build layers, which are separated in a build direction and each layer extends laterally relative to the build direction. Each layer includes an external contour defining the intersection of the layer with an exterior surface of the three-dimensional structure. Step (405) defines a tool path, which fills the three-dimensional structure, wherein the path includes partially filling one or more higher build layers along the build direction before entirely filling at least one lower build layer. At step (406), a printing tool control algorithm is generated that includes a series of control commands for controlling the printing tool to move along the tool path to form the three-dimensional structure.

Inventors

  • Peter King
  • Alejandro VARGAS USCATEGUI

Assignees

  • COMMONWEALTH SCIENTIFIC AND INDUSTRIAL RESEARCH ORGANISATION

Dates

Publication Date
20260505
Application Date
20200730
Priority Date
20190730

Claims (20)

  1. 31 CLAIMS 1. A method of determining a tool path for controlling a printing tool, the method including the steps: a) receiving an input file containing data indicative of a three dimensional structure to be formed; b) dividing the three dimensional structure into a plurality of build layers, wherein build layers are separated in a build direction and each build layer extends laterally relative to the build direction, each build layer including an external contour defining the intersection of the build layer with an exterior surface of the three dimensional structure; c) defining a tool path which fills the three dimensional structure, wherein for at least two adjacent layers, the tool path includes partially filling one or more higher build layers along the build direction before entirely filling at least one lower build layer using a continuous and non-intersecting tool path; and d) generating a printing tool control algorithm including a series of control commands for controlling the printing tool to move along the tool path to form the three dimensional structure.
  2. 2. The method according to claim 1 wherein step c) includes: 9134026 c)i) partitioning each build layer into one or more layer regions; c)ii) determining, based on a first predefined infill strategy, a first tool path section that entirely fills a first layer region; c)iii) determining, based on a second predefined infill strategy, a second tool path section that entirely fills a second layer region that is adjacent the first layer region in either the same layer or an adjacent layer, wherein an end point of the first tool path section within the first layer region is immediately adjacent a corresponding starting point of the second tool path section; Date Re9ue/Date Received 2024-02-02 32 c)iv) repeating steps c)ii) and c)iii) for all layer regions by matching tool path section start points with a corresponding tool path section end point of a previous tool path section of an adjacent layer or layer region to define a single tool path.
  3. 3. The method according to claim 2 wherein step c)iv) includes defining contour loop paths which extend around an external contour of the three dimensional structure between adjacent partition start and end points.
  4. 4. The method according to claim 1 wherein step c) includes: c)i) partitioning each build layer into a plurality of layer regions based on a feature of the three dimensional structure or build process; c)ii) for each layer region, determining a plurality of possible infilling path options, including start and end points within the layer region; c)iii) determining a precedence graph for each feature based on features which lie partially or wholly above/below other features in the three dimensional structure; and c)iv) determining an order of execution in the tool path that obeys precedence relations determined in the precedence graph such that each feature is executed only once, wherein an end point of a current feature in the sequence is adjacent to a start point of a next feature.
  5. 5. The method according to claim 4 wherein the structure includes one or more features and wherein at least one of the features include sub-areas of the structure that are infilled before other regions.
  6. 6. The method according to claim 4 or claim 5 wherein the one or more features of the three dimensional structure or build process include connecting paths between infill sections.
  7. 7. The method according to any one of claims 4 to 6 wherein the one or more features of the three dimensional structure or build process include loop paths that loop around structural features. 9134026 Date Re9ue/Date Received 2024-02-02 33
  8. 8. The method according to any one of claims 4 to 7 wherein an infilling path options include an infill strategy.
  9. 9. The method according to any one of claims 1 to 8 wherein the printing tool is controlled to perform an additive manufacturing process to form the three dimensional structure.
  10. 10. The method according to any one of claims 1 to 9 wherein the three dimensional structure forms part of a larger three dimensional object.
  11. 11. The method according to any one of claims 1 to 10 wherein the tool path is continuous such that a flow of printing material to the printing tool is maintained throughout a printing process.
  12. 12. The method according to any one of claims 1 to 11 including the step of a)i) of receiving, from a user through a user interface, one or more build parameters for building the three dimensional structure.
  13. 13. The method according to claim 12 wherein the build parameters include an infill strategy.
  14. 14. The method according to claim 13 wherein the infill strategy includes a double layer strategy wherein a tool path section in layer n+1 is the direct reverse of a tool path section in an adjacent layer region of adjacent layer n.
  15. 15. The method according to claim 14 wherein the infill strategy includes a spiral infill pattern starting at an outer layer region point and finishing at a central layer region point.
  16. 16. The method according to claim 15 wherein the infill strategy of an adjacent layer includes a reverse spiral pattern which starts at the central point and finishes at the outer point.
  17. 17. The method according to claim 13 wherein the infill strategy includes a raster pattern infill strategy.
  18. 18. The method according to claim 2 wherein the first and second predefined infill strategies are the same. 9134026 Date Re9ue/Date Received 2024-02-02 34
  19. 19. The method according to any one of claims 1 to 18 wherein dividing the three dimensional structure into a plurality of sub-regions includes partitioning the three dimensional structure into one or more volume structures prior to defining the build layers.
  20. 20. The method according to any one of claims to 19 wherein the build layers include planar surfaces.

Description

1 Title of Invention A method of determining a tool path for controlling a printing tool Technical Field [0001] The present invention relates to additive manufacturing and in particular to methods of determining a tool path for controlling a printing tool in an additive manufacturing process and subsequently controlling a printing tool in an additive manufacturing process based on that tool path. [0002] While some embodiments will be described herein with particular reference to that application, it will be appreciated that the invention is not limited to such a field of use, and is applicable in broader contexts. Background of Invention [0003] In an additive manufacturing (also referred to as "3D printing") process, a printing mechanism (referred to as a "tool") is computer controlled to follow a predefined path (referred to as a "tool path") in 3D space to build a desired object from a printing material. [0004] Typically, the path planning process for 3D printing involves a combination of (a) print head movements during which material is being added to the part as the print head moves, and (b) movements without deposition of material. The latter may be referred to as skip or jump movements. In a polymer 3D printing process, for example, the extruder motor is turned off during a jump movement. [0005] In some additive manufacturing processes, it is difficult or impossible to turn the material feed on and off quickly as doing so disturbs the material deposition process in some way. In these processes, a more suitable tool path strategy is one in which the feed is kept on for as much of the build as is possible. [0006] 3D printing conventionally involves a layer-by-layer build process, in which all tool paths for a layer n are completed before progressing to the next layer n + 1. In this regard, existing 3D printing software for producing G-code for 3D printing achieves computational efficiency by reducing a 3D problem to a 2D one. It does this by first slicing the object, i.e. finding the intersection of regularly-spaced planes with the WO 2021/016666 PCT I AU2020/050778 2 triangles in an .STL file, defining the 2D area to be filled in each layer and then performing tool path planning on this 2D area, one layer at a time. [0007] However, this layer-by-layer approach is inefficient for any three axis additive manufacturing system and especially in more advanced systems involving one or two 6-axis robot arms, which offer the possibility of performing more sophisticated three dimensional manufacturing. In systems of two robot arms (one holding the part and the other the deposition head) up to 12 degrees of freedom are possible as rotational movements can also be performed. A rigid, layer-by-layer path planning approach does not take advantage of this freedom. [0008] Some more advanced tool paths have been devised such as Fractal space filling curves such as Peano curves and Hilbert curves. However, these paths inherently involve a high number of turns for a given length of path. The number of turns can be too high for large scale robotic application, where manoeuvring a heavy part or deposition head at high speed entails considerable deceleration / acceleration. Robots suffer excessive vibration and wear if large numbers of directional changes are included in the tool path, and high-speed movement is not possible if the robot arm does not have sufficient path length over which to accelerate and reach constant velocity. [0009] To partially address some of the above deficiencies, Michel et al. "A modular path planning solution for Wire + Arc Additive Manufacturing", Robotics and ComputerIntegrated Manufacturing Volume 60, December 2019, Pages 1-11) used partitioning (segmentation) of individual object layers with different path planning strategies within each segment. They term this 'Modular Path Planning (MPP)'. In the MPP process, once a path has been generated for all segments, they are combined into a single layer path. However, the deposition is not continuous along the entire layer. Instead, when reaching the end of a section, the deposition is stopped and the torch moves to the starting point of the following section with the arc off and without feeding any material. Thus, this technique still involves multiple deactivations of the tool. [0010] Dwivedi, Rajeev & Kovacevic, Radovan (2004)"Automated torch path planning using polygon subdivision for solid freeform fabrication based on welding", Journal of Manufacturing Systems, 23(4), p278-291, used continuous path planning with monotone polygon subdivision for the welding additive manufacturing process. However, this technique is silent on extending a continuous path to other layers in a 3D structure. Thus, the technique likely follows a layer-by-layer approach. WO 2021/016666 PCT I AU2020/050778 3 [0011] Flores, J. et al, "Toolpath generation for the manufacture of metallic components by means of the laser metal deposition technique", The International Jour