Three-dimensional printing

Abstract

Methods, systems, and apparatus, including computer programs encoded on computer storage media, for working with three-dimensional object models for printing. One of the methods includes determining a plurality of infill structures in a slice of an object; and determining a path for the tool-head to create the plurality of infill structures including: determining a first portion of the path for deposition of a first infill structure during a first time period; determining a second portion of the path for deposition of one or more second infill structures that are not adjacent to the first infill structure during a second time period; and determining a third portion of the path for deposition of a third infill structure that is adjacent to the first infill structure, wherein the second time period is determined to allow the first infill structure to cool before deposition of the third infill structure.

What is claimed is: 
     
         1 . (canceled) 
     
     
         2 . A computer-implemented method comprising:
 determining, by a three-dimensional modelling system, one or more infill structures for a three-dimensional model of a solid object, wherein the one or more infill structures are located in an interior of a hollow shell of the three-dimensional model, the hollow shell and the one or more infill structures together defining a modified object for the three-dimensional model;   determining, by the three-dimensional modelling system, that creation of the modified object, by the three-dimensional printer, using the one or more infill structures and the hollow shell satisfies one or more efficiency criteria by comparing data representing the one or more infill structures and the hollow shell of the modified object with data for the solid object; and   providing data for the one or more infill structures and the hollow shell that is useable to cause the three-dimensional printer to create the modified object after determination that the one or more efficiency criteria are satisfied.   
     
     
         3 . The computer-implemented method of  claim 2 , wherein the one or more efficiency criteria comprise a strength of the modified object being within a threshold value. 
     
     
         4 . The computer-implemented method of  claim 3 , comprising determining the threshold value for the strength based on a material to be used by the three-dimensional printer to create the modified object and pressures to be applied to the modified object. 
     
     
         5 . The computer-implemented method of  claim 3 , wherein the one or more efficiency criteria further comprise (i) a quantity of material saved by creating the modified object with the hollow shell and the one or more infill structures instead of creating the solid object, and (ii) an amount of time saved by creating the modified object with the hollow shell and the one or more infill structures instead of creating the solid object. 
     
     
         6 . The computer-implemented method of  claim 3 , wherein determining the one or more infill structures comprises balancing a material necessary to support a top section of the modified object with a time necessary to deposit the material. 
     
     
         7 . The computer-implemented method of  claim 2 , wherein determining the one or more infill structures comprises selecting an infill structure to minimize material necessary to create the interior of the hollow shell while providing an appropriate strength. 
     
     
         8 . The computer-implemented method of  claim 7 , wherein determining the one or more infill structures by selecting an infill structure comprises:
 analyzing interior surface angles formed by the hollow shell;   selecting a first type of infill structure when an angle of an interior surface of the hollow shell falls within a first angle range; and   selecting a second type of infill structure when an angle of an interior surface of the hollow shell falls within a second angle range.   
     
     
         9 . The computer-implemented method of  claim 2 , wherein determining the one or more infill structures comprises:
 analyzing interior surface angles formed by the hollow shell; and   skipping generation of any infill structure for at least one interior surface of the hollow shell having an angle that does not satisfy a threshold angle.   
     
     
         10 . The computer-implemented method of  claim 9 , comprising determining the threshold angle based on a configuration of the three-dimensional printer and a material to be used by the three-dimensional printer to create the modified object. 
     
     
         11 . The computer-implemented method of  claim 9 , comprising determining different thicknesses for different portions of the hollow shell depending on a location of each of the different portions of the hollow shell. 
     
     
         12 . The computer-implemented method of  claim 11 , comprising determining a minimum thickness for the hollow shell based on a material of the modified object and expected forces that will be applied to the modified object. 
     
     
         13 . The computer-implemented method of  claim 2 , wherein the providing comprises: 
 generating slices of the three-dimensional model;   generating tool path data in each of the slices, the tool path data indicating paths for a tool-head in the three-dimensional printer; and   sending the tool path data to the three-dimensional printer, thereby causing the three-dimensional printer to create the modified object by moving the tool-head in accordance with the paths.   
     
     
         14 . The computer-implemented method of  claim 13 , wherein generating the tool path data comprises, in at least one of the slices, splitting the slice into regions for separate printing of each of the regions so that forces in each of the regions, created because of the printing, manifest at a smaller spatial scale compared to not splitting the slice into the regions for separate printing. 
     
     
         15 . The computer-implemented method of  claim 13 , wherein determining the one or more infill structures comprises using an open cell lattice infill in which X-Y sections contain no toolpaths connecting unit cells, resulting in smaller deposited beads of material during printing, which localizes contractive forces on the unit cells as the deposited beads of material cool. 
     
     
         16 . The computer-implemented method of  claim 2 , wherein determining the one or more infill structures comprises determining sizes of respective regions of infill in a slice of the three-dimensional model using a determined maximum fill line length. 
     
     
         17 . The computer-implemented method of  claim 16 , wherein determining the sizes of the respective regions of infill comprises adjusting the sizes based on a type of material to be used to create the one or more infill structures in the respective regions. 
     
     
         18 . A non-transitory computer readable storage medium storing instructions executable by a data processing apparatus and upon such execution cause the data processing apparatus to perform operations comprising:
 determining one or more infill structures for a three-dimensional model of a solid object, wherein the one or more infill structures are located in an interior of a hollow shell of the three-dimensional model, the hollow shell and the one or more infill structures together defining a modified object for the three-dimensional model;   determining that creation of the modified object, by the three-dimensional printer, using the one or more infill structures and the hollow shell satisfies one or more efficiency criteria by comparing data representing the one or more infill structures and the hollow shell of the modified object with data for the solid object; and   providing data for the one or more infill structures and the hollow shell that is useable to cause the three-dimensional printer to create the modified object after determination that the one or more efficiency criteria are satisfied.   
     
     
         19 . The non-transitory computer readable storage medium of  claim 18 , wherein the one or more efficiency criteria comprise a strength of the modified object being within a threshold value. 
     
     
         20 . The non-transitory computer readable storage medium of  claim 19 , wherein the operations comprise determining the threshold value for the strength based on a material to be used by the three-dimensional printer to create the modified object and pressures to be applied to the modified object. 
     
     
         21 . The non-transitory computer readable storage medium of  claim 19 , wherein the one or more efficiency criteria further comprise (i) a quantity of material saved by creating the modified object with the hollow shell and the one or more infill structures instead of creating the solid object, and (ii) an amount of time saved by creating the modified object with the hollow shell and the one or more infill structures instead of creating the solid object. 
     
     
         22 . The non-transitory computer readable storage medium of  claim 19 , wherein determining the one or more infill structures comprises balancing a material necessary to support a top section of the modified object with a time necessary to deposit the material. 
     
     
         23 . The non-transitory computer readable storage medium of  claim 18 , wherein determining the one or more infill structures comprises selecting an infill structure to minimize material necessary to create the interior of the hollow shell while providing an appropriate strength. 
     
     
         24 . The non-transitory computer readable storage medium of  claim 23 , wherein determining the one or more infill structures by selecting an infill structure comprises:
 analyzing interior surface angles formed by the hollow shell;   selecting a first type of infill structure when an angle of an interior surface of the hollow shell falls within a first angle range; and   selecting a second type of infill structure when an angle of an interior surface of the hollow shell falls within a second angle range.   
     
     
         25 . The non-transitory computer readable storage medium of  claim 18 , wherein determining the one or more infill structures comprises:
 analyzing interior surface angles formed by the hollow shell; and   skipping generation of any infill structure for at least one interior surface of the hollow shell having an angle that does not satisfy a threshold angle.   
     
     
         26 . The non-transitory computer readable storage medium of  claim 25 , wherein the operations comprise determining the threshold angle based on a configuration of the three-dimensional printer and a material to be used by the three-dimensional printer to create the modified object. 
     
     
         27 . The non-transitory computer readable storage medium of  claim 25 , wherein the operations comprise determining different thicknesses for different portions of the hollow shell depending on a location of each of the different portions of the hollow shell. 
     
     
         28 . The non-transitory computer readable storage medium of  claim 27 , wherein the operations comprise determining a minimum thickness for the hollow shell based on a material of the modified object and expected forces that will be applied to the modified object. 
     
     
         29 . The non-transitory computer readable storage medium of  claim 18 , wherein the providing comprises:
 generating slices of the three-dimensional model;   generating tool path data in each of the slices, the tool path data indicating paths for a tool-head in the three-dimensional printer; and   sending the tool path data to the three-dimensional printer, thereby causing the three-dimensional printer to create the modified object by moving the tool-head in accordance with the paths.   
     
     
         30 . The non-transitory computer readable storage medium of  claim 29 , wherein generating the tool path data comprises, in at least one of the slices, splitting the slice into regions for separate printing of each of the regions so that forces in each of the regions, created because of the printing, manifest at a smaller spatial scale compared to not splitting the slice into the regions for separate printing. 
     
     
         31 . The non-transitory computer readable storage medium of  claim 29 , wherein determining the one or more infill structures comprises using an open cell lattice infill in which X-Y sections contain no toolpaths connecting unit cells, resulting in smaller deposited beads of material during printing, which localizes contractive forces on the unit cells as the deposited beads of material cool. 
     
     
         32 . The non-transitory computer readable storage medium of  claim 18 , wherein determining the one or more infill structures comprises determining sizes of respective regions of infill in a slice of the three-dimensional model using a determined maximum fill line length. 
     
     
         33 . The non-transitory computer readable storage medium of  claim 32 , wherein determining the sizes of the respective regions of infill comprises adjusting the sizes based on a type of material to be used to create the one or more infill structures in the respective regions. 
     
     
         34 . A system comprising:
 one or more computers; and   one or more storage devices coupled with the one or more computers and on which are stored instructions;   wherein the instructions stored on the one or more storage devices are configured to cause the one or more computers to
 determine one or more infill structures for a three-dimensional model of a solid object, wherein the one or more infill structures are located in an interior of a hollow shell of the three-dimensional model, the hollow shell and the one or more infill structures together defining a modified object for the three-dimensional model, 
 determine that creation of the modified object, by the three-dimensional printer, using the one or more infill structures and the hollow shell satisfies one or more efficiency criteria by comparing data representing the one or more infill structures and the hollow shell of the modified object with data for the solid object, and 
 provide data for the one or more infill structures and the hollow shell that is useable to cause the three-dimensional printer to create the modified object after determination that the one or more efficiency criteria are satisfied. 
   
     
     
         35 . The system of  claim 34 , wherein the one or more efficiency criteria comprise a strength of the modified object being within a threshold value.