Patent ID: 12233602

DETAILED DESCRIPTION

FIG.1shows a conventional method of generating tool path data for use in additive manufacturing and using the tool path data to manufacture a physical object.

The method100begins at step102. In step102, object design data is developed from a design concept using conventional CAD (computer aided design) software. The object design data may comprise a volumetric representation of the object that comprises the vertices of polygons that form the object. Then, in step104, the object design data is modified and orientated for additive manufacture, and supports are added if necessary for the additive manufacture, using software such as conventional CAD software or Materialise Magics (RTM). Then, in step106, tool path data is generated from closed contours derived from the object design data using generic software or specific software for an additive manufacturing apparatus. The tool path data can be derived using a raster pattern of tool path points. Then, in step108, a database provides additive manufacturing parameters, such as laser power, specific to a material to be used in the additive manufacturing. Then, in step110, the additive manufacturing apparatus interprets the tool path data and builds the object using the specified additive manufacturing parameters for the material being used.

FIG.2shows a method of generating tool path data for use in additive manufacturing and using the tool path data to manufacture a physical object according to embodiments.

The method200begins at step202. In step202, object design data is again developed from a design concept using conventional CAD software. The object design data may comprise a volumetric representation of the object that comprises the vertices of polygons that form the object. Then, in step204, the object design data for any filled or solid geometry is modified and orientated for additive manufacture, and supports are added if necessary for the additive manufacture, using software such as conventional CAD software or Materialise Magics (RTM). Then, in step206, tool path data is generated from closed contours derived from the object design data for any filled geometry using generic software or specific software for an additive manufacturing apparatus. The tool path data can be derived using a raster pattern of tool path points.

Also in this embodiment, in step212, the object design data for any non-filled, hollow or “thin” geometry is automatically converted to object design data that comprises a parametric representation using suitable software, such as a plugin for the otherwise conventional CAD software. The parametric representation defines lines and/or surfaces for the non-filled, hollow or “thin” geometry that have specified thicknesses. Then, in step214, tool path data is automatically generated from the converted object design data for the non-filled, hollow or “thin” geometry using suitable software. This step will be described in more detail below with reference toFIGS.3,4A and4B. Also, in step216, tool path data may be automatically generated from the closed contours of the object design data for any filled geometry. Then, in step208, a database provides additive manufacturing parameters, such as laser power, based on the material and/or tool path spacing(s) to be used in the additive manufacturing. Then, in step218, the various sets of tool path data are merged. Then, in step210, the additive manufacturing apparatus interprets the merged tool path data and builds the object using the specified additive manufacturing parameters for the material and/or tool path spacing(s) being used.

FIG.3illustrates a method300of generating tool path data from a line that at least partially represents an object according to an embodiment.

In this embodiment, a structural feature of an object is represented in the object design data by a line302. The line302is shown relative to plural physical build layers304for the additive manufacturing apparatus that will be used to manufacture the object. In this embodiment, the physical build layer spacing SBLis 60 μm and the desired tool path spacing STPis 30 μm±5 μm. Other build layer spacings SBLand tool path spacings STPcan be used as desired.

In this embodiment, the line302comprises a closed hexagonal polyline comprising six straight line sections306a,306b,308a,308b,310a,310b, with each section being defined by a start vertex and an end vertex. However, in other embodiments, other line geometry such as open lines, lines having more or fewer line sections (including only a single line section) and/or one or more curved line sections may be used to represent an object as desired.

The method300begins in stage 1, in which the line sections306a,306b,308a,308b,310a,310bare grouped into “domains” based on a build angle θ for each line section. In this embodiment, the build angle θ for a line section is defined as the angle between a normal to the line section and a normal to the plane of a build layer that intersects that section. Thus, a line section that is closer to being perpendicular to the planes of the build layers304would have a higher or “steeper” build angle θ and a line section that is closer to being parallel to the planes of the build layers304would have a lower or “shallower” build angle θ. In this embodiment, the relatively more upright line sections306aand306bare grouped into a first domain, the relatively shallower line sections308aand308bare grouped into a second domain, and the relatively even shallower line sections310aand310bare grouped into a third domain.

Then, in stage 2, the line sections are sliced at the physical build layers to directly generate direct build layer points. The line sections of the respective domains are also sliced using different numbers of intermediate slicing layers depending on the build angles8for the line sections within the respective domains.

In particular, in this embodiment, the relatively more upright line sections306aand306bof the first domain are sliced at the physical build layers to directly generate direct build layer points (such as direct build layer point312). However, these relatively more upright line sections306aand306bare not sliced using any intermediate layers between each given pair of first and second physical build layers. This is because these relatively more upright line sections306aand306bcan be suitably manufactured using only a single build layer point per physical build layer.

The relatively shallower line sections308aand308bof the second domain are also sliced at the physical build layers to directly generate direct build layer points (such as direct build layer point314). Furthermore, these relatively shallower line sections308aand308bare also sliced using a single intermediate slicing layer between each given pair of adjacent first and second physical build layers to generate an intermediate layer point (such as intermediate layer point316) between each given pair of adjacent first and second physical build layers. This is because these relatively shallower line sections308aand308bwill benefit from being manufactured using more physical build layer points per physical build layer. Here, the intermediate slicing layer spacing is SIL=SBL/(n+1)=60 μm/(1+1)=30 μm.

Similarly, the relatively even shallower line sections310aand310bof the third domain are also sliced at the physical build layers to directly generate direct build layer points (such as direct build layer point318). Furthermore, these relatively even shallower line sections310aand310bare also sliced using six intermediate slicing layers between each given pair of adjacent first and second physical build layers to give six intermediate layer points (such as intermediate layer points320) between each given pair of adjacent first and second physical build layers. This is because those relatively even shallower line sections310aand310bwill benefit from being manufactured using relatively even more build layer points. Here, the intermediate slicing layer spacing is SIL=SBL/(n+1)=60 μm/(6+1)=8.57 μm.

Then, in stage 3, the intermediate layer points are projected upwards or downwards to the closest physical build layer. For example, intermediate layer point316is projected upwards to projected build layer point322. Similarly, three of the six intermediate layer points320are projected upwards to projected build layer points324. However, the remaining three of the intermediate layer points320are projected downwards to projected build layer points326. This process of projecting the intermediate layer points to the closest physical build layer allows the resultant physical object to more closely resemble the desired line geometry.

Then, in optional stage 4, the build layer points for any line sections for which intermediate layer points have been generated are also downwardly projected to a lower build layer. For example, directly generated build layer point314and projected build layer point322for the line section308aare projected downwards to generate further build layer points328and330respectively. This optional process allows the resultant physical object to have improved structural integrity.

Plural build layer points within a physical build layer may then be connected together to form a tool path for that physical build layer.

The method300ofFIG.3accordingly provides a way to generate highly representative tool path data by making use of one or more intermediate slicing layers provided between the relatively coarser physical build layers. The resultant tool path data can accordingly make better use of the resolution of the particular additive manufacturing apparatus to be used to make the object. The tool path data can also produce objects having finer detail and/or superior material and/or structural properties, when compared with existing additive manufacturing arrangements. The method300ofFIG.3also provides a way to generate tool path data from lines that represent an object (e.g. in an abstract and/or parametric manner), for example without generating closed contours directly from a volumetric (e.g. STL) representation of the object. This means that the process of generating the tool path data can be less computationally intensive when compared with existing arrangements.

Although the method300ofFIG.3shows two dimensional lines that provide one dimensional tool path data for a physical build layer, it will be appreciated that the lines would generally be defined and processed in three dimensions and thus the tool path data would generally be defined in the two dimensions for a physical build layer.

FIGS.4A and4Billustrate a method400of generating tool path data from a surface that at least partially represents an object according to an embodiment.FIG.4Ashows a perspective view andFIG.4Bshows a corresponding cross-sectional view.

In this embodiment, a structural feature of an object is represented in the object design data by a surface402. Again, the surface402is shown relative to plural physical build layers404for the additive manufacturing apparatus that will be used to manufacture the object. Again, in this embodiment, the physical build layer spacing SBLis 60 μm and the desired tool path spacing STPis 30 μm±5 μm. Again, other build layer spacings SBLand tool path spacings STPcan be used as desired.

In this embodiment, the surface402comprises an open mesh comprising 90 polygonal (triangular) surface sections or “faces”, with each surface section or “face” being defined by three vertices. However, in other embodiments, other surface geometry such as closed surfaces, surfaces having more or fewer surface sections (including only a single surface section) and/or one or more curved surface sections may be used to represent an object as desired.

The method400begins in stage 1, in which the surface sections are grouped into domains based on a build angle θ for each surface section. In this embodiment, the build angle θ for a surface section is defined as the angle between a normal to the surface section and a normal to the plane of a build layer that intersects that section. Thus, a surface section or “face” that is closer to being perpendicular to the planes of the build layers404would have a higher or “steeper” build angle θ and a surface section or “face” that is closer to being parallel to the planes of the build layers404would have a lower or “shallower” build angle θ. In this embodiment, an area of 60 relatively more upright surface sections are grouped into a first domain406, a strip of 10 relatively shallower surface sections are grouped into a second domain408, another strip of 10 relatively even shallower surface sections are grouped into a third domain410, and yet another strip of 10 relatively even shallower surface sections are grouped into a fourth domain412.

Then, in stage 2, the surface sections are sliced at the physical build layers to directly generate physical build layer lines. The surface sections of the respective domains are also sliced using different numbers of intermediate slicing layers depending on the build angles8for the surface sections within the respective domains.

In particular, in this embodiment, the relatively more upright surface sections of the first domain406are sliced at the physical build layers to directly generate physical build layer lines (such as physical build layer line414). However, these relatively more upright surface sections are not sliced using any intermediate layers between each given pair of first and second physical build layers. This is because these relatively more upright surface sections can be suitably manufactured using only a single build layer line per physical build layer.

The relatively shallower surface sections of the second, third and fourth domains are also sliced at the physical build layers to directly generate direct build layer lines (such as direct build layer line416). Furthermore, these relatively shallower surface sections are also sliced using one or more intermediate slicing layers between each given pair of first and second physical build layers to generate intermediate layer lines (such as intermediate layer lines418and420) between each given pair of first and second physical build layers. In particular, the relatively shallower surface sections of the second domain408are sliced using two intermediate slicing layers between non-adjacent physical build layers, the relatively even shallower surface sections of the third domain410are sliced using one intermediate slicing layer between adjacent physical build layers, and the relatively even shallower surface sections of the fourth domain412are sliced using two intermediate slicing layers between adjacent physical build layers. This is because these progressively relatively shallower surface sections would benefit from being manufactured using progressively more physical build layer lines per physical build layer.

Then, in stage 3, the intermediate layer lines are projected upwards or downwards to the closest physical build layer. For example, intermediate layer line418is projected upwards to projected build layer line422and intermediate layer line420is projected downwards to projected build layer line424. This process of projecting the intermediate layer lines to the closest physical build layer allows the resultant physical object to more closely resemble the desired surface geometry.

Then, in optional stage 4, the build layer lines for any surface sections for which intermediate layer lines have been generated are also downwardly projected to a lower build layer. For example, directly generated layer line416and projected layer line422are projected downwards to generate further build layer lines426and428respectively. This optional process allows the resultant physical object to have improved structural integrity.

A build layer line within a physical build layer may be used as a tool path for that physical build layer. Alternatively, plural build layer lines within a physical build layer may be connected together to form a tool path for that physical build layer.

The method400ofFIGS.4A and4Baccordingly again provides a way to generate highly representative tool path data by making use of one or more intermediate slicing layers provided between relatively coarser resolution physical build layers. The resultant tool path data can accordingly make better use of the resolution of the particular additive manufacturing apparatus to be used to make the object. The tool path data can also produce objects having finer detail and/or superior material and/or structural properties, when compared with existing additive manufacturing arrangements. The method400ofFIGS.4A and4Balso provides a way to generate tool path data from surfaces that represent an object (e.g. in an abstract and/or parametric manner), for example without generating closed contours directly from a volumetric (e.g. STL) representation of the object. This means that the process of generating the tool path data can be less computationally intensive when compared with existing arrangements.

Although the present invention has been described with reference to various embodiments, it will be understood by those skilled in the art that various changes in form and detail may be made without departing from the scope of the invention as set forth in the accompanying claims.