Patent Application
20190217534
Additive manufacturing is a method of generating three dimensional objects. In such processes, a computer-generated 3D model is converted into a physical object in a layer by layer manner as opposed to a subtractive manufacturing process to build the desired object.
The additive manufacturing process involves the generation of digital cross-sectional patterns, grids or volumetric pixels, voxels, from CAD files, 3D scans or other means and solidifying a solidifiable material layer by layer or voxel by voxel or continuously to produce at least one three-dimensional object.
Additive manufacturing processes are intrinsically linked to the material chosen to achieve the best specific properties for the 3D object. The materials could be in form of liquids, pastes, powders, gels or any other aggregate state and are usually dispensed by a plurality of methods including inkjet printing, extrusion, pumping without being limited hereto. Conversion of such materials into a solid three-dimensional object is typically performed by suitable actinic radiation and/or heat.
Known methods and apparatus for additive manufacturing based on solidifying photosensitive materials are sometimes referred to as Stereolithography, Digital Light Processing, Continuous Liquid Interface Printing, Heliolithography and Inkjet 3D printing.
In the aforementioned apparatus, a thin layer of photosensitive material, often referred to as resin, is exposed to radiation typically in the ultraviolet (UV) or visible spectrum to selectively cause the resin to crosslink or ‘cure’. Two configurations are well-known: one in which new layers are formed at the bottom surface of the growing object, sometimes referred to as bottom-up (
In a top-down configuration, new layers are formed at the top surface 1 of the growing object 2, then after each irradiation step said object is lowered into the resin vat 3 until a new layer of resin of the required thickness is coated on top, and a new irradiation step takes place.
The process of submerging the growing object in a (potentially) deep pool of liquid photosensitive material limits the functional size of the object that can be created and exposes large volumes of resin to the additive manufacturing process. In a top-down configuration, hollow objects with a fully impenetrable outer wall are filled with unwanted liquid photosensitive material. Drainage of such liquid resin through purposely created drainage apertures can cause warping and wall deformation especially for large objects when lifting the object out of the vat.
In a bottom-up configuration (
Furthermore, 3D objects generated based on solidifying photosensitive materials are only partially solidified or cured exposing large 3D objects to additional stresses through the increased weight of the growing object, causing delamination and deformation. Partially solidified or cured objects require post curing to improve their degree of cure as well as their thermal, mechanical and chemical properties.
Currently known methods for post curing include thermal heating, infrared radiation, and UV ovens. In conventional thermal heat curing, energy is transferred to the material through convection, conduction and radiation of heat resulting in long cycle times and high energy requirements. Thermal gradient during the post-curing process may result in uneven cure, residual stresses and defects in the cured polymers.
UV post curing is a continuation of the photochemical reaction which initially generates the three-dimensional object. WO 1989010249 A1 and EP 0 403 146 A2 describe a post curing method, outside of the 3D generating apparatus whereby the generated object is immersed in a liquid medium and post curing is achieved by an electromagnetic radiation source such as UV or visible light. US 20100310698 describes a post curing method as an integrated part of a top down 3D generating apparatus. In such apparatus, hollow 3D objects with a fully impenetrable outer wall are filled with unwanted liquid resin. Drainage of such liquid resin through purposely created drainage apertures can cause warping and wall deformation especially for large objects when lifting the object out of the vat.
Furthermore, post curing of internal structures of the 3D objects or solid objects is very limited if not impossible due to the interference of the holding medium with post curing radiation sources such as Infrared and microwave radiation.
Furthermore, supporting generated 3D objects in a pool of photosensitive material or partially in a separate medium adds substantial costs, dead capital or unusable material after completion of the 3D object, especially for the generation of large 3D objects.
UV post curing of multiple objects in close proximity of each other or of solid objects is difficult as UV curing only occurs in ‘line-of-sight’ meaning every point on a surface must directly exposed to the UV. Hidden areas such as inside of 3D objects with impenetrable wall or shadow areas, when post curing multiple objects simultaneously, remain uncured.
The state of the art in generation of 3D objects from photosensitive materials is such that generated objects are limited in cross-sectional size and its third dimension, and the objects' geometries are limited to thin and or open lattice wall structures. These limitations are a result of the degree of cure that can be achieved during the object generation.
The degree of cure is a function of many parameters related to the photosensitive material composition, the radiation intensity and exposure time, and layer thickness. SLA, which applies one of the highest radiation densities among photosensitive 3D object generation methods and apparatus, generated 3D objects can achieve approximately 80% degree of cure. A post-curing process using an UV chamber or thermal oven may increase curing up to 90%. It is somewhat difficult to control the post-curing times for a 3D printed object because curing times can vary with object size, material composition, temperature and UV wavelength used and ranges from minutes to hours.
In one aspect, the invention provides an additive manufacturing apparatus for generating a three-dimensional object, the apparatus comprising:
In an embodiment, the second source is positioned to allow radiation from the second source to be directed in a substantially transverse direction relative to an orthogonal axis of an imaginary plane of the carrier to carry out post curing of the printed object.
In an embodiment, the second radiation source comprises a plurality of radiation sources positioned to surround the printed object for directing electromagnetic radiation to carry out post curing of the printed object. Preferably, the second radiation source may be positioned circumferentially relative to the printed object.
In an embodiment, the second radiation source is positioned relative to a mounting arrangement, said mounting arrangement being positioned relative to the printed object to direct electromagnetic radiation to carry out post curing of the printed object.
In an embodiment, the mounting arrangement comprises an enclosure defining an internal volume to allow at least a section of the printed or partially printed object to be positioned therein. Preferably, the enclosure comprises one or more walls defining an internal space for positioning at least a section of the printed object therein. In an embodiment, one or more of the second radiation sources are positioned along the walls of the enclosure to direct electromagnetic radiation in a substantially transverse direction relative to an orthogonal axis of an imaginary plane of the carrier for post curing of the printed object.
In an embodiment, the walls are configured to allow electromagnetic radiation to be reflected or absorbed by the walls for allowing post curing of the printed objects located in the internal volume defined by the enclosure.
In an embodiment, the enclosure comprises a cylindrical or a polygonal cross section for enclosing at least a section of the printed object in an internal space defined by inner walls of the hollow member. In an embodiment, the walls of the enclosure define an internal volume that is sufficiently large for accommodating the build region to allow the carrier with the growing 3D object to move through the internal volume. The growing 3D objects may be positioned anywhere along the carrier and be positioned to move through the internal volume of hollow member. As the growing object is moving through the internal volume of the enclosure, electromagnetic radiation can be directed at the growing 3D object to increase the degree of cure so that no deformation, delamination or any of the other generation faults occurs whilst generating said 3D object.
In an embodiment, the second radiation source is movably mounted to allow movement of the second radiation source relative to the printed objected supported by the carrier. Preferably, the second radiation source is mounted along one or more guiding arrangements to allow movement of the second radiation source along one or more directions.
In an embodiment, the enclosure is mounted along the one or more guiding arrangements. Preferably, the guiding arrangement allows a plurality of enclosures to be movably positioned to locate the printed object in the internal volume defined by the enclosures.
In an embodiment, the carrier comprises a build plate which allows the solidified material to be positioned thereon. In some embodiments, the solidified material may also be adhesively fastened onto the build plate. In an embodiment, the build plate may be transparent to electromagnetic radiation. In another embodiment, the build plate may absorb electromagnetic radiation.
In an embodiment, the carrier further comprises a levelling mechanism for levelling said build plate independently relative to the carrier.
In an embodiment, the apparatus further comprises a locking mechanism for securing the printed object to said build plate of the carrier.
In an embodiment, one or more level sensors measure the distance between said build plate and said build surface.
In an embodiment, the controller receives control input relayed by said level sensors comprising executable instructions to control operation of said levelling mechanism on said carrier.
In an embodiment, the second radiation source comprises one or more of the following: an ultraviolet light source and/or an infrared light source and/or magnetron generating microwave source.
In an embodiment, the additive manufacturing apparatus further comprises: a controller operatively associated with said carrier and the first radiation source for advancing the carrier away from said build surface to form a printed three-dimensional object from the material, while also concurrently controlling operation of the second radiation source to control post curing of the printed object.
In an embodiment, the controller further comprises an input for connecting a sensor, the sensor being provided for sensing one or more characteristics of the partially printed or the printed object supported by the carrier during use and wherein the controller is configured to operate the second radiation source in response to one or more characteristics sensed by the sensor during use.
In an embodiment, the controller is operatively coupled with a drive unit for driving a mounting arrangement and effecting movement of the second radiation source mounted on the mounting arrangement to carry out post curing of the printed object.
In an embodiment, the controller is operable to drive the mounting arrangement and allow the second radiation source to be positioned at a plurality of locations for curing the printed object.
In an embodiment, the controller receives control input comprising executable instructions to control operation of the carrier, the supply unit and the first radiation source for generating the printed object on the build surface during use. Preferably, the control input may comprise information from CAD files, three dimensional scans or geometric and volumetric information related to the printed object.
In an embodiment, the controller is adapted to control duration, intensity, and/or frequency of the electromagnetic radiation emitted by the second source to carry out post curing.
In another aspect, the invention provides a method of forming a three-dimensional object, the method comprising the steps of:
In an embodiment, step (f) comprises directing radiation from the second source in a substantially transverse direction relative to an orthogonal axis of the imaginary plane of the carrier.
As previously discussed, the carrier further comprises a build plate which allows the solidified material to be positioned thereon. In an embodiment, the method comprises the step of measuring a distance between the build plate and the build surface. In a further embodiment, the method comprises the step of levelling the build plate. More preferably, the method comprises controlling the levelness of the build plate independently to the levelness of the carrier.
In an embodiment, the method comprises the step of locking the printed object to the build plate once the printed object reaches a predetermined level of cure to hold the weight and maintain stability of the generating object.
In an embodiment, the step of directing electromagnetic radiation from the second source is carried out in response to a sensing step whereby the sensing step comprises sensing one or more characteristics of the partially printed or printed object.
In an embodiment, the method further comprises the step of effecting movement of the second source in one or more directions to carry out post curing of the partially printed or printed object.
In an embodiment, the method comprises operating the carrier supporting the printed object advancing the carrier through the internal volume of the enclosure. In an embodiment, the method further comprises the steps of generating support structures for supporting and connecting a plurality of 3D printed objects.
Preferably, the support structures extend in a substantially parallel and/or perpendicular direction relative to an orthogonal axis of the imaginary plane of the carrier.
In an embodiment, the support structures may be provided for maintaining a fixed distance between a plurality of 3D objects generated by the additive manufacturing method or apparatus.
In some embodiment, the support structures may be disposed at an angle relative to the orthogonal axis to balance 3D printed objects comprising an asymmetrical cross section and/or uneven mass/weight distribution.
In an embodiment, the support structures are part of the generated object.
In an embodiment, the generated support structures are designed in a manner to allow the mechanical locking mechanism to connect with the generated support structures to offer the object stability during the object generating process.
In one embodiment, the printed object is progressively and continuously exposed to electromagnetic radiation from the second source until a substantial portion of the printed object is fully cured or cured to a specified degree of cure.
In another embodiment, one or more sections of the printed object are exposed to electromagnetic radiation from the second source either simultaneously or sequentially until a substantial portion of the printed object is fully cured or cured to a specified degree of cure.
In an embodiment, the material is preferably a photosensitive resin. Preferably, the material forms a polymer composite further comprising a photo initiator for allowing activation of the polymer by the electromagnetic radiation of the second source.
In some embodiments, the polymer composite further comprises additives having high thermal conductivity. In some embodiments, the polymer composite further comprises a hardener.
In some embodiments, the generated 3D object is hollow with a solid or a lattice structured wall.
In some embodiments the generated 3D object is solid.
The term “post-curing” generally refers to the step of directing energy in a form of but not limited to electromagnetic radiation from the second source until the material forming the 3D printed object is densified to achieve a predetermined level of thermal, mechanical and chemical properties. The built-in process of object generation and post curing in the preferred embodiment allows for the generation of large and multiple 3D printed objects. In a preferred embodiment, post curing may be carried out by utilising microwave radiation to activate a form of carbon where the polymer acquires predetermined characteristics to allow for the generation of large or multiple polymer composite objects as an integrated process of object generation. In another preferred embodiment, post curing may be carried out by utilising microwave radiation to perform heat treatment to partially solidified metal objects where the object acquires predetermined characteristics to allow for the generation of large or multiple fully heat-treated metal objects as an integrated process of object generation. In another preferred embodiment post curing may be achieved through microwave induced pyrolysis of a preceramic polymer in order to create large or multiple ceramic objects as an integrated process of object generation. Microwave post-curing of preceramic polymers may require one or more radiation sources for carrying out the post-curing. By way of example, one source may be dedicated to create a green body through cross-linking material and another source may be dedicated to pyrolyzing the green body by use of fillers or additives to form a ceramic body. The desirable level of cure required to create a green body to a ceramic body in order to create large or multiple objects requires an integrated process of object generation and post-curing controlled in conjunction with a sensing step.
Furthermore, the present invention provides a method and apparatus to generate large and multiple small or large objects. The size and the weight of these 3D objects is such that support structures are required to hold the weight and to ensure stability of those 3D objects with asymmetric design and unevenly distributed weight. Multiple support structures may be generated in between the 3D objects to maintain a desired distance between the objects. Such multiple objects may be parallel to the longitudinal axis or one above the other whereby the support structures are substantially parallel to the longitudinal axis to hold in position the lower positioned 3D object. Such multiple objects may be positioned across the build area or in a plane perpendicular to the longitudinal axis whereby the support structures are substantially perpendicular to the longitudinal axis.
The support structures may comprise the same material as used for the generation of the 3D objects or an alternative material. At the same time and in the same way as the 3D objects, the support structures are substantially post cured by the second source to provide sufficient strength to hold in position and maintain stability of the large and heavy generated 3D objects.
In some embodiments, the second source may operate in the Infrared part of the electromagnetic spectrum, providing a post curing process by rapidly heating the growing 3D objects. Large radiating heating capacities can be transmitted in a relative localised area, as compared to thermal heating, therefore enabling temperature based post curing of large growing objects as an integrated part of the 3D generation process without increasing temperature in the build region.
In another embodiment, the second source may operate in the microwave spectrum of the electromagnetic spectrum. The source may be mounted on a mounting arrangement such as a housing enclosing the microwave emitting source. Preferably, the source may be in the form of a resonator with at least one magnetron.
The microwave beams from the second source can be introduced along a wave guide fitted substantially parallel or perpendicular to the outer peripheral longitudinal wall in the resonator. The waveguide may have a spacing relative to the associated outer peripheral longitudinal side such that the microwave beam which is coupled into the resonator by it, is reflected or absorbed on the opposed longitudinal wall section.
The microwave radiation penetrates the growing objects and heat is generated by exciting fillers or other additives from within the object. Consequently, the volumetric post curing with microwave radiation is well suited for those applications where multiple 3D objects are generated simultaneously as well as for large cross sectional 3D objects especially those with internal 3D generated structures which cannot be post cured with UV, visible or infrared light. The post curing is localised thereby not affecting the 3D generation process in the build area.
For small 3D objects or for matching generation speed and post curing rate, the enclosure may be in a stationery position. The post curing in this instance may take place during or after completion of the 3D generation process. However, different 3D generating apparatus may have different 3D object generation speeds which also may vary with the type of photosensitive material used by the apparatus.
The required rate of post curing may not necessarily coincide with the 3D object generation speed. By way of example an object with a denser cross-sectional area will take longer to generate a solid object. Therefore, the faced walls may be movable with a variable speed whereby the growing 3D object moves through the internal volume of the enclosures depending on the post curing requirements of the specific 3D printed object being generated.
By way of another example, if the generation speed is slower than the time required to post cure the growing 3D object, then the 3D object may be post cured one section at the time, i.e. with one section post cured, radiation emission is ceased until such time that the 3D object has grown sufficiently to start post curing the next section.
Alternatively, additional radiation sources may be added to the enclosures to increase the radiation area along the longitudinal axis allowing for the growing 3D object, as it moves along the longitudinal axis, to be exposed to the radiation for a longer period of time. Such additional radiation sources may be incorporated in multiple faced walls whereby each enclosure may have its own adjustable speed. If multiple radiation sources are used but other 3D objects which are generated require shorter exposure times, some of the radiation sources may be switched off for a selected length of time and switched on again when required.
Radiation sources operating in other parts of the electromagnetic spectrum may be also used in the enclosures to suit specific post curing requirements. The method of delivery of these sources may be a continuous release of energy, a pulsed release of energy, or any timing, frequency and intensity that may be required to cure a specific area on an object to a predetermined specification sensed by the sensing equipment.
Any photosensitive material, with material properties required for the 3D object to be generated, may be chosen to generate the 3D objects as described. The photosensitive material may contain some specific additives to enhance the post curing process and aiding to achieve the highest degree of cure possible. As a matter of illustration and without being limited hereto, such additives may be photo initiators for radiation sources of the same frequency as the generation radiation source or for radiation sources of an alternative frequency in the Ultraviolet or Visible spectrum which continue the photo polymerisation process. Other additives may have highly thermal conductive properties to enhance the post curing with Infrared radiation. Furthermore, hardeners, forms of carbon and other additives may be used that enhance the post curing with microwave radiation.
The generated 3D objects may be, but not limited hereto, hollow with a solid wall, with or without some internal support structures or infill, or may have an open lattice structure or alternatively may be solid. More specifically the present invention aims at enabling the generation of large 3D objects These objects may be generated as a single object or may comprise multiple identical or discrete objects across the carrier. These objects may be built in a build region supported by one or more built plates and carriers, and generated on one or more static or dynamic build surfaces, and post cured by one or more secondary radiation sources located in one or more enclosures.
In order that this invention may be more readily understood and put into practical effect, reference will now be made to the accompanying drawings which illustrate a preferred embodiment of the invention and wherein:
Referring to
The apparatus 100 also comprises facing mounting arrangement for mounting a second electromagnetic radiation source 160 that is used for carrying out post curing of the printed object 114. In the preferred embodiment, the mounting arrangement comprises an enclosure 150 which is located for surrounding and positioning a section of the printed object 114 as supported by the carrier 110 during a printing operation within an internal volume defined by the enclosure 150. The internal walls of the enclosure 150 support one or more of the second electromagnetic radiation sources 160 that are preferably positioned along the internal walls of the facing enclosures 150. The configuration of the enclosure 150 allows the second radiation source 160 to be in close proximity relative to the printed object 114. The second radiation source 160 is operable to direct electromagnetic radiation in a substantially transverse direction relative to an orthogonal axis of an imaginary plane of the carrier 110 to carry out post curing of the printed object 114.
In some embodiments, the enclosure(s) 150 may be fixed. In an alternative embodiment, the facing enclosures 150 may be movably positioned. During use, the movement of the carrier 110 results in at least a section of the partially printed object 114 being positioned within an internal volume defined by the enclosures 150. The movement of the carrier 110 results in the movement of the growing object 114, parallel to the orthogonal axis L of the carrier 110 through the internal volume of the facing enclosures 150. Positioning at least a section of the growing object 114 within an internal volume of the enclosures 150 allows a plurality of the second radiation sources 160 (mounted along the internal walls of the enclosure 150) to direct electromagnetic radiation towards the growing object 114 to perform post curing of the section of the growing object 114 positioned within the facing enclosures 150.
In an embodiment, the enclosure 150 is fastened with a guiding arrangement 170 (shown in
It must be understood that the mounting arrangement of the second radiation source 160 as encompassed by one or more embodiments is not limiting and alternative configurations may be provided for directing electromagnetic radiation from the second source 160 in order to carry out post curing of the printed object 114 without departing from the spirit and scope of the invention.
The additive manufacturing apparatus may be contained or enclosed within suitable atmospheric conditions for allowing optimal operation of the object generating process. By way of example, inert gas may be used within the contained environment to provide a controlled atmosphere. Venting systems may also be used to remove by-products during the process.
During use, the first partially cured layer of photosensitive material is solidified upon the build plate 113 provided on the carrier 110 (shown in
The carrier 110 is lifted by a carrier drive unit 112 (not shown in
In an embodiment as shown in
Referring to the block diagram shown in
In at least some embodiments, the controller 180 may include a data connection port 182 for communication with a sensing device 190. In some embodiments, the sensing device 190 may take the form of an infrared camera that can sense one or more characteristics of the printed object 114. The controller 180 may be configured to operate the second radiation source 160 and the drive unit (coupled with the enclosure 150 supporting the second radiation source 160) in response to one or more characteristics sensed by the sensing device 190, during use, in order to position the second radiation source 160 at a pre-determined location for achieving post-curing of the printed object 114.
The controller 180 may be coupled with the carrier controller 119 (shown in
Large build surfaces 122 as described shown in
An exemplary method 500 for forming a three-dimensional object in accordance with an embodiment of the present invention will now be described. Like reference numerals denote like features that have been previously described. The method involves an initial step (510) of providing an input at the user interface of a computing device (such as a desktop computer, a laptop, mobile phone or a tablet device) which includes information (such as a CAD file) that relates to the 3D object to be printed. The controller 180 and the memory device 200 receive the information from the computing device and perform a second step 520 (based on executable instructions stored on the memory device 200) of activating the carrier drive unit 112 to position the carrier 110 at an initial position such that the build surface 122 defined by the position of the transparent member 120, and the build platform 113 on carrier 110 are spaced apart to define a build region therebetween. The supply unit/shallow vat 130 for the material is activated by the controller 180 in accordance with a third step 530 which releases the material on the build surface 122 to commence the 3D printing operation. The controller 180 also carried out a subsequent step 540 which involves directing electromagnetic radiation from the first source 140 through the transparent member 120 onto the build surface 122 for selective solidification of the material on the build surface 122 followed by a carrier advancing step 550 that involves advancing the carrier away from the build surface 122 by controlling the synchronised operation of the carrier drive unit 112 and the levelling mechanism 118 as the size of the 3D printed object 114 gradually increases. After a pre-determined time, a sensing step 560 is carried out by using thermal and infrared cameras in communication with the controller 180 that can signal to stay within predetermined specifications so that no undesirable malfunction such as potential hotspots, delamination, or deformation occurs. Preferably, the sensing step 560 may be carried out once the carrier 110 reaches a pre-determined height which may vary for each object. If any of the sensed characteristics observed or recorded during the sensing step 560 do not satisfy a pre-determined rule, then the second source 160 (a microwave radiation source) may be activated in accordance with a post curing activation step 570 which triggers the second source 160 to direct electromagnetic radiation from the second source 160 in a substantially transverse direction relative to an orthogonal axis of an imaginary plane of the carrier 110 to carry out post curing of the partially printed or the printed object 114. The position of the facing enclosures 150 which in turn determines the location/position of the second source 160 relative to the printed object 114 may be varied in accordance with the post-curing step of 570. The post curing step 570 is determined in accordance with the feedback received during the sensing step 560 by controlling the drive unit for the enclosure 150 (based on the feedback) to specifically direct the microwave radiation from the second source 160 to selectively carry out post curing of any regions of the printed object 114. In some embodiments, the locking arrangement 115 for securing a base of the printed object 114 may be activated once the sensor 190 determines that the base of the printed objected 114 has attained a pre-determined level of any one or more of strength, curing, post curing or any other pre-determined characteristic.
During the development of some of the embodiments, the inventors have identified that the degree of cure, reflected in generated 3D objects being only partially cured, as a limiting factor in the generation of large and multiple generated 3D objects. The embodiments of the present invention aim at providing a method and apparatus to improve the degree of cure and the generation of the growing objects as a joint process so that the size of the partially cured part of the 3D objects never exceeds the critical size beyond which they may be subjected to the issues of deformation and delamination as a result of the objects size and weight.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular is intended to include the plural and the plural is intended to include the singular unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements components and/or groups or combinations thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and/or groups or combinations thereof.
As used herein, the term “and/or” includes any and all possible combinations or one or more of the associated listed items, as well as the lack of combinations when interpreted in the alternative (“or”).
Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the specification and claims and should not be interpreted in an idealized or overly formal sense unless expressly so defined herein. Well-known functions or constructions may not be described in detail for brevity and/or clarity.
It will be understood that when an element is referred to as being “on,” “attached” to, “coupled” with, etc., another element, it can be directly on, attached to, coupled with the other element or intervening elements can also be present. It will also be appreciated by those of skill in the art that references to a structure or feature that is disposed “adjacent” another feature can have portions that overlap or underlie the adjacent feature.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2016902449 | Jun 2016 | AU | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/AU2017/050633 | 6/22/2017 | WO | 00 |
