HK1223993B - Method for fabricating an object - Google Patents

Description

Methods of making objects

Technical Field

The present invention relates to a method for making an object using a computer-controlled apparatus. In particular, the present invention relates to a method for making an object using a plurality of material strips produced by the apparatus.

Background Art

For some time, it has been possible to produce objects using various "additive manufacturing" techniques, often referred to as "3D printing." Generally, additive manufacturing involves creating a three-dimensional computer model of the object, deriving computer instructions from the model to direct a computer-controlled device to produce the object, and operating the computer-controlled device in accordance with the computer instructions to selectively produce material in successive planar layers to produce the object, such that the geometry of the object corresponds to the computer model.

While known additive manufacturing techniques can reliably produce objects, they also suffer from numerous drawbacks. For example, when objects are constructed from planar layers, these layers often have weak mechanical connections and/or lack significant chemical bonding between adjacent layers. Over time, due to these weak connections, or if subjected to specific loads or environmental conditions, the layers often separate from one another, a phenomenon known as "delamination." This is not only unsightly but also compromises the structural integrity of the object, potentially leading to the object being discarded or requiring repair.

Furthermore, many known additive manufacturing techniques use many parallel, straight strips of material to create an object. Therefore, it is common for the bonds between adjacent strips to break when subjected to a certain load, further increasing the risk of delamination of the object.

It would therefore be useful to provide a method or apparatus for manufacturing an object having strong bonds between layers and/or strips of material that are less prone to delamination than prior art methods. It would also be beneficial to provide a solution that avoids or ameliorates any disadvantages of the prior art or provides an alternative to prior art methods.

Summary of the Invention

According to one aspect of the present invention, a method for making an object using a computer-controlled device is provided, the method comprising the steps of: moving the device and making a first strip on a first notional plane; and moving the device and making a second strip on a second notional plane intersecting the first notional plane, at least a portion of the second strip being adjacent to at least a portion of the first strip and arranged at an angle between 1 and 179 degrees.

In another aspect of the present invention, a method for making an object using a computer-controlled device is provided, the method comprising the steps of: moving the device and making at least one first strip to form a first non-planar layer; and moving the device and making at least one second strip to form a second non-planar layer, at least a portion of the at least one second strip being adjacent to at least a portion of the at least one first strip and arranged at an angle between 1-179°.

In an optional aspect of the present invention, a method for making an object using a computer-controlled device is provided, the method comprising the steps of: moving the device and making a first three-dimensional curved bar; and moving the device and making a second three-dimensional curved bar, at least a portion of the second three-dimensional curved bar being adjacent to at least a portion of the first three-dimensional curved bar and arranged at an angle between 1-179°.

In another aspect of the present invention, a method for making an object using a computer-controlled device is provided, the method comprising the following steps: moving the device and making at least one first bending bar to form a first planar layer, and moving the device and making at least one second bending bar to form a second planar layer, at least a portion of the at least one second bending bar being adjacent to at least a portion of the at least one first bending bar and arranged at an angle between 1-179°.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

FIG1 is a perspective view of a generally planar object;

FIG2 is a perspective view of a free-form, cylindrical object;

FIG3 is a cross-sectional detail view of the object shown in FIG2 ;

FIG4 is a perspective view of an alternative free-form, cylindrical object;

FIG5 is a front view of a further alternative object;

FIG6 is a detailed cross-sectional view of the object shown in FIG5;

FIG7 is a detailed view of an alternative object;

FIG8 is a front view of another alternative free-form object; and

FIG. 9 is a detail view of yet another alternative free-form object.

DETAILED DESCRIPTION

This specification relates to a method for fabricating an object using a plurality of strips of material using a computer-controlled apparatus, wherein at least a portion of two strips are contiguous and arranged at an angle of 1-179° relative to each other. The strips can be fabricated on respective, intersecting, abstract planes. Alternatively, the strips can be fabricated to form respective non-planar layers, and further alternatively, the strips can be fabricated to form three-dimensional strips. The strips can also be bent and formed into respective planar layers.

Computer controlled devices are controlled by computer instructions related to the geometry of an object. The computer instructions are typically generated from a three-dimensional (3D) computer model of the object generated using computer-aided design (CAD) software or other similar software. The 3D model is generated by a user running the CAD software, or by an application executing an algorithm to automatically generate the 3D model, or by a combination of these methods. The computer instructions are typically obtained by dividing the 3D model into a plurality of paths along which material is produced, and typically one or more paths form a layer of the object. The paths (and layers) can be automatically estimated by the CAD software or other application, or can be done manually. Alternatively, the paths can be derived from a combination of automatic and manual input based on predefined functional parameters, for example, a user inputs typical forces that will act on the object, so that the geometry of the layer is optimized by the software based on an analysis of these forces.

In Figure 1, an object 1 is shown. The object 1 is made of three generally planar layers 2-4 by a computer-controlled apparatus (not shown) adapted to produce material at specified locations, guided by computer instructions relating to the geometry of the object 1. The object 1 has a bottom layer 2, an intermediate layer 4, and an upper layer 4, wherein each subsequent layer is disposed on top of a previously produced layer. Preferably, the apparatus produces the material by selectively depositing the material at specified locations, as in a typical fused deposition modeling process. Generally, the present description relates to producing the material by deposition, however it will be appreciated that other production methods (e.g., the selective solidification/curing of a substantially liquid material, commonly referred to as stereolithography) are also suitable.

The apparatus may be adapted to fabricate a material at a specified location by moving a fabrication device (e.g., a material extrusion nozzle) relative to a fixed substrate, or by moving a platform relative to the fabrication device, or a combination of these methods. This may include moving the fabrication device relative to a base surface via a six-axis robotic arm, thereby depositing the material at the specified location. Alternatively, it may include moving the fabrication device relative to an upper surface of a pool of material to selectively solidify portions of the material, these portions being supported and moved (including rotation about one or more axes) by a constructed platform, thereby allowing the fabricated material to be moved and reoriented relative to the upper surface and the fabrication device.

Each layer 2-4 of the object 1 comprises a plurality of strips 5-7 of material. The strips 5-7 are formed by an apparatus depositing the material along a plurality of paths (not shown), each path being collinear with the longitudinal axis of each strip. Each strip is formed by extruding a substantially liquid or molten material that cools and/or solidifies to form a solid strip.

The bottom layer 2 is formed of a regular array of generally parallel strips 5. The adjacent layers 3, 4 are formed of an irregular array of curved strips 6, 7, at least some of which are arranged non-parallel and/or non-concentric with adjacent strips 6, 7, and some of which are also spaced apart from adjacent strips 6, 7.

The construction of layers 2-4 of object 1 with strips 5-7 of material arranged in different directions relative to one another allows the geometry of object 1 to be optimized for different functional or aesthetic requirements, such as resistance to specific loads applied to component 1. For example, the longitudinal axes of strips 6, 7 of middle layer 3 and upper layer 4 intersect with one another, such that at least a portion of at least one strip 6, 7 abuts one another and is arranged at an angle of between 1 and 179 degrees relative to one another. Similarly, the axis of strip 5 of bottom layer 2 extends through the axis of strip 6 of the middle layer.

In this arrangement, the bonds between adjacent strips 5-7 in adjacent layers 2-4 (representing the weakest areas of object 1) are arranged at an angle to each other, providing additional support to the weaker bonded areas and thereby increasing the stiffness of object 1. For example, if a load is applied to corner A of object 1, the arrangement of strips 5-7 ensures that the weaker bonded areas between strips 7 of upper layer 4 are supported by strips 6 of middle layer 3, which are arranged at a cross and angle to the strips. Similarly, strips 5 of bottom layer 2 extend across the bonded areas of strips 6 of middle layer 3, providing further support to these strips 6. This "cross-laminated" or interwoven structure thus reduces the likelihood of fracture between strips 5-7 of any layer 2-4 due to the load applied to corner A.

Given various input parameters (e.g., the forces expected to be applied to the object 1 during use), the arrangement of the strips 6, 7 in terms of curvature of the middle and upper layers 3, 4 of the object 1 can be calculated. For example, in areas of the object 1 where significant loads may be applied, the curvature of the strips 6, 7 can be arranged to provide a large angle of cross-lamination, that is, at least some adjacent strips 6, 7 in adjacent layers 3, 4 are angled around 90°. Similarly, various curvatures of the strips 6, 7 and the arrangement of the strips 6, 7 relative to each other in the same layers 3, 4 can be calculated to specifically transmit forces across or between the layers 3, 4.

FIG2 shows an alternative object 10. Object 10 is also fabricated into layers 11-13 by computer-controlled equipment to form a core layer 11, an intermediate layer 12, and an outer layer 13. Similar to the object shown in FIG1 , each layer 11-13 of object 10 comprises a plurality of strips of material 14-16 deposited along respective plurality of paths (not shown) through the equipment.

The core layer 11 comprises a stack of generally annular strips 14, which are produced by extruding material on a plurality of respective notional first planes by a device. Each notional first plane is arranged to be parallel to or spaced apart from adjacent notional first planes and also parallel to the bottom plate surface 17.

The middle layer 12 includes a plurality of columnar strips 15 extending away from the bottom plate surface 17, adjacent to the core layer 11 and surrounding the periphery of the core layer, each columnar strip 15 being made by extruding material along a respective plurality of abstract second planes (not shown) by a device, each of the abstract second planes intersecting the first abstract plane and being arranged approximately perpendicular to the first abstract plane.

The outer layer 13 includes another stack of annular strips 16 that are adjacent to the middle layer 12 and surround the periphery of the middle layer. The outer layer 13 is made by extruding material through a device in a respective plurality of abstract third planes (not shown), and the abstract third planes are arranged to be roughly parallel to each other and spaced apart from each other, and roughly parallel to the abstract first plane.

The arrangement of the layers 11-13 of the object 10 is specifically optimized for strength/rigidity requirements. Because the strips 14-16 of the core layer 11, the intermediate layer 12, and the outer layer 13 are oriented generally perpendicular to the strips 14-16 of the adjacent layers, the structure of the object forms a three-dimensional lattice of strips 14-16 that provides support to the bonded areas between the strips 14-16 and is particularly resistant to radial or bending forces exerted on the object 10.

At the same time, the start/end positions of each strip 14, 16 in the core layer 11 and the outer layer 13 can be staggered relative to the start/end positions of adjacent strips 14, 16. For example, the first strip 14 can start and end at 0°, the second strip 14 adjacent to and on top of the first strip 14 can start and end at 30°, and the third strip adjacent to and on top of the second strip can start and end at 60°, and so on. This causes the bonds (which are weakened areas) in a single annular strip 14, 16 to be offset from the bonds in adjacent annular strips, further increasing the stiffness of the object 10.

While the first, second, and third abstract planes used in the fabrication of object 10 are abstract planar surfaces, it should be understood that one or more of these abstract planes can be configured as singly or doubly curved planes. For example, one or more of the abstract planes can be formed by extrusion and bending, thereby being curved in two dimensions. Alternatively, one or more of the abstract planes can be formed from three-dimensional surfaces, thereby being curved in all three dimensions. When the abstract planes are singly or doubly curved, the strips extruded therefrom can also follow the curvature of the planes, thereby forming curved strips.

Preferably, the object 10 is made of a material that can support its own weight immediately after being deposited by the apparatus, thereby allowing the strips to be extruded vertically away from the base surface 17. This may be achieved because the material has a high viscosity and cures quickly after deposition; the apparatus is adapted to cure the material quickly by regulating the temperature of the material, or by adding chemicals or chemical catalysts to the material through the apparatus, or by a combination of these or other methods. For example, the apparatus may be adapted to deposit more than one material simultaneously. In such an embodiment, the apparatus is allowed to simultaneously deposit materials that cause a chemical reaction when in contact with each other, such as components of an epoxy resin, to accelerate the curing of the materials to form solid strips. Alternatively, it may include depositing a curing agent simultaneously with the configured material to rapidly accelerate the curing of the material.

During the deposition process, the properties of the materials deposited by the apparatus to form layers 11-13 of object 10 can also be adjusted, allowing each layer to exhibit properties that differ from those of the other layers. For example, the tensile strength, elasticity, porosity, density, and refractory properties of each layer can be adjusted. This can be achieved by varying the amount of material deposited, changing the nozzle shape or diameter, mixing multiple raw materials in the build material reservoir, or depositing different materials from two or more adjacent deposition nozzles. Alternatively, one material can be replaced with another during the fabrication process by the apparatus alternating the material supply. By mixing two or more materials during the deposition process, the deposited materials can also be varied according to a gradient. For example, this allows the material deposited on one side of a component to be fabricated to be denser than that deposited on the other side. Similarly, materials can be replaced during the deposition process to alter the object's performance relative to forces acting on the structure, increasing the stiffness of the portion of the component that will be subjected to increased loads.

For some applications, the strength of the object 10 is further enhanced by incorporating reinforcing fibers 18-20 into at least some of the strips 14-16. These reinforcing fibers 18-20 can be made of organic or inorganic materials, such as steel, polymers, glass, carbon, aramid, high-strength polyarylate fibers (vectran), coconut shell fibers, flax fibers, hemp fibers, abaca fibers, or the strips can include a combination of fibers formed from different materials. The fibers 18-20 are typically made of a material that is more rigid than the deposited material to increase the stiffness or resistance of the strips 14-16, or the fibers can adjust other properties of the strips 14-16, such as conductivity, elasticity, or sensing ability. Preferably, the fibers 18-20 are arranged in line with the longitudinal axis of each strip 14-16 to enhance the bending resistance and/or fracture resistance of the strips 14-16. Preferably, the fibers are continuously extended through the strips 14-16 to further optimize the strength of the strips 14-16. Alternatively, the number, structure, and material of the fibers 18-20 can be adjusted during the fabrication process in order to fabricate different layers of the object with different properties. The fibers can also include cut, discontinuous bundles or fibers that are modified at the point of deposition to have other properties (e.g., a corrugated or curved profile) to increase adhesion within the material matrix.

Preferably, the apparatus is adapted to automatically incorporate the fibers 18-20 into the material before or during deposition of the material to form the strips 14-16. In the case of continuous fibers 18-20 incorporated into the strips 14-16, the fibers 18-20 are unwound from a feed (e.g., a drum) incorporating a supply of liquid or molten component material and are automatically severed by the apparatus when the apparatus has completed depositing the strips 14-16.

FIG3 is a cross-sectional detail of the object 10 shown in FIG2 , more clearly illustrating the orientation of the reinforcing fibers 18-20 in each layer 11-13. The fibers 18 of the core layer 11 are arranged in a curve around the annular strip 14. The fibers 19 of the intermediate layer 12 are arranged along the length of each columnar strip 15 and are represented by a plurality of points showing a cross-section of each fiber 19.

Figure 4 shows an alternative object 30. Object 30 is also fabricated into layers 31-33 by computer controlled equipment to form a core layer 31, an intermediate layer 32 and an outer layer 33.

Layers 31-33 are arranged similarly to layers 11-13 of object 10, with core layer 31 comprising a stack of annular strips 34, and intermediate and outer layers 32 and 33 comprising a plurality of columnar strips 35, 36 extending away from substrate surface 37 and adjoining and surrounding previously formed layers 31, 32. Each layer 31-33 is non-planar and at least a portion is singly or doubly curved, extending throughout three dimensions. For example, strips 35 are extruded away from substrate surface 37 by a machine to form a generally spiral shape around core layer 31 in a first rotational direction. Strips 36 are then extruded away from substrate surface 37 by a machine to form a similar generally spiral shape around intermediate layer 32 in a second rotational direction. This arrangement ensures that at least a portion of at least some of strips 34-36 are adjacent to one another and are arranged at angles between 1 and 179 degrees relative to one another. The extrusion of the spiral strips 35, 36 may be performed by moving the production device relative to the base plate surface 37 and/or moving and rotating the base plate surface 37 relative to the production device.

5 shows a front view of an alternative object 40. Similar to objects 10 and 30 shown in FIGs. 2-4, object 40 is fabricated into layers 41-43 using a computer-controlled apparatus to form a core layer 41, an intermediate layer 42, and an outer layer 43. Each layer 41-43 is formed from a plurality of strips 44-46 deposited by the apparatus.

As shown in Figure 5, when viewed from the front, the strips 44-46 are arranged at an angle to each other. For example, the strips 45, 46 of the middle layer 42 and the outer layer 43 form an angle α with the strip 44 of the core layer 41. The strip 45 of the middle layer 42 also forms an angle β with the strip 46 of the outer layer 43.

Generally, as angles α and β vary between 1-179°, the characteristics of object 40 are adjusted because the angular relationship between strips 44-46 of different layers 41-43 affects the bonding strength between adjacent strips 44-46 in the same layer 41-43 and contributes to the stiffness and durability of object 40.

FIG6 is a detailed cross-sectional view of the object 40 shown in FIG5, illustrating the curved arrangement of the strips 44-46.

In some cases, object 40 may be larger in size, greater than 1 m ³ , and in some cases greater than 20 m ³ , to provide functionality in a building or similar structure. In such cases, the building material may be a cementitious material, such as concrete or geopolymer. The apparatus may also be adapted to deposit and/or cure such a material, for example, by adjusting the temperature of the material or adding a chemical catalyst or other curing agent before or during deposition.

7 shows yet another alternative object 50 having a plurality of interconnected branch portions 51 and voids 52. Object 50 is fabricated into layers 53-55 by a computer-controlled apparatus to form an inner layer 53, a middle layer 54, and an outer layer 55. Each layer 53-55 is formed from at least one strip deposited by the apparatus.

Layers 53-55 are three-dimensional, non-planar layers that can be fabricated on a structure (e.g., a foam board) or in situ to repair a structure, or as independent, self-supporting components in an assembled structure. The strips of each layer 53-55 are fabricated in a direction generally perpendicular to the strips 53-55 of the previously fabricated layer to optimize the strength of the object 50. The intermediate layer 54 and the outer layer 55 are shown as partially fabricated to illustrate the orientation of the strips of each layer 54, 55. However, partially fabricated layers 54, 55 can also be used to reinforce specific portions of the object 50 and vary the strength or weight of those portions, or to provide a unique, decorative appearance, such as by forming an open weave of the material.

FIG8 shows a further alternative object 60. Object 60 is fabricated into layers 61-63 by a computer-controlled apparatus to form an inner layer 61, a middle layer 62, and an outer layer 63. Each layer 61-63 is formed from at least one strip deposited by the apparatus. Each strip is three-dimensionally curved, allowing for the formation of "free-form" branching structures (e.g., columnar nodes).

Fig. 9 is a detail diagram of an object 70 that further replaces. Object 70 is made to form three layers 71-73 by a computer-controlled device. Two inner layers 71, 72 are spaced apart from an outer layer 73 by a plurality of three-dimensional curved strips 74-76, with a gap 77 formed between the inner layer and the outer layer. The three-dimensional curved strips 74-76 are arranged to form a group of layers of three-dimensional non-planarity, wherein only a portion of the strips 74-76 in each layer are adjacent to each other. A first group of strips 74 is adjacent to the inner layer 72 and generally extends in a first direction, a second group of strips 75 is adjacent to the first group at a first node 78 and generally extends in a second direction perpendicular to the first direction, and a third group of strips 76 is adjacent to the second group of strips 75 at a second node 79 and is adjacent to the outer layer 73 and generally arranged in a first direction. The adjacent portions of the three-dimensional curved strips 74-76 at nodes 78 and 79 are arranged to be at a certain angle to each other, thereby forming a cross-laminated connection at each node 78 and 79.

The three-dimensional curved strips 74-76 may be formed of an elastic material, thereby allowing the layers 72, 73 to shift relative to each other. The voids 77 may also be filled with a specific gas or other material to affect the thermal and/or acoustic insulation properties of the object 70.

It will be understood that, in accordance with the ideas of the present invention, the present invention may be significantly modified or improved, which are also a part of the present invention. Although the present invention has been described above with reference to specific embodiments, it should be understood that this is not a limitation to those embodiments and can be specifically implemented in other forms.

Claims (8)

1. A method for manufacturing an object using a computer-controlled additive manufacturing apparatus, the method comprising the following steps: The device is moved and a plurality of first strips are created, each first strip defining a longitudinal axis, such that at least a portion of some of the first strips extend longitudinally adjacent to each other, the plurality of first strips forming a first non-planar layer; and The device is moved and a plurality of second strips are created, each second strip defining a longitudinal axis, such that at least a portion of some of the second strips extend longitudinally adjacent to each other, the plurality of second strips forming a second non-planar layer that at least partially surrounds the first non-planar layer, and At least some of the plurality of second strips are adjacent to at least some of the first strips, and the longitudinal axis of the plurality of second strips is transverse to the longitudinal axis of the plurality of first strips. 2. The method of manufacturing an object according to claim 1, wherein the step of manufacturing a plurality of first strips further comprises manufacturing the plurality of first strips into a core forming the object, and the step of manufacturing a plurality of second strips further comprises manufacturing the plurality of second strips into a shell forming the object, the shell at least partially surrounding the core. 3. The method for manufacturing an object according to claim 1, wherein the step of manufacturing a plurality of second strips further includes arranging the longitudinal axes of the plurality of second strips substantially perpendicular to the longitudinal axes of the plurality of first strips. 4. The method for manufacturing an object according to claim 3, wherein the step of manufacturing a plurality of second strips further includes arranging the longitudinal axes of the plurality of second strips in a plane different from the longitudinal axes of the plurality of first strips. 5. The method of manufacturing an object according to claim 1, wherein the device is arranged relative to a base surface, and manufacturing at least one of a plurality of first strips and a plurality of second strips further comprises: manufacturing at least a portion of a corresponding strip along an abstract path, the at least a portion of the abstract path extending away from the surface. 6. The method of manufacturing an object according to claim 1, wherein manufacturing at least one of the plurality of first strips and the plurality of second strips further comprises: manufacturing the respective strips such that at least a portion of them are unsupported. 7. The method of manufacturing an object according to claim 1, wherein manufacturing at least one of the plurality of first strips and the plurality of second strips further comprises: manufacturing the respective strips as at least a portion of the respective layer having a hyperboloid. 8. The method of manufacturing an object according to claim 1, wherein manufacturing at least one of the plurality of first strips and the plurality of second strips further comprises: manufacturing the respective strip as at least a portion of the respective layer having facets.