Patent Application
20110079936
The present invention relates generally to rapid prototyping.
In an illustrative implementation of this invention, an improved method of fused deposition is used in which a plurality of materials are heated, mixed and extruded through a nozzle. The ratio of the materials being mixed may be dynamically varied in such a manner that the composition of the extruded mixture varies in a substantially continuous gradient.
For example, thermoplastics with differing properties may be melted, mixed together and extruded through a nozzle. The ratio of the different thermoplastics being mixed may be dynamically varied, in such a way that the composition of the extruded thermoplastic mixture varies in a substantially continuous gradient.
In an illustrative implementation of this invention, the extruded mixture is selectively deposited layer by layer, building up a three-dimensional object. The nozzle is moved horizontally and vertically in this selective deposition process. The movement of the nozzle may be numerically controlled by one or more processors.
In an illustrative implementation of this invention, a thermoplastic mixture is extruded, and hardens immediately after extrusion.
The resulting 3D object may vary in structure or composition over its volume. This variation may be substantially continuous.
According to principles of this invention, an array of nozzles may be employed. At least one of the nozzles may be adapted to extrude a support material that is used to support the 3D object during deposition, and that is later removed from the 3D object. At least one other nozzle may be adapted to extrude material that remains in the 3D object after the support material is removed (“parts material”). A deposited layer may comprise a 2D pattern of parts material and support material. In each case (whether the nozzle extrudes parts material or support material), the nozzle may extrude material that varies in composition in a continual gradient.
It is helpful to briefly compare the present invention with two existing technologies.
In one existing technology, fused deposition is effected with an array of nozzles. Each nozzle in the array extrudes a single material that does not vary substantially in composition. Various nozzles are used to deposit various materials, so that the composition of the deposited layers differs discretely from layer to layer. This is quite different from the present invention, which may allow a substantially continual gradient in composition from layer to layer, or even within a particular layer.
In a second existing technology, both parts material and support material are extruded. However, each nozzle is adapted to extrude a single material that does not vary in composition. Neither the parts material nor the support material varies in composition from layer to layer, or within a single layer, in a substantially continuous manner.
The above description of the present invention is just a summary. It is intended only to give a general introduction to some illustrative implementations of this invention. It does not describe all of the details of this invention. This invention may be implemented in many other ways.
Similarly, another three different materials are inserted into chamber 9 by actuators 4, 5 and 6, respectively. In chamber 9, these three different materials are melted and mixed. The resulting mixture is then extruded through nozzle 13.
Each of the three actuators 1, 2, 3 can independently vary the rate of flow at which it inserts material into chamber 7, in such a way that the rate of flow varies substantially continuously. Thus, the three actuators 1, 2, 3 can vary the ratio of materials being inserted into chamber 7, in such a manner that the ratio of materials in the mixture exiting through nozzle 11 varies substantially continuously.
Similarly, each of the three actuators 4, 5, 6 can independently vary the rate of flow at which it inserts material into chamber 9, in such a way that the rate of flow varies substantially continuously. Thus, the three actuators 4, 5, 6 can vary the ratio of materials being inserted into chamber 9, in such a manner that the ratio of materials in the mixture exiting through nozzle 13 varies substantially continuously.
Nozzles 11 and 13 comprise an array of nozzles 15. An actuator 19 moves the nozzle array 15 horizontally. Another actuator 21 moves the nozzle array 15 vertically. For example, actuators 19 and 21 may be stepper motors.
As the nozzle moves, it selectively deposits the extruded mixture layer by layer.
Alternately, the melting and mixing may be done in separate chambers. For example,
Actuators 71, 72, and 73 can independently vary the rate of flow at which they insert material into chambers 74; 75 and 76, respectively, in such a way that the rate of flow varies substantially continuously. By so varying the rates of flow, the ratio of materials being inserted into chamber 77 may be varied substantially continuously, and the ratio of materials in the mixture exiting through nozzle 78 may be varied substantially continuously.
This invention may be implemented so that the rate of flow of materials (and thus ratio of materials entering a chamber or exiting through a nozzle) may be varied dynamically throughout selective deposition.
Alternately, only a single nozzle may be used, rather than an array of nozzles. For example,
In an illustrative implementation of this invention, the ratio of materials in the extruded mixture may be varied in such a way that the composition of the 3D object being created varies substantially continuously from layer to layer, or even within a single layer. For example,
This invention may be implemented in such a way that at least some of the variations are not substantially continuous, but are gradual. For example, one or more of the following variations may be gradual: (a) the variation in rate of material being fed into a chamber by an actuator, (b) the variation in the ratio of the materials being mixed and extruded, (c) the variation in composition, from layer to layer, of a 3D object that is produced by selective deposition, and (d) the variation in composition, within any particular layer, of a 3D object that is produced by selective deposition
In the example shown in
This digital model may employ voxels to compute properties that vary over a gradient across one or more dimensions. Voxels are advantageous for this purpose because of their representation of discrete elements defining a continuous whole, able to carry 3D information (e.g., scalars, vectors) as well as tensors (e.g., physical information). For example, in some implementations of this invention, the software may treat voxels as tensors (geometrical entities with multiple physical parameters). In some implementations, the software may compute transitions between multiple compositional phases using extrapolation functions.
This invention may be implemented in such a way that software computations distinguish between volumetric regions in which properties do not vary, and volumetric regions in which they do. A processor may output layer-by-layer pixel sheets such that when they are stacked they are represented as voxel clouds. These pixel sheets may be used to generate instructions for selective deposition of material.
This invention may be implemented using various types of rapid prototyping techniques, including various types of layer manufacturing and fused deposition.
Different types of material may be extruded. For example, a variety of thermoplastics and elastomers may be extruded, depending on how this invention is configured or performed.
This invention has many practical applications. Among other things, it may be used to 3D print a wide variety of functionally graded materials.
This invention may be implemented in many different ways. Here are a few examples:
This invention may be implemented as apparatus for fused deposition, comprising (a) at least one nozzle for extruding material, (b) at least one actuator for moving said nozzle, and (c) at least one chamber adapted for mixing a plurality of materials for extrusion though said nozzle, in such a manner that the ratio of said materials in said extruded mixture varies in a substantially continuous gradient. Furthermore: (1) said apparatus may be adapted to produce a 3D object the composition of which varies, over at least part of its volume, in a substantially continuous gradient, (2) said at least one actuator may be adapted to move said nozzle in such a way as to selectively deposit said extruded material layer by layer, (3) said apparatus may be adapted to produce a 3D object by layered manufacturing, in such a way that the composition of materials differs from layer to layer in a substantially continuous gradient between at least some layers, (4) said apparatus is adapted to produce a 3D object by layered manufacturing, in such a way that the composition of materials differs within a layer in a substantially continuous gradient, (5) said plurality of materials may comprise a plurality of different thermoplastics, 6) said plurality of materials may comprise a plurality of different elastomers, (7) said actuator may be a stepper motor, (8) said chamber may be adapted for melting said plurality of materials, (9) said apparatus may include at least one chamber adapted for said mixing at least two of said plurality of materials and may also include at least one other chamber adapted for melting at least one of said plurality of materials, (10) said nozzle may be one of an array of nozzles, and at least one of the other nozzles in said array may be adapted for extruding a support material that is adapted to be removed after said deposition.
This invention may be implemented as a method of layer manufacturing, comprising (a) extruding material through at least one nozzle, (b) moving said nozzle in a such a manner as to selectively deposit said extruded material layer by layer, (c) mixing a plurality of materials and (d) extruding said mixture through said nozzle in such a manner that the ratio of these materials in the extruded mixture varies in a substantially continuous gradient. Furthermore: (1) said ratio may be varied in such a way that said fused deposition produces a 3D object, the composition of which varies, over at least part of its volume, in a substantially continuous gradient, (2) said layer by layer deposition may be done in such a way that the composition of deposited material differs from layer to layer in a substantially continuous gradient between at least some layers, (3) said layer by layer deposition may be done in such a way that the composition of deposited material differs within a layer in a substantially continuous gradient, (4) a stepper motor may be used to actuate the motion of said nozzle, and (5) said plurality of materials may be melted in said chamber.
This invention may be implemented as apparatus for layer manufacturing, comprising (a) at least one nozzle for extruding material, (b) at least one actuator for moving said nozzle in such a way as to selectively deposit said extruded material layer by layer, and (c) at least one chamber adapted for mixing a plurality of materials for extrusion though said nozzle, in such a manner that the ratio of said materials in said extruded mixture varies gradually. Furthermore: (1) said apparatus may be adapted to produce a 3D object the composition of which varies gradually over at least part of its volume, and (2) said nozzle may be one of an array of nozzles, and at least one of the other nozzles in said array may be adapted for extruding a support material that is adapted to be removed after said deposition.
It is to be understood that the methods and apparatus which have been described above are merely illustrative applications of the principles of the invention. Numerous modifications may be made by those skilled in the art without departing from the scope of the invention. The scope of the invention is not to be limited except by the claims that follow.
This application claims the benefit of United States Provisional Application Ser. No. 61/248,555, filed Oct. 5, 2009, the entire disclosure of which is herein incorporated by reference.
| Number | Date | Country | |
|---|---|---|---|
| 61248555 | Oct 2009 | US |
