The present application claims benefit from prior U.S. provisional application serial No. 60/277,259, filed Mar. 21, 2001, entitled “SYSTEM AND METHOD FOR PRINTING AND SUPPORTING THREE DIMENSIONAL OBJECTS”.

The present invention will be understood and appreciated more fully from the following detailed description taken in conjunction with the appended drawings in which:

[0030]FIG. 1 is a schematic sectional elevational view of a release/support structure for use in the construction of a 3-D object, constructed and operative in accordance with a preferred embodiment of the present invention;

[0031]FIG. 2 is an enlarged detail of a layer of the 3-D object of FIG. 1;

[0032]FIG. 3 is a schematic illustration of an embodiment of the 3-D printing system for use in constructing the 3-D object and release/support structure of FIG. 1;

[0033]FIG. 4-A is a schematic cross-sectional elevational view of a further embodiment of release/support structure for a 3-D object;

[0034]FIG. 4-B is an enlarged detail showing the support pillar for the 3-D object according to an embodiment of the present invention;

[0035]FIG. 4-C depicts another embodiment of a pillar end used to support a cantilever of a 3-D model according to an embodiment of the present invention;

[0036]FIG. 5 depicts a schematic cross-sectional view of a yet further embodiment of release/support structure for a 3-D model;

[0037]FIG. 6-A is an enlarged detail of part of a container and a membrane forming the support structure of FIG. 5;

[0038]FIG. 6-B is an plan view of a serration used to support a thin section of a model according to an embodiment of the present invention;

[0039]FIG. 7 is a complex of pillars and membranes used to support a printed model according to an embodiment of the present invention;

[0040]FIG. 8-A is a model containing a flat insert according to an embodiment of the present invention;

[0041]FIG. 8-B is the base of a part when an insert is introduced according to an embodiment of the present invention;

[0042]FIG. 9-A is a model containing an internal graduated insert according to an embodiment of the present invention;

[0043]FIG. 9-B is the lower section of part 140 when the insert is introduced according to an embodiment of the present invention;

[0044]FIG. 10-A is a model containing a skew insert according to an embodiment of the present invention; and

[0045]FIG. 10-B is the lower section of part 150 when the skewed insert is inserted.

In the following description, various aspects of the present invention will be described. For purposes of explanation, specific configurations and details are set forth in order to provide a thorough understanding of the present invention. However, it will also be apparent to one skilled in the art that the present invention may be practiced without the specific details presented herein. Furthermore, well-known features may be omitted or simplified in order not to obscure the present invention.

List of Definitions:

The following definitions are used in this Application:

Object layer (or component) or model layer: a layer of BM (building material) included in the 3-D object;

Support layer (or component)—a layer of SM (support material) for supporting the 3-D object layer and not included in the 3-D object;

Release layer (or component)—a layer of interface material for separating the 3-D object layer from components, such as the support layer, not included in the 3-D object.

Reference is now made to FIG. 1, which is. a schematic cross sectional view of a release/support structure according to an embodiment of the present invention, generally referenced 50, for a 3-D element 52 (shown hatched) being constructed.

Element 52, set on a table 54, is shown as being a slim upright object having dimensions, whose height H is typically a large multiple of its width (W), In the example of FIG. 1, H≡15×W. Other dimensions and proportions may be used.

As will be appreciated, a slim upright object such as element 52 is likely to snap much more easily than a wider based object. Thus, in order to ensure that 3-D element does not break or snap during printing, 3-D element 52 may be supported during construction. Surrounding the 3-D element 52 may be a shaped support structure 60 that ensures that the 3-D object is adequately braced.

Element 52 is preferably constructed in layers, utilizing suitable apparatus such as embodiments described in U.S. patent applications Ser. Nos. 09/259323 and/or 09/412,618, assigned to the Assignees of the present application, and incorporated herein by reference. Other 3-D modeling apparatuses may be used. For clarity, only three layers, referenced 58A, 58B and 58C are shown. It will be appreciated that 3-D element 52 is constructed in a plurality of layers, approximately 10μ-20μ thick. Other dimensions may be used.

As shown in the enlarged detail of layer 58B in FIG. 2, each layer comprises support material 58, building material 52 and release material 56, Each of the support material 58, building material 52 and release material 56 may be, for example, a photopolymer or other substance that is curable. Curing may be done by, for example, electromagnetic radiation (e.g., X rays, UV rays, visible light, IR radiation, microwave radiation, radio frequencies, etc.). Other curing methods, such as electron beam curing, may be used. Different substances may be used, and different curing methods may be used.

Briefly, embodiments described in U.S. patent application Ser. No. 09/259323 describe apparatus including a printing head having a plurality of nozzles, a dispenser connected to the printing head for selectively dispensing interface material in layers and curing apparatus for optionally curing each of the layers deposited. The depth of each deposited layer may be controllable by selectively adjusting the output from each of the plurality of nozzles.

Embodiments described in U.S. patent application Ser. No. 09/412,618 include a system and a method for printing complex 3-D objects by using interface material having different hardness or elasticity and mixing the interface material from each of the printing heads to control the hardness of the material forming the 3-D object.

Reference is now briefly made to FIG. 3, which is a schematic illustration of a 3-D printing system according to an embodiment of the present invention, generally designated 10.

In one embodiment, the 3-D printing system 10 includes a printing head 12 having a plurality of ink-jet nozzles 14, through which interface material 16 is jetted and a curing unit 18 for curing the interface material 16 to form the 3-D element 52. The 3-D printing system 10 further comprises a process controller 24 connected to and controlling the printing head 12 and curing unit 18 as well as to a CAD system 26. CAD system 26 prepares and outputs the data for the 3-D object being produced.

A single printing head 12 may be used for dispensing the building material 52, support material 58 and release material 56 by allocating different nozzles for each of the different materials. Alternatively, separate printing heads may be used for each material. The support layer may be constituted from, for example, a separate material, from the material used for the release layer, from a mixture of release layer material and support layer material, or from any suitable combination of materials having sufficient strength to provide support to the build layers.

The 3-D element 52 is build up in layers. In one embodiment, the depth of each layer is controllable by, for example, selectively adjusting the output from each of the plurality of ink-jet nozzles 14.

As described in U.S. patent application Ser. No. 09/412,618, an object can be supported during printing by concurrently printing support material using a mixture having a different hardness or elasticity from the mixture forming the 3-D element 52. Thus, in the example of FIG. 1, 3-D element 52 can be supported, for example, by a conical shaped support structure 50. The shaped support structure 50, is preferably constituted from material having mix proportions different from the constructed 3-D element 52.

In one embodiment, the shaped support structure 50 may be released by suitable means consistent with the composition of the support structure. For example, by dissolving shaped support structure 50 in water or other solvent, or by subjecting the structure to mechanical vibrations, or alternatively, subjecting the shaped support structure 50 to ‘energy bombardment’, such as from microwaves, which would cause the shaped support structure 50 to weaken; for example to turn to gas, liquid or powder.

Alternatively, in the embodiment shown in FIG. 2, release material 56 can be used to separate the build material from the support material 58B. The shaped support structure 50 may be constituted from material having mix proportions similar to the constructed 3-D element 52, provided that a release layer 56 is inserted between the shaped support structure 50 and the constructed 3-D element 52. In this case, the release layer is generally softer than both the shaped support structure 50 and the constructed 3-D element 52. The support structure 50 can then be easily separated from the 3-D element 52.

In one embodiment, the release layer has a modulus of elasticity different from those of the support structure and the build material (typically, when measured after deposition and possibly after curing, if curing is used). In certain embodiments, such modulus of elasticity may be measured after a weakening agent (e g., solvent, radiation, temperature) is applied. Typically, the modulus of elasticity for the release layer is lower than both the support and release material (which may or may not have the same modulus of elasticity). The release layer may be constructed from, for example, a mix of support and build material, or may be constructed from a third, separate material.

Reference is now made to FIG. 4-A which is a schematic cross-sectional view of a further embodiment of a release/support structure, generally referenced 60 for a more ‘complex’ 3-D element, 62. The example of 3-D element 62 may be described as having a generally “I”-shape (as seen in cross-section), having a ‘fragile’ foot 63 supporting a wider ‘leg’ 64, which further supports cantilever ‘arms’ 66 and 68. Cantilever arm 66 is deeper than cantilever arm 68, The structure 60 is supported by support material 70. Unless the support material 70 is itself adequately retained (or sufficiently dense so as to be self-supporting), the support material 70 may ‘spread’ or bulge thus causing both cantilever ‘arms’ 66 and 68 to sag or curt.

In the embodiment shown in FIG. 4-A, a secondary support, in the form of a container 72, is used. Container 72 may be a generally box-shaped structure having an open top, which may be jetted in the same manner as the 3-D element 62 and the support material 70. Other shapes for the container may be used. Container 72 may be constituted so that it is sufficiently strong to retain the support material 70. The use of container 72 enables the use of a semi-fluid material, for example, for the support material layers. Thus, the support material may be any suitable low viscosity material capable of supporting the 3-D object being produced. Using low viscosity material as the support allows the 3-D object to be easily released by simply upending the container 72, the support layer 70 also acting as a release material.

The support material typically has a modulus of elasticity less than that of the container and the build object (typically when measured after dispensing or after curing). The modulus of elasticity of the container and build object may be the same The container 72 may be constructed layer by layer concurrently with the construction of the 3-D object 62 and the release/support 70, as described in U.S. patent application Ser. No. 09/259323. Other methods may be used.

Additional support pillars (74, 76) may be added during construction (if required) for supporting the overhangs formed from cantilever ‘arms’ 66 and 68. Reference is now made to FIG. 4-B, which is an enlarged detail of the corner of cantilever ‘arm’ 66 and support pillar 76 according to an embodiment of the present invention. Support pillar 76 may be constructed in layers during the construction of container 72. The support pillar 76 is shown as ending a distance ‘d’ below the bottom layer of cantilever ‘arm’ 66. The distance ‘d’ is preferably the thickness of one or two layers, that is 20-50 microns. Alternatively, the pillar 76 can be constructed up to the bottom layer of cantilever ‘arm’ 66, as shown in FIG. 4-C, the last layer being a single ink-jet ‘drop’. Thus, the support pillar 76 acts to prevent the cantilever arm 66 from sagging. In the embodiment of FIG. 4-B, the maximum ‘sag’ is thus the distance ‘d’ (that is, 20-50 microns).

The last layers of the supporting pillar 76 just below the cantilever ‘arm’ 66 may be narrowed, as shown in FIG. 4-B. Alternative configurations for the last layers include a point or any suitable formation, as shown in FIG, 4-C, so as to ease breaking the support structure.

Reference is now made to FIG. 5, which is a schematic cross-sectional view of a further embodiment of a release/support structure, generally referenced 80. In the embodiment of FIG. 5, a ‘complex’ 3-D structure, generally designated 82 is being constructed within a container-like retainer 84. The 3-D structure comprises a ‘foot’ 86 supporting a ‘leg’ 87, which supports an upper ‘body’ 88. Upper ‘body’ 88 further comprises a nib 90 and a ‘mortise’ 92 cut into one part of body 88. The material used to build the container may be, for example, the build material, or may be other material, such as a third material or a mix of BM and SM.

The structure 82 is supported by support material 94, which is similar to support material 70 described hereinabove with respect to FIG. 4-A.

Reference is now also made to FIG. 6, which is an enlarged detail of nib 90 according to an embodiment of the system and method of the present invention. Owing to thermal changes taking place during the construction of the interface material, there is a tendency for shrinkage to occur. The shrinkage, indicated by arrow 95, may cause ‘curling’ to occur at the ends of the layers being deposited. This is shown in exaggerated detail by the dashed lines 96. One technique to prevent ‘curling’ to occur is shown in the embodiment of FIGS. 6-A and 6-B, where the end of nib 90 is extended by disposing a few thin serrations 98, connected to the container-like retainer 84. The serrations 98 act as restraints, preventing the upward curling of the edges of the nib 90. Another technique of supporting a thin nib 102 at its lower side is shown in FIG. 5; dispensing a supporting nib 100 as an integral part of the container 84, leaving a thin gap ‘F’, and dispensing SM or a release layer over it enables the formation of the thin nib 102.

Similar to the embodiment of FIG. 4-A, additional support pillars (102, 103, 104) may be added during construction for supporting the nib 90 and the overhang formed from the upper ‘body’ 88. As described hereinabove with respect to the support pillar 76 of FIG. 4-A, support pillars (102, 103, 104) may be constructed in layers during the construction of container 84 ending a distance ‘d below the bottom layer of components 88 and 90, or ending by thinning or a point as shown in FIGS. 4-B and 4-C.

Curing is preferably carried out after the deposition of each layer. However, alternatively, curing may be optionally deferred so that curing occurs after the deposition of more than one layer.

Reference is made now to FIG. 7, depicting a cross sectional view of a 3-D model 110 according to an embodiment of the present invention. According to this preferred embodiment the 3-D model 110 is constructed layer by layer including a container 118 and support material 119.

One or more pillars such as pillars 120, 122, and 124 may be constructed in order to support the islands 114 and 116. The pillars are preferably made from the building material, but may be constructed from other material.

Thin membranes like 128, 130, 132, typically having at least thickness of a single layer, may also be dispensed and cured. These membranes may be used to stabilize the pillars by forming connection among them and by connecting them to the relatively rigid container wall 118. The membranes are preferably dispensed from the building material, but may be constructed from other material.

The linkage of said membranes 128, 130 and 132 to the container wall 118 may be continuous or by serrations 98, as shown in FIGS. 6A and 6B, or may be by other methods.

Membranes 130 and 132 are also forming the lower layer of islands 114 and 116.

Refer now to FIG, 8-A which is an embodiment of a 3-D model 130 comprising a cured BM part 132 and an insert 134. The insert 134 may be produced from a third material such as metal, plastic, wood or any other suitable material, or may be produced from build material, support material, or release material. The insert is preferably more rigid than the liquid or semi-liquid materials used to form the build object and support structures. According to an embodiment of the present invention, a plate 134 having threads 136, is inserted in the model, although any other suitable form could be used.

The method of producing a model such like 130, is by first dispensing the lower layers of the model 133, as shown in FIG. 8-B (the container not shown), where the recess 135 is left uncured or filled with SM. The recess 135 may be built slightly larger than the insert 134. When the lower part of the model 133 has attained a thickness of the insert ‘T’, the recess 135 is emptied from the uncured material, the insert 134 is inserted and the dispensing continues, filling the gaps between the cured part 133 and the insert 134.

Reference is made now to FIG. 9-A which is still another embodiment of a method of producing a 3-D model having an embedded graduated insert 144.

The method of producing such a 3-D model is similar to that shown in FIG. 8-A; the lower part of the model 142 is dispensed as shown in FIG. 9B, forming a recess 145 which is uncured and slightly larger than the insert 146. When the recess 145 has attained the form of the insert 144, the recess is emptied from the uncured support material, the insert 144 is inserted into the recess 145 and dispensing the BM continues.

Reference is made now to FIG. 10-A which is still another embodiment of a method of producing a 3-D model 150 having an embedded skewed insert 154.

The method of producing such a 3-D model is similar to that shown in FIG 8-A; the lower part of the model 153 is dispensed as shown in FIG. 10-B, forming a recess 155 which is uncured, filled with SM, (not shown) and slightly larger than the insert 154. When the recess 155 has attained the form of the insert 154, the recess is emptied from the SM, the insert 154 is inserted into the recess and dispensing continues.

It will be further appreciated that the present invention is not limited by what has been described hereinabove and that numerous modifications, all of which fall within the scope of the present invention, exist. Rather the scope of the invention is defined by the claims, which follow: