Method and apparatus for fabricating three dimensional models

Abstract

An apparatus and method for fabricating a three dimensional model from a composite model formed or a plurality of successive layers of model material and sacrificial mold material. Each successive layer is constructed by depositing, drop-by-drop, at least one line of sacrifical mold material delineating at least one boundary of the model material within the layer and thereafter depositing the model material onto all delineated regions of the layer by spray deposition. Each successive layer is completed by a planing process which removes the undesired thickness of both the sacrificial and the model materials. Following completion of the composite model, the sacrificial mold material is removable from the composite model, by a process effecting only the sacrificial mold material, to produce the three dimensional model. A device, for depositing the model material at the rate faster than the rate that the mold material is deposited, is also described.

1 . A method of fabricating a three dimensional model on a layer by layer basis, the method comprising, at each layer of the three dimensional model, the steps of:
 forming a mold with mold material; and   filling the mold with a model material deposited at a rate faster than a rate that the mold material is deposited.   
     
     
         2 . The method of fabricating the three dimensional model on the layer by layer basis according to  claim 1 , further comprising the step of using a spray jet device for depositing the model material at the rate faster than the rate that the mold material is deposited. 
     
     
         3 . The method of fabricating the three dimensional model on the layer by layer basis according to  claim 1 , further comprising the step of:
 filling at least one of a void and a support region of the three dimensional model, on a layer by layer basis, by creating at least one filler element which is bounded by mold material and filled by model material.   
     
     
         4 . The method of fabricating the three dimensional model on the layer by layer basis according to  claim 1 , further comprising, at each layer of the three dimensional model, the step of:
 removing a desired thickness of the mold material and the model material to reduce a fabricated layer to a selected thickness of the mold material and the model material.   
     
     
         5 . The method of fabricating the three dimensional model on the layer by layer basis according to  claim 2 , further comprising the step of providing the spray jet device with a propellant for propelling the model material and a separate delivery and temperature control for controlling a temperature at which the model material is deposited. 
     
     
         6 . A method for fabricating a three dimensional model, the method comprising the steps of:
 fabricating a composite model formed of a plurality of successive layers including a model material forming the three dimensional model and a sacrificial mold material forming a sacrificial mold for the model material, wherein each successive layer is formed by the steps of:   a) depositing at least one line of a sacrificial mold material delineating at least one boundary of the model material within the layer by a drop-by-drop deposition;   b) depositing the model material onto regions of the layer delineated by the at least one boundary of the model material at a rate faster than a rate at which the sacrificial mold material is deposited;   c) removing a thickness of the sacrificial mold material and the model material to reduce the fabricated layer to a selected thickness of the sacrificial mold material and the model material; and   d) repeating steps (a) through (c) until the three dimensional model is completed.   
     
     
         7 . The method for fabricating the three dimensional model according to  claim 6 , further comprising the step of:
 separating the three dimensional model from the composite model by removing the sacrificial mold material by a process effecting only the sacrificial support material.   
     
     
         8 . The method for fabricating the three dimensional model according to  claim 6 , further including the step of forming a void in the three dimensional model by the step of:
 in each layer having a region included in the void, depositing lines of sacrificial mold material in a grid pattern delineating the region of the layer included in the void, whereby the grid patterns in successive layers having regions in the void forming partitions of sacrificial mold material that form filler spaces for receiving the model material to form filler elements of model material separated by the sacrificial mold material partitions occupying the void.   
     
     
         9 . The method of  claim 8  for fabricating the three dimensional model including the void in the model, further comprising the step of:
 removing the sacrificial mold material from the composite model to release the filler elements of the model material from the composite model thereby to form the void in the three dimensional model. 
 
     
     
         10 . A system for fabricating a three dimensional model on a layer by layer basis, the system comprising:
 a drop-on-demand device for forming a mold of mold material; and   a high deposition rate device for filling the mold with a model material at a rate faster than a rate at which the mold material is deposited.   
     
     
         11 . The system for fabricating the three dimensional model on the layer by layer basis according to  claim 10 , wherein the high deposition rate device is a spray jet device. 
     
     
         12 . The system for fabricating the three dimensional model on the layer by layer basis according to  claim 10 , wherein the model further comprises:
 at least one filler element for filling at least one of a void and a support region of the model on a layer by layer basis, and the at least one filler element is bounded by the mold material and filled by the model material.   
     
     
         13 . The system for fabricating the three dimensional model on the layer by layer basis according to  claim 10 , wherein the system further comprises:
 a removal device for removing a desired thickness of the mold material and the model material to reduce the layer to a selected thickness of the mold material and the model material.   
     
     
         14 . The system for fabricating the three dimensional model on the layer by layer basis according to  claim 11 , wherein the spray jet device includes a propellant for propelling the model material and a separate delivery and temperature control for controlling the temperature at which the model material is delivered. 
     
     
         15 . A system for fabricating a three dimensional model formed of a plurality of successive layers including model material forming the three dimensional model and sacrificial mold material forming a sacrificial mold for the model material, the system comprising:
 a drop-on-demand device for depositing, via drop-by-drop deposition, at least one line of sacrificial mold material delineating at least one boundary of the model material within a layer;   a spray device for depositing the model material, by spray deposition, at least onto regions of the layer delineated by the at least one boundary of the model material; and   a removal device for removing a desired thickness of the sacrificial mold material and the model material to reduce the deposited layer to a selected thickness of the sacrificial mold material and the model material.   
     
     
         16 . The system for fabricating the three dimensional model according to  claim 15 , wherein the system further includes:
 a separation process for effecting removing only the sacrificial mold material and freeing the three dimensional model from the sacrificial mold material.   
     
     
         17 . The system for fabricating the three dimensional model according to  claim 15  in which a void is included in the model, wherein:
 in each layer having a region included in the void, the drop-on-demand device deposits lines of sacrificial mold material in a grid pattern delineating the region of the layer included in the void, whereby grid patterns in successive layers having regions included in the void forming partitions of sacrificial mold material that form filler spaces for receiving the model material deposited by the spray device to form filler elements of model material separated by the sacrificial mold material partitions occupying the void. 
 
     
     
         18 . The system for fabricating a three dimensional model according to  claim 15 , wherein the system further includes:
 a process effecting only the sacrificial mold material for removing the sacrificial mold material to thereby release the filler elements of the model material from the three dimensional model to thereby form at least one void in the three dimensional model.