Systems and methods for delivering materials for printing three dimensional (3d) objects

Abstract

A delivery system for delivering a plurality of layers of a powder to a three dimensional (3D) printing system for printing at least one 3D object, the delivery system comprising: a rotatable drum having a rounded photosensitive outer surface, a hopper unit comprising a container for storing the powder, wherein the hopper unit is configured to dispense the powder on the photosensitive outer surface of the rotatable drum. The delivery system further comprises a delivery unit comprising a movable delivery plate having a conductive outer surface, an engine for moving the delivery plate to a working chamber of the 3D printing system, one or more charging electrodes configured to charge the rotatable drum, a charging unit configured to charge the delivery plate. The movable delivery unit is further configured to: electrically and successively attract the dispensed plurality of layers from the rotatable drum outer surface to its conductive outer surface; and transfer the attracted plurality of layers to the working chamber by electrically rejecting the attracted plurality of layers into the working chamber.

What is claimed is: 
     
         1 . A method for delivering at least two types of materials to a working chamber, the method comprising:
 dispensing respectively on each photosensitive outer surface of at least two rotatable drums one material of the at least two types of materials;   electrically and successively attracting the at least two types of materials from the respective rotatable drum surface to a movable delivery plate conductive surface forming a, layer comprising said attracted at least two materials; and   transferring the layer to the working chamber by electrically rejecting the layer from the delivery plate into the working chamber.   
     
     
         2 . The method of  claim 1 , wherein each of said at least two rotatable drums has associated therewith a hopper unit comprising a container for storing respectively the one material of said at least two materials, wherein the step of dispensing dispenses the one material from the hopper unit onto the photosensitive outer surface of the rotatable drum. . The method of  claim 1 , wherein each of said at least two rotatable drums has associated therewith one or more charging electrodes, and the method further comprises charging the rotatable drum using the one or more charging electrodes. 
     
     
         4 . The method of  claim 1 , further comprising charging the delivery plate using a charging unit. 
     
     
         5 . The method of  claim 1 , wherein the movable delivery plate is configured to be connected to an engine to move the delivery plate, and wherein the method further comprises moving the delivery plate to the working chamber and delivering simultaneously the at least two types of materials to the working chamber using said delivery plate. 
     
     
         6 . The method of  claim 1 , further comprising delivering simultaneously the at least two types of materials to the working chamber using said delivery plate. 
     
     
         7 . The method of  claim 1 , further comprising coating the conductive surface with one or more layers of insulating materials. 
     
     
         8 . The method of  claim 1 , wherein using non-conductive or conductive powder materials as said at least two types of materials. 
     
     
         9 . The method of  claim 2 , comprising coating said container of said hopper unit with one or more layers of insulating materials. 
     
     
         10 . The method of  claim 1 , comprising cleaning the photosensitive outer surface of each of said at least two rotatable drums with a respective cleaning unit. 
     
     
         11 . The method of  claim 1 , comprising cleaning surfaces of said delivery plate with a cleaning unit. 
     
     
         12 . The method of  claim 1 , comprising transferring the plurality of layers to a working surface of the working chamber one after the other; and fusing said plurality of layers using an energy head to generate at least one 3D (three dimensional) object. 
     
     
         13 . The method of  claim 12 , wherein said energy head is a laser head and the method. comprises applying a focused laser beam to a given area of each of layer of said plurality of layers corresponding to a selected cross-sectional area of a model of a molded 3D object, in accordance with CAD cross-sectional data of the selected cross-sectional area of the model in such a way that each layer is fixed to the layer below. 
     
     
         14 . The method of  claim 12 , comprising compressing said plurality of layers. 
     
     
         15 . The method of  claim 13 , further comprising pressing the received plurality of layers to form dense powder layers. 
     
     
         16 . The method of  claim 15 , further comprising sintering said dense powder layers. 
     
     
         17 . The method of  claim 15 , further comprising sintering all but one of said dense powder layers, said one of said dense powder layers comprising a material which may not be sintered. 
     
     
         18 . The method of  claim 1 , comprising synchronizing, using a processor, a movement rate of said delivery plate with a rotation speed rate of said at least two rotatable drums. 
     
     
         19 . The method of  claim 1 , comprising moving the movable delivery plate synchronously with multiple points located respectively above said at least two rotatable drums.