System and method for direct inkjet printing of 3d objects

Abstract

A direct inkjet printing system for fabricating a part by an additive manufacturing process includes an ink delivery system operative to circulate the ink, a printhead associated with the ink delivery system, the printhead operative to dispense ink from the ink delivery system through a plurality of nozzles and based on a defined pattern, a building table for receiving the dispensed ink one layer at a time based on the defined pattern, wherein the part is formed from a plurality of layers of the ink dispensed from the printhead and a drying station operative to perform a drying process on layers of the ink dispensed from the printhead on a per layer basis.

1 . A direct inkjet printing system for fabricating a part by an additive manufacturing process, the system comprising:
 a printhead operative to dispense ink from an ink delivery system through a plurality of nozzles and based on a defined pattern;   a building table for receiving the dispensed ink one layer at a time based on the defined pattern, wherein the part is formed from a plurality of layers of the ink dispensed from the printhead; and   a drying station operative to perform a drying process on layers of the ink dispensed from the printhead on a per layer basis,   wherein the building table is operable to advance into the drying station on the per layer basis.   
     
     
         2 . The system according to  claim 1 , wherein the building table is movable in the printing direction and in the cross printing direction for scanning the plurality of layers while the printhead dispenses the ink. 
     
     
         3 . The system according to  claim 1 , wherein the building table includes a building platform that is rotatable. 
     
     
         4 - 5 . (canceled) 
     
     
         6 . The system according to  claim 1 , comprising a mat positioned on the building table, wherein the mat is operative to receive the dispensed material, wherein the mat is adapted to provide a surface tension that is higher than a surface tension of the ink dispensed thereon. 
     
     
         7 . (canceled) 
     
     
         8 . The system according to  claim 6 , wherein the mat is inkjet paper. 
     
     
         9 . The system according to  claim 1 , wherein the drying station comprises:
 a housing;   a sliding door for receiving the building table into the housing;   a blower operative for circulating air in the housing; and   a heating unit operative to heat the air circulated by the blower.   
     
     
         10 . The system according to  claim 9 , wherein the drying station is operative to impinge jets of hot air on the layers of the ink dispensed on the building table, wherein the drying station includes a nozzle plate through which the hot air is jetted. 
     
     
         11 . (canceled) 
     
     
         12 . The system according to  claim 1 , comprising two drying stations. 
     
     
         13 . The system according to  claim 1 , comprising a first printhead for dispensing building material and a second printhead for dispensing support material. 
     
     
         14 . The system according to  claim 1 ,
 wherein the ink that is dispensed by the printing head has a viscosity of 10-20 cps at the dispensing temperature.   
     
     
         15 - 16 . (canceled) 
     
     
         17 . The system according  claim 1 , wherein the ink that is dispensed by the printing head is ink that is formulated with at least one of ceramic powder, encapsulated metal micro-particles and soluble polymer. 
     
     
         18 - 19 . (canceled) 
     
     
         20 . The system according to  claim 1 , wherein the ink that is dispensed by the printhead is adapted for sintering. 
     
     
         21 . The system according to  claim 1 , wherein the ink delivery system is operative to circulate the ink with gravitation based circulation. 
     
     
         22 . The system according to claim comprising a roller operative to flatten a plurality of layers at a time, wherein the roller is operative to be lowered toward the dispensed ink on demand. 
     
     
         23 . (canceled) 
     
     
         24 . The system according to  claim 1 , comprising a maintenance station operable to align with a position of the printhead during idle periods of the system and to be displaced from the printhead during printing, wherein the maintenance station comprises a nozzle operative to spray cleaning fluid on the printhead and blotting paper with a mechanism for raising the blotting paper toward the printhead. 
     
     
         25 . A method for direct inkjet printing by an additive manufacturing process to fabricate a part, the method comprising:
 dispensing droplets of ink in a layerwise manner according to a pattern defined for fabricating the part, wherein the ink is formulated with at least one of ceramic powder, encapsulated metal micro-particles and soluble polymer;   advancing the building; table into a drying station on a per layer basis; and   drying the droplets of ink in the drying station on a per layer basis.   
     
     
         26 . The method according to  claim 25  comprising;
 printing a layer in a two step process; and 
 drying the droplets of ink in the drying station after each of the irs and second steps, 
 wherein the first step of the two step process includes scanning a first array of the droplets in a printing direction with one pixel gaps in a cross printing direction and wherein the second step of the two step process includes scanning a second array of the droplets in the printing direction with one pixel gaps in a cross printing direction, wherein the second array fills at least a portion of the one pixel gaps formed by the first array. 
 
     
     
         27 . (canceled) 
     
     
         28 . The method according to  claim 26 , comprising dispensing droplets of support material in a layerwise manner according to a pattern defined for supporting the part during fabrication, wherein a layer of droplets of support material is dispensed subsequent to forming a corresponding layer of the droplets of ink for fabricating the part. 
     
     
         29 . The method according to  claim 25 , comprising rotating the layer by 90 degrees prior to printing a subsequent layer. 
     
     
         30 . The method according to  claim 25 , wherein the droplets of ink are dispensed with a printhead including an array of nozzles and wherein the printhead is displaced by a half a pixel distance in a crossing printing direction prior to printing a subsequent layer. 
     
     
         31 . The method according to  claim 25 , comprising flattening each of a plurality of layers at a time. 
     
     
         32 . The method according to  claim 25 , comprising sintering the part.