Pumping system and method for 3D printing

A method for printing a three-dimensional (3D) object using a thermoset resin comprising:

• providing a three-dimensional (3D) printing system including a pneumatic dispense gun for mixing the thermoset resin and a catalyst and dispensing a catalyzed resin to a rotary dispense valve for application of the catalyzed resin to a substrate on a table, the dispense gun comprising a catalyst injection unit and a mixer for mixing the catalyst with the thermoset resin, wherein the mixer is downstream of the catalyst injection unit and the catalyst injection unit comprises a catalyst injector and a distribution ring surrounding the catalyst injector;
• one or more first pumps for pumping the thermoset resin from a first storage container to the pneumatic dispense gun;
• and a second pump for pumping the catalyst from a second storage container to the dispense gun, wherein the pneumatic dispense gun and rotary valve are disposed on a gantry that moves in an x and y direction above the table;
• pumping the catalyst and the thermoset resin to the pneumatic dispense gun;
• intimately mixing the thermoset resin and the catalyst to provide the catalyzed resin;
• dispensing the catalyzed resin to the rotary dispense valve;
• and
• dispensing the catalyzed resin from the rotary dispense valve onto the substrate to form the 3D object as the gantry moves relative to the table.