Print head for stencil printer

A method for printing solder paste comprising:

• supplying viscous material to an elongate chamber of a print head with two supply cartridges in fluid communication with the elongate chamber, the two supply cartridges being configured to deliver viscous material to inlets provided at ends of the elongate chamber;
• applying pressure to the viscous material with an elongate plunger to displace the viscous material onto a substrate;
• sensing pressure within the elongate chamber to maintain the viscous material at a desired pressure with two or more pressure transducers positioned within the elongate chamber along a length of the elongate chamber;
• and
• positively controlling the amount of viscous material discharged from the elongate chamber during a print stroke by controlling the amount of viscous material delivered to the elongate chamber and actuating a plunger actuator coupled to the elongate plunger to move the elongate plunger, the plunger actuator including at least one ball screw coupled to the elongate plunger and a stepper motor coupled to the housing and the at least one ball screw to drive the movement of the elongate plunger within the elongate chamber under the control of a controller,
• wherein sensing pressure within the elongate chamber includes averaging readings taken from the two or more pressure transducers positioned within the elongate chamber to control pressure of viscous material within the elongate chamber.