A dispenser for dispensing a volume of viscous material on a substrate includes a frame, a gantry system coupled to the frame, and a dispenser unit coupled to the gantry system. The dispenser unit includes a housing having a chamber, and a piston disposed in the chamber. The piston has an elongate body and is configured to move between a pre-dispense position and a dispense position within the chamber. The dispenser unit further includes a motor to drive the movement of the piston within the chamber. The motor includes a rotating shaft, a wheel coupled to the rotating shaft, the wheel having at least one drive magnet, and a driven magnet disposed between wheel and the piston. The dispenser further includes a nozzle coupled to the housing. The nozzle has an orifice to dispense viscous material. Other embodiments of the dispenser and methods of dispensing are further disclosed.