Viscous non-contact jetting method and apparatus

A nozzle plate subassembly for use with a highly viscous jetting apparatus having an expelling mechanism and a jetting needle having a longitudinal axis and an outlet from which the highly viscous material is jetted during use, comprising:

• a nozzle plate having opposing first and second surfaces with a jetting chamber formed in the first surface, the jetting chamber having sides, an open top, and an opening in a bottom opposite the top which bottom opening is in fluid communication with an outlet that opens onto the second surface of the plate and is configured to be placed in fluid communication with the jetting needle during use, the outlet having a longitudinal axis substantially aligned with a longitudinal axis of the jetting nozzle during use and substantially perpendicular to the first surface, the nozzle plate having an inlet channel in the first surface which is in fluid communication with the jetting chamber, the inlet channel entering a side of the jetting chamber and not extending to the juncture of the chamber sides with the outlet, a portion of the jetting chamber defining an expellable volume of material of about 1 μl or less;
• a metering chamber formed in the first surface and having sides and an open top opposite a closed bottom, the metering chamber having a volume of between about 1 μl or less, the inlet channel being in fluid communication with the metering chamber.
• a flexible diaphragm sized to fit over the first surface sufficiently to cover the jetting chamber, metering chamber and inlet channel, the diaphragm having opposing first and second surfaces with the second surface forming a fluid tight seal with the jetting chamber, metering chamber and inlet channel during use and the second surface configured to form an air tight seal with an abutting surface during use.

A method of dispensing minute quantities of a highly viscous material from an outlet of a jetting needle by an expelling mechanism that deforms a flexible diaphragm into a jetting chamber having sides, an open top covered by the diaphragm and an outlet in the bottom of the jetting chamber that is in fluid communication with the jetting needle, the method comprising:

• placing the jetting needle, outlet and jetting chamber on a common longitudinal axis;
• placing an inlet channel in fluid communication with the side of the jetting chamber, the inlet channel not extending to juncture of the chamber sides with the chamber outlet;
• forcing the highly viscous fluid through the inlet channel into the jetting chamber;
• deforming the flexible diaphragm into the jetting chamber and against the chamber sides a distance sufficient to block the inlet channel and to abut the chamber sides adjacent to the juncture with the outlet, the deformation occurring with sufficient force to expel a predetermined volume of material from the needle outlet as a drop.

An apparatus for rapidly dispensing minute quantities of a highly viscous material from a jetting needle when an expelling mechanism is activated, comprising:

• a nozzle plate having opposing first and second surfaces with a jetting chamber formed in the first surface, the jetting chamber having sides, an open top, and a bottom having an opening that is in fluid communication with an outlet on the second surface that is adapted to connect to the needle, the chamber being in fluid communication with an external fluid reservoir containing said material during use;
• a flexible diaphragm over the open top of the jetting chamber, the diaphragm having a central protrusion extending toward the opening in the bottom of the chamber, the diaphragm being sufficiently flexible to deform into the jetting chamber a distance sufficient so that the central protrusion blocks the opening in the bottom of the chamber during use;
• a support structure having an opening aligned with the top of the jetting chamber to allow the diaphragm to deform into the jetting chamber when the expelling mechanism is activated;
• and
• a mechanism cooperating with the support structure and providing sufficient force to compress and seal the diaphragm around the top of the jetting chamber.