Viscous non-contact jetting method and apparatus

• US 8,757,511 B2
• Filed: 01/04/2011
• Issued: 06/24/2014
• Est. Priority Date: 01/11/2010
• Status: Active Grant

• Current Assignee: Graco Minnesota Incorporated (Graco Incorporated)
• Original Assignee: Advanjet
• Inventors: La, Duong, Chin, Wai Ching Bessie, Ciardella, Robert L.
• Primary Examiner(s): Tran, Len
• Assistant Examiner(s): Le, Viet
• Application Number:
  US12/984,463
• Publication Number:
  US 20120085842A1
• Time in Patent Office: 1,267 Days
• Field of Search: 239/583, 239/569, 239/330, 417/413.1, 417/53, 417/478, 417/479, 417/441, 251/331, 347/68, 347/69, 347/70
• US Class Current: 239/93
• CPC Class Codes: B05C 11/1034 specially designed for conducting intermittent application of small quantities, e.g. drops, of coating material B05C5/0225, B05C11/1026 take precedence
• CPC Class Codes: B05C 5/001 incorporating means for heating or cooling the liquid or other fluent material B05C11/1042 takes precedence
• CPC Class Codes: B41J 2/04 generating single droplets or particles on demand
• CPC Class Codes: B41J 2202/05 Heads having a valve
• CPC Class Codes: H01L 21/6715 Apparatus for applying a liquid, a resin, an ink or the like H01L21/67126 takes precedence

Abstract

This invention concerns a method and apparatus for dispensing minute quantities of highly viscous material from a jetting needle when an expelling mechanism is activated using a nozzle plate with a jetting chamber having a top formed by a diaphragm and a bottom in fluid communication with a jetting needle. Fluid enters the chamber from an inlet channel and is jetted from the chamber by deforming the diaphragm to block the channel and expel a drop of fluid from the needle. A diaphragm driven metering chamber and/or reservoir chamber can optionally be used provide fluid to the jetting chamber.

Claims

1. 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 nozzle plate having an inlet channel formed in the first surface and in fluid communication with the jetting chamber, the inlet channel entering a side of the jetting chamber and not extending to the opening in the bottom of the jetting chamber;

a flexible, elastomeric diaphragm being sufficiently flexible to deform into the jetting chamber a distance sufficient to block the inlet channel and to provide a fluid seal over the top of the jetting chamber, the diaphragm having a rigid central protrusion extending toward the opening in the bottom of the chamber;

a support structure located to cooperate with the nozzle plate to compress the diaphragm between the support structure and nozzle plate, the support structure having an opening aligned with the top of the jetting chamber which opening is in sufficient communication with the expelling mechanism to allow the diaphragm over the top of the jetting chamber to deform when the expelling mechanism is activated; and

a clamping mechanism holding the diaphragm and nozzle plate together with sufficient force to provide a fluid seal at the top of the jetting chamber.

2. The apparatus of claim 1, wherein the inlet channel is formed in the first surface and the mechanism provides a fluid tight seal with the inlet channel during use and provides an air tight seal with the support structure during use.

3. The apparatus of claim 1, further including is metering device comprising:

a metering chamber formed in the first surface and having sides and an open top opposite a closed bottom, the inlet channel being in fluid communication with the metering chamber;

a first channel placing the reservoir chamber in fluid communication with a fluid reservoir the flexible diaphragm extending over inlet channel and the metering chamber, the diaphragm being sufficiently flexible to deform into the metering chamber a distance sufficient to block the inlet channel at the metering chamber.

4. The apparatus of claim 1, further including a dual chamber metering device comprising:

a reservoir chamber formed in the first surface and having sides and an open top opposite a bottom, the reservoir chamber configured to be placed in fluid communication with a source of highly viscous material to be dispensed by the apparatus;

a metering chamber formed in the first surface and having sides and an open top opposite a closed bottom, the inlet channel being in fluid communication with the metering chamber;

a first channel formed in the first surface placing the reservoir chamber and metering chamber in fluid communication, the first channel being in fluid communication with the reservoir chamber and the metering, chamber;

the flexible diaphragm extending over the first channel and the inlet channel and the metering and reservoir chambers, the diaphragm being sufficiently flexible to deform into the metering and reservoir chambers a distance sufficient to block the inlet channel at the metering chamber and to block the first and second ends of the first channel at the metering and reservoir chambers.

5. The apparatus of claim 3, wherein the diaphragm flexibility and the width of the inlet channel are selected so the diaphragm extends into the inlet channel during use.

6. The apparatus of claim 3, further comprising a metering projection urged against the diaphragm and varying the volume between the diaphragm and the bottom of the metering chamber.

7. The apparatus of claim 1, wherein the expelling mechanism produces a force that deforms the diaphragm sufficiently to abut the sides of the jetting chamber between the inlet channel and the bottom of the jetting chamber which is in fluid communication with the outlet.

8. The apparatus of claim 1, wherein the expelling mechanism produces a force that deforms the diaphragm sufficiently to force the diaphragm into a portion of the outlet at the juncture of the outlet with the bottom of the jetting chamber.

9. The apparatus of claim 1, wherein the diaphragm has a hardened insert located over the jetting cavity when the diaphragm is in a relaxed configuration.

10. The apparatus of claim 1, wherein the diaphragm has a thickened protrusion located over and extending partway into the jetting cavity when the diaphragm is in a non-jetting configuration during use.

11. The apparatus of claim 1, wherein expelling mechanism includes a solid projection impacting the diaphragm over the jetting chamber and forcing the diaphragm into the jetting chamber so the diaphragm abuts the sides of the jetting chamber.

12. The apparatus of claim 1, further comprising, a position adjustment mechanism interposed between the nozzle plate and the support structure to cause relative movement of the nozzle plate and support structure and vary the compression of the diaphragm.

13. The apparatus of claim 12, wherein the adjustment mechanism comprises a rotating threaded member varying the amount of relative movement.

14. The apparatus of claim 1, further comprising the jetting needle in fluid communication with the outlet of the jetting chamber, the needle having a volume greater than a volume of the jetting chamber measured between a bottom of the inlet channel and the intersection of the outlet with the jetting chamber.

15. 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 that is in fluid communication with the needle, the chamber being in fluid communication with an external fluid reservoir containing said material during use;

a flexible, elastomeric diaphragm over the open top of the jetting chamber, the diaphragm having a rigid 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 clamping mechanism cooperating with the support structure and providing sufficient force to compress and seal the diaphragm around the top of the jetting chamber.

16. The apparatus of claim 15, wherein the protrusion is integrally molded with the diaphragm.

17. The apparatus of claim 15, wherein the protrusion comprises an insert made of a harder material than the diaphragm and fastened to the diaphragm.

18. The apparatus of claim 15, wherein the protrusion comprises an insert made of a harder material than the diaphragm and molded to the diaphragm.

19. The apparatus of claim 15, wherein the protrusion has a flange on opposing sides of the diaphragm.

20. The apparatus of claim 18, wherein the protrusion has a curved semi-spherical surface facing the opening in the bottom of the chamber and impacting the jetting chamber during use.

21. The apparatus of claim 18, wherein the expelling mechanism deforming the diaphragm is a solid object which pushes the diaphragm against the chamber sides.

22. The apparatus of claim 18, wherein the expelling mechanism delivers an impact force to deform the diaphragm.

23. The apparatus of claim 15, wherein the protrusion is made of metal.

24. The apparatus of claim 23, wherein the flexible diaphragm has a durometer between shore 50-90 A.

25. The apparatus of claim 15, wherein the flexible diaphragm is made of silicone or neoprene.

26. The apparatus of claim 15, wherein the elastomeric diaphragm is made of a material having a durometer between shore 50-90 A.