Computer controlled method for dispensing viscous fluid

• US 5,711,989 A
• Filed: 03/07/1996
• Issued: 01/27/1998
• Est. Priority Date: 11/19/1992
• Status: Expired due to Term

• Current Assignee: Nordson Corporation
• Original Assignee: Nordson Corporation
• Inventors: Smith, James C., Abernathy, Ronald N., Aguilar, Stanley C., Maiorca, Philip P., Christofferson, John L., Babiarz, Alec J., Meier, Mark S., Bouras, Carlos E., Ciardella, Robert L., La, Duong
• Primary Examiner(s): Czaja, Donald E.
• Assistant Examiner(s): PADGETT, CALVIN F
• Application Number:
  US08/612,179
• Time in Patent Office: 691 Days
• Field of Search: 118/323, 118/324, 118/679, 118/712, 118/713, 118/302, 118/663, 118/696, 118/697, 118/698, 348/87, 348/88, 348/135, 364/269, 364/DIG. 1, 382/145, 382/141, 222/61, 222/154, 222/196, 222/420, 239/71, 239/102.1, 239/751, 239/227, 427/421, 427/424, 427/96
• US Class Current: 427/8
• CPC Class Codes: B05B 12/085 responsive to flow or pressure of liquid or other fluent material to be discharged B05B1/3006, B05B1/323, B05B7/1254 take precedence
• CPC Class Codes: B05B 17/04 operating with special methods
• 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: B05C 5/0225 characterised by flow controlling means, e.g. valves, located proximate the outlet B05C5/0258, B05C5/0275 take precedence; supply valves upstream the coating head B05C11/1036
• CPC Class Codes: B23K 2101/40 Semiconductor devices
• CPC Class Codes: B23K 3/0607 Solder feeding devices
• CPC Class Codes: H01L 21/56 Encapsulations, e.g. encapsulation layers, coatings
• CPC Class Codes: H01L 2224/83 using a layer connector
• CPC Class Codes: H01L 24/83 using a layer connector
• CPC Class Codes: H05K 13/0469 by applying a glue or viscous material
• CPC Class Codes: H05K 2203/013 Inkjet printing, e.g. for printing insulating material or resist using ink-jet printing to form a conductive pattern H05K3/125
• CPC Class Codes: H05K 2203/163 Monitoring a manufacturing process
• CPC Class Codes: H05K 3/305 Affixing by adhesive
• CPC Class Codes: H05K 3/3485 Applying solder paste, slurry or powder thick film methods for applying conductive paste or ink patterns H05K3/12
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product

Abstract

A computer controlled method for high speed viscous fluid dispensing includes the steps of providing a dot generator and moving the dot generator along at least X and Y axes. The dot generator is controlled to repeatedly eject jets of viscous fluid that break away from the dot generator as a result of their forward momentum and fly to the surface of an adjacent substrate to create dots. The method may further comprise the step of monitoring the size and location of the dots through a vision system. The method may further comprise the steps of assigning dot sizes to specific components based on user specifications or a component library. The method may further comprise the step of optimizing the dot placement paths by aligning the in-line points of dot formation.

Claims

1. A viscous fluid dispensing method, comprising the steps of:

providing a viscous fluid dot generator for rapidly ejecting jets of a viscous fluid to form dots on a surface of a circuit board substrate positioned adjacent the dot generator without wetting the surface;

moving the dot generator transversely adjacent the surface of the substrate; and

controlling the dot generator so that it repeatedly ejects jets of the viscous fluid during its transverse movement to form dots on the surface of the substrate at a plurality of predetermined locations by pre-triggering the dot generator to eject the jets before the dot generator is directly over the corresponding predetermined locations where the dots are to be formed on the surface of the substrate.

2. A method according to claim 1 and further comprising the step of controlling the dot generator during its transverse movement to vary the amount of viscous fluid ejected to thereby form dots of predetermined different sizes on the substrate surface.

3. A method according to claim 1 wherein the dot generator rapidly ejects jets of viscous fluid by rapidly reducing the volume of a chamber containing the viscous fluid.

4. A method according to claim 1 and further comprising the step of drawing the viscous fluid through the dot generator at a priming station before ejecting the jets of viscous fluid to form dots on the surface of the substrate.

5. A method according to claim 1 and further comprising the step of calculating an optimum straight line path of movement of the dot generator so that a subset of a plurality of dots to be formed on the surface of the substrate can be formed in a single path of the dot generator along the optimum straight line path.

6. A method according to claim 1 wherein the dots are formed at a rate of more than four drops per second.

7. A method according to claim 1 wherein the viscous fluid is selected from the group consisting of solder paste, solder flux, solder mask, grease, encapsulant, potting compound and silicone.

8. A method according to claim 1 wherein the viscous fluid is an adhesive.

9. A method according to claim 1 and further comprising the steps of detecting the ejection of the jets of the viscous fluid and generating signals representative of each ejection.

10. A method according to claim 1 wherein the dot generator is controlled to eject jets of the viscous fluid to form dots of predetermined different sizes on the substrate surface based upon stored calibration data.

11. A method according to claim 1 and further comprising the steps of measuring the diameter of a dot formed on the substrate surface and calibrating the dot generator based on the measured diameter.

12. A method according to claim 1 and further comprising the step of determining the position of a dot formed on the substrate surface in order to determine dot placement accuracy.