Adhesive Nozzle Characteristics - Managing Stringing and Tailing

Category: Adhesives and Dispensing
Post Date: July 20, 2004
Author(s): Steve Marongelli, Product Marketing Specialist, Surface Mount Division, Universal Instruments

Description
This article focuses on the phenomenon of adhesive stringing that can be attributed to various characteristics of the dispense nozzle:
- The inside diameter of the nozzle: Called the nozzle ID. This dictates the smallest dot dispensed from that nozzle. A good rule of thumb is that the smallest possible dot that can be dispensed is typically twice the nozzle ID.

- The distance between the nozzle and the board: Called the nozzle stand-off. The nozzle stand-off usually dictates the height of the dispensed material.

- The correct volume of adhesive: This represents the amount of material dispensed through the nozzle at a given time. The volume of material dispensed is controlled by the stroke of the piston when using a Piston Positive Displacement style pump, or by the number of revolutions of the screw when using an Archimedes style pump.

For more information, contact a Universal Sales Rep.