EFD Ultra 325TT User Manual page 73

Ultra TT User's Guide
®
Version 1.2
A NORDSON COMPANY
Dwell Time
Dwell Time measures how long the dispensing head stays at the final position after the end of
dispensing before retracting. This may be necessary to give the fluid a chance to detach from the
tip and onto the substrate, i.e. increasing the Dwell Time can reduce "stringing" of material.
The units are in seconds. Typically, 0 - 20 ms (0.020 sec) is sufficient.
Reverse Time
This parameter is only required when the 790 Auger Valve has been selected in the Setup mode.
At the end of dispensing a dot, the valve is reversed for the specified time period to remove any
material from the tip of the needle. The Reverse Time value should be set according to fluid/paste
viscosity. Generally, 10 ms (0.010 sec) is sufficient.
Backtrack Gap
This is the vertical distance that the dispensing head moves up after completion of a move. At the
end of a move, the dispensing head is raised up by the amount set in the Backtrack Gap, before
moving the Backtrack Length back over the line that was just dispensed. This encourages
congealed fluids to detach and distributes any excess fluid back across the line.
The units are either in inches or millimeters. Backtrack Gap should be at least double the Dispense
Gap.
73