Manual

6-28 Beginning Programming
Suckback
At the end of dispensing a line or a dot, the valve is reversed for the Suckback period to remove any
material from the tip of the needle. The Suckback value should be set according to fluid viscosity.
Generally, 10 ms (0.010 seconds) is sufficient.
Dwell
The Dwell is how long the Dispensing Head stays at the final position of a move before retracting. This
allows residual fluid to detach from the needle tip before the Dispensing Head moves to the next location.
The units are seconds. Typically, 0-20 ms (0.020 sec) is sufficient.
Post Dispense Line Parameters
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 raises the Backtrack Gap, and then moves 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 inches. Backtrack Gap should be at least double the
Dispense Gap.
Backtrack Length
This is the horizontal distance that the Dispensing Head moves back over the dispensed line after moving
up the Backtrack Gap distance. This encourages congealed fluids to detach and distributes any excess
fluid back across the line. The units are inches. Typically, 30-40 mils (0.030-0.040 in) is sufficient.
Backtrack Speed
This is the speed that the Dispensing Head travels when moving along the Backtrack Length. The units
are inches/second. Typically, 2 in/sec is sufficient.
Retract Distance
This is a vertical distance that the Dispensing Head moves after the Backtrack Gap and Backtrack Length
dispensing commands have completed. Figure 6-12 shows the relationship between Retract Distance,
Backtrack Gap and Backtrack Length. The Retract Distance must be within the Safe-Z Height defined in
Initial Setup. The units are inches. Typically, 250 mils (0.250 inch) is sufficient.
Figure 6-12 Post Dispense Line Parameters
Retract Distance Backtrack Length
Backtrack Gap