Manual

8-12 Beginning Programming
Dots
FMW can dispense precision dots as well as lines. Dots are used in surface mount adhesive
(SMA) applications. For this exercise, use the valve conditioning fluid. The conditioning fluid
simulates the characteristics of SMA fluids.
The size of the dots and characteristics of the dispensing are controlled by Dot Parameters in
the Edit Dot Parameters.
You will learn how to program and dispense dots on the workpiece. Next, you will learn how
to alter the size of the dots and re-perform the dispense.
Estimated time to complete: 30 minutes.
To view the customizable parameters for Dot Parameters:
1. In the FMW Main Window, click on Teach a Program.
2. In the Programming Window, click on Edit and select Edit Dot Parameters.
> A dialog box opens indicating the type of valve installed on your dispensing
system and which valve, Valve 1 or Valve 2, is currently active.
3. Click on OK.
> The Dot Parameters dialog box opens.
> Use the horizontal scroll bar to see all the columns.
> Below are brief explanations of the parameters.
Valve-On Time
This parameter controls the time the valve is on while positioned over the dispensing location.
The time interval affects dot size. The longer the Valve-On Time, the larger the dot. The
units are in seconds. The typical value is 30 ms. However, the Valve-On time can be as long
as 6 seconds, depending on the desired dot size and fluid properties.
Dwell
The Dwell is how long the dispensing head stays at the final position of a move before
retracting. This gives the fluid a chance to attach to the substrate. Increasing the Dwell can
reduce “stringing” of material. The units are seconds. For most solder pastes and adhesives,
30 ms is sufficient. However, the Dwell can also be set as long as 6 seconds for very elastic
fluids.
Dispense Gap
The Dispense Gap is the distance between the substrate you are dispensing on and the needle
tip during dispensing. This distance is one of the more common adjustments to optimize
dispensing programs. The units are in inches. Typically, the Dispense Gap is set to half the
dot diameter.