Pace TF 2000, Руководство пользователя

Страница: 43 / 69

Page 42 of 67
During this phase, the solder balls reach solder melt and form a joint
between the package and the pads. It is critical for all areas of the
array to reach solder melt together and all solder balls remain in a
liquid state for at least 15-20 seconds.
Generally, the device should not be exposed to temperatures higher
than 220 ºC. Always consult the device specifications for maximum
temperature recommendations. As a rule of thumb, a safe “maximum
temperature” is the maximum temp specified by the manufacturer
minus 20ºC. Lower temperatures and shorter times are common in
CSPs and FCs.
The lowest temperatures possible should always
be used to ensure safety of the device and PCB.
Cool Down Phase
The cool down phase is necessary to bring the temperature of the
package, solder joints and PCB under the package below solder melt
temperatures. Cooling should be controlled. A good reference is to
use the same cool down rate as for ramp up. The cooling fan on the
TF 2000R will remain on for 55 seconds from the start of the cool down
cycle. Some types of components (like CBGAs) should be allowed to
cool without external assistance from the cooling fan.
General
Using the baseline defaults in memory locations 00, 01 and 02 will provide
a good starting point for profile development. The reflow graph provides
an excellent tool for monitoring profile parameters and fine tuning or
perfecting the profile development process.
When adjusting profile parameters “on-the-fly”, all changes are reflected
immediately on the profile development screen and graph.
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com