CHAPTER 1: DESCRIPTION
UNIFLOW
®
4 PULSED HEAT CONTROL
1-2 990-908
The operator is coached by visual displays on a Liquid Crystal Display (LCD) screen if out-of-range
entries are made, or when out of limits or alarm/error conditions occur.
Up to 63 heat profiles (the records containing the joining parameters to be used during the joining
cycles) can be programmed, stored, and recalled for use.
Reflow soldering is a multi-step metal joining process where: Two solder-coated parts are brought into
intimate contact, using a preset force.
The temperature of the two parts is raised to a preheat temperature for a preset time to activate
the pre-applied flux. The flux removes the surface oxides from the solder-plated parts.
The temperature is then raised to the reflow temperature for a pre-set time to melt the solder
between the parts.
Cooling is then initiated to allow the solder to solidify.
Upon reaching the pre-set cool temperature, the reflow head can be retracted, removing force
from the parts.
Heat sealing or ACF Final Bonding is a multi-step process that creates an electrical conductive adhesive
bond between two items. These items are typically flexible and rigid circuit boards, glass panel
displays, and flex foils.
With an applied force, two parts are brought together with an adhesive foil, flex, or paste in
between them. The temperature then may be raised to a preheat temperature as a step toward
the final sealing temperature.
The temperature is then raised to the sealing temperature. A plastic deformation of the
adhesive material occurs creating a conductive interface between the two items.
Cooling and curing of the adhesive occurs while the applied force is maintained to stabilize the
joint.
The Control has several features which detect temperatures outside of process requirements:
1) Peak Temperature Limits: Upper and lower temperatures can be set for the peak temperature
during the Preheat and Reflow process cycles.
2) Average Temperature Limits: Upper and lower temperatures can be set for the average
temperature during the Preheat and Reflow process cycles.
3) Envelope Limits: Upper and lower boundaries can be established for the Rise to Preheat,
Preheat, Rise to Reflow and Reflow process cycles.
4) Maximum Process temperature: A maximum temperature, which applies at any time during
Control operation, can be set. The Control will then abort the process and stop heat to the
thermode if the temperature is ever reached.
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