Pace TF 200, Operation & Maintenance Manual

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Board Preparation
Prepare the land pattern as per your company specifications. The most widely used methods are as follows:
1. Prefill - The PCB land pattern is prefilled using a soldering iron. Care must be taken to insure that
all lands are tinned with an equal deposition of solder (provides a uniform appearance).
2. Solder Paste - Apply an equal amount of solder paste on each land using a solder paste dispenser to
control deposition. Take care to insure that the proper amount of paste is dispensed. If too much
paste is applied, solder bridges will form on the lands. If an insufficient amount of paste is applied,
solder joint formation will be unacceptable (open/starved joints). The PCB assembly (or rework
area) should also be preheated (in accordance with your company requirements) after solder paste
deposition to remove any volatiles (e.g., solvents) in the paste. The PACE Heat Wave (HS-200)
system is highly recommended for this preheating application.
Component Positioning
The ThermoFlo has the capability of placing many SMD components properly. In some instances (e.g., fine
pitch FlatPack placement) however, the user may prefer to position a component and solder tack it in place
prior to final soldering. The following procedure is extremely useful when installing leaded components.
1. Using a PACE HandiPik (vacuum holding device) or tweezers for handling or holding, position the
component leads to align with the land areas.
NOTE
A flux paste may be applied to corners of the PCB land pattern to temporarily
hold the component in place.
2. Using a soldering iron with a fine pointed tip, tack two or more lead to land locations at opposite
corners of the component. This will provide stability during subsequent handling throughout the
soldering process.
26
General Process Guidelines