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7.5.3 Soldering Surface Mount Gull Wing Components, Hot Gas Method

 
Outline
This procedure covers the general guidelines for soldering surface mount Gull Wing components. There is basically only one type of Gull Wing component. Whether leads are on two sides or four sides, or whether the component is large or small, the soldering principles are the same.

Minimum Skill Level - Intermediate
Recommended for technicians with skills in basic soldering and component rework, but may be inexperienced in general repair/rework procedures.

Conformance Level - High
This procedure most closely duplicates the physical characteristics of the original, and most probably complies with all the functional, environmental and serviceability factors.

Acceptability References
IPC-A-610 12.0 Surface Mount Assemblies
Procedure References
1.0 Foreword
2.1 Handling Electronic Assemblies
2.2 Cleaning
2.5 Baking And Preheating
7.1.1 Soldering Basics
7.1.2 Preparation For Soldering And Component Removal
7.1.3 Solder Joint Acceptability Criteria
Tools and Materials
Cleaner
Cleaner
General purpose cleaner for removing contamination.
Hot Air Tool
Hot Air Tool
Tool and nozzles to deliver precise flow of hot air.
Microscope
Microscope
Precision microscope with stand and lighting for work and inspection.
Solder Paste
Solder Paste    Proprietary
Solder paste for component soldering and rework.
Wipes
Wipes
Nonabrasive, low-linting wipes for cleanup.
Images and Figures
7.5.3 Soldering Surface Mount Gull Wing Components, Hot Gas Method
Surface Mount Gull Wing Component
7.5.3 Soldering Surface Mount Gull Wing Components, Hot Gas Method
Figure 1: Add a small bead of solder paste along the row of pads.
7.5.3 Soldering Surface Mount Gull Wing Components, Hot Gas Method
Figure 2: Move the tool back and forth to heat all the solder joints until complete solder melt is observed.

Procedure
  1. Add a small bead of solder paste along the row of pads. (See Figure 1)
  2. Place the component in position.
  3. Adjust the pressure and temperature output of the hot air tool.
  4. Direct the hot air over the component with the hot air tool tip approximately 2.50 cm (1.00") from the solder joint. This initial heating will pre-dry the solder paste.
    Note: Solder paste has a dull flat appearance when dried.
  5. When the solder paste has dried, move the hot air tooltip to approximately 0.50 cm (0.20") above the component. Move the tool back and forth to heat all the solder joints until complete solder melt is observed. (See Figure 2)
  6. Remove the tool. Wait a moment for the solder to solidify.
  7. Clean, if required, and inspect.
Procedure for reference only.