The Third way for reworking SMDs

Hybrid technology

Hybrid rework systems combine medium-wave infrared radiation with hot air

Advantages:

• Easy setup
• The low flow velocity hot air supporting the IR radiation improves heat transfer, but cannot blow away components
• Heat transfer does not depend entirely on the flow velocity of hot gas at the component/assembly surface (see hot gas)
• No requirement for different nozzles for many component shapes and sizes, reducing cost and the need to change nozzles
• Adjustment of the heating surface possible through various attachments if required
• Heating even very large / long and exotically shaped components possible, depending on the type of top heater
• Very uniform heating possible, assuming high quality hybrid heating systems
• Gentle reflow process with low surface temperatures, assuming correct profile settings
• No compressed air required for the heating process (some systems use compressed air for cooling)
• Closed loop temperature control directly on the component possible by applied thermocouple or pyrometric measurement. This allows compensation of varying environmental influences and temperature losses. Enables use of the same temperature profile on slightly different assemblies, as the heating process adapts itself automatically. Enables (re)entry into the profile even on hot assemblies
• Direct setting of target profile temperatures and gradients possible through direct control of component temperature in each individual soldering process.
• No increased oxidation due to strong blowing of the solder joints with hot air, reduces flux wear or flux blowing away
• Documentation of the temperature elapsed on the component for each individual rework process possible

Disadvantages

• Temperature sensitive nearby components must be shielded from heat to prevent damage, which requires additional time for every board. Shield must cover also from gas flow
• Convective loss of energy at the component possible