A reflow soldering equipment / machine is the second major equipment after pick-and-place machine in any SMT line.
There are many reflow soldering methods and each method has advantages and disadvantages. Equipment cost, maintenance cost and yield are some of the leading decision factors.
The most widely used reflow processes in electronics are: vapor phase and infrared.
Vapor phase process is very versatile and it can be applied to assemblies of any shape. Many models of phase process are available in both batch and in-line types. The capital costs of the vapor phase and infrared processes are comparable but the operation cost may be higher for vapor phase.
Infrared equipment has been widely used in the hybrid industry, but at a much higher temperature, for firing thick film deposits on ceramic substrates. The same equipment was initially tried for reflow soldering on glass epoxy substrates with terrible results: burning, charring, and warpage of boards. Now the electronics industry has made tremendous progress in redesigning heating elements to eliminate earlier problems.
The development of a reflow profile for each product is key to obtaining optimum yields no matter which reflow system is used. With an appropriate profile, any of the systems will work.