With the exception of the automated system mentioned in my last post, there is little difference in the actual performance of the various forms of preheaters. The choice is based on convenience and the ability to provide adequate heat to raise the assembly to the required temperature while using the maximum conveyor speed. Also, in smaller machines, the geometrical size is a limiting factor.
Within the SMT industry, there are many component manufacturers who put limits on the rate of preheating. When checking the performance of preheaters, run the assemblies that have the largest thermal mass, the heaviest components, heat sinks, and ground or voltage planes to see if it can be brought to the desired temperature. Additionally, you should think about whether the temperature will need to be adjusted often throughout a work day. A faster response preheater would be more ideal if you need to increase throughput and efficiency. Otherwise, you may want to choose the simplest preheater that will do the job with the least amount of cleaning and maintenance. Remember that a reduction in output is inevitable as the preheater ages or when the voltage supply decreases.
If you want to compare preheaters, here are links to all the models discussed in this series:
The next mini-series will discuss the parts of the soldering station and how they influence reliability as well as the operations of the wave solder machine as a whole.