Soldering process application details

The work processes from the process sequence partial model are detailed, with the work steps being defined on the basis of the production concept and the intermediate steps such as cleaning inserted. In the rehow soldering process the work steps are solder-paste application, component placement, and rehow soldering. 

It is beyond the scope of this chapter to provide a detailed explanation of SPC. Rather, there will be a qualitative discussion of process control that addresses those factors affecting circuit board assembly, beginning with defect types in electronic solder joints. Then the discussion will turn to process control as it pertains to the basic assembly steps (e.g., dispensing, pick-and-place, etc.). The various material sets (e.g., circuit board, solder paste, flux, etc.) will be incorporated in the discussion. Also, the use of Pb-free soldering technology will be addressed where applicable. 

In concert with take-back programs, there are also outright bans on the use of certain hazardous and toxic materials, among them lead (Pb). Therefore, it is the focus of this handbook to discuss, in detail, the materials serving as alternatives to lead (Pb) in solders, where its major application by far is electronic assembly. In addition, this handbook discusses the process implications of these alternatives, unique materials characteristics, and their potential rehabihty impacts. 

A recent development in the production of composite solder, termed as in situ method, introduces the compatible intermetallic reinforcements in the solder matrix during the processing of the solder itself Details of the procedures used to achieve such an in situ composite solder are not available in the current published literature since the patent application for the process by the inventors is still pending. 

---