Manual operations are now the most expensive element of manufacturing, so any process that can save time and money and improve quality has to be win-win. In addition, some traditional manual operations have associated health and safety risks that can be removed or reduced by automation. Two of these are selective soldering and selective conformal coating.
At CT Production, we are using the latest generation of automatic selective soldering machine which offers exciting new benefits in terms of capability, cost and quality. The constant increase of product functionality has led to many PCBs being populated on both sides with higher surface mount density. However, through-hole components are still used for higher power or interconnection purposes, sometimes fitted to both sides of a PCB. Therefore fewer PCBs can be mass soldered on a standard wave solder machine, so these machines are becoming less used.
A selective soldering machine can be programmed to raise and lower its solder nozzle automatically to solder joints of a specific component, or to ‘wave’ solder a row of joints at a time, with parameters and head size adjusted according to need. This creates a faster, yet consistent high quality result compared to the alternative of hand soldering.
Earlier machine versions were bulky, costly, difficult to programme, and slower than a hand solder operator. The ACE machine in use at CT Production has proven itself to be consistent to IPC class 3 standards of joint quality. Even dense, multilayer PCBs with thick copper, where a powerful soldering iron has failed, are successfully soldered.
Conformal coating requirements are also on the increase and this has always been a costly, messy, space-consuming process of masking, hand spray, touch-in, de-masking, all with associated health risks. Automated selective conformal coating replaces this with a clean, tidy and controllable process that saves time and money and improves quality.
The PWA machine in use at CT Production is fully programmable, having three nozzles for coarse, medium and fine needle application. The coating is applied in one neat operation in a safe contained area the size of a small SMT machine. After passing through a focussed UV light curing process, the material we use is touch dry within 30 seconds of application,. It represents a huge time and cost saving over manual coating and delivers consistent quality.
Many customers are already benefitting from these processes and some interesting case studies of improved performance have resulted. Other automated processes CT Production has invested in include encapsulation (potting) and inspection (AOI) which offer similar benefits of lower costs, consistent quality and result in a superior service.
Alan Trevarton Managing Director
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