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We asked the SMART Group to provide some of its members’ views on how technology has been implemented over the past 30 years, and the pressures and changes forced on it by progress in design.
Waste from electrical and electronic equipment (WEEE) is the fastest growing waste stream in the UK, and in Europe the annual amount of WEEE is growing at a rate that is three times faster than the average annual rate of normal municipal waste collected.
After the application of solder resist as part of the board manufacturing process legend is applied by screen printing and then a curing operation.
Scoring offers the benefits of minimum wasted design space and thus allows maximum utilisation of laminate material during the production of a panel of PCBs
Dissolution/erosion of the plating or coating is not a new issue, but with the introduction of lead-free soldering materials, new process stages like selective soldering and higher process temperatures, it is a real issue, as the pictures show.
Solder coverage relates to the ability for solder to wet successfully across the pad surface, and decreased coverage is often highlighted when an alterative surface finish is used on the pads of the printed board.
It’s a fact that lead-free fillet tear in plated through hole joints is not uncommon. The images show two examples of this phenomena; optically and by using real time X-ray inspection.
Microsections are an essential tool in the quality evaluation and control of PCB manufacture. It is very important that the people who produce and assess these microsections are trained and supervised by a person who is well versed in the methods of PCB manufacture.
In any process there are always opportunities to improve, reduce the number of process stages or reduce the cost of manufacture.
The term solder bead is used to differentiate it from solder balls. A solder bead is a solder ball, but its location is normally constant, unlike solder balls. Solder beads are located on the side of chip components between the terminations.
There are two types of solder balls generally seen after wave and selective soldering; consistent/repeating or random balls.
There are essentially three methods of selectively soldering through hole components on a predominately surface mount printed board design. Arguably there are five if robotic or manual hand soldering are included, but the latter is not automated.
Every company that is operating a wave/selective soldering system has it, but what is it and how can you reduce it or dispose of it?
The SMART Group has launched its Lead-Free Defect Guide2, and free copies will be available at National Electronics Week.
An ever increasing number of via holes are being used in modern printed circuit design and as with most electronics, they are getting smaller. A via hole is a connection through the board or only to selected layers of the board. They are used to make interconnections but not required to have leads soldered through the holes.