... show that bonding is not as good as with the other named surfaces. Therefore, the self-centralising effect is noticeably lower and requires greater precision | MULTILAYER CIRCUITS INDUSTRY | of solder paste pressure. In addition, the test for soldering ability showed that emphasis should be placed on a suitable flux agent, as this, in | MULTILAYER CIRCUITS INDUSTRY | addition to the thermic effect, also leads to the removal of the OSP layer. In Europe, there is a lack of enthusiasm for OSP, especially | MULTILAYER CIRCUITS INDUSTRY | due to the great demands made on the flexibility of lead-free surfaces, plus the need for multi- soldering using a variety of thermic processes with | MULTILAYER CIRCUITS INDUSTRY | standard flux agents. DIFFERENT INDUSTRIAL STRUCTURES – DIFFERENT SURFACES It is, therefore, not surprising that, especially in Asia, OSP is as popular as chemical tin | MULTILAYER CIRCUITS INDUSTRY | is in Europe, or chemical silver in the US. An environment of mass production with long-term planning – often in-house – using a single thermic | MULTILAYER CIRCUITS INDUSTRY | soldering process makes OSP the absolute favourite. As long as Europe is oriented towards ...
[ Multilayer Circuits Industry ]


... possible. PCB`s should be taken out due to the „first-in, first out“ rule. The the polyethylene packages should be taken away just before the | MULTILAYER CIRCUITS INDUSTRY | assembling. Remaining PCB`s should be repacked again. To avoid exposure to draught, the packages should be stored in boxes. A.4 3 ) Soldering tests PCB`s | MULTILAYER CIRCUITS INDUSTRY | stored for over several months and being transported under questionable conditions, should be submitted again to a soldering test, being equivalent to your soldering process. | MULTILAYER CIRCUITS INDUSTRY | A.5 4 ) Heat conditioning of the PCB`s In any case we suggest a drying process of the PCB`s in a stove to reduce the | MULTILAYER CIRCUITS INDUSTRY | moisture in the PCB`s to an acceptable minimum. Following parameters can be recommended: A6) Drying time: Temperature C° 8 hours 120 10 hours 100 18 | MULTILAYER CIRCUITS INDUSTRY | hours 80 Lower drying temperatures are also possible but need much more exposure time. We also suggest to put the PCB`s vertically in the stove | MULTILAYER CIRCUITS INDUSTRY | by using a rack. Good results can be achieved if the assembling process of the PCBs is started immediatedly ...
[ Multilayer Circuits Industry ]


... otherwise lead to PCB failure after a number of operational hours. An electrical test is needed to check the actual functions of a PCB. | MULTILAYER CIRCUITS INDUSTRY | It is an essential if inner layers need to be tested, as is the case with multi-layers. In two position measurements all connections in the | MULTILAYER CIRCUITS INDUSTRY | PCB are checked for stoppages and short circuits . All SMD pads and plated through holes are checked. The electrical test can be conducted as | MULTILAYER CIRCUITS INDUSTRY | a parallel or finger test. PARALLEL TEST: For the parallel test a control adaptor is constructed, consisting, e.g. of several synthetic sheets positioned above each | MULTILAYER CIRCUITS INDUSTRY | other and fitted with control pins. An adaptor programme must be written to reflect the actual holes in each individual synthetic layer of the adaptor. | MULTILAYER CIRCUITS INDUSTRY | The pin positions are identical to the control points enabling an overall PCB test within seconds. The control adaptors are all the more expensive the | MULTILAYER CIRCUITS INDUSTRY | higher the density and the lower the grid distances between control points. The adaptors can also only be ...
[ Multilayer Circuits Industry ]