Circuit Boards Maker the component category with the smallest SMD pitch of a PCB or Printed Circuit Boards should be selected.

... Immersion tin demonstrates a good soldering ability, but is slightly at a disadvantage compared with SnPb, because the thin immersion tin layer cannot be | CIRCUIT BOARDS MAKER | completely dissolved. Multi-soldering is possible, as well as pressing techniques, thanks to the thinness of the layer. The thin tin layer does, however, has its | CIRCUIT BOARDS MAKER | disadvantages. The inter-metallic copper-tin phase is approx. 0,25 mµ thick when delivered. During storage, the diffusion of copper in the tin surface continues, causing the | CIRCUIT BOARDS MAKER | thickness of the pure copper or tin layers to decrease. If the blended metal reaches the surface it becomes coated with a non- removable oxide, | CIRCUIT BOARDS MAKER | making soldering impossible. Storage possibilities of immersion tin PCBs are, for this reason, considerably limited compared with conventional SnPb techniques: stored PCBs should be used | CIRCUIT BOARDS MAKER | up within 3 months and if time exceeds 6 months, heavy processing problems can occur. The price of immersion tin is between that of the | CIRCUIT BOARDS MAKER | classical SnPb and the immersion ...
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... capillary effect leads to an increase of more than 0,17 % a gas pressure of 8-10 bar can be reached, causing delamination Even if | CIRCUIT BOARDS MAKER | delamination tests are made after production, the danger of delamination can rise again due to unsafe transportation and long storage times. Therefore we would like | CIRCUIT BOARDS MAKER | to give you following proposals to avoid the described problems: A.2 1 ) | STORAGE CONDITIONS PCB`S | should be stored in heated and dry | CIRCUIT BOARDS MAKER | rooms. Constant low humidity is necessary before the soldering processes start. A rapid fall in temperature of more than 7 degrees causes condensation on the | CIRCUIT BOARDS MAKER | stored PCB`s. Humidity should never exceed 65 %. The package must be kept intact although the polyethylene packages capability of keeping humidity away is not | CIRCUIT BOARDS MAKER | really reliable. A.3 2 ) Storage time | THE STORAGE TIME OF PCB`S | should be as short as possible. PCB`s should be taken out | CIRCUIT BOARDS MAKER | due to the „first-in, first out“ rule. The the polyethylene packages should be taken away just before the assembling. ...
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... to higher layer count multilayers, smaller holes and finer lines. These techniques, however, have not always been able to satisfy designer's often desperate needs | CIRCUIT BOARDS MAKER | to overcome real estate constraints whilst trying to maximise component configurations. As a result new alternatives such as buried vias, blind vias or a mixture | CIRCUIT BOARDS MAKER | of both have been successfully utilised by designers trying to maximise board real estate by increasing the density of lines and pads. However, many manufacturing | CIRCUIT BOARDS MAKER | and design issues must be addressed before adventuring down this path. Due to the many additional oper- ations, the cost of a blind or buried | CIRCUIT BOARDS MAKER | via board is significantly higher than that of a multilayer of the same layer count. | BURIED VIAS | A buried via is a copper-plated | CIRCUIT BOARDS MAKER | hole, imbedded in the board, that interconnects two internal layers. The buried via process starts by drilling holes on thin core laminate. These cores are | CIRCUIT BOARDS MAKER | then metallised, imaged and etched before being laminated. Individual ...
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