Circuit Boards A void in the metallic deposit of a plated-through hole Printed Circuit Boards (PCBs)

... or chemical procedures, OSP is basically just a one-step process. Chemical tin, chemical silver and chemical nickel-gold are therefore, far more expensive; HAL only | CIRCUIT BOARDS | marginally so. Doubts - just a European attitude? So, what are the disadvantages ? European users, in particular, can list quite a few: the predominant | CIRCUIT BOARDS | one being, that for mixed components and other multi-thermic processes, the organic protection layer breaks off at temperatures above 150° C . All in all, | CIRCUIT BOARDS | the area of use for soldering at higher melting temperatures has not yet been reliably tested. In addition, OSP does not bond. The ability to | CIRCUIT BOARDS | bond with soldering paste – in particular with lead-free soldering paste – depends greatly on the soldering procedure, such as convection ovens with or without | CIRCUIT BOARDS | a nitrogen atmosphere, high cooker ovens, etc Tests so far show that bonding is not as good as with the other named surfaces. Therefore, the | CIRCUIT BOARDS | self-centralising effect is noticeably lower and requires greater ...
[ Circuit Boards ]


... outflow and to smooth out uneven or rough edges. Special attention was given to environmental compatibility and safety conditions. Furthermore, the facility was designed | CIRCUIT BOARDS | to accommodate future expansions. The requirements were as follows: - LP formats: Up to 640 x 610 mm - LP thickness: 0.30 – 10.0 mm | CIRCUIT BOARDS | - Materials: FR- 4, BT-epoxy, polyimide, “Thermount”/RCF - Heat ramp rates: 5-6°C/min. (measured as a package) Great emphasis was put on automation for stacking and | CIRCUIT BOARDS | for enclosed separation sheet circulation. The flow directions for the transport sheets and separation sheets are intentionally interrupted after de-stacking, enabling cleaning of sheets or | CIRCUIT BOARDS | buffering of empty stacks. With the aid of vacuum, a lot less pressure is required, resulting in less distortions and virtually no air entrapment. Another | CIRCUIT BOARDS | plus is that very little resin flows from the multilayer. The finished result is a board with lower dielectric constant, preferred for impedance controlled boards | CIRCUIT BOARDS | which are ...
[ Circuit Boards ]


... written to reflect the actual holes in each individual synthetic layer of the adaptor. The pin positions are identical to the control points enabling | CIRCUIT BOARDS | an overall PCB test within seconds. The control adaptors are all the more expensive the higher the density and the lower the grid distances between | CIRCUIT BOARDS | control points. The adaptors can also only be used for one specific type of PCB which explains the high set-up costs for the test. FLYING | CIRCUIT BOARDS | PROBE TEST: As PCB series are not always produced in mass, the flying probe test was developed as an alternative solution for small or medium-sized | CIRCUIT BOARDS | series. Manoeuverable probes move to the control points without necessitating an adaptor. As the points are checked individually, the time required for a complete check | CIRCUIT BOARDS | depends on the number of test points. In extremely complex layouts the test can take up to 30 minutes. Electrical testing of PCBs is costly | CIRCUIT BOARDS | and time intensive. However, it is obvious that testing is necessary. Just consider the consequences of ...
[ Circuit Boards ]