... proposals to avoid the described problems: B STORAGE CONDITIONS PCB`s should be stored in heated and dry rooms. Constant low humidity is necessary before | PRINTED CIRCUIT BOARDS | the soldering processes start. A rapid fall in temperature of more than 7 degrees causes condensation on the stored PCB`s. Humidity should never exceed 65 | PRINTED CIRCUIT BOARDS | %. The package must be kept intact although the polyethylene packages capability of keeping humidity away is not really reliable. C STORAGE TIME The storage | PRINTED CIRCUIT BOARDS | time of PCB`s should be as short as possible. PCB`s should be taken out due to the „first-in, first out“ rule. The the polyethylene packages | PRINTED CIRCUIT BOARDS | should be taken away just before the assembling. Remaining PCB`s should be repacked again. To avoid exposure to draught, the packages should be stored in | PRINTED CIRCUIT BOARDS | boxes. D SOLDERING TESTS PCB`s stored for over several months and being transported under questionable conditions, should be submitted again to a soldering test, being | PRINTED CIRCUIT BOARDS | equivalent to your soldering process. E HEAT CONDITIONING OF ...
[ Printed Circuit Boards ]


... | REFLOWING | The melting of an electrodeposit followed by solidification. The surface has the appearance and physical characteristics of being hot dipped. | | PRINTED CIRCUIT BOARDS | REGISTRATION | The degree of conformity of the position of a pattern, or a portion thereof, with its intended position or with that of any | PRINTED CIRCUIT BOARDS | other conductor layer of a board. | RESIN EPOXY-MATERIAL | used for impregnating glass weave. | RESIN | Recession The presence of voids between the | PRINTED CIRCUIT BOARDS | barrel of the plated-through hole and the wall of the hole, seen in microsections of plated-through holes in boards exposed to high temperatures. | RESIN | PRINTED CIRCUIT BOARDS | SMEAR | Resin transferred from the base material onto the surface or edge of the conductive pattern normally caused by drilling. Sometimes called Epoxy Smear. | PRINTED CIRCUIT BOARDS | | RESIST COATING MATERIAL | used to mask or to protect selected areas of a pattern from the action of an etchant solder, or plating. | PRINTED CIRCUIT BOARDS | | RING VOIDS | The absence of substance in a localized area, as an missing Ring in a ...
[ Printed Circuit Boards ]


... RELIEFS |are surrounded by voids in the ground (clearances) and the clearances lack sufficient annular rings to ensure connections, the clearances must be enlarged | PRINTED CIRCUIT BOARDS | to meet manufacturing capabilities, thus causing the thermal to be isolated from the rest of the ground plane. This may be the case with internal | PRINTED CIRCUIT BOARDS | layer files, but the external files can show the same data, such as the surface mount component's length and width. The operator must determine whether | PRINTED CIRCUIT BOARDS | the aperture wheel calls out X first and Y second or Y first and X second. The wrong choice may cause the surface mount land | PRINTED CIRCUIT BOARDS | to short into another feature or become oversized or undersized. A mistype of a circle instead of a square may deprive the SM component of | PRINTED CIRCUIT BOARDS | a land that is sufficient to ensure the component is level during wave soldering. When typed incorrectly, soldermask clearance sizes can result in mask on | PRINTED CIRCUIT BOARDS | lands or enlarged clearances that expose traces. Open Road: When asking a fabricator to manually manipulate the ...
[ Printed Circuit Boards ]