... No possible soldermask flaking. Spacing between the drills is just right. You hand the data set to the fabricator, and voila! No unexpected phone | MULTILAYER BOARDS INDUSTRY | calls, no changes in the layout, and the fabricator happily sends back a good set of boards on time. Our recommendations for the correct storage | MULTILAYER BOARDS INDUSTRY | of PCBs and MLBs A.1 ) Brief desricption of the problem: PCB`s, especially Multilayer boards are extremly sensitive towards moisture The microscopic structure of the | MULTILAYER BOARDS INDUSTRY | Multilayer material develops a strong capillary power that soaks up the humidity of the surrounding air. Even under very dry conditions it is a question | MULTILAYER BOARDS INDUSTRY | of time that water accumulates in the stored PCB`s. For example: At storage conditions of 20 C° and 35 % of humidity the weight of | MULTILAYER BOARDS INDUSTRY | the epoxyraisin of the Multilayer PCB`s rises 0,12 % due to the accumulation of moisture. If the capillary effect leads to an increase of more | MULTILAYER BOARDS INDUSTRY | than 0,17 % a gas pressure of 8-10 bar can be reached, causing delamination Even if delamination tests are made ...
[ Multilayer Boards Industry ]


... bar can be reached, causing delamination Even if delamination tests are made after production, the danger of delamination can rise again due to unsafe | MULTILAYER BOARDS INDUSTRY | transportation and long storage times. Therefore we would like to give you following proposals to avoid the described problems: A.2 1 ) | STORAGE CONDITIONS | MULTILAYER BOARDS INDUSTRY | PCB`S | should be stored in heated and dry rooms. Constant low humidity is necessary before the soldering processes start. A rapid fall in temperature | MULTILAYER BOARDS INDUSTRY | of more than 7 degrees causes condensation on the stored PCB`s. Humidity should never exceed 65 %. The package must be kept intact although the | MULTILAYER BOARDS INDUSTRY | polyethylene packages capability of keeping humidity away is not really reliable. A.3 2 ) Storage time The storage time of | PCB`S | should be | MULTILAYER BOARDS INDUSTRY | as short as possible. PCB`s should be taken out due to the „first-in, first out“ rule. The the polyethylene packages should be taken away just | MULTILAYER BOARDS INDUSTRY | before the assembling. Remaining PCB`s should be repacked again. To avoid exposure to draught, the ...
[ Multilayer Boards Industry ]


... (0.002" to 0.003") and also convert them to a smaller size. (a) Allowing the operator and CAM software to convert lands could lead to | MULTILAYER BOARDS INDUSTRY | errors in the design and, later, undesirable output. (b) Unintentional swaping of X and Y locations. (c) Offset or shift of original placement due to | MULTILAYER BOARDS INDUSTRY | the software errors with the datum for the feature. * Conversion of draws is also necessary if the Gerber files used to plot the artwork | MULTILAYER BOARDS INDUSTRY | are used to generate an electrical test netlist and fixturing files. All fixturing software must convert lands in order to produce a dependable netlist, that | MULTILAYER BOARDS INDUSTRY | is, one that will test all points. If draw to flash is not completed when generating these files, the software will not place a test | MULTILAYER BOARDS INDUSTRY | point for that feature, leaving that net untested. Open Road: Output plane layers in a negative format. THIEVING AND COPPER BALANCING Thieving and copper balancing | MULTILAYER BOARDS INDUSTRY | is the process of adding a copper pattern to the outer layers of a board. Balanced copper helps to ensure even ...
[ Multilayer Boards Industry ]