... drills, the pad should have a surround of at least 300µ around the hole. 7 Pad 7.1 If non-plated holes are positioned on one | CIRCUIT BOARDS | pad, the pad must have a surround of at least 500µ larger than the hole. Otherwise some/all of the pads may be removed. 8 Solder | CIRCUIT BOARDS | Resists 8.1 Please refrain from oversizing when drafting solder resists, i.e. the solder stop spaces are 1:1 to the pads. This facilitates the incorporation and | CIRCUIT BOARDS | required stretching of the solder resists during the manufacturing process. 9 Silkscreen 9.1 In order to perfectly reproduce silkscreens, the type must be at least | CIRCUIT BOARDS | 1mm high and the stroke at least 200µ thick. Also, all surrounding solder areas must be clear of component print for at least 250µ or | CIRCUIT BOARDS | imperfect print and printed solder areas may result. 10 Non-plated Holes 10.1 This refers to plated through PCBs: If we do not have any information | CIRCUIT BOARDS | from you as to which holes are to be plated-through and which are not, we will determine this to the best of our knowledge. 11 | CIRCUIT BOARDS | Data ...
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... mechanism, high peak powers and short laser pulses give the best microvia results. Each material has a unique ablation threshold, above which vaporization occurs | CIRCUIT BOARDS | for a given wavelength and laser fluence (energy/area). | MOST LASER-BASED SYSTEMS | are typically configured for direct microvia formation, which means that each microvia | CIRCUIT BOARDS | is drilled one at a time at high speed. With this technique, the size of the focused laser beam usually defines the size of the | CIRCUIT BOARDS | microvia or the drilling speed or both. UV lasers often produce the smallest focal spots (5 to 20 microns in diameter), and when used to | CIRCUIT BOARDS | form larger vias, the laser beam can either be expanded or trepanned to accommodate the larger diameter. With trepanning, the laser beam usually moves in | CIRCUIT BOARDS | a full circle or a spiral pattern, starting from the center of the via and removing material as it spirals outward to the circumference of | CIRCUIT BOARDS | the via. Trepanning, however, affects throughput by reducing the number of vias that can be ...
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... low humidity is necessary before the soldering processes start. A rapid fall in temperature of more than 7 degrees causes condensation on the stored | CIRCUIT BOARDS | PCB`s. Humidity should never exceed 65 %. The package must be kept intact although the polyethylene packages capability of keeping humidity away is not really | CIRCUIT BOARDS | reliable. A.3 2 ) Storage time The storage time of | PCB`S | should be as short as possible. PCB`s should be taken out due | CIRCUIT BOARDS | to the „first-in, first out“ rule. The the polyethylene packages should be taken away just before the assembling. Remaining PCB`s should be repacked again. To | CIRCUIT BOARDS | avoid exposure to draught, the packages should be stored in boxes. A.4 3 ) | SOLDERING TESTS PCB`S | stored for over several months and | CIRCUIT BOARDS | being transported under questionable conditions, should be submitted again to a soldering test, being equivalent to your soldering process. A.5 4 ) Heat conditioning of | CIRCUIT BOARDS | the PCB`s In any case we suggest a drying process of the PCB`s in a stove to reduce the ...
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