h a l f b a k e r yExpensive, difficult, slightly dangerous, not particularly effective... I'm on a roll.
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Category should be Business:Manufacturing.
The most common printed circuit board material, FR4, is a kind of prepreg (pre-impregnated) fiberglass. That material is made in a bulk roll process. Later, after delivery, the board is drilled for through holes. It's possible to form the holes while the
prepreg is still wet, though.
The idea is to use a press drum with one pin for each via the board will later receive. The prepreg is cured on this form long enough for hole stability, then flattened without removing the holes. Copper cladding can happen normally, but assuming registration is not lost on the line (use a non-clad margin), the copper can then be pierced/punched in the same pattern.
Advantages: Eliminate drilling, a serial x-y positioning process, and substitute with a parallel forming one. Activate through-holes in the pierce/punch step and save a chemical activation process for through-hole plating.
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How much would the hole's position or shape adjust during the later steps (cooling/forming)? If they move out of spec enough to cause mounting problems or vibration sensitivity to mounts, then you may end up scrapping the whole board, as filling holes is usually cost prohibitive. |
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I have no idea what you just said. |
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Well, accuracy's not a massive concern, really - holes normally have plenty of play in them (the ones I've seen, anyway). Surely this is adding a process to get rid of a process, though? |
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<holds hearing trumpet to ear> excuse me? [iamnafets] |
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[accuracy's not a massive concern, really - holes normally have plenty of play in them ] |
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Well, yes for some old school tech, but for fine pitch tech this won't work. But it get's my vote, for a hydraulic solution to a phonetic problem. |
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[eh9], are you referring to a process to manufacture pre-drilled PCB prototyping boards (like Vectorboard), or a process to make custom PCBs? |
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Many cheap consumer devices use punched phenolic. |
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The substrate is economical only if made in large quantities. As soon as you make it "pre-punched" it is customised and good for only one job. There will be mountains of waste when the pcb design changes to accommodate the newer part with a different footprint, because the manufacturer stopped the old one because it was too cheap and margins too low. |
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