libera/#neo900/ Saturday, 2018-06-30

Joerg-Neo900I hope you're using blind vias. Right? But then, how would what you just mentioned become a problem?02:38
houkimetrying to avoid using blinds. It seems like it is possible to limit special vias to laser microvias.12:37
houkimeand laser microvias - to single-layer deep surface to GND.12:41
houkimewhich is handy becaquse these can be produced from outside wihout a need for between-laminations processing.12:43
houkime*well, maybe + vias-in-pad for sth12:51
houkimeit might be profitable to replace thermal vias with laser microvias and delete blind-drilled completely.12:56
houkimebecause obviously if you need a large number of holes it is better to do it with laser than to drill mechanically and change drillbits and all that stuff.12:58
houkimehowever i don't know for sure. Need to calculate.13:00
DocScrutinizer05with a density like what we got on Neo900, I don't think we can bve picky about vias. And afaik laser microvias are more expensive than normal even blind or buried vias. Particularly when you need stacked microvias to jump between non-adjacent layers13:06
houkimeThe density doesn that bad really.13:07
houkime*doesn't sem that13:07
DocScrutinizer05anyway PCB houses seem to not honor any such "optimization". In fact they have calculation models that give a bonus to often used technologies and they don't care at al how many steps this involves since it's all automated anyway13:07
DocScrutinizer05I've seen 10 pcieces of a PCB being *cheaper in total* that ONE piece of exactly same PCB. I've seen single layer more expensice than double layer more expansive than 4-layer. I've seen vias not getting calculated at all, no matter which type, as long as there are less than N of them per cm^2 (in average or not)13:11
DocScrutinizer05like "1 piece: 760 EUR, take 10 and get them for 71EUR per unit"13:12
DocScrutinizer05I gues the difference of 50EUR is getting rif of the surplus 9 since they can't make less than 10 anyway ;-P13:13
houkimeanyway, if the design can be completed without using blinds it is better this way. normal vias can be changed to blind effortlessly anytime if extra flexibility is needed.13:15
houkimefor now it doesn't really seem it is needed. Just a better ompmat routing and everything should be be ok13:16
DocScrutinizer05I'd like to see us demonstrating mastering the needed skillset in proto_v2 already, *before* we go proto_v3 with FP515 that needs inpad capped blind vias no matter what13:16
DocScrutinizer05mind you, prot_v2 *should* also test/evaluate the PCB and HW house13:19
* enyc meows14:14

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