Drill size for PCBway, anyone know? - Page 1
Forum section: electronics / projects

author: tkamiya
author_rank: Super Contributor
timestamp: September 23, 2020, 10:16:06 pm
content: According to this charthttps://www.pcbway.com/capabilities.htmlPCBWay can use 0.2 to 6.3mm drills. What it doesn't say is what step... What would happen if I said 0.3mm or 0.4mm? I've tried asking them but ran into language issues. Does anyone know?Also, which one is right? This one says something that actually does not make any sensehttps://www.pcbway.com/pcb_prototype/Pinted_Circuit_Board_Prototype.html0.15mm +/- 1mm?

author: Someone
author_rank: Super Contributor
timestamp: September 23, 2020, 11:51:40 pm
content: Its a moving field, so lots of their documentation is out of date. As you pick smaller drills, the pool of lines bidding on the job goes down and the price goes up (pcbway expose this to you). 0.15mm is doable, but they might not like a 40x aspect ratio! If you want specific support and tolerancing you need to deal with the operators of the fab directly and not several layers back through customer support, that requires paying more or driving volumes.

author: tkamiya
author_rank: Super Contributor
timestamp: September 23, 2020, 11:55:23 pm
content: The "joys" of dealing with off-shore manufacturers!

author: Someone
author_rank: Super Contributor
timestamp: September 24, 2020, 12:13:09 am
content: Not sure this is anything to do with their physical location. You are looking at a low cost partly-automated service, and wanting technical sales/support. Well: they cut that out of their business model to push the price down.It cuts back the other direction too, some times the pool services will accept jobs that no-where else could do for the low prices because other shops (who also invested in the higher performance machines) insist on having more layers of support and checking a part of their business model.

author: Siwastaja
author_rank: Super Contributor
timestamp: September 24, 2020, 11:44:26 am
content: They definitely do have 0.3mm and 0.4mm available. I think they have issues documenting this because they have so many sizes it's seldom an issue.

author: thinkfat
author_rank: Unknown
timestamp: September 24, 2020, 12:41:09 pm
content: Quite likely they'll also shift the hole size requested to the next larger one they have available. Their manufacturing constraints should take that into account, e.g. when specifying minimum hole-to-hole distance and minimum annular ring of vias.

author: Siwastaja
author_rank: Super Contributor
timestamp: September 24, 2020, 12:52:27 pm
content: Quote from: thinkfat on September 24, 2020, 12:41:09 pmThis is the key; if you follow the rules, you shouldn't have any problem, UNLESS you have a very special case of mechanical constraint requiring super-tight fit.

author: BrianHG
author_rank: Super Contributor
timestamp: September 24, 2020, 01:03:26 pm
content: Yes, for 'PCBWay' simplify your drill size selection as much as possible. Like, only deal with 4-6 different sizes for your whole PCB. I've received boards from them with the wrong tooling altogether while the first initial shipment from them was fine.Something to watch for.

author: NorthGuy
author_rank: Super Contributor
timestamp: September 24, 2020, 03:03:39 pm
content: I'm not sure about big holes, but there are often positioning holes for plastic pins in various connectors, and they always get the correct size so far.Recently I had a design with 3 mm plated through hole. I have now measured one of the holes and it was 2.94 mm. Given the HASL finish, this is very good accuracy.

author: Siwastaja
author_rank: Super Contributor
timestamp: September 24, 2020, 05:10:40 pm
content: Larger holes, like 3mm, may be actually routed; this is because they have to do routing anyway, and they can route all different large hole sizes using one routing bit. You can see this if you look very carefully; you'll find a slight bump or "discontinuation" where the routing ended. I have seen this in 3.2mm holes I tend to specify for M3 screws. This way, they can have arbitrarily close steps of different sizes exceeding some minimum limit, so you can get 4.15 or 4.2 or 4.25 mm holes no problem without them carrying such drill bits.