OSHPark plated slots - Page 1
Forum section: electronics / general

author: westfw
author_rank: Super Contributor
timestamp: May 19, 2017, 02:06:11 am
content: Has anyone tried to use plated slots at OSHPark? Their documents say "it will probably work", but I'd like to be more certain than that.The actual part is a USB-B connector (full-sized), so I'm interested in a pretty short, 40mil slot (the minimum width, according to the documents.) (Does anyone have a library part for a USB-B connector, with slots, that has worked at OSHPark. or ... anywhere?)

author: Rerouter
author_rank: Super Contributor
timestamp: May 19, 2017, 02:10:24 am
content: I cannot say for ohs park, but itead has made me some pretty skinny plated slots in the past, was for securing an encoder

author: ataradov
author_rank: Super Contributor
timestamp: May 19, 2017, 02:36:32 am
content: Dave tried in the recent video on Nixie clock. It failed miserably.Although it failed on the stage of generating the preview pictures, so if your previews look ok, then you are probably fine.

author: LabSpokane
author_rank: Super Contributor
timestamp: May 19, 2017, 03:59:56 am
content: Slots work if you follow the guidelines on OSHPark's site. Draw the slot inside a pad with the lines on layer 20. This is different than other board shops where you draw the slot on layer 46 (mill layer).This slot is 0.040 x .120".

author: LabSpokane
author_rank: Super Contributor
timestamp: May 19, 2017, 05:32:54 pm
content: I forgot to add, that I've used OSHPARK's design guidelines and it worked fine. I'd post photois if the PCB but I think I used them all. Will try with the next batch.

author: westfw
author_rank: Super Contributor
timestamp: May 21, 2017, 05:31:31 am
content: Hmm. Thanks! The hole in your pad is smaller than the slot. Is that permitted? (I guess so!) Required?

author: mahi
author_rank: Regular Contributor
timestamp: May 21, 2017, 12:01:16 pm
content: Quote from: ataradov on May 19, 2017, 02:36:32 amIf Dave would have taken a few minutes to read the Oshpark design guidelines his board would have looked just fine. Nevertheless I agree with him that Oshpark would not have been a good choice for a board of that size.Quote from: westfw on May 19, 2017, 02:06:11 amI can't help with the USB connector but Oshpark can manufacture plated slots if you stick to their design guidelines. Officially they do not support such features and you will get a warning upon uploading your designs that there are unsupported drilled slots, but so far the PCBs I received always had correct slots.

author: LabSpokane
author_rank: Super Contributor
timestamp: May 21, 2017, 02:41:55 pm
content: Quote from: westfw on May 21, 2017, 05:31:31 amRequired for a plated slot, I believe. I used Eagle for my board, FWIW.I have to say that a feature which is so common should never be this ambiguous to reliably obtain. Autodesk and OSHPark both need to get this solved.

author: latigid on
author_rank: Contributor
timestamp: May 21, 2017, 04:02:05 pm
content: I went through this the other week with Elecrow. I tried to give them similar gerbers (pad/SMT drawn on, hole, milling path). They took a few days before asking me to remove the holes, and that the slots were too narrow. Some time later (after an email issue apparently) they said the slot was still too narrow at 0.13mm, because they weren't using the path but the area of the milling lines. I widened the lines to 0.8mm and apparently that was good enough!Slots are a pain in the ass though; there's no easy way I know of to get them drawn in EAGLE without DRC going nuts. You have to manually attach "thermals" to planes too.

author: LabSpokane
author_rank: Super Contributor
timestamp: May 21, 2017, 04:22:35 pm
content: Quote from: latigid on on May 21, 2017, 04:02:05 pmI believe fab shops want your design in terms of finished part dimensions. They generate the tool paths from those. They'd go crazy if they had to differentiate between tool paths and dimensions in one file.

author: ajawamnet
author_rank: Regular Contributor
timestamp: May 21, 2017, 07:35:12 pm
content: I use Altium, so not sure how much this will help...What happens with AD, is that the plated slots are in a second drill file. Note on the PDF attached (page 2) how the table calls it out.If you look at the two drill files - one for holes, one for slots - note that the slotted one looks more like Gcode for a CNC vs and Excellon file...In the slots file, you'll see a G01 - in CNC, that's a controlled feed, set by the F parameter. Usually the CAM guy at the board house will know what feeds to use as well as what depth (they usually stack the PCB in batches, depending on drill aspect ratio).I do a lot of CNC in house:http://ajawamnet.com/http://www.ajawamnet.com/ajawam3/swarf/swarf.htmcnc -http://www.ajawamnet.com/ajawam3/swarf/maxnc.htmlI do a lot of plated slots for stuff like that Allegro part that's in this example...BTW the example is one of AD's example PCB's I was using on the forum for showing accordion unions in AD17...

author: westfw
author_rank: Super Contributor
timestamp: May 22, 2017, 12:01:49 pm
content: Ok; thanks everyone. The design has been sent off to OSHPark and I'll see how it comes out. (Mahi's photos look great!)QuoteWhat I'd PREFER is to have a specification "when drilling plated holes, one of the tools available is a milling bit of diameter xxx. You can provide a milling layer with paths drawn in that width, and we'll mill along those paths with that bit." WYSIWYG, the designer is responsible for taking the tool size into account, and use a separate gerber file for the additional tool action (but the same process step, if I'm interpreting the process correctly.) Some vendors might have a CNC drill that can't do milling, which would be too bad (but is probably increasingly uncommon), and they should just say so.This "draw a line in a weird layer, inside a pad but outside the hole of the pad, and we'll figure out that it's the outside edge of a slot you want milled" is ... uncomfortable.

author: LabSpokane
author_rank: Super Contributor
timestamp: May 23, 2017, 06:36:32 pm
content: This is what I received from OSHPark. Design dims: 0.040x.120. Finished dimensions are about 0.44 x .125. Close enough for me.