Plated Slots with Eagle at JLPCB - Page 1
Forum section: electronics / general

author: jpanhalt
author_rank: Super Contributor
timestamp: March 27, 2020, 09:20:43 pm
content: Cad program: EAGLE 7.2 through 7.7I have a new board (2" x 3.8") to send off that has PTH and non-PTH holes and slots. The holes are pretty obvious how to do. For slots, it gets more complicated. Dimension (layer 20) gives non-plated slots, big holes, and outline.My question is how to ensure those slots that need to be plated are plated. Oshpark gives a good description of how to do it with Eagle as there is no "slot" tool in Eagle. Basically build with layers, use vias, or use an elongated pad and Milling (layer 46) to make the slots that need to be plated. I am considering sending to JLPCB.I wrote customer service, described the Oshpatk method, and asked whether that method would work for them. JLPCB sent a prompt reply. The part I am still not sure about is how to ensure plated slots. Here's the reply I got. The non-plated is clear and typical.QuoteWhat layer? There is no layer per se that I see for doing that. Does that mean to drill at either end and mill in between? What if one wants the narrow ends to have flats too?

author: wraper
author_rank: Unknown
timestamp: March 27, 2020, 09:36:30 pm
content: If you upload gerber files it's simple as if there is copper on top of slot (on copper layers), slot will be plated, otherwise not.

author: jpanhalt
author_rank: Super Contributor
timestamp: March 28, 2020, 02:50:06 am
content: @wraperThank you for the response. I don't see why it is complicated either, but the Oshpark procedure and the comment from JLPCB about plated slots "being on a separate layer" are unclear to me. For example,Oshpark says a plated slot needs an annular ring, but the underlined sentence implies that is not true.Here is the Oshpark procedure:QuoteIf that last sentence is all you have to do, then why won't a simple milled slot with copper on the bottom work? Is the single layer referred to by JLPCB for plated slots also the .GKO layer, the only difference between plated and no plated being copper on the bottom?

author: wraper
author_rank: Unknown
timestamp: March 28, 2020, 12:40:22 pm
content: Annular ring means there must be copper around slot, so exactly what I said.As of separate layer, it just means that slot itself should be on mechanical layer just as non plated slot.

author: wraper
author_rank: Unknown
timestamp: March 28, 2020, 12:45:13 pm
content: Quote from: jpanhalt on March 28, 2020, 02:50:06 amYou need copper on top and bottom.

author: jpanhalt
author_rank: Super Contributor
timestamp: March 31, 2020, 04:46:59 pm
content: I am still wary of sending something off based on the communication I had with JLCPCB. I have been playing with a lot of options in Eagle, including making a device called "slot" that would is similar to a testpad. It is difficult to get Eagle to pour copper over both sides that way.Here are 2 solutions that seem to work:1) Milling onlyLayer build up is:Milling (46)b-Stop(30)Bottom(16)Top(1)t-Stop(29)2) OSHPark build:Layer build up is:Same as MillingAdded 2 vias (18)(Ignore the outline in Document layer)My concern is that absence of an annular ring in the first option will mess up the plating. Apparently, Oshpark developed its own CAM routine to deal with that structure and plate an annular ring. Absence or presence of a small annular ring would not be a big problem, so long as the slot is plated. I have asked JLCPCB about the Oshpark option, and the person replying didn't respond to that part of my question.My question for those who have dealt with JLCPCB, PCBWay, and/or Steeed is will option 1 give a plated through slot? Will there be an annular ring? Finally, if you have ever submitted the Oshpark construction to those vendors, what happened?

author: wraper
author_rank: Unknown
timestamp: March 31, 2020, 05:05:30 pm
content: Quote from: jpanhalt on March 31, 2020, 04:46:59 pmI doubt you understand what annular ring is. It is simply presence of copper around the hole. Nothing to do with with any objects like pads in your software.

author: jpanhalt
author_rank: Super Contributor
timestamp: March 31, 2020, 05:39:25 pm
content: Quote from: wraper on March 31, 2020, 05:05:30 pmWhen I carefully look at a board with plated holes, the plating in holes with annular rings appears more consistent and smother than in holes without such rings.Do you know how to construct a plated slot with an annular ring in Eagle?

author: wraper
author_rank: Unknown
timestamp: March 31, 2020, 06:33:50 pm
content: Quote from: jpanhalt on March 31, 2020, 05:39:25 pmAnnular ring is literally copper around the hole. Nothing to do with rings as such, solder mask or pads inside the software. It's not necessarily round to begin with. Both of your variants have annular ring. When annular ring is mentioned, it's in regard that width of copper around the plated hole should not be narrower than certain value determined by manufacturing technology.