As a follow-up: I submitted a board to jlc today – you just upload a zip and it scans all the files, tells you that it is 4-layer, XxX size, etc. After selecting enig, mask color and such, one handy option is to request production approval (I forget exactly how they phrase it) – then they send their massaged gerber files that they will use for production for you to check in gerber viewer and then approve production. This does put your order on hold, but not by much if you watch for their notification email and check/approve right away. They have a similar option if you are getting assembly (which is great to verify chip orientations).
So I found that a new usb-c connector I am trying out (and made a footprint for) was changed in their gerbers to fatten the pads (and leave less clearance between pads, even though my pads had proper clearance and annular-ring). I figure they know what is optimum for their process so no prob, but I did ask them for guidance on tweaking my fp. This is also my first test of slotted holes. I just made standard kicad oval pth slots, though I did point them out with a note on the edge cut layer.
This was my original footprint (0.2mm clearance and 0.15mm ann-ring):
And this is what jlcpcb did to it:
Since they do flying test probe short/open tests for free, I have no problem with them doing this, but I wish they had told me. It should be a quick qc check to scan through their gerbers, but now I need to squint more to see if they changed anything else. I have had this happen with other vendors as well. But I really love jlc – cheaper and faster than pcbway or myro and a tenth of the cost of a excruciatingly-long 4-week turn at advanced circuits here in the US.
Speaking of adding extra stuff on edge cuts for fab (v-score, slots…) which breaks kicad drc and 3d view, is there a way to put the extra stuff on a user layer, and merge edge cuts with that user layer to create the .gm1 gerber?
Here is what jlc says about it:
"Please kindly make sure that the v-cut lines, cut outs, millings and slots are in the same layer with the board outline. If it is not in the same layer with the board outline, it will be missed. So please kindly check it before you place your order.If it is missed due to they are not in the same layer with the board outline, we will not responsible for it.(If the slots are to be plated, it needs to be with the drill holes in the same layer, or it will be missed easily)."