Hey, I’m wondering how are you dealing with the order number print when ordering from jlcpcb. Is it printed on the back side, or the front side by default? Is it even worth removing it for circa 2€?
Ouch. I’m going to put that on the back side then.
Or get a black Sharpie. …
That’s for sure, but better not to use it, right…
Personally I ask them to put it inside a box I draw on the silkscreen:
This way I can hide it behind a component!
So, is aluminum any stiffer than FR4?
I ran a comparison by taking two 10 cm wide panels, one Al and one FR4 (both fabricated by JLCPCB), and putting each up on a couple of blocks with a weight in the center; then I took pictures. Granted this was not a very precisely controlled experiment, and in particular the two panels were not the same design with the same holes. But I think it’s enough to tell me the two are not very different in stiffness.
One other difference is the FR4 panel has copper pours on both sides while the Al panel has no pours. I’d be surprised if that makes a big difference but am prepared to be shown my guess is wrong.
The photos of the panels under the deflection test remind me of being at college and learning structural mechanics. The deflection looks small in both cases, however, most of the stiffness of a module is gained when connecting the panel to the pots and jacks that are soldered to the main PCB, This forms a truss-like structure with the stiffness being governed by the connections to the PCB and panel.
Now it would be interesting to see the same test as above when the modules are constructed, maybe with photos taken before and after the load is applied so the change in deflection can be seen.
Adding broad washers to jacks and pots; either top, bottom or both can be very effective in reducing any deformation as does using a plate of rigid rectangular plastic in place of a washer to match the bend to the panel shape. Alternatively if you offset the stiff plastic with standoffs you can make a very rigid structure. Like stacked boards.
Has anyone ever tried this type of stitching around a mounting hole with JLC? I’ve seen it on a few commercial PCBs. The idea is that by adding vias, the pad is more strongly bound to the board, and is more resistant to stripping from torque applied to it.
 just to add, I’ve never had a pad strip. I think you’d be doing something quite wrong if it does. But still, could be a nice little feature.
i havent, but the idea seems sound. Be sure to check 2x the tolerances so they dont reject the design.
These seem pretty common on the first few boards I pulled out my scrap box. I doubt JLC will have an issue with that, vias can go really close to the edge.