Sunday, April 12, 2020

Using PCB material for a Front Panel: I said it wouldn't work, and I have no idea why I said this. It works.

Before all this bizarre and tragic COVID hibernation stuff began, I was at a local geeky synth meetup discussing (of course) DIY front panels, going through my usual diatribe about using PCBWAY "alubase" material to provide my inexpensive metalwork. I was pretty damn proud of myself. But then! one of the much smarter members told me that's stupid--and expensive--why not just use PCB material for this? Much cheaper! Much Easier! Mo Better!

I said, well you can't because--because.....because??

Turns out there is no because!! Of course, PCB material works great for front panels.

Yeh, and any PCB fab shop can make these. You already have the board layout right?  Just throw another gerber in there in the same run for the front panel. Viola.

So who came up with this DIY breakthrough? No idea, but the Meetup tech I was talking to was turned onto using PCB material for front panels because LMNC uses it in his VCO kit (oh no!!).

So it must work, right?

All Hail this dude?

Let's motorize this pursuit! Using Eagle CAD, I created a front panel design for a NOISE! board from Reverselandfill that, after many PCB level repairs to fix some of traces I savagely busted, worked again. It desperately needed a front panel--Orig. post about this module is here.

Creating the new raw front panel was easy--I measured the board, created a quickee PCB with just the dimensions and drills (and nothing else), created a gerber, and off it went to JLCPCB along with some other "real" PCB layouts.

You can try adding Gerberized silkscreens for the legends, but for this project I didn't do that. I used Mr. Label instead (blog post about Mr. Label is here--1001 uses?)  Yeh, I get all graphics and fonts etc. I can dream up and are easily printed out on my super cheap laser printer.

Mr Label ready to apply

Say What? JLCPBC didn't process the order right away (it was "Under review" for at least a couple of days) They figured that I forgot to put traces and a soldermask in the gerber and didn't want me to go wah-wah. But I emailed them again: this was for a front panel! And after they pretty quickly gave me the thumbs up. So I paid 'em and waited.

The PCB for "front panel only" showed up in Sunny N. California about 6 days later. After a serious amount of Howard Hughes ready Covid scrub downs I was ready to work.

So what: a few things about this--first, the PCB material is more brittle than aluminum, and if you crack the panel you probably have to start over, so best you can, make sure you get the layout right or close to right the first time.

Second, you might need a large metal file (I did anyway) to file away excess material, for me, it appeared that the panel shipped back to me was maybe 1mm-2mm off on one side. But it was pretty easy to file the PCB stuff down to size.

Third, color issues? since I was working with a black background in Illustrator, I used black PCB material. This turned out to be a good thing, because even though the Mr. Label didn't quite fit  (I put his jock strap on crooked?) the colors matched and everything looked good. I also found that black sharpee matches the flat black color of JLCPBCs black panels pretty well. I have used that in the past to cover up minor mistakes.

Fourth, you can move around the holes if you want! If you have a preexisting PCB front panel that's not quite right try this: put some tape on the back of the hole you want moved.  Then: fill the hole with JBweld. JBW sticks to PCB material like...glue? Next: after the jbweld cures, file things do so the hole is filled but flush. Drill out new holes if needed--you can drill small holes and then go at them with a hand held T handled reamer, a great tool for enlarging holes in PCB material. Finally: Paint or cover.

Right: original PCB.  Left: new holes for pots.

Here's an early attempt w/ PCB and Mr Label:

While I was at it, I created a better Mr. Label for one of the modules from my CEM VCO project, to replace the one that burned up rel good:

Look Mum, No Covid?  Damn I hope so. I will be using a lot more PCB material for front panels in the near future. If there's a reason to get back to aluminum I'll do that, but for now, PCB works and I'm happily taking in the fumes. You should do the same, but not the Corona Kind, rather, the good kind. Stay safe!

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