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I tried an experiment making a "scribe nozzle" for my Ender 3 FDM printer.? Raw pcb stock coated with Dykem layout fluid/laquer was scribed, then etched in Ferric Chloride.? This was mostly a resolution test and I think it can out rather well.? Here is a link to some photos of the project:?

I welcome discussion/questions!

Is that spring loaded, or do you just rely on the flatness of the PCB and accuracy of the 3D printer?

I noticed the lines look slightly wobbly. How securely is the scribe held in there? Press fit? Glued or soldered in?

--
Steven Greenfield AE7HD

Some elasticity from a drop of RTV silicone behind the scribe in the nozzle, but it _does_ require accurate bed leveling.? I actually dulled the scribe point with a diamond hone down to about 0.003" to avoid cutting the copper, which _did_ cause too much drag.? I'm using a BLTouch sensor and 16 point M29 command with a flat glass plate on the bed.?
The scribe to nozzle bore fit is +0.002", slide fit.? Not sure what you are referring to as "wobbly".? This surface mount board shows pretty fine detail:??(note the scale).

Let me know if I be of any further assistance!

73,
Brent, AB1LF

This is really exciting to see! I documented my approach to a similar technique some years ago, and would love to compare notes:?

Wow Matt!

My little experiment pales by comparison!? That is some serious work.? To be honest, I mostly did mine to see if it would work.? No drilling, just a couple of single layer surface mount boards

There were really only a couple of things that caused me fits:

- I drilled the of-the-shelf brass nozzle just far enough from the back end to keep the scribe from falling through.? Took two tries.
- I really wanted a small spring to put behind the engraver tip, but couldn't find one at the time, so I used the RTV in the back of the hole.? Made the flatness more critical.? Some time later I found that the flint spring from a disposable lighter would be much better.
- The carbide point on the engraver was too sharp!? I was scribing through the copper at first.? That wouldn't seem like a problem except that the extra drag ruined the line resolution and accuracy.? Dulled it a bit on a diamond lap.

Again, my admiration and congratulations on the great work you did!

Take care sir,
Brent

Hey Brent, sorry for the slow reply. Thanks for all your compliments! Some initial thoughts from my experience with the scriber, and the pressure issues you've faced:

I ended up using a spring from a ball-point pen behind the scriber tip. That lets it have a range of gentle pressure, and the amount of pressure is adjusted by moving an optical endstop. It really doesn't take much to scratch off the paint, and the less you use the less the tip drags and goes out of alignment. You can also make much faster paths, which allows more concentric laps around each area without increasing the "print" time too much.

The spring-backed scriber raised the challenge of letting the scriber move up and down freely while staying aligned. That's what the odd assembly with 4 (actually 6) bearings allows to happen. There must be a simpler solution, but that's what I came up with.

I don't know if any of that is helpful for your setup, or if any of that could be adapted. I would love to follow your progress on this, so, even though I took a while to reply, I hope you keep updating us!