homemade pcbLast update: Wed Apr 17 07:02:29 2024
  Making PCB at home is not that hard, and there's many ways to. Here are my experiments with a Laser and results.
👉 Hey! You can also do nice Homemade Solder Stencils to go with it!
Laser engrave masking technique
Principle
Apply a mask to your blank PCB (paint) and remove the part to etch-out with your low-power laser.
Bill of materials
Blank PCB
Can of black paint (mate if possible)
IPA
triple-zero iron wool
Ferric Chloride
gloves, goggles, etc
Procedure
PART 1 : PREPARATION
Take your PCB, rub them thoroughly with iron wool until they shine. Then give them a nice rub-rub with IPA to remove dust and grime. Then don't touch them anymore with your greasy fingers.
Then give them a good layer of canned black paint (the mater the better). And then let it dry, the drier the better so wait a couple days to be on the safest side...
PART 2 : PCB design
Do your design normally, but follow the below rules.
With Cadsoft/Autodesk Eagle 🦅
Limit yourself to single side. The less vias you have the less you'll have to wire on the back.
Vias: default are small, make them bigger (2.5mm)
Signal: make them fat at 1mm minimum
DRC Rules - Clearance: set to 25mil for all the Different signals (all the wire only)
DRC Rules - Sizes: set minimum width at 0.6mm. It's fat but that is a minimum to ensure the wire is still here post etching.
With KiCad 🚀
Limit yourself to single side. The less vias you have the less you'll have to wire on the back.
Vias: default are small, make them bigger (2.5mm)
Signal: make them fat at 1mm minimum
DRC Rules - Clearance: set to 25mil for all the Different signals (all the wire only)
DRC Rules - Sizes: set minimum width at 0.6mm. It's fat but that is a minimum to ensure the wire is still here post etching.
PART 3 : PCB design transfer
With Cadsoft/Autodesk Eagle 🦅
From Eagle export top layer + holes to image in monochrome (600DPI min)
Swap left/right, invert colors if needed: the BLACK is what you will REMOVE/ETCH == the COPPER is WHITE
In Lightburn:
Import the image to Lightburn and adjust the size
Burn settings: 35mm/s at 95% (one pass enough)
With KiCad 🚀
File > Fabrication Outputs > Gerbers (*.gbr) ...
Select the F.Cu or B.Cu (IF YOU PICK BACKGROUND REMEMBER TO FLIP L/R it before transfer) with "Plot on all layers" the Edge.Cuts layer
Generate also the Drills with the bottom button "Generate Drill Files..."
Open the layers in Gerbv, put the copper layer in black, the drills in white, and export to PNG (600 DPI) AND to SVG
In Lightburn:
Import both PNG and SVG: use the SVG (right size) to adjust the size of the PNG, then delete the SVG from the project
Swap left/right, invert colors if needed: the BLACK is what you will REMOVE/ETCH == the COPPER is WHITE
Burn settings: 35mm/s at 95% (one pass enough)
PART 4 : Cleanup
With hot water + soap (important) remove the remaining the burnt paint
Wash GENTLY to not remove the rest of the paint mask
Dry, then clean with some IPA and tissue. Important to ensure a good etching later, so remove all the grim! IPA, soft tissue and elbow grease go a long way.
PART 5 : Etching
Be safe, goggles, gloves, aeration (or do it outside) etc... Ferric Chloride is no joke.
Do not touch the board masking paint: it's not gone but minutes in acid made it easy to rub with your fingers: just touch the sides with non-metallic tools (lesson learnt the hard way).
Use 100% Ferric Chloride (undiluted)
Warm your solution to 40-50 degrees C (bain marie in closed container)
Drop the board inside and with plastic/wood agitators, raise/lower the board to force some fresh solution. Ferric Chloride is quite siruppy and your contribution is needed.
Alternate: put the board in the Ferric Chloride container, put the container in a big bucket of hot water, and rock it on the water. Works quite well, check if finished via transparency.
Depending on size of the board and freshness & temperature of your solution, it might take 10 good minutes or more
When all the copper is gone (check by transparency) then rinse the board thoroughly with water
PART 6: Final Cleanup
Clean with water thoroughly
Remove the remaining mask paint with steel wool and elbow grease (go easy and don't ruin what you etched). Kitchen grime remover or very high grade sandpaper works well too.
Finish cleanup with IPA and clean tissue
PART 7: Drill
Drill the holes for the pads:
Use a 1mm drill bit.
Low torque/high speed setting recommended (to be clear speed rather than torque)
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