Changes
Added sodium persulfate instructions from workshop
* Need an insolation box
* Number of step for the process
== Components ==
* HCl + H2O2 / Acide chlorydrique + Peroxyde d'Hydrogène (eau oxygénée) => [http://hackaday.com/2012/04/30/etching-your-own-boards-really-really-fast/ HCl+H2O2 method on Hackaday]
==Procedure"Toner transfer" PCB etching==There are 3 main steps*Printinghttp://www.riccibitti.com/pcb/pcb.htm*Transfer*ExposureTest print design : [http://www.dr-lex.be/hardware/hwimages/Etchingtoner-design.png]
===Printing=Photoresist PCB Etching==* Print your layout (reversed!) on a glossy support (iMainly inspired from [http://sfprime.e. magazine paper) with a laser printernet/photocopier. Inkjet printers don't workpcb-etching/index.htm]
===Parts===* Cut the paper to the size of the PCBUv light (UV LED strip or DIY UV LED fixture?)* Pre-coated photoresist positive pcb* Lye (NaOH)* Ammonium persulfate (or Ferric Chloride, available at Fixme hackerspace)
===PCB Layout===
The pcb layout should be the positive (black parts are where copper will stay) and *mirrored* image, full size (1:1) of the layout.
Remove the PCB & Layout from the exposure box Remove the the layout paper (if you want to reuse it, you can dry it) ===Development===We use a 1% Lye (Sodium Hydroxide = NaOH) solution for development. (Add 10 grams of Lye to a liter of water) To know if the development process is finished, take a look to the traces. They should be clearly distinguishable. ===Etching=== The etching solution is a 200g/L ammonium persulfate mix (or Ferric Chloride). The etching process can take to over an hour. To speed up this shit, you can add heat and/or bubbles to the solution. The solution should take a blue to deep blue hue. The reaction is (NH_4)_2 S_ 2 O_8 -> CuSO4 + (NH4)_2 SO. The resultant liquid is less harmful than ferric chloride but should still be continuedtreated with other chemical waste == Photoresist etching with Sodium Persulfate ==# Print inversed PCB on two layers of transparencies, and make sure that there is visible text to be able to identify the side later# Place glossy side of transparency on the glass of the UV exposure box, and the matt side (with the toner) face up - you should be able to read the text inverted now# Peel back the protective film from the pre-sensitised PCB, and carefully place it over the transparency# Expose for ~3 minutes (time needs to be experimented with still), with a weight (such as one of the bottles) on the cover for pressure## Whilst the PCB is getting exposed, pour 1cm worth of soda (french: soude) into a container## Prepare another container with just water, to rinse of the soda# Remove PCB from UV exposure box, and place into soda solution. Stir and agitate until the soda and PCB until there are no more violet traces that leave# Remove PCB from soda solution, and rince off with water in other container - use plastic tweezers to handle it# Attach PCB to support wire, and place the PCB into the Sodium Persulfate solution, and wait until you can see the resin (should take ~20 minutes)## Whilst waiting, pour the soda back into its bottle, and rinse the containers# After you can see the resin, remove the PCB before the traces get etched away, and rinse it off# Pour Sodium Persulfate back into its container and clean up (photos to come)
== Safety ==
== Schedule ==
* 13 décembre 2012: First workshop [[http://www.doodle.com/8fyynphtyzyi8ika Doodle ]]
== See Also ==
* [[PCB_Fab]]
* [http://www.engscope.com/pcb-fab-tutorial/ Fairly in depth tutorial]
* [http://nononux.free.fr/index.php?page=elec-brico-outils#!elec-brico-outil-largeur-piste-pcb Outil de calcul de largeur de pistes]
== Participant ==
