* 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.
===Transfer===* First of all, use This layout is printed on standard paper with a fine steel wool laser printer (or copier) and set the toner density to clean your PCB material before transferthe maximum value. Do not touch This will make the surface with your fingers, as they are acid (somewhere between 4black part really dark so the light can not pass trough.5 and 6 pH)
* Put The paper is then drenched in a 'drying' oil (like sunflower seed oil). This will make the printed layout on white parts of the copper boardpaper transparent. Remove the extra oil carefully.
* Set your iron to the max. temperature and apply a lot of pressure without moving (for 2-3 minutes ?)===Exposition===
* Motion Remove the iron around for 5 minutes plastic protection on the boardPCB. Place the printed side of the layout against the copper side of the PCB. Remove the air bubbles captured under the greased paper
(to be continued)Place the PCB & Layout inside the exposure box. Then let the UV light do the work for 2 minutes 30 seconds ''This is a '''completely arbitrary''' timing, we should test different values''
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 ==