It is possible to make good quality circuit boards using laser print outs and transfering them to the copper board (iron, then wetting the laser print and loosening the toner) then etching with Ferric Chloride. If one sticks to 0.030" PCBs then they can be cut using regular scissors. For double sided boards / or single sided with through hole parts, center punch then drill with a dremel on a drill stand or stick to SMT / single sided and solder on wire-wrap wire for bridges.
Be aware that there are some problems with this method, chiefly due to incomplete or light traces. You'll need to check the board carefully after you make it.
Also:
Marion D. Kitchens says:
I have had good results as follows: Using a plastic film intended for the purpose, print a negative image with a laser printer. This will iron onto clean copper nicely of you are careful. I find it works better if I heat the copper board on the iron, and then roll the film sheet onto the moderately hot copper. I use a roller from the photo lab, and roll with light pressure. Too much pressure will smear the toner. I have been able to get copper traces between the 0.10 pins of IC's this way. Good luck...
Lawrence Lile says:
I went round and round with all kinds of iron-on PCB transfers, and other unsatisfactory methods. Started out with a laundry marker drawing PCB's by hand back in the '70's. Do some studying and set yourself up to make photoetched PCB's, you won't regret it.I use Kepro for photoetching supplies. They have a nice tutorial on etching your own board, if you want to save some money. Prices are great. They have a kit called KEPROCLAD, a 4"x6" single sided board with chemicals. I buy them in bulk. They have a nice tutorial on making PCB's
My etcher consists of a 2 gallon plastic laundry tub (for secondary containment) with a 2 quart plastic ice container inside. The ice container holds ferric chloride (it was a handy size - no I don't use it for ice) The whole thing is heated with a hair dryer stuck in the side of the laundry tub (heat to 110 F) and stirred with a little low pressure compressed air line in the bottom of the etch tank (not absolutely neccesary to stir, just makes it go faster). I put it together for about $15, and I can make a board in 20 minutes. It really doesn't take much equipment to make your own PCB, a glass tray and the proper exposure lamp is really all you need.
Tony Nixon says:
I've been using Ferric Chloride for years now and it serves my purposes well. If you look at the method I use at http://www.bubblesoftonline.com/projects/pcb.html, you will find that the solution lasts a long time with excellent results. I've been using the same batch for years. I don't know if it's recylable, but all I know is, when it turns green, it's dead.
Robert A. LaBudde says:
You should be able to regenerate the solution electrolytically by using iron and a copper electrodes. Iron will oxidize from one electrode and copper will plate out on the other. So the copper electrode is the cathode and the iron one is the anode.I would suggest connecting a ammeter in series and increasing the driving voltage up from zero until current starts flowing, then stop. The necessary voltage should only be ~ 1 V.
Too high a voltage and you'll electrolyze the water or hydrochloric acid present. So stop quick if you see any bubbles on the electrodes, and don't breathe any funny colored fumes!
The standard potential for the cell
Fe | FeCl3 | CuCl2 | Cuis -0.78 V, with the driving EMF cathode at the Fe electrode and the anode connected to the Cu electrode.
Unfortunately, it takes a lot of current to plate out the copper. A double-sided, 12-sq.in. board at 1 oz/sq.ft./side contains 4.7 g Cu. Therefore it takes 2.4 amp-hrs of current to plate it out!
Using iron nails as electrodes, you can drive about 0.1 A, so the process would take about 24 hrs for each circuit board. For totally spent etchant (i.e., 200 sq. in. per pint) the process could be up to 15x longer!
Obviously a larger surface electrode is needed to allow more current flow.
But now there's the problem of an efficient, high current, low voltage power supply.
Anyone got any ideas on how to efficiently generate 1 A @ 1 V?
No, but I can generate .997 V @ around 100 A using a Ordinary "Instant On" soldering iron like those sold by Weller or Radio Shack IE a 100 W soldering Iron. Take two HEAVY copper wires, and mount in place of the tip and connect to a 25 Amp or higher bridge rectifier. This should do the trick.+By the way, a double-sided 3" x 4" pcb will use about $.20 of etchant, if you buy in large containers (e.g., 1/2 gal.), so this is more an intellectual exercise than a major cost-saving issue.
Gary says:
I Electro-etch most boards. (Reverse Electroplating) Than just a bit of Ferric Chloride to finish them off at the end as it is impossible to Electro-etch the last little bit. This Reduces my cost to almost Nothing.I am using Old Sulphuric Battery Acid, Deluted 4 to 1 with water! This concentration, as well as spacing between electrodes and plate sizes, All determine current draw at any specific supply voltage! Most Other kinds of Acids may be used, but Sulphuric Acid is quite common. And usually available for Free from places that Recycle Car Batteries as they need to remove it before processing the lead. The Wire Lead soldered to the Circuit Board is an Enamaled Wire. The Enamal and Solder will protect this wire from being etched away!
Here I am Using a Power Supply, current limited to 4 amps, but this is a nominal current. The amount of current will determine how fast the etching goes. But it will also determine how hot the solution gets! Too hot is a problem! Additionally, too much current will result in poor etching. The Collector Plate (NEGATIVE) Electrode I am using is Stainless Steel, Because it stands up better over time! But almost any type of metal plate can be used! The PCB connects to the POSITIVE Wire.
It is useful to determine a good current level for etching with your particular solution. Once you have successfully etched a board, Divide the current by the area in Sq Inches. This will give you a Nominal Operating current "Per Sq Inch" of circuit board. You can now easily and relialably etch any size of board by multiplying its Sq Inches by this figure.
Reverse Plating can continue until most of the copper is removed from the board. As the copper gets etched away to almost nothing, the etching will automatically come to a stop. Once you are at this stage, you can now "Finish" the board in a "Ferric Chloride Solution".
See:
http://www3.telus.net/chemelec/Projects/Etching/Etching.htmAlso: Instead of using the "Tin Solution" to coat your boards, I would suggest you look into an "Electrolysis Nickel Solution". It does a MUCH BETTER JOB and Does Not Oxidize like the tin does. It is also a Good Electrical Conductor and adheres to the solder very well.
Nevr-Dull as a PCB cleaning aid seems to improve toner adhesion and a super clean surface with little effort.
Earl T. Hackett, Jr. says: "Many anti tarnish compounds contain amines that form very strong bonds to copper and often act as a base for adhering other materials. They are commonly used in photoresist compositions to enhance adhesion. Toner may (note I said may) actually stick better to an amine treated surface. Amines are readily removed in acidic etching systems so they shouldn't cause any problems in later processing steps."
Try electrocleaning PCB in say 5% sodium hydroxide, sodium carbonate or caustic dishwashing detergent. Dennis Hayes, during the very early days of Hayes Microsystem's was literally making modems on his dinning room table. He used to tin his boards, populate them with plastic dips and then run them through the dishwashing machine (On cold with NO heated dry...). Then he took them out and dryed them....
See also:
Archive:
Questions:
| file: /techref/pcbetch.htm, 11KB, , updated: 2007/2/20 20:00, local time: 2008/7/9 04:24,
38.103.63.18:LOG IN
|
| ©2008 These pages are served without commercial sponsorship. (No popup ads, etc...).Bandwidth abuse increases hosting cost forcing sponsorship or shutdown. This server aggressively defends against automated copying for any reason including offline viewing, duplication, etc... Please respect this requirement and DO NOT RIP THIS SITE. Questions? Please DO link to this page! Digg it! <A HREF="http://massmind.org/techref/pcbetch.htm"> PCB Etch, PCB Echant, Printed Circuit Board fabrication</A> |
| Did you find what you needed? |
Welcome to massmind.org! |
|
.