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PCB Manufacturing

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PCB manufacturing consists of many steps, such as PCB CAM, Panelization, Copper patterning, etc. This group is mainly talked about the problems during PCB manufacturing!

Community > Groups > PCB Manufacturing > Etch a single sided PCB
Etch a single sided PCB
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alejandro.rostro

Making a PCB is very simple; it does not consume a lot of time and the results look professional. After reading this How-To and watching the step by step video, you will be able to make your own PCB in your workshop using just a few inexpensive materials.
Many people use protoboard and point-to-point wire everything, but needing multiple copies of the same circuit is the reason that forces many away from using protoboard. After making your first circuit board, you might not point-to-point wire anything again!
For your first circuit board, one goal is to keep the circuit single sided so you can etch using single sided copper clad. This will allow you to gain some experience before moving on to double-sided. If you need topside traces, simply run a few jumper wires on the top. There are many complete circuit layouts you could try like the Hack a Day design challenge winner.
Here is a list of materials you will need to produce a single-sided board. With the exception of the copper clad and PCB drills, everything on this list is easily obtained at your local store.
Materials: Muratic acid, common household hydrogen peroxide, safety goggles, good quality magazine pages (cut to 8×11), laser printer, single sided 1 ounce copper clad, a plastic container the board will fit in, soft plastic brush, clothes iron, lacquer thinner, rubber gloves, paper towel, tin snips, drill or rotary tool, PCB drill bits, Scotch Brite scrubbing pad, good ventilation, 5-gallon plastic pail full of water.
Now, here is how you do it:
Print the bottom side layer on a piece of paper from a high quality magazine. Use one actual page from the magazine, the thicker and shinier the magazine paper the better, but do not use the cover. You must use a laser printer, not an inkjet. If your printer uses ink cartridges and not toner cartridges, it will not work. If you do not have a laser printer, you can work around this by printing to white paper and using a photocopier set to the darkest setting to copy the layout to the magazine paper. If the paper jams in the printer, you are not using a thick-enough magazine page. Again, do not use the magazine covers, as they do not work.
Magazine pages are used because they work well, and they are cheap! The reason they work is because the paper is very glossy and the toner does not adhere well to the glossy pages. The printing used on the magazine page is ink and it does not come off, but toner does. Toner is actually a plastic polymer, and different toners may yield varied results. In our experience, a genuine HP toner cartridge was used with great success; an Office Max brand yielded poor results. The sole purpose of the toner is the protect the copper below it from etching away, you only want the uncovered areas to etch.
Next, wash your hands to remove any oils. Keep handling to a minimum once the pages are printed and do not touch the laser printing with your fingers; this could get oils on the printing. Keep pages as flat as possible.
Very carefully, remove the copper clad from the packaging. Do not touch the copper surface for the same reason as above. You can cut the copper clad to size using a tin snip if needed. Use the Scotch Brite scrubbing pad to gently buff the surface (Scotch Brite is a popular brand of of plastic scrubbing pad meant to emulate steel wool). Do not use steel wool because it will embed steel into the copper. Clean off the residual dust with a slightly damp paper towel.
Find a hard, very flat, sturdy, heat resistant surface. Empty the water out of the clothes iron and set the iron on the hottest setting. Allow the iron to get hot.
This is both side of a piece of copper clad. Place the blank side facing down and copper side facing up. Align printing/paper onto copper clad board with the printing facing the copper. Do not allow it to move.
Firmly press the iron onto the back of the magazine paper, sandwiching it between the copper clad and the iron. Pressing hard without moving the iron, hold the iron perfectly still for one full minute. Do not move the iron at all during this minute, and push hard, really hard!
Then, for four more minutes, slowly move the iron around making sure to put a lot of pressure on the paper, but not allowing the paper to slide on the copper. When done, let the board fully cool before you move it at all. This will allow the toner to adhere to the copper and prevent you from being burned.
Put the board in cold water and let soak for five minutes. After five minutes, try to peel the wet paper from the board leaving only the toner/print from your laser printer. Only the toner should be left adhering to the copper. If the paper does not come off easily, let it soak in the water for a while longer. If necessary, rub with your finger to remove any paper, leaving only the toner. It’s ok if there are a few excess paper fibers stuck to the toner.
If you find not every trace adhered to the copper clad or it is misaligned, use lacquer thinner and paper towel to clean the toner from the copper board and start over. If the traces look good then move on. Inspect the traces carefully, however, because what you see now will be your finished product.
In a well-ventilated area with a fan, add 2-cups hydrogen peroxide to a plastic container. Gently pour in 1-cup Muriatic acid, to create the etching solution. Always wear goggles, gloves, and do not inhale the fumes. Do not use any metal containers, measuring cups, stainless steel sinks, or tools with this mixture as this mixture will aggressively etch metal. Acid safety, think “triple A”, for Always Add the Acid, it’s whatever is in the container that will end up splashing. This etching solution, while made with common chemicals, should command respect. It is dangerous to yourself and surroundings, treat it with respect. Ferric Chloride is another common etching solution, it is not a safer solution to use, both are equally dangerous.
Put the board copper side up in the plastic container filled with etching solution. Use a soft plastic brush to gently wipe the board. You will notice the copper begin to dissolve. It takes about 3-4 minutes to get all the exposed copper dissolved. You just have to watch to make sure it is gone in all areas between the traces. Do not leave the board in the etching mix for too long as the traces will dissolve under the toner that is protecting them.
Wearing rubber gloves, take the board out of t
he etching solution and inspect it to see if all the exposed copper is dissolved. If it’s not, put the board back in and use the plastic brush to brush over this area. If it is dissolved, rinse the board under water for one minute washing it clean. Dry the board with a paper towel.
At this point, the solution is used-up because of all the copper that has been dissolved within it. Dispose of the solution by diluting it in a 5-gallon pail of water. When mixed with the 5-gallon pail of water, the acid level and copper content was well below test limits in the water sample we sent out to be analyzed (restrictions in your area may differ). You may further reduce the amount of copper in the solution by not etching areas of the board that are not required. Consider adding ground planes in large open areas, and using less etchant when making smaller boards.
Use lacquer thinner (paint thinner and acetone do not work well) and a paper towel to remove any toner left on top of the copper traces.
Tinning prevents the copper from oxidizing, which can make it hard to solder to in the future. If you choose, you can tin all the traces with solder and a soldering iron now. This actually makes drilling much easier because it helps to center the drill bit. Make sure to clean off excess flux if you do this. You could use Tinit to chemically plate the copper. Here is a different tutorial describing its use.
Drill all the holes for the through-hole parts using the correct size PCB drill bit and rotary tool. Drill large mounting holes with a normal drill. PCB drill bits are carbide and made to drill through fiber glass that would quickly dull standard bits. There are a few very common sizes of bits and these are often sold in packs. We use .0260″ for IC holes and .0310″ for resistors and caps.
Print out the top side silkscreen layer on magazine paper and iron this onto the top side, using the same processes as above. Again, run under water and peel off the paper. Now you have the component ID’s on the top side.
Here is a different video using essentially the same method:
You can make really nice PCBs of your own circuit design using this simple method, and we look forward to seeing your future projects using this method coming in on the tip line. Look for more How-Tos like this one in the How-To category.
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Statement: This post is only the personal view of the author and does not represent the opinions of ALLPCB.com.

Clement

A great sharing for beginners. Thanks for your efforts and I will follow you and keep reading your posts.

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