Dry Film Solder Mask

This Instructable is about dry film solder mask, in other words, is the green stuff that is on top of the circuit board.
I like to use smd components in my circuits board because I don't have a computerized drill machine and do in it by hand for a big
boards are really tedious.

Soldering smd components in a copper board without dry solder mask, especially for those little capacitors and resistor of 402 in size, becomes a tough challenge and of course those micro controllers with almost zero space between pins.

So I decided to use the UV curable Ink, sounded very good on those ebay stores with before and after pictures.
I bought a couples of syringes with a success of just one time,  0.1% of my tires worked with a pretty ugly board with an uneven surface an the pads and vias where not square are rounded. 

The Ink sometimes cured, other times it didn't.  Applying the art work is somehow complicated because you have to put it over a wet paint unless you find this miracle tape that is sold in the shipping supplies that is glossy on one side and barely stick to the paint, but not always.

What is for sure is that you are going to get messy and the ink is nothing easy to take out of your hands.

I did a little more research in the web and I found this dry film solder mask,  at least is dry meaning no mess and easy to handle.
I tried and worked wonderfully, no mess, easy, fast and your board looks almost comparable with the professional ones.

to buy the film you can go to my ebay page at this location:

http://www.ebay.com/itm/Dry-Film-Solder-Mask-5-sheets-of-12-x-8-5-in-/150921619738?pt=LH_DefaultDomain_0&hash=item2323a1291a

You can check out these two videos from Youtube:

http://www.youtube.com/watch?v=SDIycwAghL4

http://www.youtube.com/watch?v=VNYIVZgbi9M&feature=related

For making the printed circuit board go to my new instructable here

https://www.instructables.com/id/Dry-Film-Photopolymer-for-making-circuit-boards/

Step 1: Materials

These are the material to make it work;

Laminator:  I use this GBC HeatSeal H220 Quickstart Pouch Laminator is kind of expensive, like $86 bucks, but I am pretty sure you can use the iron to do it, the same procedure that is used for the toner transfer method  Just make sure to put something between the iron and the film, like a rag or a piece of paper and don't over burn it.

One thing that I found is that don't iron your copper clad over a cold surface even though your copper clad gets hot the toner and the dry film does not stick good.
One time I was ironing my art work over my kitchen counter top that is granite and it was kind of cold and the toner never transfered correctly to the copper clad. The first time that I tried the toner transfer method and worked successfully was when I was ironing over a piece of wood. The same applies to the dry film solder mask.

UV light source.  What I use is a 36 Watts UV nail lamp,  $28 bucks on ebay.

Sodium Carbonate:  What is that?  Soda ash or Washing soda.   Go to your near big box store and buy for $7 bucks, in the pool section, the thing that says PH increaser (soda ash),  don't buy sodium bicarbonate is Sodium Carbonate and is powder not liquid.

And finally you need a tray and a brush, (tooth brush is ok).

Step 2: Laminating

The procedure is simple.


First we start with your already etched and cleaned board.  No grease or any kind of contaminant on the board.

Cut a piece of dry film a little bigger than your board.
The film comes with two transparent protective films one on each side.
One side is glossy and the other is dull.  With the help of two pieces of tape, figure 2, remove the transparent protective film on the dull side.
Adhere the edge of the film to the edge of the board and then run it through the laminator  3 or 4 times or iron it until sticks good.  Avoid air bubbles and wrinkles they don't look good.

Let it cool for 1 minute.

Step 3: Exposure

Cover the board with the artwork matching vias and pads.
Expose the board to the Uv light for about 1 minute.
Take it out and leave it rest for 5 minutes.

Step 4: Development

After 5 minutes remove the second protective film with the help of a tape.
Prepare a solution of 10 grams of sodium carbonate on one liter of water. Actually you are going to use less so you can do 5 grams on half liter of water or less.
Sink the board in the solution and gently start scrubbing with the brush until all pads and vias are exposed.
Increase the rubbing pressure for those vias and pads that are a little difficult to remove.
Rinse with water and remove the left overs that are hanging out on the board edges.

Step 5: Curing

Wipe the board with a rag and let it dry.
Expose it again to the UV light for at least 30 minutes for complete cure of the solder mask.
And that's it.  You have a perfect board with solder mask like the professionals.
Just stuff your board with the components and your circuit board is ready!!!

Thanks for watching
Hope this would be helpful!!!

Comments

[kprasad6]

This is image of my pcb which i made at my home
The desihn is made in cadsoft eagle professional.The pcb is made with toner transfer qnd then the solder mask and silk screen is applied through screen printing.I used these stuffs for solder masking and silk screen.The final pcb looks very professional and i an very happy with these results.The screen printing i know is a very laborious process but i can't find other stuffs in my city like uv crucable ink or something like that of a stuffing agent.So i have to go through the process which i find best in my city.I applied the anti solder ink to both the sides of my pcb to improve it's looking.The silk screen is done with a PVC white ink through screen printing.

[hysamrashed]

This is the best way very good

[DougA3]

I'm a bit late in commenting, but if it will help anyone, I have some tips.

First, the nail lamps are completely inadequate for either pc boards or this solder mask. What DOES work, is a 3W UV LED with output at 400nM. It is right at the sweet spot of sensitivity for dry films like this. My exposure time went from minutes to 10 SECONDS after switching to the LEDs. They are under a dollar US each on ebay. I use a 20 LED array at about 500mA per lamp, but fewer will work fine.

Second, the board MUST be cleaned with a proper abrasive. NEVER sandpaper or steel wool. Most PCB manufacturers recommend powdered pumice.

Third, the board must be DRY, DRY, DRY. Even the mask spec sheet says dry the board first with heat, as the water will vaporize in the laminator and make bubbles.

Fourth, most stock laminators are way too hot. I built an external controller for mine so that the temperature is adjustable. Just under 100C is best, as it won't boil any water that is present.

Good luck to all!

[ramparts]

i used ebay dynamak but results were terrible .

One thing that they say is that needed to be heated to 40 degrees,the revelation worked but the mask gets all wrinkled and looks awfull

Does it really need to be heated?

One other thing is the time exposure and the dark light envoyerment rest time.

What do you recomend 1 minute?10 seconds ,40 seconds?

I use a cheap 1 lamp nail uv

Best Regards

JOSÉ

[GenesisMaster]

"Hope this would be helpful!!!"
It is indeed, because we can protect the traces of our PCBs with this method. But I would like to know if we can add a silkscreen to the PCB with the same method WITHOUT damaging it?

[Whiternoise]

I bought some of this a while ago and while the result looked cosmetically perfect, when it came to soldering it was easily damaged by the tip of the iron (only a 12W job). I'm guessing I didn't cure for long enough, but any input would be useful.

Cheers, Josh

[fred27]

I just tried a second board with even better results. I even managed to etch away some text in the solder mask layer.

I included the final step in the manufacturer's instructions - heat for 60 minutes at 150C. I didn't notice any smell so I think it should be OK to do in the oven without poisoning anybody or making your wife angry.

[fred27]

Thanks for a great Instructable. I just made my first solder masked board and it turned out great. (The photo taken on my phone in poor light doesn't do it justice.)

It was a CNC milled through hole board so a had little more "contour" on the surface than yours. I found that passing the mask through the laminator once cold and then once again on the lowest heat setting worked best. Too much heat and pressure caused the mask to be a bit thin over some tracks.

I also only used 2 bulbs in the UV nail lamp. I took out the side two to decrease the chance of light creeping under the transparency. It still seemed bright enough and worked well.

[cpeniche]

Looks great. I am going to try to run it first on cold and then with less heat. I noticed as well that with too much heat you get a thinner mask. I will publish the exact process parameters that are recommended in the specifications for those guys that can control the heat and pressure of their laminators or the intensity of their uv lamp.
I remember also that after curing the mask for at least 30 minutes with the UV light they recommend to heat it in an oven but I don't have here right now with me the exact temperature and time. But what I remember is that the oven shouldn't be used again to cook food because the solder mask expells fumes.

Great job and I am glad that you liked the product!!!

I also offer the dry film photopolymer in case you need to go with thinner vias and more complicated circuits that are difficult to route with cnc machines. I have a instructable for this product as well here, just search for dry film photopolymer.

[raypsi]

This may seem lame, can you etch a board using this stuff will it survive ferric chloride solution? and what is the resolution how small of a via could you make?
I got a teflon sheet for T shirt transfers to use with an Iron.

[cpeniche]

You can etch the board with this film and of course will survive the ferric chloride. BUT your are going to have a very hard time trying to remove it. This stuff is made to last and stay there forever. To remove it you have to use a stripper solution. I don't know how the solution is made but I think this is not something easy to find in the stores.

[raypsi]

Thanks I'll be getting sum next week, I got an electric palm sander with aluminum oxide sand paper and then wet sandpaper to make it smooth once I get down to the copper, Then use a halogen chop light with the uv filter removed to expose it.
I remember how to make sodium bicarbonate into sodium carbonate, on a cookie sheet in the oven at 400 degrees F for 30 minutes.

[cpeniche]

Hi

Know I am showing here in the instructable how to use the dry film phtotopolymer that is designed for etching circuit boards. I think with this photopolymer you can go up to 40 micrometer of resolution and is very easy to use.

Search for dry film photopolymer for making circuit boards.

Hope you like it

[lookwhatjoeysmaking]

now all you need is to add silk screen

[TOAST2218]

I work at a shop that makes circutboards, and silk screening is the way to go. If you want to mass produce the boards, otherwise this is a great and inventive consumers way of doing this.

[tronicgr]

Maybe you can print on this film the silkscreen layer and stick it on the top... but what can you use for white ink?

[cpeniche]

For the silk screen let me do an experiment. I will print the components layout on the board using the toner transfer method and on top I will apply the film. The film is green but may be transparent enough to see through .

What I am sure is that the toner doesn't stick to the film, I already tried and it didn't work.

[offtherails2010]

AWESOME & FINALLY us home-brewers can have professional looking PCB's too !!!

VERY NICE FIND !!!

One Quick Question though...

Was the artwork matching vias and pads printed on what looks like transparency media ? Or Tracing Paper ? Or Something else ?!!!!?

[cpeniche]

Is a transparency. You need the UV light harden the paper except for the vias and pads that later are going to be remove with the help of the sodium carbonate.

[offtherails2010]

thats great - thanks !!!!

very nice & clear photo's, im already hooked !!!

but would you do bulk discounts on this Dynamask ???