[REQ] PCB by LASER

[Ichan]

Hi Dreamcat,

I have a method for transfering the toner to copper without using any heat, I use "pain relief rubbing oil" as in the picture attached - i believe you can find similar thing in your place. I use photoresist for making pcb now, but this is the way I always do in the past.

Basically it is a solvent to the toner but evaporate very slowly, maybe a mixture of mineral oil + a little turpentine oil will do but haven't tried it.

Here is the steps:
- moist the copper surface with the oil using your finger or tissue, do not put too much oil - just moist.
- lay down the paper with toner to the oiled copper surface carefully, make it flat.
- wet your finger with water and press the paper gently from the back little by little using your wet finger until all the paper looks "transparent"
- the toner will be stick to the copper, and the paper start to soak.
- depend on the paper used, remove it by using plenty of water.

And for the paper, you can make your own transfer paper by coating an ordinary "photocopy paper" with PVA (Poly Vinyl Alcohol) solution, also Dextrin coated paper will work too.

-ichan

[DreamCat]

I has been make 5mil width wire use toner paper some times. really!
but it depend on the quality of toner, and 5mil width copper is too easy peeling.

Dear Ichan , I will try to use lubricating oil do it next time.

[Ichan]

Hi Dreamcat you should try it, on my experience success rate is a lot better than ironing. Ironing method will depend very much on the cleanliness of the copper substrate and the flatness of the pcb + iron.

-ichan

[DreamCat]

I'm thinking which kind of solvent can dissolve the colloid of toner so that toner could be completely spalling.

[Ichan]

Just go to a grocery and buy some rubbing oil 

I'll ask someone here to make video of it, give me several days.

-ichan

[carbontracks]

If you have the money to shell out for a CNC laser setup, then you might as well get an ultraviolet exposure setup.  This is what we do at my work for quick prototypes.  You start out with copper board with photoresist already coating both sides (can be bought many places), then you make masks using overhead transparencies and a standard printer.  Put the masks over the copper board, then do a 40 second UV exposure.  Take it out and rinse it with dilute NaOH for a minute to remove the unexposed photoresist.  Then you're ready to etch with whatever method you want.  After etching, wash off the leftover photoresist with methanol.  When I do this the whole process generally takes about a half hour for a double sided board (drilling holes and vias is another story...).  I've gone down to 12mil traces comfortably with this method.  Could probably push it to 10mil, but I don't see the need.

Not sure what UV exposure tables cost new or surplus, but I can't imagine it being as much as a laser cutter.  And it would be much easier to DIY.

[sgoum]

I have made my own UV exposure table using 4 uv lamps like this http://www.xoxide.com/colcatblac.html and using an old scanner as a case. Its very cheap and works like a pro.

[Ichan]

Hi,

Here is the video of toner transfer without using any heat: http://ifile.it/jewx8ly/TonerTransfer.mp4 (2.31MB).

The video duration is about 1 minute in 4x real time speed, so the actual process is about 4 minutes not including the Ferric Chloride etching process.

Better and easier than ironing... 

-ichan

[DreamCat]

Thanks Ichan, it seems very nice. which kind paper were you used for it?

anyone know which other solvent can be used as alternative? I can't buy it.

[Parmin]

Ichan
That is the damnest easy technique!
Definitely worth a try!   I will go out and buy some of the oil thingy from nearby $2 shop NOW!
Thanks for sharing this!.

[iphone]

Hi Dreamcat,

 I use photoresist for making pcb now, but this is the way I always do in the past.

-ichan

What is the diffrent between those 2 (in term a result) ?

[Vague]

I have been using the laser transfer for a while now. I have found the best paper to use is the shiny paper left after you have removed sticky labels from a sheet of stick labels.
Once you have ironed it the paper just lifts off no need to soak. You can even use this more than once.  I think this might work really well with Ichans method, since the toner doesn't stick to the paper very firmly

Posted on: 01 October 2010, 10:09:31 - Automerged
I have just looked up the composition of rubbing oil. It consists of eucalyptus oil,  camphor, and methyl salicylate. I guess the main solvent is the eucalyptus oil

[Ichan]

Dreamcat, the paper used is home made Dextrin coated paper.

http://en.wikipedia.org/wiki/Dextrin

Mix Dextrin with water to make a viscous liquid (semi paste) then ask other people to screen print it into 80gr photocopy paper. PVA will work too but it tend to foamy when screen printed, maybe hand bar coater will work with PVA. Most commercial water based transfer paper is PVA coated paper.

What is the diffrent between those 2 (in term a result) ?

In term of result, photoresist will give the best accuracy and sharpest edge.
Toner transfer quality will be limited by the quality of the laser printer print out, while photoresist method need good quality masking film which make it difficult for DIY.

I guess the main solvent is the eucalyptus oil

Probably. I just buy a new one to get the packaging, here is the ingredient written:

- Menthol Crystals 20%
- Eucalyptus oil 15%
- Methyl Sallicylate 15%
- Camphor 5%
- Essential Oil 12%
- Base to 100%

Seeking the web using english keyword make me know that it is actually product of singapore:

http://www.axebrand.com.sg/product.html


-ichan

[Altair]

I originally started making my own printed circuit boards right out of High School in 1972. I used pre-stick pads and line tape applied to clear plastic film which was then used to make an Orange Color Key negative. A board was sprayed with photo-resist from GC Electronics, then KPR was used to develop the board after exposure from a 150 watt ultraviolet 'food warming' light. From there the board went into the plastic etch tank that was heated with a fish tank warmer.  Etching would usually take around 20 minutes. 

Fast forward about 38 years and I find myself setting-up a small circuit board manufacturing operation for prototyping control circuits for a Store Fixture Company I work for.  I heard they needed to fabricate a prototype circuit board in advance of producing 1000 store displays used to sell LED light strips.  Nobody in our company of 250 employees (other than me) had ever done anything like this before so I was nominated.  I actually expected that I could get us set-up within a couple of days but I soon found out that you can't easily get many of the essential materials anymore, such as Kodak Orange Color Key.  Google brought me most of the answers I needed so I was off and running. 

One very cool alternative to the standard etching tank that I found was the use of plastic Ziploc bags and a roller.  Here is where I found the source of this technique:
http://www.pulsarprofx.com/pcbfx/main_site/pages/tech_support/no_etching_tank/no_etching_tank.html

Pulsar's Technique #2: "Brayer" has proven to be the best alternative and produces absolutely no mess at all!  I had a little trouble finding the Brayer roller (locally) but I finally found one at an art supply store. By the way, despite what the Pulsar article says, you will NOT find the Brayer Roller at Michaels.  I purchased a couple of photographic chemical trays from a local photography supply company and cut a piece of 1/8" acrylic plastic to lay in the bottom of my new chemical tray.  The purpose of the plastic is to provide a completely flat surface in the bottom of the tray to use to support the circuit board inside of the bag.  These trays have deep channels molded into the bottom, which, if your circuit board is small, can allow the corners to dip down and potentially cut through the Ziploc bag(s).  I was able to etch a 2" x 3" double sided board in less that 3 minutes, using cold ferric chloride!  I have now etched 10 boards with the same original volume of acid and so far no sign of slowing down.  With this method, my small supply of acid will last FAR longer than when I used my old large tank.

[hunter07]

Hey,
Could you re upload the file(tonertransfer.mp4)
thank you..

[Ichan]

Unfortunately i don't have the file anymore, searched the hd and backup cd's - nothing found, i am sorry about that. Looks like i delete the entire video editing directory not long after i upload it.

Perhaps someone still have it?

-ichan

[blip]

Hi everybody.

I'd like to add some info to this topic. Here is a blog where I describe how I adapted a ShapeOko2 CNC to use a 0.5W 808nm laser diode (from EBay) and make PCBs. You may find some of the information useful.

http://gabuleu.blogspot.com

[Ichan]

How is the result of lasered painted pcb on your website etched? Does it etched good?

-ichan

[blip]

I haven't tried to etch yet. I'm still fine tuning everything, including the workflow from Eagle to GERBER to GCode. I'll post my results here. I'm also trying to find a cheap solution for a 5W laser, like the one from OptLaser that can be found here: http://optlasers.com/en/41-cnc-modules

[optikon]

I haven't tried to etch yet. I'm still fine tuning everything, including the workflow from Eagle to GERBER to GCode. I'll post my results here. I'm also trying to find a cheap solution for a 5W laser, like the one from OptLaser that can be found here: http://optlasers.com/en/41-cnc-modules

Surely with all that money invested you would have a goal or some estimate of performance vs low cost (professional) PCB fab these days.

[blip]

I've posted my first etching attempts to my blog:

http://gabuleu.blogspot.com

They were done with a solution of H202+white vinegar+kitchen salt described here:

http://www.instructables.com/id/Is-the-best-PCB-etchant-in-every-kitchen-/

Macroscopically they look good, but microscopically they still lack quality.

My goal is to be able to make prototypes easily and quickly at home. If possible, by using different materials and techniques. Maybe I'm spending too much money (less than 2kUSD) or time on that, but I believe the flexibility pays.

I have updated the blog with some videos and pictures.

I appreciate your feedback.

Best regards!

[solutions]

Etch with an isolation milling pattern is not a good idea

Why are you patterning with vector instead of raster?

[Ichan]

Lasering a paint coated pcb is my current method for a quick pcb prototyping, some things i found important:

- the paint must be very very dry, spray very thin paint 3 times, make sure the paint completely dry on each.
- sand the copper surface by a fine sand paper before painting (grit #800 or finer)
- lasered surface will have some paint residue left which can be difficult to be etched
- to remove the residue wet rub it with abrasive detergent like VIM or similar using finger or a hard sponge
- fresh warm ferric chloride is perfect as it doesn't generate bubbles while etching like the acid base etchant

Show your next experiment please.

I myself prefer vector isolation (2 or 3 vector overlap) than raster as it is much faster and cleaner edge, for generating isolation milling path i like to use Sprint Layout.

-ichan

[blip]

Hi! Thanks for your comments. I'll try to do a better spray painting. I was not investing too much in it because I was focusing my efforts on the laser etching. Now that it is done, I'll review the other steps.

I tried many ways of transferring the PCB pattern to GCODE. My first tries were to export a GERBER from Eagle and then transform it to PNG using Gerbv. Finally I would load the PNG to MeshCAM and generate de GCode with very well defined parameters. I was taking a long time and the process was confusing MeshCAM because of the PNG input. I was getting pixelated output, full of strange track borders.

Now I'm generating the insulation pattern using PCB-GCode, directly from Eagle. This is a ULP script that does a nice job, transforming a vector layout directly into GCode. This is the easiest process I found until now.

But I'm looking for a substrate that can be laser etched, so I can etch the tracks into it, drill the holes with the laser and, after that, deposit copper using simple chemical methods. If this works, the result will have the vias already covered with copper, dispensing other steps in the production. As a substrate, I was thinking of using wax, but I could find no wax that absorbs 808nm. Maybe with UV it is easier, but 150mW of UV does nothing to the substrates I tested.

I may buy and install a 5W laser head from OPTLasers. They have a nice product for 500 dollars, with analog modulation and emission in 445 nm. But I prefer to spend this money after I have tried all the cheaper options.

Thanks for your comments. This is a nice forum.

Posted on: December 29, 2015, 10:49:35 22:49 - Automerged
It could be also possible to etch the tracks on the paint using laser and deposit something over them to protect them from chemical etching. The next step would be to remove the paint from the rest of the board using solvent and insert it into a chemical etching bath. 

Anyway, the greatest prize for me would be to end the process with copper plated holes.

[Ichan]

I just see your youtube video, it is a very slow process.

What i use for this is a china made laser cutting machine with 80W glass tube, it can do isolation path vectors in 40 mm/s speed.

I ever tried lasering the pcb copper surface using 20W fiber laser, once it can go through it the underlying epoxy substrate charred badly.

What kind of laser source which is 5W you mentioned?

-ichan