Author Topic: Best printer for toner transfer  (Read 6088 times)

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Online SilverSolder

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Re: Best printer for toner transfer
« Reply #25 on: June 02, 2020, 02:28:21 pm »

[...]

"Large black area" for me is about 20mm x 20mm square.

[...]


I don't think that would be a problem on my printer, which prints VERY dark and rich on smaller areas.  I'll try it later on today just for fun, let's see what we get!

 

Offline RoGeorge

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Re: Best printer for toner transfer
« Reply #26 on: June 02, 2020, 03:27:56 pm »
Eco printing (toner saver) mode enabled or disabled? Draft or high quality mode?

The idea is to convince the printer to use as much toner as possible, so enough toner will end up on the PCB.

For that, disable any "eco friendly", any "toner saver", any "grey dithering", and any "draft" settings.  Use "high quality", "high contrast" or "presentation" settings.  If manual adjustment is allowed, make the printer to pour more toner.

Offline moffy

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Re: Best printer for toner transfer
« Reply #27 on: June 03, 2020, 02:05:47 am »
Has anyone tried a Kyocera printer for toner transfer?
 

Offline tooki

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Re: Best printer for toner transfer
« Reply #28 on: June 03, 2020, 06:32:08 am »
making a professionnal pcb is so cheap today that I don't bother anymore with making my pcb at home.
not speaking of the disposal of chemical acids.
I would better invest in a small cnc to make small pcb quickly by milling, but not a toner transfert method.
Absolutely not. PCB milling is a pain in the ass.

The toner transfer method works great if done properly. This means buying real toner transfer paper, not old catalog pages, using a proper laminator, not a freaking clothes iron, and real etchant, not witches brews of acids and peroxide. Done that way, I can consistently etch clean 10 mil (0.25mm) traces, and probably thinner, I just haven’t tried yet.

At some point, I do wanna try the acetone vapor approach to improving density of large fills. They also make solvent sprays specifically for this purpose.
 
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Online SilverSolder

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Re: Best printer for toner transfer
« Reply #29 on: June 03, 2020, 05:55:41 pm »
making a professionnal pcb is so cheap today that I don't bother anymore with making my pcb at home.
not speaking of the disposal of chemical acids.
I would better invest in a small cnc to make small pcb quickly by milling, but not a toner transfert method.
Absolutely not. PCB milling is a pain in the ass.

The toner transfer method works great if done properly. This means buying real toner transfer paper, not old catalog pages, using a proper laminator, not a freaking clothes iron, and real etchant, not witches brews of acids and peroxide. Done that way, I can consistently etch clean 10 mil (0.25mm) traces, and probably thinner, I just haven’t tried yet.

At some point, I do wanna try the acetone vapor approach to improving density of large fills. They also make solvent sprays specifically for this purpose.

I found that the toner spray idea did make the toner smoother and more even,  but was unable to make up for there not being enough toner present on large black areas in the first place.

 

Offline KL27x

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Re: Best printer for toner transfer
« Reply #30 on: June 03, 2020, 08:54:43 pm »
The printer isn't that important, it's the toner which matters. Some types of toner work great, some are ok, and others don't work at all. In some cases an alternative toner cartridge can be better than a genuine one. And if you found the right one, the vendor could change the toner type in a few years, but that's less likely for genuine toner cartridges.
Like Moffy, I had one of the few cheap Brother printers which did not work for toner transfer. I think most of their printers are the same flavor of vanilla as all the others, but there are/were a few with a higher melting point toner.

Dumping/refilling a cartridge with generic toner powder worked for a pretty long time.* But the toner did cumulative damage to the printer. The print quality degraded over time, until the printer was useless. Swapping back to normal Brother toner didn't fix it, so I guessed it was the drum, at the time. You could buy replacement drums for that particular model; they were separate from the toner cartridges. But I ended up buying a new printer for different reasons, so I don't know if that would have fixed it, for sure. But the drum is the only other easily replaceable part, and it cost $100, IIRC... so in any case, the toner might be what matters, but your printer might not like normal toner. I recall trying to carefully clean the drum, but I didn't get anywhere.

*It lasted maybe the most of one full refill cartridge? I was also using a lot of magazine paper at the time. I don't know; maybe that affected the printer?
« Last Edit: June 03, 2020, 09:34:30 pm by KL27x »
 

Offline KL27x

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Re: Best printer for toner transfer
« Reply #31 on: June 03, 2020, 09:12:02 pm »
Mind you that to me, the bottom copper layer of a mostly single-sided board up to maybe 3x4" is what qualifies as a large solid area of resist. I initially experienced pin-holing in these solid areas using some types of toner transfer paper and methods. But they largely disappeared when I did 2 things.

I pre-etch my boards to give the surface a porous texture, then I transfer at a very high temperature to ensure the toner is fully melted to liquid. The Pulsar paper comes off with water and leaves no fibers. Because of the pre-etch, there are no smudges or fattened traces. This method makes for a near 100% success rate for the transfer. The transfer will look just a tiny bit ragged on the edges under a loupe, but after the etch is done, the board is just as good and usually better, compared to a low temp transfer that has crisper edges after the transfer is done but will often have more ragged traces by the time the etch is complete (usually in only select spots, while most of the board is great). The pre-etched hi temp transfer looks worse, but what you see is what you will get.

I also got away from acid peroxide and onto proper cupric etchant.

So I'm not sure if it was one or the other or maybe both having an effect. But for w/e reason, I no longer get pinholes in solid pours. I had some of that green foil stuff, quite a bit in fact, for which I paid good money. And I binned it. Including an unopened package. That's how little difference it makes to me, now. It wasn't worth even the little space it takes up, not even for an emergency-has-to-be-right board. The foil step was now extraneous/redundant, as far as I was concerned, at the time.

Check your print, carefully. And check your resist, after the transfer. It might be a little different, depending on your methods. Label backing paper in particular might have some issues with the print itself. But on many transfer papers, I think you'll find a pretty good print. So while a problem perhaps exists, where larger solid areas reach some limit of toner density due to printer technology, there are potentially other more imortant factors which you may be able to affect in the rest of your process.
« Last Edit: June 03, 2020, 10:15:28 pm by KL27x »
 

Offline moffy

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Re: Best printer for toner transfer
« Reply #32 on: June 04, 2020, 12:09:49 am »
KL27x, you say you transfer at high temp? How exactly do you do that?
 

Offline KL27x

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Re: Best printer for toner transfer
« Reply #33 on: June 04, 2020, 06:23:45 am »
KL27x, you say you transfer at high temp? How exactly do you do that?
I took the plastic cover off my laminator, so I can shoot the board with a 1200W heat gun at full blast right as the board enters the laminator. I have measured temp of a piece of 4x6" 0.06" FR-4 board exiting the back of the laminator at 260F, max, after several passes. With the heat gun blasting it, it exits out the back of the laminator at about 360F. Even at full blast, slowly waving the heat gun over the board at point blank, it causes no damage on regular size boards. With the super thin stuff (0.007" thick FR-4), I have to back off just a touch, else the paper thin board will bubble. 

So the deal is, I pre-etch the board by dipping it in my cupric chloride etchant for a few seconds, let it drip dry for 5-10 seconds, then dunk the board in tap water. Dry it off with the heat gun. While it's still warm, put the paper on and run it thru the laminator once, leaving the heat gun to warm up on full blast. Then I shoot the board with the heat gun on the second and final pass through the laminator. I have the habit of flipping the board on the second pass to blast the opposite side from the transfer paper (Pulsar). But when I do a double-sided board, I shoot directly over the paper on the second pass, and that works fine, too.

It doesn't matter how hot the board/paper gets.

I just screwed a wood board to the bottom of the laminator for a base, to make it stable, and I used it like that for 8-9 years. I finally enclosed the mess of loose wires, switch, twist on terminals, and LED board into an MDF housing over the side of the laminator, seeing as it has lasted this long and doesn't seem any worse for the wear. 
 

Offline moffy

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Re: Best printer for toner transfer
« Reply #34 on: June 04, 2020, 06:32:23 am »
Thanks KL27x for the info, sounds interesting. I was looking for cupric chloride in Australia and it doesn't look to be very available. What do you think then of Ferric chloride?
 

Online xavier60

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Re: Best printer for toner transfer
« Reply #35 on: June 04, 2020, 06:49:33 am »
The remaining  green liquid after a batch of ferric chloride has been well used is cupric chloride. That's why the mix seems to keep etching PCBs although rather slowly.
Spent H2O2/HCL mix is also cupric chloride.
After a lot of reading, I'm still not totally certain how to maintain a cupric chloride solution, apart from knowing that it needs some time between uses to regenerate by absorbing oxygen and adding some HCL  occasionally.
Warm, it will etch a PCB in 8 minutes for me.
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Offline KL27x

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Re: Best printer for toner transfer
« Reply #36 on: June 04, 2020, 06:55:10 am »
Thanks KL27x for the info, sounds interesting. I was looking for cupric chloride in Australia and it doesn't look to be very available. What do you think then of Ferric chloride?

Ferric chloride is excellent.
The remaining  green liquid after a batch of ferric chloride has been well used is cupric chloride. That's why the mix seems to keep etching PCBs although rather slowly.
Spent H2O2/HCL mix is also cupric chloride.
After a lot of reading, I'm still not totally certain how to maintain a cupric chloride solution, apart from knowing that it needs some time between uses to regenerate by absorbing oxygen and adding some HCL  occasionally.
Warm, it will etch a PCB in 8 minutes for me.
Making/having cupric chloride and actually etching with cupric chloride are 2 different things. If you put peroxide in it, you are technically etching (a little bit) with cupric chloride, but 95+ percent of your board is being etched by acid peroxide, directly. The cupric reaction is completely bypassed. So you can't get professional-level etching with cupric chloride unless you try a little harder than that; you are probably best to use ferric or ammonium persulfate if you want to get really good etch quality. There's no way cupric will etch a board in 8 minutes; that's the acid peroxide talking.

I use air-regenerated cupric. This requires a very large surface area of contact with air. In my case, I achieve this with a very high volume of very fine bubbles. I ran out of hydrogen peroxide about 5 years ago. I used up the last of it cleaning cupric stains off concrete. No peroxide ever gets added to my cupric etchant. There's no point. Peroxide will recharge cupric, instantly. But a fully charged tank of cupric will etch barely more than diddly squat; it's the peroxide in there that makes your neon green "cupric" etch. Real cupric is opaque spinach green, very dark, while it is etching. And it is much slower. It takes me at least 15 minutes to etch even a half oz board. 1 oz takes about 30-45 minutes.
« Last Edit: June 04, 2020, 07:16:33 am by KL27x »
 

Online Domagoj T

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Re: Best printer for toner transfer
« Reply #37 on: June 04, 2020, 07:14:01 am »
snip
I adopted your heatgun tip from an earlier discussion about toner transfer and it's been working fine for a while now. It's especially effective on thicker boards, but I'm getting nowhere near 360F (180C). I get good transfer when my IR thermometer says 80+ C (180F). It's just a cheap ebay thermometer, but the boards are "barely-able-to-hold-by-edges" hot, so I believe the thermometer is at least in the right ballpark. The difference may be that I use vinyl foils for transfer, not paper. They're cheap, available anywhere, double duty as sticky tape, and most importantly available in transparent and translucent versions, which is great for double sided boards.
I also tried your pre-etch tip, but got miserable results. The difference is I used hydrochloric acid + peroxide, so that might be the reason for failure, and on that note, I know it's quite a job, but I'd like to ask you if you would mind writing up a step by step guide for all things cupric chloride related (chemical aspects of initial production, etching and maintaining, as well as etching process, storage). Just like xavier, I tried making sense of it but different articles on the net got me confused.
 

Online xavier60

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Re: Best printer for toner transfer
« Reply #38 on: June 04, 2020, 07:23:26 am »
I haven't added hydrogen peroxide to it since I started my batch of cupric chloride 3 years ago, HCL only.
Before I started pre-etching, I had this annoying problem, I think caused by the detergent I was using to clean the PCB.
At the start of etching, I could see shiny patches on the copper that would eventually take way longer to etch than most of the PCB resulting in areas of over etching.
Now I give the PCB a quick scrub with stainless steel wool then maybe 10 seconds of pre-etch. I repeat if the copper doesn't have uniform matte appearance.

EDIT: The SG of my batch is now 1.154
« Last Edit: June 04, 2020, 07:46:31 am by xavier60 »
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Offline KL27x

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Re: Best printer for toner transfer
« Reply #39 on: June 04, 2020, 07:32:53 am »
DomagojT:
Well, I couldn't get a consistent reading off bare copper with my IR gun. I was measuring on bare FR-4, not copper clad. I dunno if that makes the difference in temp you're seeing. But so-hot-you-can-barely-hold-it-by-the-edges sounds exactly right. :)

If you don't do the pre-etch, you must get some smearing, though? I don't know how other etchants will work for this part, though.

Cupric? There's tons of info out there. Just one part people get wrong. Everything seems to think that adding peroxide is ok. It's only ok if you're ok with etching with acid peroxide and getting the etch-accuracy of acid peroxide. Which, on the scale of proper etchants, can't really get any worse. It's as bad as it gets.

I'm no expert; I just know what works for me. I use a plastic bubble wand, the kind that makes a fine bubble curtain in an aquarium. I run compressed air through this wand, regulated to somewhere in the neighborhood of 20 psi. And it makes mad fine bubbles. A 125 psi 5 gallon air tank will run 10" section of this wand for about an hour. This 10" section of bubblewand is at the bottom of a thin, vertical etch tank.

Using this setup, I etch a 1 oz board in about 30-45 minutes. A half oz board takes maybe 15-20 minutes. I don't know how good I'm running; maybe cupric can etch much faster, yet. But I don't know how xacier60 is etching anything in 8 minutes using plain cupric. I'm pretty sure cupric will never be as fast as ferric, even.

Yeah, I wet scrub the board with a large gauge stainless steel wool and a dab of dish soap, then rinse, then pre-etch, then rinse again, then blowdry. Yes, the pre-etch screens out oil spots; if the board is clean, it will be a uniform color (kinda peachy/rosy, with my etchant), if you blow-dry it. (If you let it air dry, it will turn black with white/green streaks; and that works fine, too; just don't wait too long before transferring, or the surface will start to disintegrate into powder).
« Last Edit: June 04, 2020, 07:51:08 am by KL27x »
 

Online xavier60

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Re: Best printer for toner transfer
« Reply #40 on: June 04, 2020, 08:08:30 am »
I was being overly conservative. I have just test etched a small scrap of 1 oz PCB in 7 minutes.
Temperature makes a large difference to etching rate. I float my sloshing container in hot tap water.

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Online Domagoj T

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Re: Best printer for toner transfer
« Reply #41 on: June 04, 2020, 08:39:15 am »
I measure the temperature of the backing paper (vinyl foil is laminated to regular or tracing paper), so while accuracy is questionable, the consistency should be there and I shouldn't be getting reflections from metal surface.
No, I don't get smearing unless I overdo it with the heat gun, but at that point I'm approaching the bubbling point of FR4. Since I apparently don't need such high temperature anyway, I don't risk it.

Can you leave it unsupervised for majority of the 30-45 minutes etch, or do you need to babysit it? Do you get undercutting?
Do you need to bubble the etchant after/before the etch to revitalize it, or is it enough to bubble it during etching alone?
 

Offline RoGeorge

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Re: Best printer for toner transfer
« Reply #42 on: June 04, 2020, 08:46:55 am »
I was being overly conservative. I have just test etched a small scrap of 1 oz PCB in 7 minutes.
Temperature makes a large difference to etching rate. I float my sloshing container in hot tap water.

Search for the "PCB etching ziplock bag sponge" or similar.  Works without heating, etches in seconds instead of minutes, uses only a teaspoon of ferric chloride, no mess and no need to clean the etching tray or tank afterwards, and so on.

Something similar with this, except you can put a small piece of dishwashing sponge and the PCB inside a (ziplock) plastic bag, then dispose the bag and the sponge:

« Last Edit: June 04, 2020, 08:51:04 am by RoGeorge »
 

Offline KL27x

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Re: Best printer for toner transfer
« Reply #43 on: June 04, 2020, 08:57:25 am »
I was being overly conservative. I have just test etched a small scrap of 1 oz PCB in 7 minutes.
Temperature makes a large difference to etching rate. I float my sloshing container in hot tap water.
I don't do heaters, so there's that. But in the summer, I'm peaking out at upwards of 110F. :) Love the internet: hot tap water should apparently be no hotter than 120F in my country.

I also run my tank lean on acid. Higher acid increases the etch rate fairly significantly, IIRC. But it also decreases the etching accuracy. My internet source was some paper by a guy name.. Sechel? Something like that.*** My own experience is limited and biased, but it seems to match. I routinely run my tank devoid of acid. I can tell because the etching hits a wall, but also the head on the etchant grows and bubbles over like crazy (adding acid at this point looks like a Gas-X commercial). The etchant will also locally turn blue where you squirt in plain water, when the acid is really low/out. I use maybe a turkey baster of 30% HCl per 6x9" panel, depending on the coverage. I routinely add some acid just before etching each successive board, and/or during etching if the process stalls out.

*** I found it http://techref.massmind.org/techref/pcb/etch/CuCl2.htm    ; but in fact, Seychell's entire paper entirely ignores accuracy and is focused on speed, alone; the only con he seems to mention regarding excess acid is the amount of fumes. Adam Seychell's focus on etching speed may have got some people off track. And his estimations for amount of recharged etchant needed to etch a given area of 1 oz copper appear to be extremely optimistic to me, but maybe that was affected by acid concentration.*%* From the opening statement, it seems like he wrote this specifically with the idea of a hobbyist using a vertical bubble tank for strictly air-regeneration, but he never describes what is requires to achieve this in practice. Many people believe you throw an aquarium bubbler in there, and you're good to go. That will work if you use a 2-3 gallon tank for a small board once every day or 2. For a vertical etching tank, 2-3 gallons is pretty big. And when you're done with the corrected revision, a day or 2 is a long time to wait to spin the new board. Most of us might only etch boards once or twice a year, if that. But when we are doing it, we're sometimes burning the candle on both ends to solve problems that need to be solved. Air regeneration is simply not practical with an aquarium pump. It would be appropriate for tiny-scale, regular production, of a same-board-a-day, or whatnot. But we don't work like that. A big part of the allure of toner transfer is you are completely free to make mistakes and immediately fix them. Ordering boards, there are a lot of details you might forget and then remember after submitting the order. Or you might not notice your obvious mistake until you receive the boards, week or 3 later.

I measure the temperature of the backing paper (vinyl foil is laminated to regular or tracing paper), so while accuracy is questionable, the consistency should be there and I shouldn't be getting reflections from metal surface.
No, I don't get smearing unless I overdo it with the heat gun, but at that point I'm approaching the bubbling point of FR4. Since I apparently don't need such high temperature anyway, I don't risk it.

Can you leave it unsupervised for majority of the 30-45 minutes etch, or do you need to babysit it? Do you get undercutting?
Do you need to bubble the etchant after/before the etch to revitalize it, or is it enough to bubble it during etching alone?

I have never even set a timer; the boards are fine to sit in there for an extra hour, even. The traces start to get thinner, but it is a long time before there are any problems with my 8/8 boards. The traces get thinner, but thinner all over, and not more ragged. It's crazy. I have forgotten a board overnight, once. Obviously, the air ran out after the first 1-1.5 hours. The board was ruined and most of the resist was floating at the top. But a lot of the traces were still there, only they were 2 mils thick. I will never get anything looking like a rat chewed on it; it doesn't happen.

It's enough to bubble it during etching, alone. But if you wanted to, it takes maybe (wild guess) 5 to 7 minutes for my fine bubble blaster to turn the cola in my 0.4L tank back to mountain dew.* So if you wanted to get a little head start on the next board, I suppose you might bother to regenerate it. In a matter of weeks, it will regenerate on its own, just sitting there. 

Adam Seychell: "If you want to be pedantic then the solution can be aerated after each etching job until the color is a completely transparent bright green, i.e. Cu1+ concentration  << 1 g/L."

*So my system isn't going to win any races, but it finishes a board on one setup/air-tank, unsupervised, and that's where I stopped caring. So I don't know how much faster you could get with better regeneration. The original plan, using a top end fish tank bubbler, it did not do the job. I think those only get up to 4 psi, or so. Using an aquarium pump to put air through either a tube with holes or stone or wand, nope. That doesn't regenerate the cupric for squat. It took hours to recharge a tank vs minutes with the higher volume of finer bubbles I get with compressed air/wand. I couldn't practically etch anything without adding peroxide, using wimpy bubblers... yield was terrible on fine pitch boards... and yet it took me months or maybe even years before I was convinced of this, myself, that the majority of the internet is completely wrong, thinking you can etch with cupric... then recharge it, after; uhhh, no. Unless you use a relatively enormous quantity of etchant for the board.

edit: http://www.chemcut.net/wp-content/uploads/2015/03/Chemcut_Bulletin_8_Cupri_Chloride_Proces_-Parameters.pdf
According to this info, increasing free acid increases the etch speed, but it also proportionally increases the amount of relative undercutting. Temperature changes the etch speed, but it has essentially no effect on undercutting. So running at 130-160F will increase the speed, if your equipment can handle it. But for a home user doing one-offs, a heater might not matter as much. The specific gravity apparently hardly effects speed at all, as long as you're within a wide band. And it, also, has almost no effect on undercutting. According to this link, you can etch a 1 oz board in something around 100 seconds** using cupric chloride in a heated spray etcher. Cu2 vs Cu1 is measured with an electrical probe in order to determine the amount of regenerative agents added in the recharging loop (chlorine gas or 35% peroxide), and the tank is run with some Cu1 left in there, to prevent excess reagent from being added (excess chlorine gas would escape into the atmosphere; excess H2O2 would turn the etchant into mountain dew acid peroxide). So for a home user trying to get the best possible accuracy and not concerned too much with absolute speed: keep the acid down, don't put peroxide in there, and be patient. Heater can technically increase speed, but air regeneration rate will inevitably be the weak link, anyways. As long as the etchant is not frozen, it will etch boards at a rate at least comparable to warm ammonium persulfate, at the worst; it'll take longer when it's cold, but accuracy will not be affected; it won't be practically unusable, like cold ammonium persulfate etchant.

** I think with spray etching, you will perhaps be able to keep a higher concentration of Cu2:Cu1 on the surface of the board? I mean, you are continually flooding the surface of the board with near-fullly charged etchant. It would also be reasonable to assume there will be a higher rate of atmospheric oxidation of copper; hence there could be more etching via acid directly dissolving copper oxides.

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
*%* Let's examine closer. From his paper, Seychell states you should be able to etch half-coverage 1 square decimeter of 1oz copper with 1.6L of charged etchant. Who knows if this means etch time of hours or more, due to scraping the bottom of the barrel at the end? But anyhow, a square decimeter is 15.5 square inches. A 4x6" board is 48 square inches, double-sided. So it should take... 4.9 L of charged cupric to etch an average 4x6" double-sided 1 oz board. This is 1.3 US gallons.

6x9" double-sided (I do this size, regularly) would take 11.15L, or 3 US gallons. My tank holds ~3.4% of that. With my setup, it's all about the regeneration, because this is the only way it is practical (i.e. 99% of us should stick with ferric or acid peroxide; and yeah, you can call it etching with cupric, if you like). With 3.4% of the volume, I can crank out these boards in succession if and when needed. Refill the air, swap the boards, add some acid and water (1 turkey baster of acid vs 3 more gallons of green koolaid).
« Last Edit: June 05, 2020, 08:27:26 am by KL27x »
 

Offline Pawelr98

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Re: Best printer for toner transfer
« Reply #44 on: June 04, 2020, 01:25:52 pm »
Myself I use an Ricoh Aficio SP 100 I got for free from my uncle.
OEM toner I guess (never changed it, I only use it for PCB making).

For toner transfer I use an old soviet iron, which is set to blazing hot temperatures.
Beeing old it's rather heavy and has a flat surface (no steam holes or anything modern irons have).

After making the transfer I just peel away the paper while still hot.
Other people recommend soaking the paper in water but the hot method is quicker and easier.

Any imperfections I fix using a pen marker.
 

Offline KL27x

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Re: Best printer for toner transfer
« Reply #45 on: June 05, 2020, 08:58:24 am »
I measure the temperature of the backing paper (vinyl foil is laminated to regular or tracing paper), so while accuracy is questionable, the consistency should be there and I shouldn't be getting reflections from metal surface.
No, I don't get smearing unless I overdo it with the heat gun, but at that point I'm approaching the bubbling point of FR4. Since I apparently don't need such high temperature anyway, I don't risk it.
Interesting. I wonder if the vinyl seals against a clean board, keeping the melted toner in place?
And when you tried the pre-etch, perhaps the porous surface leaked (or sucked in via capillary action) some of the toner from out of this perfect "mold?" I previously mentioned my transfers definitely gain some fuzz around the edges vs a "normal transfer." But nothing that really shows up much after the etch (and I mean under a microscope). It sounds like your high temp + vinyl method leaves very clean edges, comparable to the "normal transfer."

I suppose the paper is on the back? To help feed through the printer? I bet it helps to keep the vinyl from melting, too. It sounds like it's holding up pretty well, though, to the heat gun.
« Last Edit: June 05, 2020, 09:01:23 am by KL27x »
 

Online Domagoj T

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Re: Best printer for toner transfer
« Reply #46 on: June 05, 2020, 10:45:37 am »
Yeah, for one sided boards I print the artwork on plain A4, then stick the self adhesive vinyl only over the area where the artwork is and print again on that same paper. I do this because as the PCB gets larger it gets trickier to stick the vinyl to the paper without creases and bubbles (standard 10 x 15 cm / 4'' x 6'' is not a problem, but for bigger boards it is fiddly). For double sided PCBs I again pront on paper, but then lay tracing paper over that and stick the vinyl on the tracing paper. Simply because it makes aligning much easier.
Vinyl sticks to the PCB but only lightly (comes off without tearing or stretching), and after transfer it does appear as if it's pressed to accommodate the thickens of toner, so it might be sealing.

When I tried pre-etch, I got splotchy copper surface that toner wouldn't stick to reliably, so a lot of traces wouldn't transfer.

Anyway, this is what I can achieve without any special precautions. I don't have any raw boards around at the moment, so this assembled on will do (I should really clean the flux a bit better :-[):

The thin vertical trace that goes between pins is 15 mil (0,381 mm), the thicker ones are 30 mil (0,762 mm).

Oh, as standard practice, I tin all my traces as soon as I strip the toner. Black smudges are toner residue, and I have no idea how to get that off reliably. Acetone soaked rag sometimes leaves them and they never go away.
 

Online SilverSolder

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Re: Best printer for toner transfer
« Reply #47 on: June 05, 2020, 01:12:28 pm »
Yeah, for one sided boards I print the artwork on plain A4, then stick the self adhesive vinyl only over the area where the artwork is and print again on that same paper. [...]

I have also tried printing on vinyl, using that exact method - it worked really well for me too.  The results were not quite as sharp as the Pulsar paper when I tried it, but definitely playing in the same league and maybe if I had persevered with different temperatures etc. it could get as good.

Another thing I've been meaning to try, is to cut the PCB artwork out of vinyl (I have a cutting machine) and using it as a straight mask against the etchant -  you can make surprisingly fine artwork with a vinyl cutting machine - and definitely no problems with pin holes or large black fills!

 

Online Domagoj T

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Re: Best printer for toner transfer
« Reply #48 on: June 05, 2020, 01:19:23 pm »
I've been thinking about that too, but I don't have the vinyl cutter. What I'm not particularly crazy about with that idea is picking all the tiny bits of cut outs that need to go.
The results would need to be drastically better to justify all that work, and I'm not sure just how much better can it get and how much better than 10 or 20 mil I need. After all, for me, the biggest issue with diy PCB production are vias, not traces.
 

Offline poorchava

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Re: Best printer for toner transfer
« Reply #49 on: June 05, 2020, 03:02:15 pm »
I've stopped etching boards myself due to availability of cheap Chinese services, but when I was doing that, I was using HP4000. Actually I bought it used for 50€ and have had it for 12 years now. And it's still going. I only had to buy network card for it due to lack of LPT in my PC. Old as hell, but reliable as hell for home use.

On the other hand I've found that toner type is more important than then printer itself. In my case aftermarket replacement gave better results than genuine HP toner.
I love the smell of FR4 in the morning!
 


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