PCB Toner transfer by 'METAL PLATE' method

[camerart]

Hi,
TITLE CHANGED and REMOVED PREVIOUS COMMENTS REGARDING LAMINATORS.
This is now for any comments using: Two metal plates, each lined with 2mm silicon sheet, sandwiching (screwed together) single or double sided PCB, with toner transfer paper/or other printable mediums, which are then heated for the transfer.

Here are some other posts where laminators are discussed:
https://www.electro-tech-online.com/threads/toner-transfer-papers.113206/page-5#post-1297257

https://www.electro-tech-online.com/...me-without-blowing-money.151430/#post-1300653

Camerart.

 

[camerart]

Hi,
Just did a test.
Plates-Plastic-silicon-Transfer paper-PCB-transfer paper-silicon-plastic, wrapped in rubber bands. Placed in Microwave for 20 mins. The plastic was starting to melt, but the transfer almost worked, so this needs investigating.

I tried the silicon in the microwave on it's own, and it got hot, so this appears to be how the heat could be injected.

Questions: If anyone knows, the dangers of materials like the ones above?
+ The temperatures needed to transfer the image?
+ The max temperatures of known silicon etc? (I believe food silicon-200C Industrial-300C ?) (The silicon I've been using is very soft and can be cut by pushing my nail into it)
Please reply. C.

 

[camerart]

Hi,
The method I have chosen is to use two plates to compress a sandwich of Metal-Silicon sheet-Image-PCB-silicon sheet-Metal. (Double sided possible) Clamp together with Screws/Bolts and place in toaster for a time found by experiment. Leave till warm (Not sure about the actual temperature) peel apart and Circuit!
Here is an image of my first test, this is app 30x50mm, also an image after soldering most of the components.
I am trying next with larger/thicker plates.
C.

 

[Superdat]

Different! I would have some concerns about using a toaster, all the ones I have seen have very accessable heating elements.
Other than that, it's sort of like a laminator without the rollers.
I used a solid state A/C relay to slow my laminator motor down.The motor was stopped then restarted before it lost all momentum. There is no noticeable increase in heat from the motor. After some tweaking of the On to Off ratio, I managed a stutter free speed reduction. I think I got about 4:1
Works well on a single pass, but my laminator does have heat adjustment and a high maximum temperature (170C +).
I've also stopped using the commercial transfer paper, I found it is so non sticky that small detail sometimes falls off or at least goes missing somewhere.
I've gone back to using satin finish magazine paper and I get much better results. IMO the extra hassle of soaking the paper to remove it is worth the inproved quality.
I notice on your PCB that some of the holes are incomplete. This was happening to mine until I went back to magazine paper.
To avoid jams I cut the transfer paper to size then masking tape the leading edge onto regular A4 which has an image of the pcb printed on it as a reference.
I found that a whole sheet of magazine paper jams very easily.

 

[Pommie]

I've given up making my own. When you can get ten 50x50 mm double sided boards made for $20 ($2 each) it just isn't worth it. Also, with smt I can now fit most projects into 50x50 mm.

Mike.

 

[camerart]

Hi,

I've given up making my own. When you can get ten 50x50 mm double sided boards made for $20 ($2 each) it just isn't worth it. Also, with smt I can now fit most projects into 50x50 mm.

Mike.

Hi M,
As I keep having to change my designs (poor planning) this would be quite expensive and not as quick for one off tests, but I'll look out for a similar company here, in case I ever get better at accurate designing.
Thanks, C.

 

[camerart]

Different! I would have some concerns about using a toaster, all the ones I have seen have very accessable heating elements.
Other than that, it's sort of like a laminator without the rollers.
I used a solid state A/C relay to slow my laminator motor down.The motor was stopped then restarted before it lost all momentum. There is no noticeable increase in heat from the motor. After some tweaking of the On to Off ratio, I managed a stutter free speed reduction. I think I got about 4:1
Works well on a single pass, but my laminator does have heat adjustment and a high maximum temperature (170C +).
I've also stopped using the commercial transfer paper, I found it is so non sticky that small detail sometimes falls off or at least goes missing somewhere.
I've gone back to using satin finish magazine paper and I get much better results. IMO the extra hassle of soaking the paper to remove it is worth the inproved quality.
I notice on your PCB that some of the holes are incomplete. This was happening to mine until I went back to magazine paper.
To avoid jams I cut the transfer paper to size then masking tape the leading edge onto regular A4 which has an image of the pcb printed on it as a reference.
I found that a whole sheet of magazine paper jams very easily.

Hi S,
Sound like you've got a good system. I'm still waiting for larger silicon sheet to try larger PCBs, and the plates I've had made.
The toaster is a 60s one and as in the throwing out area after all of these years. (Only because one of the contacts fell off) The elements are better than the good quality ones we've got today. There are metal rods separating, the 'toast' from the elements, and I switch on from the wall socket.
A friend of mine was explaining about the holes on the tracks, and that he sprays his with Acetone to spread them before transferring, I've yet to try this.
Thanks, C.

 

[Superdat]

Pommie said: I've given up making my own. When you can get ten 50x50 mm double sided boards made for $20 ($2 each) it just isn't worth it. Also, with smt I can now fit most projects into 50x50 mm.

Hi,
That's fine if you can find something to do with the other 19! I'm very much into one offs and usually much larger e.g. 100x160
I know that SMD would make them much smaller but my 20:20 vision is more like 2:2 now ;-) So DIY isn't really an option. I can mange 1206 resistors/caps which helps with size reduction. For me doing everything myself is part of the interest, I get to design a circuit, layout the pcb, make the pcb, program the microprocessor, debug and fault find, then use what ever I've made. I don't just copy whole circuits, I may use other ppls work as a reference of how to do something, but once I understand the concept I do it in a way that takes into account my abilities, available hardware etc.
I have made one item that isn't readily available (auto dew heater for telescope) but it would be easy to copy and probably quite expensive if it was made as a commercial item so I haven't looked into going any further with that. I'm also retired so I'm not looking for a new career.
I think most hobbyists are into one offs, anyone who can do something with 20 identical pcbs (without giving them away for free) is likely semi or full professional. Then time and accurately reproduced pcbs is as they say money. I'd say there's a whole spectrum of ppl with a variety of reasons for DIYing to paying someone else to do it. You do what's right for you.

 

[camerart]

Hi,
I've just tried my latest plates! for PCB 75mm+ x 100mm+
Here's a photo of the first test. I can see holes in the tracks. There are a few black marks left on the transfer paper, but not as many as missing from the board.
Are they:
Poor laser printing?
Not enough heat?
Not cool enough before separating?
NOTE: The central PIC 44PIN is 12mm square total.
C.

 

[BobW]

I've been using a cheap laminator that I got from Office Depot several years ago. No need to slow it down or any other mods. One pass through, and the toner is nicely stuck to the board. Sometimes, I'll pass it through twice just to make sure. The only thing that I've found to be important is to let the laminator warm up for at least half an hour before using it, even though the ready light may come on after 10 minutes. It takes a while for both rollers to reach their steady state temperature.

Actually, I did make one modification. I used a file to elongate the bearing guides for one of the rollers so that I can feed thicker PC boards through it. Since they're spring loaded, it still works fine with thin materials.

 

[camerart]

I've been using a cheap laminator that I got from Office Depot several years ago. No need to slow it down or any other mods. One pass through, and the toner is nicely stuck to the board. Sometimes, I'll pass it through twice just to make sure. The only thing that I've found to be important is to let the laminator warm up for at least half an hour before using it, even though the ready light may come on after 10 minutes. It takes a while for both rollers to reach their steady state temperature.

Actually, I did make one modification. I used a file to elongate the bearing guides for one of the rollers so that I can feed thicker PC boards through it. Since they're spring loaded, it still works fine with thin materials.

Hi B,
Have you done double sided board? I chose this method, because others mentioned creep when using rollers.

Can you post any results please?
C.

 

[BobW]

I've done few double sided boards with toner transfer, but not too many. In my opinion, double sided toner transfer is more trouble than it's worth, but it can be done.

A common problem is that the patterns come out of the printer slightly compressed or stretched in one dimension so that they don't match up perfectly. So, you should print both patterns on the same sheet side by side. Then cut out the patterns and line them up to make sure that they can be perfectly superimposed. If they're okay, then you can tape them together in position on two opposite ends and slip the PC board in between. Be very careful as you feed it into the laminator. Hold it tightly as you feed it into the laminator to make sure that things don't shift. Like most things, it may take a bit of practice.

Another option is to do one side at at time. Completely cover one side of the board with resist (I use fast drying spray lacquer), and apply the toner transfer to the other side. Then etch it. Remove resist from both sides. Drill two of the through holes to use as alignment guides when attaching the second toner paper. Don't forget to cover the already etched side with more lacquer. It doesn't always work perfectly, and I wouldn't try to do intricate designs.

There are a few black marks left on the transfer paper, but not as many as missing from the board.
Are they:
Poor laser printing?
Not enough heat?
Not cool enough before separating?

With the paper that I use, I've never had to use any physical force to separate it. I just drop the board, with paper attached, into a dish of soapy water, and let it sit until the coating on the surface of the paper dissolves and the paper floats away. This may take a half hour or more, but there's never a risk of untransferred toner. None of the toner remains on the paper. It all transfers to the board.

Also, toner may not stick to the board properly unless the board is scrupulously clean. Make sure it's clean and degreased before applying the toner. Once the board is clean, don't let your fingers touch it. Handle it by the edges only.

 

[camerart]

Hi B,
All appreciated, thanks.

As I have chosen to try the 'Metal plate' method, I have changed the title so that any comments will either improve the results of this way, or prove it doesn't work well enough.

NOTE: If the components are available to make the 'metal plates' silicon, etc, this could be used in none electrical environments, with ingenuity.

For alternatives to this method, here are some other posts where laminators are discussed:
https://www.electro-tech-online.com/threads/toner-transfer-papers.113206/page-5#post-1297257

https://www.electro-tech-online.com...me-without-blowing-money.151430/#post-1300653
C.

 

[jpanhalt]

Here are some other posts where laminators are discussed:
https://www.electro-tech-online.com/threads/toner-transfer-papers.113206/page-5#post-1297257

https://www.electro-tech-online.com...me-without-blowing-money.151430/#post-1300653
C.

Your second link doesn't seem to involve toner transfer. It is about using the photoresist method and making the exposure mask on laser printers.

I have used that method (photoresist method) for double-sided boards for more than 15 years without a failure. If you plan to use a photoresist, maybe another thread is warranted as including that discussion here could lead to a lot of disastrous confusion.

 

[camerart]

Your second link doesn't seem to involve toner transfer. It is about using the photoresist method and making the exposure mask on laser printers.

I have used that method (photoresist method) for double-sided boards for more than 15 years without a failure. If you plan to use a photoresist, maybe another thread is warranted as including that discussion here could lead to a lot of disastrous confusion.

Hi J,
True, the links are for people that don't want to use the 'metal plate' method.
C.

 

[jpanhalt]

I use a "sandwich" method with photoresist when doing a double-sided board, which is almost all of the time now.

Let's hope your intent is clear to everyone and no one tries to do toner transfer from a polyester transparency.

 

[camerart]

I use a "sandwich" method with photoresist when doing a double-sided board, which is almost all of the time now.

Let's hope your intent is clear to everyone and no one tries to do toner transfer from a polyester transparency.

Hi J,
Noted, 'sandwich' mostly changed to 'Metal plate' (Please check)
C.

 

[camerart]

Hi,
2nd test. Longer toasting.
One one of the transfers, one of the thicker tracks shows pitting, but much better than first test.
The same track is pitted on the PCB.
I notice many scratches, due to over eager cleaning, NOTED.
C.