pcb design?

[Dave]

Why doesn't the ink get stripped off by the laser printer?

Dave

[Tim S]

Dave coughed up some electrons that declared:

It doesn't work like that.

The blue sheet is almost waxy, but just good enough to receive the toner and survive the fusion bar. There's no ink besides the toner.

So the blue sheet comes out with an image of the tracks just adhering to it.

When pressed to a copper board with a hot iron, the toner melts and finds it get's on better with the copper so it sticks to that instead and releases from the blue sheet.

The toner, being basically plastic gunk resists the etchant well and thus a PCB is born.

Cheers

Tim

[Dave]

I shouldn't have used the word ink, I meant toner, but thanks for that.

I wonder how those iron on tee shirt paper sheets would work with this.

Dave

[brass monkey]

This brings back memories. 45 years back I needed to make 12 pcbs (electronic organ). Made 12 copies of the layout on a diazo?/ammonia copier, covered the copper boards with masking tape, attached the diazo and cut around it and through the masking tape with craft knife, peeled out the masking tape tracks and sprayed with car paint, removed the rest of the tape and etched. Bloody nightmare :) Still working. Last pcb, I used a photoplotter, a tad better.

[dennis]

Anyone tried modifying a laser so the PCB runs through the transfer roller to pickup the plastic toner and then cook it in an oven?

[Clint Sharp]

In message , "dennis@home" writes

Very much doubt it would work with bare PCB material because the laser printer relies on the toner/media being able to hold an electric charge so copper clad board would conduct/dissipate the charge.

Using an old fuser assembly from a laser printer sounds like an ideal way of transferring press n peel layouts though, I might have a go at this if I can find a fuser with a solid roller instead of the flimsy film type that seems to be widely used these days.

[Man at B&Q]

the PCB runs through the transfer

Laminating machine, if you can find one that will take the thickness of PCB material. There is a recommendation for a particular model (probably long obsolete now) out there somewhere.

MBQ

[meow2222]

If you dont have all the facilities, its usually quicker to use an alternative to an etched pcb, as long as the projects not too big. Veroboard, or copper pads only board with added wires work for many circuits.

Pad and wires boards can simulate a multilayer pcb btw, you just put your first layer of wires in place, using very fine gauge, then a layer of paper, then the next set of wire tracks. And handle gently. Once theyre in, place the components. Obviously bending the wire ends over where everything goes thru is essential.

For very small circuits one can go with something like ugly bug construction. I even tried a cardboard pcb once - I needed to make a tool there and then - ok with very light components, but anything as bulky as a 1000uf lytic is a no-no on such a weak board.

NT

[Clint Sharp]

In message , Man at B&Q writes

Good idea.. But I'd have to buy one. Fuser assemblies I can get hold of much more easily and they're almost 100% guaranteed to be able to melt the toner (with certain exceptions) so I may have try an experiment with the next one I lay my hands on.

[Tim S]

dennis@home coughed up some electrons that declared:

Not sure, but someone has definately tried making little PCBs in the CD tray in an inkjet, possibly with modified ink - you'd have to google for it. Either that, or they were printing the UV mask directly onto photo sensitive board. It was a while ago and I mostly ignored the article because I don't have a CD tray.

[Tim S]

[e-mail] coughed up some electrons that declared:

If you can stretch to a decent gun, wire-wrap is good. Very solid, quick and the results can be neat - or a total ratsnest.

[geoff]

In message , Clint Sharp writes

Can you get hold of an Epson C1000 fuser assy ?

[meow2222]

I never really got into wire wrap. Does it work ok on round component legs, or does it need the thick square legs I've always seen it on?

NT

[Alan]

In message , Fred wrote

Download some free software, use a laser printer and a (clothes) iron to transfer the design to a copper clad board before etching. See

some free basic software try chemicals

[Alan]

In message , Steve Walker wrote

So is the free paper that the junk mail merchants put through your letter box :)

[Tim S]

[e-mail] coughed up some electrons that declared:

The square legs are critical to it working - the wire bites into the corners forming a gas tight seal - so good wire wrap can last forever, more of less.

The usual way is to use special wire wrap chip sockets, and solder everything else to special pins, after inserting said pin.

HTH

Tim

[meow2222]

thats what I thought

but then surely you've lost any advantage of wire wrap. And it has a pretty big downside, the task of following what 'tracks' go where is almost hopeless. Plus its so easy to miss a connection during construction. Horrid system!

[Tim S]

[e-mail] coughed up some electrons that declared:

That's true enough. But you can achieve very high connection densities in a fairly robust way. Densities that would be very difficult on veroboard or it's variants (and would take longer to solder all the wires as well as all the components).

Cheers

Tim

[Dave Plowman (News)]

My foray into wire wrapping some years ago said not.

[Clint Sharp]

In message , geoff writes

Do you know, I've don't think I've ever worked on an Epson laser that I can remember, mainly Lexmark/IBM and HP machines, the odd Oki one here and there... Are you having a problem finding one or is it just that they're expensive?