Hi all

I have purchased a laminator today which I intend to put to use as the tool for toner transferring my PCB patterns to copper clad sheet.

First up 1.6mm copper clad fits

Secondly I have opened it up and figured out the wiring and what controls the temperature.

Thirdly For transferring toner to copper a temperature of between 135-165 degrees C is needed.

The picture, scuse the roughness, shows the wiring of the unit. Now what I plan on doing is changing the 2 thermal switches for a single 160degree C rated thermal switch.

I have temporarily removed the B145 thermal switch and run the unit to test it with a toner transfer and it does the job but obviously I need to regulate the temp.......... as it starts smoking otherwise

Is it OK to change the 2 existing for the 1? I have to confess to not quite understanding how they work within the circuit. One is marked B115 the other B145. But they are in parallel so I don't quite get how they function as a pair. Also the heated rollers don't seem to be in circuit at first glance but they get hot obviously and when the peak temp is reached the LED lights up.

Any guidance gratefully received

Fenris

 

Neat idea.

Instead of modifying the temperature circuit, which is probably OK, think about changing the speed of the feed, to allow the heat to soak in longer.

 

Hi Bill

I did think of a relay driven by a 555 timer to do the trick With protection diodes to stop the emf spike. I'll look into it ta

A thought occurs! Use a dimmer switch fitted in one of the motor lines. The rollers still get their full supply and the motor can be slowed down a tad.


regards

Dave

 

Be careful, dimmers don't handle inductive loads well. Still, worth a try, you might have a premature failure of the dimmer though.

 

Hi Bill

Ah! I had a vague feeling there was a technical issue with the latter. Perhaps a PWM'd relay switch is the better option then.

regards

Fenris

 

Try the dimmer first, their cheap, and relays don't do PWM well.

 

Will do thanks ............. Nothings ever straight forward is it

regards

Fenris

 

Just try running the laminator as it is, if anything it will probably be a little cool so you just run the PCB through a number of times (quickly so it doesnt cool down).

The dimmer will only be able to make the laminator cooler, it cant get hotter because the thermal switch will cut power to the heaters.

Re the 2 switches, is there a "thickness" switch? It is typical for a laminator to have 2 heat settings, which is usually 2 heats as they use a synchronous AC motor so they cant change speed.

Those thermal switches are probably 115'C and 145'C, if that is the case just use the hotter (thicker) setting on the machine (if there is a setting) and no need to mod it.

 

Reread the posts. We're talking about slowing the motors down, so the parts stay under the heat longer.

 

Hi Bill

Well the dimmer switch didn't quite cut it in the end. The motor lost torque and it kept stalling. But.................I have come up and implemented a solution which seems to be working well, so far, in tests.

I dismantled an old clothes iron. The temperature control is a bi-metal strip which is bolted to the iron's plate. Two snipped wires, and a bolt later I had the thermostat out. I removed the thermal switches from the laminator bolted the irons thermostat to it attached the two wires dialed up polyestor and away we go.

I had to fettle the case of the laminator a tad so that the thermostat would fit due to it's being quite tall. The knob for the same has been kept and is being used to set the temperature.

I have just done a 100mm x 150 mm toner transfer with it and it looks perfect. I did 5 passes to warm the PCB and 10 to transfer.

Please note anyone thinking of trying something similar- This is 240V AC and should not be undertaken lightly. Safety safety safety!!!!!!!

regards

Fenris

 

Reread the posts. We're talking about slowing the motors down, so the parts stay under the heat longer.

Hi Bill, yeah I saw that, which is why I mentioned that it was probably a synchronous motor and can't be slowed. You can only slow non synch motors like those noisy brushed "universal" motors in electric drills and power tools (which would be very unsuitable motor for a laminator).

Sorry if it sounded like I was trying to take the thread in the wrong direction, as usual I typed in a hurry while i'm doing other internet tasks.

 

Pictures?

 

Hi Guys

Here are some pictures of the fitted thermostat and the circuit board I transfered onto using it. The original thermal switches where merely screwed into a channel in the aluminium block which contains the heaters and shrouds the rollers.

The bolt that fixed the clothes iron thermostat to the plate was bigger in diameter but it's tip had a slight taper to it. Using a junior hacksaw I cut a groove in the screw, parallel with the length, at the bottom so it would cut it's own thread in the channel of the heater shroud where the original thermal switches where fitted. I needed a 2mm spacer to take up some of the length of the bolt as it bottomed out in the channel before tightening up properly. I also put some thermal transfer paste between the mating faces.

I do intend to box around the thermostat where it protrudes as a matter of safety. The unit will also need 'feet' to support it now due to the protrusion.

The small round item is one of the original thermal switches.

regards

Fenris

 

Can you show larger images for the laminator? I think you have a good idea there. Does the laminator heat both rollers or just one?

 

Hi there

I will take some more photo's tomorrow and get them up. both rollers are heated so there is an element in the upper and lower ali shroud. there is also a thermal fuse wired in series between the 2 heaters rated at 192 C which is held against the ali shroud. I managed to blow it with my first tests prior to fitting the irons thermostat.

I suppose, in theory, so long as there is a fixing point or one can be made it would be possible to convert any laminator to this method and it's turned out cheaper and less complicated than some methods I have seen which is what has stopped me trying it sooner.

regards

Fenris

 

Hi Chaps

Here are a few more pictures of the unit. Hope these help.


EDIT: I did 2 PCB's with it today. this time 6 passes to heat the PCB and only 8 to transfer. The result was better delineation of the holes in the pads. Quite a few, on the first attempt, had blurred to almost nothing. A washing up sponge, rough side, was used to clear off the remains of the photo paper once the majority had been removed.

This was done under cold running water and care was taken but the overall speeding up of the process and retained quality of the transfer is fantastic. I attach a picture of 4 PCB's. From left to right they are.

An original done with a clothes iron, my first attempt with the laminator and the 3rd and 4th are todays hot off the press PCB's. I think you will see the overall improvement especially the holes.
regards

Fenris

 

Just a suggestion, Once you've etched a board made with this move it into the finished projects collection. Nice job.

 

Hi Guys

Here are some pictures of the fitted thermostat..

Hello,very interesting, you've convinced me and I immediately bought a laminator and a thermostat for iron. But you've just replaced the thermostat? And the thermal fuse? Do you have removed it ?

thanks,ricci