DIY credit card sized laminated PCB's

[en2oh]

Hi folks,

Has anyone got experience or suggestions for making a plastic coated PCB tag?
I'd like to essentially make a thin (say 3 or 4mm thick) plastic card with a printed circuit embedded within it.

Any suggestions/recommendations?

Thanks
Nitrous

 

[throbscottle]

Umm, I think you made a typo - 3 or 4 mm thick is rather thicker than normal PCB's. How complex do you want it and what's it for? Could be problem soldering components when the substrate is plastic due to it melting - what materials do you have a choice of?

Okay here's one suggestion. Get your thin plastic and stick some self adhesive copper foil to it, etch as for a pcb, laminate it so it doesn't come unstuck eventually.

Another suggestion. Get your thin plastic and paint the traces on with conductive paint. You could create a mask so you get nice clean lines. I don't think conductive paint is very sturdy, so again, you'd need to laminate it. Never used the stuff so wouldn't like to guess how solderable it is, though I believe you can.

You probably can get real pcb material in the kind of thickness you actually want.

 

[en2oh]

I guess I wasn't clear. I have a PCB board that I want to encapsulate in PVC or something similar (like an RFID tag).
Thanks

 

[ronsimpson]

I see board thickness from 0.254mm to 8mm. Either extreme is not cheep.
You might look at flex PCB which is copper & plastic.

 

[ronsimpson]

I guess I wasn't clear. I have a PCB board that I want to encapsulate in PVC or something similar (like an RFID tag).
Thanks

The material that is on the handles of tools, a soft plastic, comes in a 1 gallon bucket. You can dip your PCB in that and it becomes water tight.

 

[en2oh]

Regular thickness PCB, with surface mount components. The size is ~credit card. I want to embed the board and components in an opaque plastic. The end result should be a credit card shaped, tag with a printed circuit buried in the plastic. Smooth top and bottom.

Is that clearer?

 

[en2oh]

Yes, that is sort of the idea. A bit like potting compound but, it needs to be smooth and more like an RFID tag. I wondered if there was a proprietary laminating product that would do this.

 

[throbscottle]

I mis-read o/p. Duh. Sorry.

 

[en2oh]

I appreciate any feedback
Thanks for responding

 

[Joe G]

what about fiberglass resin/hardener, like is used for automotive. I've made quick molds from blocks of wax, and just poured the mixture in (vacuum if wanted to eliminate any voids). brushing on a first coat then putting in "mold" works also. also, have you looked at smooth-on.com, they have some niffy products.,

 

[ronv]

Neat site Joe.

 

[Joe G]

thx. they have some really good how-to 's jfyi.

 

[en2oh]

Thanks Joe,
I'll have a look at that site.

 

[alec_t]

Car body-filler will probably do the trick. Using strips of cardboard, plastic, etc, make a 3mm-4mm high 'fence' for the card area. Use an old loyalty card or similar bit of plastic as a base. Apply a thin coat of filler mix to the base. Put pcb on top. Add more filler mix up to the top of the fence. Apply a thin film of mould-release (WD40, margarine, petroleum jelly, whatever) to a sheet of rigid material. Put this material 'butter-side down' as a lid on the filler and press to extrude spare filler from the sandwich. Leave with a weight on top for the filler to harden.

 

[en2oh]

Thanks Alec_t

 

[Blueteeth]

0.8mm FR4, single or double sided is fairly cheap from places like ebay shops, and they'll cut it to size for you. As for encapsulating, nothing really beats epoxy resin It's cheap, can be very clear, tough, and easy to use. Getting a all round perfectly flat (read: transparent) is difficult without a mold and polishing.

What I used to do for flat objects is buy sheets of clear acrylic, sandwich what you wish to embed between them (in your case, a PCB, my case, leaves or a silicon wafer) then fill it in with epoxy. As the refractive index of epoxy is so close to acrylic you won't see the 'join' and it'll appear as one solid block - plus you'll have both sides nicely polished already. Then you would only have to file/sand/polish the edges, which is FAR easier to do than a large flat surface. A dremel is recommended for a true polish job (buff wheel + toothpaste), but it can be done by hand with progressively higher grits of wet/dry paper, followed by a flame polish.

One more tip - if you're using molds, a great mold-release agent is parcel tape. I've never seen epoxy stick to the shiney side.

Apologies if someone has covered that already, I just skimmed the posts and wanted to add my two cents/pennies

 

[en2oh]

Thanks for your reply, Blueteeth
Fortunately, I'm actually NOT trying to make a transparent tag. Quite the opposite.
I was thinking of the flexible PCB material for the base.
Doug

 

[kubeek]

Could you post the circuit of the tag your´re making, or PM it to me? I am doing master thesis on creating a 13.56MHz field-powered tag, so I would love to see your approach.

 

[en2oh]

Hi Kubeek,

The term "tag" may be a bit misleading. This is not an RFID project.

Sorry for the confusion

Doug

 

[Blueteeth]

Oooh sorry man, you mean like laminating a flex pcb?