Laser cutting Kapton tape.

[Steve Baker]

I know it's possible to laser cut Kapton tape...but I have some questions:

1) Is it OK to cut the self-adhesive kind of Kapton tape?
2) What settings are reasonable for tape?
3) I'm trying to create peelable stickers - so I need to stick the tape to
some kind of backing that the laser won't cut. If I were to stick it onto
a sheet of regular aluminum kitchen foil - would the laser be able to cut
the tape without cutting the foil?
4) I've only seen Kapton come in that golden color - can you get it in black?
5) Are there other kinds of self-adhesive tape that it would be OK to cut
in this manner?

-- Steve

[Amishacker]

These won't be the best answers, but they express my concerns.

I know it's possible to laser cut Kapton tape...but I have some questions:

1) Is it OK to cut the self-adhesive kind of Kapton tape?

Relatively OK. Certainly most adhesives are starch or polyurethane based. 'decently ventilated area' but not severely carcinogenic or poisonous.

The laser will mostly blow it to carbon and gas anyway:

http://en.wikipedia.org/wiki/4,4%27-Oxydianiline

No chlorine, just organics. AOK 

2) What settings are reasonable for tape?

 

http://www.ladyada.net/library/smt/laserstencils.html

30% speed 100% power 600 dpi? 

3) I'm trying to create peelable stickers - so I need to stick the tape to
some kind of backing that the laser won't cut.  If I were to stick it onto
a sheet of regular aluminum kitchen foil - would the laser be able to cut
the tape without cutting the foil?

I would not sanction putting anything IR reflective in there.

Aluminum foil counts.

You could look for something with high thermal conductivity and thermal mass that doesn't reflect, like granite...

Or... ask these guys for IR transparent Selenide glass perhaps

https://www.inventables.com/

If it's IR transparent (in the correct wavelength) it should be untouched

 

4) I've only seen Kapton come in that golden color - can you get it in black? 

Kapton plastic is polyimide

http://en.wikipedia.org/wiki/Polyimide

The opacity varies, and you can get black Kapton plastic (probably pigmented) but I think the application for the tape constrains the color.

...which begs the question: Why that particular tape?

 

5) Are there other kinds of self-adhesive tape that it would be OK to cut
in this manner?

Yeah, this sounds like a Matt, Danny, or Martin question, but I think I can box out the basics.

Lots of tapes are OK

Don't reflect the laser, don't burn plastics that contain chlorine, try not to start a fire.

http://www.pololu.com/docs/0J24/3

If it's made of organics (CHON) it's probably fine.

Nix PVC and metal, and you should be OK

I would suggest trying this first:

http://www.uline.com/Product/Detail/S-11925/3M-Strapping-Tape/3M-860-Black-Economy-Strapping-Tape-3-4-x-60-yards?pricode=WU325&gadtype=pla&gclid=CMzjop-Zn7MCFcaiPAodbU8ALA

Experimentation will prove the point, but please don't hurt our laser.

...and get a second opinion. Mine is considered but not authoritative.

[Steve Baker]

Amishacker wrote:
> These won't be the best answers, but they express my concerns.

Very helpful though!

> I know it's possible to laser cut Kapton tape...but I have some questions:
>>
>> 1) Is it OK to cut the self-adhesive kind of Kapton tape?
>>
>
> Relatively OK. Certainly most adhesives are starch or polyurethane based.
> 'decently ventilated area' but not severely carcinogenic or poisonous.
> The laser will mostly blow it to carbon and gas anyway:
> http://en.wikipedia.org/wiki/4,4%27-Oxydianiline
> No chlorine, just organics. AOK

That's one less concern.

> 2) What settings are reasonable for tape?
>
> http://www.ladyada.net/library/smt/laserstencils.html
> 30% speed 100% power 600 dpi?

Aha! That's for a 30 to 40 watt laser - so I'm guessing 60% or so power
on our 60 watt beast.

> 3) I'm trying to create peelable stickers - so I need to stick the tape to
>> some kind of backing that the laser won't cut. If I were to stick it
>> onto
>> a sheet of regular aluminum kitchen foil - would the laser be able to
>> cut
>> the tape without cutting the foil?
>
>
> I would not sanction putting anything IR reflective in there.
> Aluminum foil counts.

Ah...good point! That's why I ask first and cut later!

> You could look for something with high thermal conductivity and thermal
> mass that doesn't reflect, like granite...
>
> Or... ask these guys for IR transparent Selenide glass perhaps
> https://www.inventables.com/
> If it's IR transparent (in the correct wavelength) it should be untouched

The problem is that I want to stick the tape onto some sort of backing
material - then laser through the tape, leaving the backing material more
or less intact. Then I can hand someone the whole thing and they can peel
the Kapton "stickers" off of the backing as needed. A traditional waxed
paper backing would be great - but I don't think it's going to be easy to
control the laser power accurately enough to cleanly cut the tape while
leaving the paper alone.

Glass and granite are obviously not going to be much use for that!

I suppose that at 30% speed on the laser, I could use thin plywood as the
backing material. It would get etched but not cut through...then (as a
bonus) I could still cut through both tape and plywood to chop up an
entire sheet of stickers into individual chunks to give to people.

>> 4) I've only seen Kapton come in that golden color - can you get it in
>> black?
>
> Kapton plastic is polyimide
> http://en.wikipedia.org/wiki/Polyimide
>
> The opacity varies, and you can get black Kapton plastic (probably
> pigmented) but I think the application for the tape constrains the color.

You're probably right. It turns out that there *is* a black variation of
Kapton ("Kapton-B") - but it comes in slabs and I don't see anyone selling
it as tape.

> ...which begs the question: Why that particular tape?

My thinking went like this:

I need a material that's

a) Black
b) Flexible
c) Self-adhesive
d) Safely laserable

Something like electrical tape would be great - except that it's PVC and
that's a no-no for lasering because of the chlorine. Other tapes are
known to catch fire easily - so those are out. I know that kapton cuts OK
and doesn't catch fire easily - so it seemed to me to be a candidate.

I've looked at cloth too - but I need very small pieces of it (like
1"x1/4") - and something like cotton or silk is gonna fray at the edges
and fall apart. It would have to be something synthetic that would melt
and seal around the edges...but then we're back to plastics again.

>> 5) Are there other kinds of self-adhesive tape that it would be OK to
>> cut in this manner?
>
> Yeah, this sounds like a Matt, Danny, or Martin question, but I think I
> can box out the basics.
> Lots of tapes are OK
> Don't reflect the laser, don't burn plastics that contain chlorine, try
> not to start a fire.
> http://www.pololu.com/docs/0J24/3
> If it's made of organics (CHON) it's probably fine.
> Nix PVC and metal, and you should be OK

Right.

> I would suggest trying this first:
> http://www.uline.com/Product/Detail/S-11925/3M-Strapping-Tape/3M-860-Black-Economy-Strapping-Tape-3-4-x-60-yards?pricode=WU325&gadtype=pla&gclid=CMzjop-Zn7MCFcaiPAodbU8ALA

Yeah - that's a possibility. Polypropylene is purely organic (just carbon
and hydrogen) - so I presume it's safe to cut so long as whatever coloring
they put in it is OK. It's just tough to find details on whether it's
likely to catch fire in the laser or something like that.

> Experimentation will prove the point, but please don't hurt our laser.
> ...and get a second opinion. Mine is considered but not authoritative.

Yeah - being very sure not to hurt the laser is definitely my largest
concern. Getting a second opinion is why I posted my question here!

-- Steve

[Amishacker]

I think you're on the right track Steve, you just scared me with the aluminum foil.

I wring my hands because I'm not used to answering technical questions with brains like Martin, Matt, and Danny around.

I'm not an authority on anything, I just read alot. So there you are.

Anyway, part of the polypropylene idea was that I know it isn't likely to burn and is used in sutures.

About as pedestrian a plastic as I can think of, from a safety standpoint

But. I am concerned that it will shrink and melt, thus deforming in unworkable ways.

If the laser power is just right, it should blast a very precise area and avoid this problem.

My confidence on that is not high, though.

Please let me know where the experiments take you.

[Matt C.M.]

Aluminum foil is fine as a backing, the machine bed is an aluminum sheet, and you can cut directly on that.  The glass blocks IR, and the beam is going to be way too disperse to damage the glass by the time it reaches it.

[Amishacker]

Not to contradict you on aluminum foil Matt, but just to be sure:

http://www.heatshieldradiantbarrier.com/physics_of_foil.htm

There is definitely a reason the honeycomb is shaped like it is. Besides ventilation.

Dispersal is a big factor, since anything less than a focused beam has less net power than most heat lamps.

...but aluminum foil and 'space blankets' are the two most IR reflective materials in common use.

Bad idea? http://en.wikipedia.org/wiki/Space_blanket

If we're OK with trying it, I would prefer to be proven wrong.

I've got plenty of space blankets, and they're thin enough that they might even cut if absorbed heat amount to anything.

I don't like cringing in anticipation of uncertain physics, but I like damaging prized tools even less.

Can anyone speak from experiment on this topic?

[Matt C.M.]

you can cut WITHOUT the hex grid you know. and that plate is solid aluminum.

[Amishacker]

I did not know that you can safely cut with the aluminum plate under that grid in focus, no.

I know metals can be cut by laser if the focus and power are sufficient, but I was concerned that reflected IR would heat the lens gantry and deform the lens or mirrors there.

Certainly, industrial lasers that cut metal have a large metal heat-sink around the laser aperture, which presumably is as much for hot ablated material as reflected IR.

http://upload.wikimedia.org/wikipedia/commons/c/c4/Industrial_4kW_laser_with_flying_optics_system.jpg

Like I said, I don't want to be superstitious. Can we test with a mylar space blanket, or would that be a Bad Idea?

It might be useful to laser-cut that material for Jon's balloon obsession.

[Martin Bogomolni]

You -can- cut directly on the metal plate.. the reason we choose not
to, is that the metal plate will become discolored, and the item being
cut will be cut -very- poorly as the smoke will spread and discolor
the back side.

This works well for very thin things though, and you can cut thin
things (like paper, labels, etc) since they make little smoke or
residue.

-M

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[Matt C.M.]

I have cut mylar, it works fine.  It does tend to shrink and curl if the power is too high.