Experience with PETG?

[Sean Bullock]

I have a job coming up that requires cutting and engraving PETG 3/8" thick. Never worked with this material before. How does it behave under the laser? Comments? Suggestions?

[Brian Robison]

Hi Sean,
I wonder what the heck it is.
If I had to guess it would be Poly Pro with talc and glass fillers?

[Scott Challoner]

Are you sure it's not supposed to be PETG? I just got a sheet of PETG to play with, but I haven't tried it yet. It's supposed to cut nicely and is called "an economical alternative to polycarbonate." I believe it's a type of polyester.

[Brian Robison]

Now that would be.....are you ready?
Polyethylene Terephthalate Glycol Comonomer

[Scott Challoner]

Of course. Everyone knows that.

[Mike Null]

And it cuts sloppy. Melts easy.

[Doug Griffith]

I have cut a ton of PETG and it is very sloppy. Smells pretty bad too.

[Larry Bratton]

I've never tried PETG, but I was told by a representative of a company that makes it, that it melts when lasered and is not good product for it. Subsequently, I took his word and never tried working with it.

[Jack Harper]

I too have tried cutting on the laser and found the same results. It cuts quite nice on the waterjet though.

[Sean Bullock]

You are absolutely right. I must have misunderstood the gentleman as I was discussing his project over the phone. PETG it is.

So, here is another question: why would he want to use PETG (keep in mind he is an optical engineer) for a wave guide, ex. edge-lit sign, rather than use acrylic? What properties does PETG have that might create some advantage over acrylic? Or is he just using it because he doesn't know what else to use?

[Mike Null]

If he's an optical engineer he knows how to check the characteristics of materials. It is an FDA approved material for food contact for whatever that's worth.

It is also very much resistant to certain chemicals which was the spec of my customer.

This is Brian's field so I'm sure he can offer documentation.

[Richard Rumancik]

I have cut PETG .062" thick. It will cut but tends to turn a bit whiter at the cut line, in my experience. The edge tended to stay a bit sticky for some reason. There will also be some raising along the edges. For a "light pipe" application acrylic is commonly used and will laser with a glossier edge than will PETG. I don't think you will have good success with trying to engrave it. You can make a mark but it won't have a good appearance.

Although it may not be a common name lots of soda bottles are made from this material.

[Martin Reynolds]

I cut lots of PETG. It is a dirty material, and your laser will need frequent cleaning to catch all the white dust that settles. Plus, you need a good ventilation system as the smell can get around a bit more than acrylic odors. Edge quality can be very nice, but it is also very sensitive to flashback and air assist.

I would not expect much from the engraving, but it is worth a try.

It is a very tough material, but it also scratches easily.

[Bill Cunningham]

Now that would be.....are you ready?
Polyethylene Terephthalate Glycol Comonomer

On no!! Not another one of those chemical names!! it took me quite a while to remember pentaerythritol tetranitrate (PETN)!! Although cutting it on a laser could be a real blast

[Sean Bullock]

I cut lots of PETG. It is a dirty material, and your laser will need frequent cleaning to catch all the white dust that settles. Plus, you need a good ventilation system as the smell can get around a bit more than acrylic odors. Edge quality can be very nice, but it is also very sensitive to flashback and air assist.

I would not expect much from the engraving, but it is worth a try.

It is a very tough material, but it also scratches easily.

Can you suggest a setting for the cutting? working with 3/8" thk material.

I will be engraving, but only to about .004". He wants a frosted effect for the engraving much like one might get with acrylic, so I figure I will go about 80% black on the graghic. How does that sound?