Plastic take out food container lids appear laser engraved - how can they do it?

[Mayo Pardo]

I'm guessing the plastic container company offers this service for an additional cost per piece, but how can they sell what's essentially a throw away disposable container (although they do mention that it's reusable) with an engraved lid and still make it affordable to the restaurant?

The lid is polypropylene.
The fast food place has their logo and slogan and other graphics on it, and the marking feels slightly raised on the surface.
It's not screen printed or pad printed on - the plastic has a frosted look in the lettering and graphics.

Maybe it's more likely they laser engrave in reverse the mold that's used for making the lids?
I searched online and found the company that makes these and photos are shown on this page:
http://www.cubeplastics.com/products/customer-branding

[Scott Marquez]

My guess is that you answered your own question and the branding was done in the mold.
Scott

[Keith Downing]

My guess is that you answered your own question and the branding was done in the mold.
Scott

My guess as well.

[Dave Sheldrake]

If they have a belt fed galvo that would be very cheap to do on a production run

[Kev Williams]

My bet: They're not engraving the plastic. They're etching vacuum or injection mold inserts with a fiber. The mold(s) themselves (there's 4 different shapes in the display pics on the website) are likely 9 or 12 cavity blanks. All it would take is to laser etch dirt cheap 1/16" aluminum drop-in inserts, then start the molding...

When done with a run that customer's inserts get filed away for later use, then next customers inserts go in, lather rinse repeat...

[Gary Hair]

"We can add our unique venting mechanism to any customized embossed lid"

The key to the answer is "customized embossed lid". Pretty sure Kev hit the nail on the head with the custom insert for the mold.