Engraving polypropylene

Hello, I am trying to engrave on black Polypropylene and I am having no luck yet. The end result looks very melted, it is not a nice crisp design.
This is the product I am trying to do engraving on:

Anybody has had any luck with such material? If so, what settings did you use?

The plastic is about 1.5 millimeters thick and the case is 1" high when closed.

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https://www.ulsinc.com/materials/polypropylene

Polypropylene (PP) is a thermoplastic commonly referred to as a polyolefin. Commercially available products based on polypropylene include Formex™ and Statex™. Polypropylene can be processed with a 9.3 or 10.6 micron CO2 laser without an appreciable difference in process quality. Polypropylene does not readily absorb the energy of the 1.06 micron fiber laser. Cutting of polypropylene can be performed with a CO2 laser to produce a clean non-discolored cut with a slight raised edge near the point of ablation. Laser engraving and laser marking of polypropylene are possible using a CO2 laser. However due to the relatively low melting point of polypropylene, this can lead to localized melting and a non-uniform surface at the point of laser interaction.

Looks like you’re going to have to experiment with this…

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I think I’d try multipass fast and low power to give the material time to cool in between visits of the laser. Perhaps also lower lpi may non-intuitively give more crisp results for a similar reason.

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Hi, thanks for the ideas. What is LPI?

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LPI = Lines per inch. At the higher resolutions the lines actually overlap, plus even if they didn’t, the heat would because the plastic may not cool completely so more likely to melt when the next pass travels nearby.

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I had a similar need. The Engrave settings were 1000 / 50 / 270 with green painter’s tape as masking. My surface height was 0.364 in. I’m happy with the result.

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