Help Me Mr. Wizard or Ned!

I saw this and wanted your input. Is my laser toast?

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So let’s talk first about what is Enduramark. I’ve looked at the patent before and it’s composed of a mixture of fine glass frit, fine clay and molybdenum oxide. They are claiming that the molybdenum oxide is a pigment and the clay is a thermal absorber for the laser energy. The clay helps melt the glass frit into which the molybdenum oxide is suspended. So the mark left on the metal is glass bonded to the metal, which is colored by the molybdenum oxide.

So using “Molylube”, which contains primarily molybdenum disulfide, will not be the same marking end product.

It seems likely that the molybdenum disulfide is being heat bonded to the metal by the laser. There is plenty of scientific literature that talks about heat bonding molybdenum disulfide to metal surface, granted the temperatures (300-400C) I’ve seen so far are typically less than 40W CO2 temperatures.

The general chemistry quoted in that link is true and the literature does indicate that you can convert the disulfide to the trioxide by roasting at elevated temperatures in air. But, I’m not convinced that the conversion rate during laser engraving will necessarily be large enough to result in a large amount of thermally decomposed molybdenum disulfide, and therefore lots of sulfur dioxide to become sulfuric acid.

So unless you are doing a lot of engraving with molylube I wouldn’t necessarily be concerned. It would be interesting to put some pH range paper in the path of the exhaust while engraving molylube to get an idea of how acidic is the exhaust.

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Thanks for the reply and explanation.

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Well I wanted to know how well molybdenum disulfide (MoS2) absorbed CO2 laser energy (10.6 um). This is in the infrared region and in IR spectroscopy 10.6um would translate to 943 cm-1. I couldn’t find a really good scan of MoS2 but, from what I did find, it appears that MoS2 is not a particularly strong (perhaps even weak) absorber at this wavelength.

So that would mean it’s less likely to quickly thermally decompose from lasering.

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