What to do when a low-power engrave comes out inconsistent?

[AhnoldZ]

To elaborate on palmercr’s reply above:

As I’ve posted before the waist size is listed in the specs of a laser. (The waist size is the minimum cross-section of the beam in the laser cavity.) This is because it is a fundamental property of the laser and determines many other properties of the beam. Focusing a laser beam does not change this property, you will always get a waist, and never a point.

For more information about the properties of laser beams I would refer people to this article:

Gaussian beam

The article is specific to a ‘Gaussian Beam’ which is what you get if the manufacturer of the laser took care to make sure the laser produced this fundamental mode and not a higher harmonic. It’s called the TEM00 mode. (The laser cavity is a resonant system and as such supports multiple wave modes. An acoustic analogy might be a drum.) The GF specs used to note the that the TEM00 mode was produced:

Eye protection specifications?

So this is actually on teh technical specs page: Custom Laser — Custom CO2 laser tube operating at 10,600 nm averages 40W for Basic Model and 45W for Pro Model Laser Quality — TEM00 tube produces smaller spot size and greater power density, increasing engraving precision and cutting speeds Fixed Alignment — Factory calibrated optical system does not require user calibration Sealed Optics — Enclosed optical path with cleanable and replaceable windows protects the laser optics to avoid cleaning…

And there have been posts before that this is not the standard for hobby lasers:

The importance of air assist

Also the laser is TEM0. Many other hobby lasers use TEM1 so I think that type is more commonly available. edited to add: Noticed at Maker Faire demo that the kerf is really tiny due to the TEM0 mode. Nice feature if you plan to do fine engraving.