I'm recovering from surgery so I'm moving a bit slow, but I managed to make an initial pass at looking into my new NEJE A40640 laser module. 

Here is what comes in the box.  Don't mind the damage to the box, that was my dog's fault.  Notice that there is no power supply or laser glasses with this module. Sadly they don't have an option to buy those parts.  

The 30w module came with a 12v 3a power supply and the 40w module is suppose to use a 12v 4a supply.  If you do the math then 12v * 3a is 36w, or just a bit shy of the 40w needed to run the laser at full power.  I will try to dig up a proper 4a power supply, but not today, the 3a module should be enough for now.

If you look at the modules, they are very close to each other but there are subtle differences.  For starters the cooling fins on the 40w module are longer. Also the lens is offset to the right about 1.5 mm on the 40w module.

The lens is both smaller and shorter, only 13.5 mm in diameter and sticking 3.5 mm above the housing.  If you screw the lens all the way in then it focuses about 22 mm below the bottom of the housing.  Mine came unscrewed by one turn with a focus height around 17 mm (or was it 13?).  Anyway I decided to set both of my modules to a 22 mm focus height, that will make them relatively even when comparing them together.

I pulled both lenses off and drew an outline of the resulting spot size at both 10 and 20 mm from the end of the housing.  The NEJE N40630 came out to 9x3.5 mm at 10 mm distance and 16x5 mm at 20 mm distance.  The end of the spot was cut off by the lens holder, so this is probably an underestimate.  The NEJE A40640 module has a spot size of 3x2.5 mm at 10 mm and 5x4 mm at 20 mm.  So it is true that the 40w module has a much slower divergence, that should result in a much smaller dot size, in theory.

I did not take a picture of it but it appeared that the 40w module had a larger spot size than the 30w module under the microscope.  This is wildly subjective because the spot size changes dramatically as you increase the energy and the microscope can't view the spot head on, so it is possible that the microscope changed orientation between readings.  There was also an interesting pattern of dots that appeared around the dot when it is in full focus.  I don't know if this is a side effect of having light emitted in two orthogonal orientations or not.

Anyway I need to work up an air assist nozzle for this, then I can try to make a head to head comparison.

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I found this new cad/cam program and wanted to drop a note on it.  It is thin on documentation but it appears to have limited rotary support built in.  Unfortunently it does not seem to have a trial demo, so there is no good way to verify that it would work for my rotary axis.

https://www.routcad.com/english/cad_cam/routcad25d.html

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Here is an interesting way to generate dovetail connections with a laser. I cant remember if I mentioned it before or not, but I thought it was creative enough to be worth mentioning twice just in case.

https://hackaday.io/project/170065-laser-cut-dovetail-enclosures