I finally fired up the laser today. It's the 60W model from Full Spectrum Engineering.
No problems at all. It measured 60W with my Ophir laser power meter. Beam diameter at the laser is about 3/16".
Since I've been in laser-light-show mode for a long time, I wanted to see what the beam divergence was on this laser.
The large black circle in this picture is the beam hitting thermal paper 58.5 feet from the laser.
I shot the laser at my concrete basement wall for about 30 seconds and then found the warm spot by feeling of the wall.
I then taped a piece of thermal paper over the spot and fired the laser for about 5 seconds.
The brown area in the middle of the spot is where the paper started to char.
This picture is of the back of the thermal paper, showing the charred area.
The spot dimensions are 2.75" wide and 3" tall. There seems to be an area above the main spot that's affected by rising heat.
I used 2.75" as the beam diameter for the divergence calculation.
The calculated divergence is 3.65 mR. That seems a little high, but I don't have the specs on the laser. (Henry - you want to chime in?)
So, the farthest my cutting head can get from the laser is about 11 feet. At that distance, the beam diameter will be about 0.67". That is for the entire spot.
If I use the diameter of the charred area (1") to calculate the divergence, the spot size at 11feet will be 0.34".
The reason I want to know this is because the entry hole for my cutting head is 0.4" in diameter. It looks like the beam will be larger than the hole and may cause ghosting like hoda113 is reporting on his system.
We'll just have to see...