Cutting Power & Speed vs different focus lens (6mm acrylic)

[Tech_Marco]

Per a customer request, I have ran a few test on a F4 100W laser tube on a piece of 6mm acrylic with three different focus point lens
The lens are high quality one with following focus point:
1) 50.8mm
2) 63.5mm
3) 68.5mm

To cut through 6mm with a 50.8mm focus lens, the speed was 15mm/s. As a result, the side effect of inclination is more obvious
For the 63.5mm focus lens, the speed was dropped to 12mm/s and just barely to cut through. The side effect of inclination is less compare to the 50.8mm
The last one was 68.5mm and the speed need to tuned down to 10mm/s. The inclination problem seems must less compare to the previous two lens.
Engraving resulted better with 50.8mm and power seems more intensive than the 68.5mm.

I did a last cut on a 4.5mm acrylic (better quality acrylic) the result was perfect with 68.5mm and 10mm/s speed. The cut was clean inclination side effect was not noticeable with naked eyes

I'll do more test on wood and will post it here once completed. Hope this is helpful for you guys to select proper focus lens for your job.
The pictures link can be found here:

>> viewtopic.php?f=16&t=1770 <<


Marco