I have an Ortur LM3 10 watt and just getting started.  I would be interested in the settings you used.  The  engraving is very clean and looks good.  I am just finishing up my  enclosure for it and an inline exhaust fan going outside.  It was not easy getting the hole through the wall to the outside with the snow yesterday. 

My Ortur is 15 watt.   Laser Master 2 purchased 2 yrs ago as I remember.   Settings were 90% power 85 mms per sec.  speed.   Air on.   Air is supplied by a aquarium air pump.   Exhaust goes out a window, have a insert and close the window down on that.     4 inch hose through the insert    Think the air helps get a clean image.   Ortur now has a air pump available, was not available when I put my laser together.    I too have an inline exhaust fan, variable speed.    Use Lightburn for the software.    The Lightburn software s a lot more than I will ever need or use or will ever learn.    Hope this answers the question.     

Thanks for the comment on the blocks.  

Ron