Here is the Results i got using the Laser Machine, The Material i used is MDF Wood, here are the results i got for laser engraving.
After that i went to try the kerf Adjustment, i did two tries, one with smaller sample and another one with bigger sample.
Here the total rectangle length = 60mm
number of rectangles = 12
rectangle length after engraving = 58.22mm
k = (60-58.22)/12 = 0.148mm
similarly here
Here the total rectangle length = 120mm
number of rectangles = 12
rectangle length after engraving = 118.53mm
k = (60-58.22)/12 = 0.1225mm