I am new to CNC, and very new to woodworking, and have been having newbie troubles for past few weeks.

Today I've tried cutting a piece of oak, and ended up with damaged work.

Here is the picture:



What puzzles me is that other side of the same piece ended up perfect, like this (sorry for the blur):




Area I was cutting was 20 x 20cm.

I am not sure if this (breakage and 'hairy edges') happened because of wood, or because of something else.

Any pointers that could help this newbie are much appreciated

Thanks.