Also a good idea to ground right to your work piece if you are able to.
The pic compares a cut on 5/16" that was grounded only through the table to a 1/2" sample that was grounded directly to the plasma cutter.
Good Luck! 
The pic compares a cut on 5/16" that was grounded only through the table to a 1/2" sample that was grounded directly to the plasma cutter.
