Lainaathis is usual problems for all machine that working without counter ballance and just using Beark system ,...if you all pay attention to AL THE Man , his explain very well the situation , but let me added , on my experience for break that work with Dc voltage ( 100 Volt or more) after EMG push , or machine cut off , the must problems in cause of dusty or dirty the the break surface plate ,...you can clean it very easy ,... and also after 5 years or 10 years the springs needs to change already ,... also for new break it needs to have adjust befor put on the machine ,..usually you need the Gap between 0.2 up 0.6 mm it just enough , more than this you have falling down the Z axis ,...be sure !