I run a Calypso Hammerhead Mark IID. When I start to run my pattern about one quarter of the way thru the cutting head start to lose home and drift ever so slowly to the yb side. By the end of the pattern the cutting head is off by about a quarter inch. I am not getting any faults and the machine returns to soft home at the proper place. It seems as if the motor is losing its encoder position or as if  there is backlash present. There is no gantry slag or motor slag. Any ideas?

There are a whole bunch of reasons this could be happening. It could be encoder error, it could even be a software issue with offsets not being correctly removed at the end of a cut or traverse line. Is it truly good for the first quarter of the distance, or is it just not noticeable? That info would be helpful. Also, is it repeatable in all areas of the table?

The pattern runs fine for the first or so quarter  as we mic the lines. It starts to go off about a quarter of the way in and it does not happen at the same spot all the time. It happens in several differant areas around the table.

being that it is intermitent would lead one to belive it is some sort of noise or interference. Has the machine always had an issue or is this a new thing that just started recently? Loose wires, bad grounds, all easy things that your should check before you pay the $$ to have it serviced.