Need Help!- edged part

[CNC_FAN]

Hi;
I have one of those Toshiba 4 axis stepper driver board from ebay which is controlled by
mach3 program.i have a good power supply for that.
my retrofit mill is from central machinary that I am using it as a CNC.
here is the problem:

the parts i cut has depth line like steps on it and every layer that is cut is a little off from previous one.
seems like if i cut squire pocket top and left side has sign of steps but right & bottom side is clean cut.

I am not sure if i lose some steps or there is other reasons involved.
the part i am cutting is plastic and the feed rate is 6 IPM at 1400 RPM with 1/4 endmill.
is there anybody the knows the resone(s) and solutions for this problem?

Thanks

[fatal-exception]

Sounds like you spindle is out of tram with your table.

Search Google for more information about tramming.

Paul

[CNC_FAN]

i will do my research thanks for respond