Actually, I had done that. My assumption was that the motors never had sufficient torque , but the balsa was very forgiving. I was doing production work and using multiple depth passes on 3/8 stock. I am assuming, therefore, that the load on the motors was minimal.
When I began to cut MDF, I tried cutting a simple pocket, .125 deep at 58ipm, with a .1875 tool, and it failed to cut evenly. By evenly, I mean that the x y went off the normal circular pattern. When I slowed down the machine, things improved, but I was still puzzled by the drastic errors. We're talking about the work being ruined due to the errors. When I reduced the feeds, things looked almost good, except for the z failing to drill all the way down. The motors sounded fine; the work was not coming out right. I purchased the machine for Balsa and had never worked with MDF. When I cut pine of similar thickness, things were fine. I have to assume that the mdf's high density places major strains on the motors.
All of this, however, does not explain why I cannot make the motors slip by increasing the acceleration.
If the motors do indeed have that much torque, then the original feed of 58ipm would not have created all the errors in cutting.
When these things happen, it's like going back to school to study math 101.
tony