I like the price point of stepper equipment, but am concerned about accuracy.

Has there been any thought put into a closed loop stepper system? Something simple like an encoder that would tell the controller that the X,Y,Z step was actually done (by getting a single pulse back from the encoder on the leadscrew or somewhere). If the controller does not get its pulse in Xus, then don't ACK the last command back to software.

CAM software would put out a code, and wait for an interrupt or logic change on a pin to ACK that cmd and then issue the next.

Would this be overly complex to implement? Has it been done? Anyone come up with anything simple? Or is a general use stepper setup no real danger of getting out of position 'sync' with where the software thinks it is?

I can only think that backlash errors would ALWAYS put the cutting tool in a different postitin than the software thinks its at.