Unipolar stepper motor with ULN2003?

[irving2008]

oh dear... there are three problems, but not in the circuit as such...

1/ you are probably using the wrong sort of motor... this type of circuit only works with very small motors rated to work on 12v, not high power steppers of the sort you'd use on a CNC machine

2/ Not reading/understanding datasheet and the limitations of this chip

3/ the basic lack of current limiting in a unipolar design (which I suppose is a circuit problem but is related to problem 1)

what motor are you using? what is the DC resistance of each coil? and how are you trying to drive it (one phase at a time, or overlapping phases?)