About the current on the label of the motor, i would rather think of it like a maximum, instead of a target to be hit.
About the current level on the driver chip, we actually change that with a onboard potentiometer.
The torque will be proportional to the said current level. On the label if the max current rating is lower, the max torque will most likely be lower. On the adjustment pot, if we decrease the current then ofc torque is decreased accordingly. So "the amount of torque you actually need" - you will probably find out yourself by adjusting the pot on the driver.
The driver regulates regardless of which motor type is there. In this sense the stepper motor can not draw whatever curent it wants, but motor can only get what the driver gives him. E.g. can have a motor rated for 5A, but a driver rated of 2A and adjust the driver pot to only put 1A in the motor. The point is, you dont need to match these in your purchase. But if you want to look out for something about matching these two current values, then is better for motor rating to be higher than driver rating, at least for one coz the driver rating is probably given as rms.
What you should be careful about instead, is to get motors that are low resistance, e.g. probably something like 1-2-3 ohms and have a current rating of 1-1.5-2A-... and even more. This means the coil has a thick wire, which translates in a low number of turns because its inside same space form factor, so lower inductance. Stay away from high inductance motors, which have more number of turns, hence thin wire, hence lower current rating and ofc higher resistance - this latter type does not match our usual drivers and power supply.
About the current level on the driver chip, we actually change that with a onboard potentiometer.
The torque will be proportional to the said current level. On the label if the max current rating is lower, the max torque will most likely be lower. On the adjustment pot, if we decrease the current then ofc torque is decreased accordingly. So "the amount of torque you actually need" - you will probably find out yourself by adjusting the pot on the driver.
The driver regulates regardless of which motor type is there. In this sense the stepper motor can not draw whatever curent it wants, but motor can only get what the driver gives him. E.g. can have a motor rated for 5A, but a driver rated of 2A and adjust the driver pot to only put 1A in the motor. The point is, you dont need to match these in your purchase. But if you want to look out for something about matching these two current values, then is better for motor rating to be higher than driver rating, at least for one coz the driver rating is probably given as rms.
What you should be careful about instead, is to get motors that are low resistance, e.g. probably something like 1-2-3 ohms and have a current rating of 1-1.5-2A-... and even more. This means the coil has a thick wire, which translates in a low number of turns because its inside same space form factor, so lower inductance. Stay away from high inductance motors, which have more number of turns, hence thin wire, hence lower current rating and ofc higher resistance - this latter type does not match our usual drivers and power supply.