Question: if a machine cannot make parts that meet specifications usl...

If a machine cannot make parts that meet specifications (USL and LSL), what can be done to improve this situation:

		Everything mentioned here
		Do a 100% inspection to separate good from bad parts and rework parts that can be corrected
		Perform controlled experiments to determine the main sources of variation and try to solve them
		Shift production to a different (better) machine, i.e. decrease standard deviation σ
		Ask the customer to relax the specified limits, i.e. make the (USL – LSL) difference larger