Precision CNC machining demands tight repeatability to keep part-to-part variation inside tolerance. Thermal growth, tool wear, fixture shifts, measurement error, and material inconsistency are the main drivers. Statistical process control charts and measurement system analysis identify root causes quickly. Real shop examples—aluminum ribs, stainless stems, copper EDM parts—show reductions from 0.018 mm to 0.005 mm spread using live compensation and gage studies. Practical steps include baseline audits, torque control, coolant discipline, and regular GR&R checks, delivering higher yield and fewer customer complaints.
