Meaning
Degree to which a motion system can reach a specific target location within a defined tolerance. Engineers evaluate precision positioning accuracy by comparing the average of several attempts to reach a point against the true coordinates.
Target Consistency
High performance motors and encoders are required to maintain a low margin of error. When the precision positioning accuracy is high, the machine can reliably place the tool within a few microns of the intended spot. This capability is necessary for micro-machining and semiconductor fabrication where feature sizes are extremely small.
Resolution Limit
Smallest increment of motion the system can detect influences the final result. Improving the precision positioning accuracy often involves upgrading the feedback sensors to provide higher resolution data to the controller. Without fine resolution, the system cannot make the tiny adjustments needed to stay on target because the digital feedback would lack the granularity to register the difference between a successful move and a slight overshoot.
Repeatability Assessment
Consistency over thousands of cycles determines the long term value of the equipment. A system might have high precision positioning accuracy in a single test but fail to maintain it during a long production shift. Verification of this consistency under load is a critical step in the machine commissioning process.
