Measurement skills is a science with its own system, covering a variety of disciplines, and strong theoretical and practical. The basic knowledge of measurement skills for cartoning production lines is the basis for mastering measurement skills and completing the measurement of geometric parameters of mechanical products. Measurement: The operation is to measure the value of the measured object. During this operation, the measured object is compared with the standard quantity of the recurring measurement unit, and the measurement result is expressed in terms of the ratio of the measured object to the unit quantity and its accuracy. For example, using a vernier caliper to measure the diameter of a shaft is to compare the object (diameter of the shaft) with a specific measurement method (measured with a vernier caliper) and the length unit (mm). If the ratio is 30.52 and the accuracy is ±0.03mm, the measurement result can be expressed as (30.52±0.03) mm. Many measurement processes include: measurement object, measurement unit, measurement method and measurement error.