This paper presents a micro-coordinate measuring machine (micro-CMM) for large-scale dimensional measurement of a micro-slit on a precision die coater by using a shear-mode micro-probe. A glass micro sphere with a nominal diameter of 52.3 μm was attached on one end of a tapered glass capillary tube as a probe tip ball. The micro-slit width of a slot die coater with a nominal slit width of 85 μm was measured by the micro-CMM. The probe tip was placed in the slit for the measurement. The effective working length of the probe was confirmed experimentally to be at least 1 mm. In order to measure the gap width uniformity over the entire slot die length of 200 mm, an air-bearing linear slide with a travelling stroke of 300 mm was employed in the micro-CMM to position the probe along the length direction of the slot die. The angular alignment error and the motion error of the air-bearing linear slide as well as those of the stages for positioning the probe along the direction perpendicular to the length direction of the slot die were investigated for evaluation of the expanded uncertainty of gap width measurement.

This paper presents on-line qualification of the effective diameter of the micro-stylus tip ball of a micro probing system for precision length measurement of micro-features on precision parts by utilizing a set of gauge blocks as the qualification artefact, which is composed by one calibrated gauge block and two supporting gauge blocks that are wrung together for a good mechanical stability. The qualification artefact is aligned side by side with the precision part to be measured for enabling a rapid transfer between the qualification step of the probe two-point tip ball diameter and the length measurement step of the precision part. Based on the proposed setup, on-line qualifications of a micro-stylus with a nominal tip ball diameter of 52.6 μ m were carried out by using two methods referred to as Method A and Method B, respectively. Method A is operated by probing the opposite sides of the gap between the two supporting gauge blocks separated by the calibrated gauge block, and Method B is operated by probing the opposite sides of the calibrated gauge block supported by the two supporting gauge blocks. Intensive uncertainty analyses based on the experimental results and the geometrical models were carried out to compare the performances of these two methods. Method A, which was confirmed to be more accurate and faster than Method B, was then employed to measure the width of a micro-gap on a precision part with compensation of the determined effective two-point tip ball diameter.

Microstructured roll workpieces have been widely used as functional components in the precision industries. Current researches on quality control have focused on surface profile measurement of microstructured roll workpieces, and types of measurement systems and measurement methods have been developed. However, low measurement efficiency and low measurement accuracy caused by setting errors are the common disadvantages for surface profile measurement of microstructured roll workpieces. In order to shorten the measurement time and enhance the measurement accuracy, a method for self-calibration and compensation of setting errors is proposed for surface profile measurement of microstructured roll workpieces. A measurement system is constructed for the measurement, in which a precision spindle is employed to rotate the roll workpiece and an air-bearing displacement sensor with a micro-stylus probe is employed to scan the microstructured surface of the roll workpiece. The resolution of the displacement sensor is 0.14 nm and that of the rotary encoder of the spindle was 0.15μ. Geometrical and mathematical models are established for analyzing the influences of the setting errors of the roll workpiece and the displacement sensor with respect to the axis of the spindle, including the eccentric error of the roll workpiece, the offset error of the sensor axis and the zero point error of the sensor output. Measurement experiments are carried out on a roll workpiece on which periodic microstructures are a period of 133 μm along the circumferential direction. Experimental results demonstrate the feasibility of the self-compensation method. The proposed method can be used to detect and compensate the setting errors without using any additional accurate artifact.