Application of calibrated X-ray computed tomography in micro-scale hidden structure dimensional measurement

X-ray computed tomography (XCT) is employed as a non-destructive high-resolution tool to measure both external and internal geometrical features' dimensions. The XCT study investigates a high-density stainless steel dog bone sample, a low-density glass fiber with defects and standard artefacts including a hidden step height (nominal value: 120 μm, Type A1) and eight standard cylinders with certified reference diameters ranging from ϕ 0.1299 mm to ϕ 5.1960 mm. For the dog bone sample, XCT's volumetric pixel (voxel size) is adjusted to 20 μm at a voltage of 120 KV applied to the X-ray source. The external dimensions, up to 45 mm, measured by XCT are compared favorably to corresponding dimensions measured by a calibrated digital caliper with a resolution of 0.01 mm. The deviation between XCT and the caliper is found to be less than 30 μm for millimeter dimensions up to 45 mm of the dog bone sample. The deviation of the hidden step height (nominal value: 120 μm) is less than 1.0 μm between XCT and a laser confocal microscope traceable to SI. The paper explores XCT's application in dimensional measurement using a high-density stainless-steel dog bone sample and a low-density glass fiber sample with defects. The results indicate that XCT achieves accurate measurements for dimensions up to 45 mm and is effective in revealing hidden defects from 30 μm to 50 μm in the glass fiber sample. In addition, eight standard cylinders with certificated reference diameters from ϕ 0.1299 mm to ϕ 5.1960 mm are measured by the proposed XCT, showing a maximum deviation from the reference diameter of less than 6.0 μm. Along with the related experimental results, it demonstrates XCT is a promising tool for conducting micro-scale external and internal dimensional measurements.