Background Inertial-confinement-fusion target capsules require high spherical-profile consistency and accurately distributed surface features. For polymer target capsules carrying cross-scale modulated structures, stable microscale material removal, tool-path stitching between the two hemispheres, full-surface profile measurement, and coupling of multi-axis motion errors remain major obstacles to submicrometer fabrication and quantitative evaluation.

Purpose This study aims to establish an integrated ultra-precision fabrication and measurement methodology for cross-scale modulated structures on glow-discharge-polymer target capsules, with emphasis on stable material removal, equator-avoiding feature distribution, spherical-surface tool-path generation, conformal profile measurement, and motion-error separation.

Methods A minimum uncut chip thickness model and a specific cutting energy model were established based on material-flow partitioning near the stagnation point and the elastic-plastic removal mechanism. An overall angular-offset strategy was developed to move microspherical pits away from the equatorial reversal region while maintaining their distribution uniformity. Direct-forming and spiral-trajectory machining programs were generated by transforming feature coordinates and tool paths from the mathematical spherical coordinate system to the machine-tool coordinate system. For profile measurement, single-point nanometer displacement sensing was integrated with XZBC multi-axis conformal scanning. A multi-body error-transfer model and a rotary-error separation framework were further constructed to evaluate and compensate for the effects of B- and C-axis motion errors. Typical capsule samples were subsequently fabricated and measured.

Results The minimum uncut chip thickness of the glow discharge polymer was determined to be approximately 0.2–0.4 μm. Below this range, the specific cutting energy increased sharply, and material removal was dominated by ploughing and elastic recovery; above this range, stable cutting became more achievable. The angular-offset strategy prevented microspherical pits from crossing the equatorial stitching region without introducing the pronounced distribution nonuniformity caused by direct pit deletion. Error-transfer simulations showed that B- and C-axis angular deviations could introduce non-negligible profile errors. Experimental fabrication produced microstructures with a profile peak-to-valley value of 0.266 μm and a surface roughness Ra of 20.3 nm. Conformal scanning reconstructed the hemispherical profile of a 2 mm-diameter capsule, and the measured local microstructure profile errors were 0.146 μm and 0.152 μm.

Conclusions The proposed framework integrates material-removal modeling, equator-avoiding feature distribution, machine-coordinate tool-path generation, conformal scanning, and motion-error compensation. It provides a feasible technical route for the submicrometer fabrication, spherical-surface measurement, and quantitative error evaluation of cross-scale modulated structures on polymer target capsules.