共形天线的石英纤维/氰酸酯复材微通道激光加工工艺 (特邀)

Objective Quartz fiber/cyanate resin composites have gained significant application value in high-end aerospace equipment such as conformal radar radomes due to their excellent mechanical properties, thermal resistance, and dielectric characteristics. With the increasing demands for integrated "structural-transmission-radiation" performance in modern manufacturing, high-precision fabrication of micro-cavity arrays on three-dimensional curved shells has become essential for achieving specific microwave functionalities. However, the processing of these materials presents significant challenges. Traditional mechanical processing methods often result in defects such as fiber extraction, resin carbonization, and interlayer micro-cracks, while also struggling to achieve high-precision conformal micro-cavity structures. Ultrafast laser processing demonstrates advantages in non-contact and high-precision capabilities. To address these issues, this study systematically investigates femtosecond laser processing techniques for quartz fiber/cyanate composite microchannels, exploring controllable fabrication processes for high-quality microchannel arrays. This research provides theoretical foundations and technical support for the precision manufacturing of high-performance conformal radomes. Methods This study developed a femtosecond laser micro/nano processing experimental system. The system employed a Yb∶KGW high-frequency femtosecond laser as the light source (Fig.2), delivering a 240 fs pulse width with a tripled wavelength of 343 nm, maximum single-pulse energy of 200 μJ, and continuously adjustable repetition frequency ranging from 10 to 200 kHz, while maintaining a focused spot diameter of 4 mm. Spectral characterization of the quartz fiber/cyanate composite was performed using a UV-Vis-NIR spectrophotometer, revealing a characteristic absorption peak at 355 nm, which provided a scientific basis for laser wavelength optimization (Fig.3). The system integrated a high-speed galvanometer scanning device and a three-dimensional precision displacement platform, enabling precise control of laser power, scanning speed, repetition frequency, and scan cycles via ScanMaster software. Quantitative analysis of microchannel morphology, depth, and sidewall steepness was conducted using confocal microscopy, while scanning electron microscopy (SEM) performed multi-scale characterization of fiber/matrix interface states, surface quality, and defect features (Figs.5-8). The system systematically evaluated the impact of various process parameters on processing quality. Results and Discussions Under optimized parameters, the microchannel array achieves dimensional consistency error below 5%, depth uniformity within ±3 μm, sidewall steepness exceeding 85°, roughness (Ra) under 0.8 μm, and heat-affected zone (HAZ) under 10 μm (Fig.8), fully meeting the manufacturing requirements for conformal antennas.The parameter analysis reveals that a power exceeding 140 mW induces fiber microcracks and resin carbonization, while a scanning speed below 4 mm/s increases groove width by 30% and exacerbates interfacial delamination. After six scans, the system reaches depth saturation with the Ra value deteriorating from 0.6 μm to 1.2 μm (Figs.5-7). This establishes a critical power window of 110-130 mW and a multi-pass low-energy strategy to balance efficiency and quality. Under optimized conditions of P=120 mW, v=10 mm/s, and three scans, the cross-microchannel array exhibits no fiber extraction, carbonization, or edge chipping as confirmed by SEM, while confocal microscopy verifies intact interfaces without delamination (Fig.8). The process demonstrates exceptional parameter control precision and removable material management, meeting the stringent requirements for dielectric structure consistency in conformal radomes. Conclusions This study establishes a UV femtosecond laser processing system for quartz fiber/cyanate composite microchannels. The process features non-contact operation, high precision, and minimal damage, achieving optimal geometric accuracy and surface quality through coordinated control of power, speed, and scan frequency. Spectral characterization and experimental results demonstrate that the material exhibits an absorption rate >85% at 343 nm, with UV laser processing efficiency 3.2 times higher than infrared wavelength, and a heat-affected zone width <10 μm. Under laser power P=120 mW, scan speed v=10 mm/s, repetition frequency 10 kHz, and three scans, the dimensional consistency error of the processed cross-microchannel array is <5%, sidewall steepness >85°, surface roughness Ra<0.7 μm, with no fiber pull-out, interface delamination, or resin carbonization defects. This process fundamentally resolves delamination issues caused by traditional mechanical processing, providing a viable technical pathway and reliable process assurance for manufacturing high-precision dielectric structures in conformal radomes.