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Ferrous materials are widely used in the mould industry because of their excellent properties. However, ferrous materials are regarded as difficult-to-cut materials for diamond turning due to their affinity for diamond. The resulting catastrophic tool wear leads to high machining costs in ultraprecision turning. The unpaired d-electrons in the workpiece are regarded as the dominant element causing catastrophic diamond wear during the turning. However, an insightful method for unpaired d-electrons in existing assisted machining schemes is still lacking. As a type of diamond tool, polycrystalline diamond (PCD) tools are inexpensive to appropriately carry out wear experiments. Therefore, in this study, a novel assisted method based on a magnetic field (MF) was applied to suppress the PCD tool wear. Experimental results demonstrated that the MF-assisted machining can reduce the flank wear of PCD tools by 30.6%. The spin polarisation of d-electrons by the MF was the dominant mechanism inhibiting the chemical reaction and graphitisation, and thus suppressing the PCD tool wear. Simultaneously, the suppression of machining system vibration by the Lorentz force also had a positive effect on the suppression of the PCD tool wear. The innovative method provides an assisted machining scheme to inhibit the catastrophic wear of PCD tools.

Deep lunar rocks carry geological information about the primitive Moon and are of great scientific value. In this paper, a coring robot for deep lunar rocks was proposed for the lunar environment based on the wire-line sampling device. This robot consists of the coring executor on the ground to assist in coring tube replacement and sample storage and the wireline self-excavating coring (WSC) robot for active drilling underground, which can provide autonomous deep coring on the moon. Subsequently, based on Prandtl’s failure mechanism and the prediction equations of the mechanical properties of the lunar soil, the mathematical relationship between the ultimate support force and the depth of the support point of the WSC robot was constructed. Additionally, the drilling scheme of the WSC robot at different depths was also determined. The constraint model of the impact module was established, and the structural parameters were optimized through non-linear programming to achieve the maximum impact energy. Simulations of the impact process were then carried out in explicit dynamics. The simulation results show that the optimized impact module can effectively drill through the lunar rocks. This result validates, to some extent, the drilling capability of the WSC robot in lunar rocks. The research work can provide technical reference and theoretical support for deep coring lunar rocks.

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The Moon is the closest extraterrestrial celestial body to the Earth. Sampling and analysis of lunar regolith or rocks can pave the way for the development and utilization of lunar resources. The acquisition of lunar regolith samples with original stratigraphic information by astronauts on the lunar surface is one of the essential missions in the manned lunar landing project. Therefore, to maintain the original stratigraphic information of the lunar samples during the sampling process while further improving the coring rate and sampling depth, a handheld dual-mode lunar regolith coring device is proposed in this paper. The device innovatively combines impact penetration and rotary drilling sampling, which allows the selection of a suitable sampling method according to the environment. In addition, this study designs a synergic coring device that can be operated by the astronaut and carried on the lander or rover based on the handheld coring device, which can ensure safe and stable coring mission. The mechanical analysis is carried out for the key properties in the coring device, the corresponding mechanical model is established, the structural parameters are optimally designed, and the performance analysis is carried out accordingly. Finally, the impact and drilling process of the coring device is simulated in explicit dynamics, and the results show that the optimized impact module can effectively penetrate the lunar rocks. The research work will provide technical reference and theoretical support for the design of human–machine synergic coring devices in manned lunar exploration missions.