Effective suppression of vibration is essential for surface quality and tool longevity in machining. This study assesses the viability of Electromechanical Impedance Spectroscopy (EMIS)-based structural health monitoring as a compact alternative to microphone-assisted Fast Fourier Transform (FFT) analysis during the milling of Al-7075-T6. Experiments were conducted with a constant axial depth of cut of 0.5 mm while feed rate (50–70 mm/min) and spindle speed (1200–4300 rpm) were varied. A surface-bonded piezoelectric sensor recorded impedance signatures simultaneously with acoustic data. Dominant modes detected by EMIS lay between 90 Hz and 1.5 kHz and coincided with FFT peaks. The discrepancy between the two methods remained within 1.54–10.78%. The close agreement indicates that a single EMIS sensor can provide reliable, operator-independent vibration diagnostics without the extensive signal-conditioning infrastructure required by microphones. EMIS offers a pathway for real-time, closed-loop vibration control in milling applications.
Electrohydrodynamic inkjet printing technology can generate femtoliter-scale droplets, which provides significant advantages in additive manufacturing. With these advantages, electrohydrodynamic inkjet printing technology shows broad application prospects in repairing micro/nano-scale complex structures in flexible electronic devices and high-resolution displays. During the repair process, precise control of printed droplet volume is required according to target volume requirements. However, due to the complexity of the printing process, traditional theoretical and simulation methods face challenges in achieving effective volume control. This paper proposes a supervised learning-based electrohydrodynamic droplet volume control method. The algorithm innovatively establishes new strategy samples through historical datasets, which include the deviation between current droplet volume and target volume, current process parameters, and changes in process parameters for the next iteration. Based on a feedforward control strategy, we employ a multilayer perceptron (MLP) supervised algorithm to achieve printing parameter recommendation, significantly improving printing efficiency. Volume control experiments conducted on the established electrohydrodynamic printing platform show that the standard volume filling rate can reach 98%, and the control can be completed within a single control cycle.
Electrohydrodynamic direct-writing (EDW) is widely applied in the field of micro-nano manufacturing due to its advantage of rapid deposition of line structure. However, due to the difficulty of bending-torsion coupled modeling for EDW with large deformation, the mechanism and effective control strategies of EDW still unclear. This study firstly establishes a three-dimensional geometrically exact model for EDW using Euler angles. It contains differential equations for the mass conservation, the jet geometry, the jet kinematics, the jet dynamics, and the electric field and charge. Euler angles are used to exactly describe the jet’s geometric variation. A theoretical electric field description for non-uniform electric field is introduced. The universality of the model is validated by reducing the governing equations system to a two-dimensional steady-state situation. The geometrically exact model established in this study is useful for revealing the mechanism of EDW and exploring its control strategies.
TDM PON technology widely deployed since the early and has evolved with ease to support the increasing bandwidth demands of FTTH. This research work presents the design and performance evaluation of a bidirectional 20 Gbps Time and Wavelength Division Multiplexed Passive Optical Network (TWDM-PON). The system designed by eight channels operating at 2.5 Gbps each and is analyzed using return-to-zero (RZ), non-return-to-zero (NRZ), carrier-suppressed return-to-zero (CSRZ) and duo-binary (DB) modulation formats. Performance metrics such as Q-factor and bit error rate (BER) are evaluated under varying input power conditions. The performance comparison is made in terms of Q factor and BER for varying transmitter powers. It is found that DB modulation format gives best performance when power budget improvement is sought. For low power condition (less than -15 dBm) DB modulation format gives superior performance. High dispersion tolerance in DB makes the system better with low power budget.
