Application Cases

Experiment Name: Experimental Study on Electrohydrodynamic Jet Printing on Flexible Substrates

Objective: To design and fabricate an electrostatic focusing electrode that effectively mitigates the influence of substrate effects on electrohydrodynamic jet printing. Additionally, a combined nozzle was designed and manufactured to reshape the distribution of the electrostatic field around the nozzle, thereby reducing the impact of polarization and charge accumulation in flexible substrates on the printing process. The influence of process parameters on the printed microstructure was further investigated, enabling the on-demand electrohydrodynamic jet printing of micropatterns on flexible PET substrates.

Testing Equipment: High-voltage amplifier, function generator, host computer, etc.

Experimental Procedure:

Figure 1: Schematic Diagram of the Electrohydrodynamic Jet Printing Experimental Setup

The electrohydrodynamic jet printing platform consists of hardware and software control systems. The hardware comprises five modules, as shown in Figure 1: the electric field control module, fluid supply module, motion control module, heating module, and vision module. The electric field control module establishes an electric field between the conductive nozzle holder and the substrate. The fluid supply module delivers liquid to the nozzle at the required flow rate. The motion control module provides various motion forms necessary for printing. The entire system is integrated and coordinated using LabVIEW.

The electric field control module consists of a function generator and a high-voltage amplifier, as shown in Figure 2. The function generator produces the required voltage waveforms, which are then amplified by the high-voltage amplifier to the desired voltage range. The host computer communicates with the function generator via USB, RS232, or GPIB interfaces. The function generator connects to the high-voltage amplifier using BNC connectors to minimize signal loss. The amplified signal is transmitted to the conductive nozzle holder via SHV high-voltage cables. The function generator serves as the excitation source, capable of producing 16 standard waveforms and user-defined waveforms with adjustable edge times. Parameters can be controlled manually or through software programming, making it widely applicable in electronic testing and measurement.

High-voltage amplifiers are categorized into unipolar and bipolar types based on waveform polarity. Unipolar amplifiers can only amplify signals with a constant direction, such as steady DC or pulsed DC signals, while bipolar amplifiers can amplify AC signals but are typically several times more expensive. Considering experimental requirements and cost-effectiveness, a unipolar high-voltage amplifier was selected for this platform. This amplifier features an output voltage range of 0–2000 V, an input signal bandwidth of 0–10 kHz, and a fully solid-state design that protects against arc discharge and short circuits. It ensures stable and reliable performance, accurate output response, high slew rate even with capacitive loads, and low-noise operation. The nozzle holder, made of stainless steel, secures the nozzle position and connects to the high-voltage amplifier via SHV high-voltage cables to establish the electric field between the nozzle and substrate.

Figure 2: Schematic Diagram of the Electric Field Control Module Connection

The fluid supply module consists of a pump, fluid connection device, and nozzle, as shown in Figure 3. Depending on the type of prime mover, pumps for electrohydrodynamic jet printing include precision syringe pumps and air pumps, each requiring different fluid connection devices tailored to experimental needs.

Figure 3: Schematic Diagram of the Fluid Supply Module Connection

The motion control system includes a motion control card, adapter board, drivers, and a three-axis displacement platform. The heating module comprises electric heating elements, a substrate support plate, a temperature sensor, and a temperature controller. The vision module consists of a CCD camera and a light source.

Experimental Results:

An experimental platform for electrohydrodynamic jet printing was developed, detailing the composition and principles of each functional module. Two different fluid control devices were designed and fabricated based on ink viscosity. Furthermore, a control system for the electrohydrodynamic jet printing platform was developed using LabVIEW. This system enables printing along user-defined motion trajectories and supports the printing of arbitrarily complex two-dimensional patterns. It integrates all system components, achieving coordinated control among the functional modules.

Recommended High-Voltage Amplifier: ATA-7015

Figure: Specifications of the ATA-7015 High-Voltage Amplifier

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