Effect of Front and Back Suppressing Vibration on Actuation Waveform Design of DoD Inkjet Printer to Droplet Speed and Volume

Abstract

One of the operational issues that are generally encountered on the print-head performance is residual vibration. For good performance of droplet, the satellite and ligament of an ink droplet must be suppressed during the jetting process. It was proved that the suppressing vibration is viable to control the droplet's speed and volume. Two kinds of suppressing vibration with front and back position of suppressing pulse from the main pulse were investigated. The suppressing vibration was proved to be an effective way of damping the residual vibration and reducing the droplet volume and speed. By analyzing two types of actuation waveforms effect on droplet quality, this paper analyzes the distinctive effect of front and back suppressing vibration on droplet quality.

Printed Electronics Technologies for Additive Manufacturing of Hybrid Electronic Sensor Systems

“…[66] Jetting instabilities may arise as a result of cross-talk between the actuators of the nozzles inherent to printhead designs at certain operating points, though this has been shown to be mitigated through proper waveform tuning and optimization. [67,68] Solvent-based inks may experience evaporation at the nozzle orifice, creating a concentration gradient between the orifice and pumping chamber and/or leaving behind solids that may clog the nozzle orifice. The practical relevance of this effect has been reported by Sowade et al [9] As part of their investigation of electrical defects in printed structures they observed the quality of an array of inkjet-printed TFTs.…”

“…[ 66 ] Jetting instabilities may arise as a result of cross‐talk between the actuators of the nozzles inherent to printhead designs at certain operating points, though this has been shown to be mitigated through proper waveform tuning and optimization. [ 67,68 ]…”

Actuating Voltage Waveform Optimization of Piezoelectric Inkjet Printhead for Suppression of Residual Vibrations

“…Although the optimized standard waveform can emit the ink droplet, there are residual vibrations after the ejection of the first droplet, as shown in Figure 6 b–d. The next droplet properties will be different from that of the first one if these residual vibrations are not damped, which can affect the jetting process [ 9 , 10 , 11 , 12 ]. Through quick damping of these residual vibrations and bringing the ink channel to rest after the ejection of the first droplet, the maximum jetting frequency of the inkjet printhead can be increased.…”

“…These unwanted pressure waves are referred to as residual vibrations. These residual vibrations take several microseconds to decay, which affect the velocity and volume of the second droplet to be fired, thereby affecting the printing quality [ 9 , 10 , 11 ]. Due to these residual vibrations, satellite droplets are also formed that can fall on an undesired position on a substrate [ 12 ].…”

Inkjet Printing Optimization: Toward Realization of High‐Resolution Printed Electronics

“…[119,120] The position of the suppressed vibration pulse (hereafter known as suppression pulse) either in front or back of the main pulse also has great impact on drop formation. [121] In the case of waveform with front-suppression pulse, the ink is able to generate a stable spherical drop with speed range of 2-6 m s −1 for applied voltage of 14 to 18 V. On the contrary, the back-suppression pulse allows ejection of drop at higher speed (4-11 m s −1 ), causing secondary drop with ligament beginning to appear at voltage of 16 V. Other critical waveform parameters, such as rise time (t R ), fall time (t F ), dwell time (t D ) and echo time (t E ), have strong influences on the jetting behavior of inks. General guideline for waveform optimization is typically conducted by observing the drop formation, resulting from scrutinizing over wide range of t D (or known as pulse width) and t E with the associated voltage amplitudes (V D and V E ) at predetermined t R and t F .…”