A Low-Cost Flash Photographic System for Visualization of Droplets in Drop-on-Demand Inkjet

Jiang, Huicong; Merritt, Brett Andrew; Tan, Hua

doi:10.2352/j.imagingsci.technol.2018.62.6.060502

Cited by 5 publications

(4 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…1, including a high-speed camera (Phantom Miro M310), 12X magni cation lens (Navitar 1-50486), pulsed LED light source (Metaphase HiSLED-1003), and mounting platform. Additionally, our imaging system can utilize the ash photographic technique to capture the dynamics of µm droplets with high spatial and temporal resolution (Jiang et al 2018), where a pulse generator (Berkeley Nucleonics model 505) is used to trigger the pulsed light source and a high-resolution CCD camera (Thorlabs 340M-GE) asynchronously. Frame rates of the Phantom camera are 11.5k and 120k fps (frames per second) for mm and µm droplets, respectively.…”

Section: High-speed Imaging System and Droplet Dispensationmentioning

confidence: 99%

Absorption of millimeter- and micrometer-sized droplets on nylon powder

Tan

2022

Exp Fluids

Self Cite

View full text Add to dashboard Cite

Absorption of droplet by the powder media is a ubiquitous phenomenon in many natural and engineering processes, in which the diameter of droplets ranges from tens of micrometers (μm) to a few millimeters (mm) depending on the speci c condition. In this study, we investigate the absorption process following the impact of the droplet with radii varying from mm-to μm-scale on nylon powder substrate. The uid properties are varied by mixing the deionized water with isopropyl alcohol at different volume ratios. A syringe pipette tip is used to generate droplets of diameter ranging from 2.08 to 2.30 mm, whereas a drop-on-demand inkjet device is used to dispense droplets of diameter ranging from 88 to 140 μm. The absorption process of the single droplet is captured by a high-speed imaging system. We nd that for mm-and μm-droplets there exists different critical surface tension below which the imbibition into the nylon powder can occur. With the proposed nondimensionalization process, the scattered data of dimensionless absorbed volume V and dimensionless time τ for different uids generally collapse into a power law relation V~ τ α , where the exponent α for mm-sized and μm-sized droplets is 0.856 and 0.518, respectively. The experimental data of μm droplets generally agree with the prediction of the Washburn equation for the unidirectional capillary ow, i.e. V~ τ 0.5 . However, the results of mm-droplets favor more the prediction of the 3D radial ow (i.e., a hemispherically advancing in ltration front inside the powder), V~ τ.

show abstract

Section: High-speed Imaging System and Droplet Dispensationmentioning

confidence: 99%

Absorption of millimeter- and micrometer-sized droplets on nylon powder

Tan

2022

Exp Fluids

Self Cite

View full text Add to dashboard Cite

show abstract

“…Numerous scholars have conducted research in this area. Kwon [6] developed a method based on stroboscopic method, achieving observation and measurement of high-frequency droplet ejection; Based on the fundamental principle of the single stroboscopic method, Jiang [7] realized the observation of droplet ejection and its impact on the substrate. Zhao [8] constructed a corresponding droplet observation system, successfully capturing images of the formation process of droplets with a diameter of 50µm, and on this basis, identified four different states of droplet formation.…”

Section: Introductionmentioning

confidence: 99%

P‐16.2: A Method for Detection of Ink Droplet Volume Distribution Based on Bayesian Theorem

Li,

Yue,

et al. 2024

Symp Digest of Tech Papers

View full text Add to dashboard Cite

Inkjet printing technology is an emerging manufacturing technique for OLED display devices, where changes in droplet volume after continuous printing are a common issue. Changes in ink properties and disturbances from external environmental factors inevitably lead to variations in droplet volume, which may result in printing defects. Therefore, it is necessary to monitor the volume of droplets during production to ensure they meet production requirements. However, existing techniques for measuring droplet volume are time‐consuming and cannot complete the inspection of all nozzles within a limited time interval.This paper proposes a droplet volume distribution detection method based on Bayesian Theorem. By acquiring historical droplet volume data from the nozzles to design a prior distribution, and inspecting a subset of nozzle volumes, the posterior distribution of ink droplet volume is derived using Bayesian Theorem in conjunction with the prior distribution. Finally, the accuracy of this method was verified on the NEJ‐PR200 inkjet printing equipment. The results show that after sampling 10% of the nozzles, the estimated distribution trend is consistent with the actual situation, and after sampling 20% of the nozzles, the estimation error is less than 3% in the mean volume of ink droplets. Moreover, as the number of samples increases, the accuracy of the estimation also gradually improves.

show abstract

“…Jung described a high-speed imaging which was used to analyze the impact and spreading the drops onto smooth glass surfaces [ 20 ]. Jiang et al used a low-cost microcontroller board (typical cost is less than a hundred US dollars) as the pulse generator in a flash photographic system [ 21 ]. Martin et al also described the measurement of the volumes of small (10–100 µm) liquid drops is important in a number of fields including inkjet printing, liquid dispensing, and spraying [ 22 ].…”

Section: Introductionmentioning

confidence: 99%

In Situ Image Acquisition and Measurement of Microdroplets Based on Delay Triggering

Chang

Zheng²,

Xie

et al. 2019

Micromachines

View full text Add to dashboard Cite

An in situ image acquisition apparatus based on delay triggering for visualizing microdroplets formation is described. The imaging system includes a charge-coupled device camera, a motion control card, a driving circuit, a time delay triggering circuit, and a light source. By adjusting the varying trigger delay time which is synchronized with respect to the signal for jetting, the steady sequential images of the droplet flying in free space can be captured real-time by the system. Several image processing steps are taken to measure the diameters and coordinates of the droplets. Also, the jetting speeds can be calculated according to the delay time interval. For glycerin/water (60:40, mass ratio), under the given conditions of the self-made pneumatically diaphragm-driven drop-on-demand inkjet apparatus, the average of diameter and volume are measured as 266.8 μm and 9944 pL, respectively, and the maximum average velocity of the microdroplets is 0.689 m/s. Finally, the imaging system is applied to measure the volume of 200 microsolder balls generated from the inkjet apparatus. The average diameter is 87.96 μm, and the relative standard deviation is 0.83%. The results show good reproducibility. Unlike previous stroboscopic techniques, the present in situ imaging system which is absence of instantaneous high intensity light employs two control signals to stimulate the microdroplet generator and the charge-coupled device (CCD) camera. Hence, the system can avoid the desynchronization problem of signals which control the strobe light-emitting diode (LED) light source and the camera in previous equipment. This technology is a reliable and cost-effective approach for capturing and measuring microdroplets.

show abstract

A Low-Cost Flash Photographic System for Visualization of Droplets in Drop-on-Demand Inkjet

Cited by 5 publications

References 0 publications

Absorption of millimeter- and micrometer-sized droplets on nylon powder

Absorption of millimeter- and micrometer-sized droplets on nylon powder

P‐16.2: A Method for Detection of Ink Droplet Volume Distribution Based on Bayesian Theorem

In Situ Image Acquisition and Measurement of Microdroplets Based on Delay Triggering

Contact Info

Product

Resources

About