Closed-Loop Control of Silicone Extrusion-Based Additive Manufacturing Based on Machine Vision

2021 ◽  
Author(s):  
Xiaoqing Tian ◽  
Yaling Li ◽  
Dingyifei Ma ◽  
Jiang Han ◽  
Lian Xia
Keyword(s):  
Additive Manufacturing ◽  
Machine Vision ◽  
Manufacturing Process ◽  
Closed Loop ◽  
Ccd Camera ◽  
Control Model ◽  
Loop Control ◽  
Vision Control ◽  
Images Processing ◽  
Printing Speed

Abstract In this paper, the control of strand width uniformity in extrusion-based additive manufacturing process based on machine vision is studied. Firstly, the images of the strand width are collected frame by frame by a CCD camera. Secondly, through a series of processes of images acquisition, images processing including images filtering, images binarization and information extraction, the useful information of strand width is obtained. Then, the theoretical relationship between the strand width and printing speed is obtained through experimental research, and a control model is obtained. Finally, by using the control model and the strand width obtained from images processing, the printing speed is adjusted to an appropriate value, which eventually led to the stabilization of the strand width. The uncontrolled and logarithmic controlled, are studied in this work. The results show that the logarithmic controlled strand width is more stable than the uncontrolled strand width. Therefore, the instability of strand width in material extrusion-based additive manufacturing process can be effectively solved by machine vision control.

scholarly journals Localized electrodeposition micro additive manufacturing of pure copper microstructures

2021 ◽  
Author(s):  
Wanfei Ren ◽  
Jinkai Xu ◽  
Zhongxu Lian ◽  
Xiaoqing Sun ◽  
Zheming Xu ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Electrochemical Deposition ◽  
Closed Loop ◽  
Pure Copper ◽  
Closed Loop Control ◽  
Helical Spring ◽  
Loop Control ◽  
Helical Springs ◽  
Atomic Force ◽  
Microscopic Morphology

Abstract The fabrication of pure copper microstructures with submicron resolution has found a host of applications such as 5G communications and highly sensitive detection. The tiny and complex features of these structures can enhance device performance during high-frequency operation. However, the easy manufacturing of microstructures is still a challenge. In this paper, we present localized electrochemical deposition micro additive manufacturing (LECD-μAM), combining localized electrochemical deposition (LECD) and closed-loop control of atomic force servo technology, which can print helical springs and hollow tubes very effectively. We further demonstrate an overall model based on pulsed microfluidics from a hollow cantilever LECD process and the closed-loop control of an atomic force servo. The printing state of the micro-helical springs could be assessed by simultaneously detecting the Z-axis displacement and the deflection of the atomic force probe (AFP) cantilever. The results showed that it took 361 s to print a helical spring with a wire length of 320.11 μm at a deposition rate of 0.887 μm/s, which could be changed on the fly by simply tuning the extrusion pressure and the applied voltage. Moreover, the in situ nanoindenter was used to measure the compressive mechanical properties of the helical spring. The shear modulus of the helical spring material was about 60.8 GPa, much higher than that of bulk copper (~44.2 GPa). Additionally, the microscopic morphology and chemical composition of the spring were characterized. These results delineated a new way of fabricating terahertz transmitter components and micro-helical antennas with LECD-μAM technology.

The Intelligent Control Method of Additive Manufacturing Flow Based on the Measurement of the Line Width

2014 ◽  
Vol 904 ◽  
pp. 352-356
Author(s):  
Rui Yan Wang ◽  
Ting Chun Shi ◽  
Yi Zhang
Keyword(s):  
Additive Manufacturing ◽  
Line Width ◽  
Intelligent Control ◽  
Closed Loop ◽  
Control Method ◽  
Solid Model ◽  
Current Line ◽  
Loop Control ◽  
Forming Precision ◽  
Displacement Speed

Based on the closed-loop control theory in the paper, an intelligent control method of additive manufacturing based on the measurement of the line width is studied. The setpoint with the current line width which is scanned by the CCD sensor is compared, the relative relationship between the displacement speed of the forming equipments workbench and the rate of flow of the nozzle could be controlled. The Results of the study shows intelligent control of solid model and scaffoldss accuracy, pores shape and porosity, the forming precision is improved greatly makes the cell differentiation, attachment and crawling easy.

Experimental Research on Deflection Control of Cantilever Beam Based on Hybrid Photovoltaic/Piezoelectric Actuation Mechanism

2016 ◽  
Author(s):  
F. Lu ◽  
X. J. Wang ◽  
Y. F. Liu
Keyword(s):  
Ultraviolet Light ◽  
Cantilever Beam ◽  
Closed Loop ◽  
Uv Light ◽  
Control Model ◽  
Closed Loop Control ◽  
Piezoelectric Actuation ◽  
Loop Control ◽  
Actuation Mechanism ◽  
Plzt Ceramic

When ultraviolet light illuminates on polarized PLZT ceramic, a large voltage can be generated between the electrodes due to the anomalous photovoltaic effect. The shape control of flexible shell can be realized by using hybrid photovoltaic/piezoelectric actuation. In this paper, a novel non-contact deflection closed-loop control model of cantilever beam based on hybrid photovoltaic/piezoelectric actuation can be proposed. The photovoltage of PLZT ceramic irradiated by ultraviolet light is applied to drive PVDF actuator. The closed-loop control equations of deflection of cantilever beam is derived based on the mathematical model of PLZT ceramic with coupled multi-physics fields and the constitutive model of cantilever beam. Then, parameters of deflection control equations of cantilever beam during illumination phase and light off phase are identified through the deflection static experiment. After that, the deflection closed-loop control experiment of cantilever beam based on hybrid photovoltaic/piezoelectric actuation mechanism is carried out to verify the control model. The experimental results show that the deflection of cantilever beam with a simple on-off control method can achieve the target value by applying UV light to PLZT ceramic. It also should be noted that, the deflection curve of cantilever beam illuminated by strong UV light has an undesirable fluctuation.

A State-of-the-Art Review on Aerosol Jet Printing (AJP) Additive Manufacturing Process

2019 ◽  
Author(s):  
Roozbeh Ross Salary ◽  
Jack P. Lombardi ◽  
Darshana L. Weerawarne ◽  
Prahalad K. Rao ◽  
Mark D. Poliks
Keyword(s):  
Additive Manufacturing ◽  
Flexible Electronics ◽  
Manufacturing Process ◽  
Device Fabrication ◽  
Synthesis Process ◽  
Monitoring And Control ◽  
Loop Control ◽  
Wide Range ◽  
Jet Printing ◽  
Aerosol Jet Printing

Abstract The goal of this work is to forward a comprehensive framework, relating to the most recent research works carried out in the area of flexible and hybrid electronics (FHE) fabrication with the aid of aerosol jet printing (AJP) additive manufacturing process. In pursuit of this goal, the objective is to review and classify a wide range of articles, published recently, concerning various aspects of AJP-based device fabrication, such as material synthesis, process monitoring, and control. AJP has recently emerged as the technique of choice for integration as well as fabrication of a broad spectrum of electronic components and devices, e.g., interconnects, sensors, transistors, optical waveguides, quantum dot arrays, photodetectors, and circuits. This is preeminently because of advantages engendered by AJP process. AJP not only allows for high-resolution deposition of microstructures, but also accommodates a wide renege of ink viscosity. However, AJP is intrinsically complex and prone to gradual drifts of the process output (stemming from ink chemistry and formulation). Consequently, a large number of research works in the literature has focused on in situ process characterization, real-time monitoring, and closed-loop control with the aim to make AJP a rapid, reliable, and robust additive manufacturing method for the manufacture of flexible and hybrid electronic devices. It is expected that the market for flexible electronics will be worth over $50 billion by 2020 [1].

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