scholarly journals Influence of Diamond-Like Carbon Coating on the Channel Deformation of Injection-Molded Microfluidic Chips during the Demolding Process

Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 2914
Author(s):  
Yilei Wang ◽  
Bingyan Jiang ◽  
Mingyong Zhou ◽  
Jiachen Chen ◽  
Can Weng
Keyword(s):  
Elastic Recovery ◽  
Mold Insert ◽  
Interfacial Interaction ◽  
Gyration Radius ◽  
Diamond Like Carbon ◽  
Microfluidic Chips ◽  
Dlc Coating ◽  
Channel Deformation ◽  
Injection Molded

Injection molding is one of the main techniques for manufacturing microfluidic chips. As an important stage, the demolding process in injection molding will directly affect the quality of the functional unit of microfluidic chips (polymer microchannels), thus limiting the realization of its functions. In this study, molecular dynamics (MD) simulations on the demolding process were carried out to investigate the influence of diamond-like carbon (DLC) coating on the channel deformation. The channel qualities of polystyrene (PS), polymethyl methacrylate (PMMA), cyclic olefin copolymer (COC) and polycarbonate (PC) were analyzed after demolding with nickel (Ni) and DLC-coated mold inserts, respectively. In particular, the non-bonded interfacial interaction energy, elastic recovery and gyration radius of polymer molecular chains were further studied. The results showed that the non-bonded interfacial interaction energies could be significantly reduced by DLC-coating treatment on the mold insert. Moreover, common channel defects such as molecular chain separation, surface burrs and necking did not occur. The treatment of DLC coating could also significantly reduce the change in the gyration radius of polymer molecular chains, so the morphology of the polymer channel could be maintained well. However, the change in the elastic recovery of the polymer channel was increased, and the opening width became larger. In a word, DLC-coating treatment on the mold insert has great application potential for improving the demolding quality of injection-molded microfluidic chips.

scholarly journals Surface Reformation of Medical Devices with DLC Coating

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 376
Author(s):  
Mao Kaneko ◽  
Masanori Hiratsuka ◽  
Ali Alanazi ◽  
Hideki Nakamori ◽  
Kazushige Namiki ◽  
...  
Keyword(s):  
High Pressure ◽  
Medical Devices ◽  
Diamond Like Carbon ◽  
Steam Sterilization ◽  
Dlc Coatings ◽  
Chrome Plating ◽  
Living Body ◽  
Dlc Coating ◽  
Pressure Steam ◽  
Adhesion Friction

We evaluated the adhesion, friction characteristics, durability against bodily acids, sterilization, cleaning, and anti-reflection performance of diamond-like carbon (DLC) coatings formed as a surface treatment of intracorporeal medical devices. The major coefficients of friction during intubation in a living body in all environments were lower with DLC coatings than with black chrome plating. DLC demonstrated an adhesion of approximately 24 N, which is eight times stronger than that of black chrome plating. DLC-coated samples also showed significant stability without being damaged during acid immersion and high-pressure steam sterilization, as suggested by the results of durability tests. In addition, the coatings remained unpeeled in a usage environment, and there was no change in the anti-reflection performance of the DLC coatings. In summary, DLC coatings are useful for improving intracorporeal device surfaces and extending the lives of medical devices.

Multi-objective optimization of injection-molded plastic parts using entropy weight, random forest, and genetic algorithm methods

2020 ◽  
Vol 40 (4) ◽  
pp. 360-371
Author(s):  
Yanli Cao ◽  
Xiying Fan ◽  
Yonghuan Guo ◽  
Sai Li ◽  
Haiyue Huang
Keyword(s):  
Genetic Algorithm ◽  
Random Forest ◽  
Regression Model ◽  
Process Parameters ◽  
Multi Objective Optimization ◽  
Entropy Weight ◽  
Multi Objective ◽  
Injection Molded ◽  
Plastic Parts

AbstractThe qualities of injection-molded parts are affected by process parameters. Warpage and volume shrinkage are two typical defects. Moreover, insufficient or excessively large clamping force also affects the quality of parts and the cost of the process. An experiment based on the orthogonal design was conducted to minimize the above defects. Moldflow software was used to simulate the injection process of each experiment. The entropy weight was used to determine the weight of each index, the comprehensive evaluation value was calculated, and multi-objective optimization was transformed into single-objective optimization. A regression model was established by the random forest (RF) algorithm. To further illustrate the reliability and accuracy of the model, back-propagation neural network and kriging models were taken as comparative algorithms. The results showed that the error of RF was the smallest and its performance was the best. Finally, genetic algorithm was used to search for the minimum of the regression model established by RF. The optimal parameters were found to improve the quality of plastic parts and reduce the energy consumption. The plastic parts manufactured by the optimal process parameters showed good quality and met the requirements of production.

Diamond-Like Carbon Coating—It'S Application for Polymeric Substrates

1991 ◽  
Vol 239 ◽  
Author(s):  
Fred M. Kimock ◽  
Alex J. Hsieh ◽  
Peter G. Dehmer ◽  
Pearl W. Yip
Keyword(s):  
High Speed ◽  
Protective Coatings ◽  
Ion Beam ◽  
Chemical Exposure ◽  
Optical Systems ◽  
Impact Behavior ◽  
Organic Liquids ◽  
Diamond Like Carbon ◽  
Dlc Coating ◽  
The Impact

ABSTRACTWe report on a recently commercialized Diamond-Like Carbon (DLC) coating that has been deposited on polycarbonate at near room temperature, via a unique ion beam system. Aspects of high speed impact behavior, chemical resistance, abrasion resistance, and thermal stability of the coating are examined. Results of scanning electron microscopy studies indicate that adhesion of the DLC coating is very good; no delamination of the coating was found on ballistically tested specimens. The well-bonded DLC coating did not cause the impact performance of polycarbonate to become brittle. Chemical exposure test results show that the DLC coating is capable of protecting polycarbonate from chemical attack by aggressive organic liquids. These ion beam deposited DLC coatings have considerable potential as protective coatings for optical systems.

scholarly journals Enhancement of Multilayer Perceptron Model Training Accuracy through the Optimization of Hyperparameters: A Case Study of the Quality Prediction of Injection Molded Parts

2021 ◽  
Author(s):  
Kun-Cheng Ke ◽  
Ming-Shyan Huang
Keyword(s):  
Gradient Descent ◽  
Training Model ◽  
Learning Rate ◽  
Stochastic Gradient Descent ◽  
Activation Functions ◽  
Molded Parts ◽  
Injection Molded ◽  
Testing Accuracy ◽  
Model Training

Abstract Injection molding has been broadly used in the mass production of plastic parts and must meet the requirements of efficiency and quality consistency. Machine learning can effectively predict the quality of injection molded part. However, the performance of machine learning models largely depends on the accuracy of the training. Hyperparameters such as activation functions, momentum, and learning rate are crucial to the accuracy and efficiency of model training. This research further analyzed the influence of hyperparameters on testing accuracy, explored the corresponding optimal learning rate, and provided the optimal training model for predicting the quality of injection molded parts. In this study, stochastic gradient descent (SGD) and stochastic gradient descent with momentum were used to optimize the artificial neural network model. Through optimization of these training model hyperparameters, the width testing accuracy of the injection product improved. The experimental results indicated that in the absence of momentum effects, all five activation functions can achieve more than 90% of the training accuracy with a learning rate of 0.1. Moreover, when optimized with the SGD, the learning rate of the Sigmoid activation function was 0.1, and the testing accuracy reached 95.8%. Although momentum had the least influence on accuracy, it affected the convergence speed of the Sigmoid function, which reduced the number of required learning iterations (82.4% reduction rate). Optimizing hyperparameter settings can improve the accuracy of model testing and markedly reduce training time.

Fabrication of Nano- and Micro-Scale UV Imprint Stamp Using Diamond-Like Carbon Coating Technology

2006 ◽  
Vol 6 (11) ◽  
pp. 3619-3623
Author(s):  
Eung-Sug Lee ◽  
Jun-Ho Jeong ◽  
Ki-Don Kim ◽  
Young-Suk Sim ◽  
Dae-Geun Choi ◽  
...  
Keyword(s):  
Nanoimprint Lithography ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Adhesive Layer ◽  
Diamond Like Carbon ◽  
Coating Process ◽  
Ion Beam Lithography ◽  
Two Photon ◽  
Dlc Coating ◽  
Two Photon Polymerization

Two-dimensional (2-D) and three-dimensional (3-D) diamond-like carbon (DLC) stamps for ultraviolet nanoimprint lithography were fabricated with two methods: namely, a DLC coating process, followed by focused ion beam lithography; and two-photon polymerization patterning, followed by nanoscale-thick DLC coating. We used focused ion beam lithography to fabricate 70 nm deep lines with a width of 100 nm, as well as 70 nm deep lines with a width of 150 nm, on 100 nm thick DLC layers coated on quartz substrates. We also used two-photon polymerization patterning and a DLC coating process to successfully fabricate 200 nm wide lines, as well as 3-D rings with a diameter of 1.35 μm and a height of 1.97 μm, and a 3-D cone with a bottom diameter of 2.88 μm and a height of 1.97 μm. The wafers were successfully printed on an UV-NIL using the DLC stamps without an anti-adhesive layer. The correlation between the dimensions of the stamp's features and the corresponding imprinted features was excellent.

scholarly journals Selected Physicochemical Properties of Diamond Like Carbon (DLC) Coating on Ti-13Nb-13Zr Alloy Used for Blood Contacting Implants

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5077
Author(s):  
Magdalena Antonowicz ◽  
Roksana Kurpanik ◽  
Witold Walke ◽  
Marcin Basiaga ◽  
Jozef Sondor ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Physicochemical Properties ◽  
Fundamental Problem ◽  
Circulatory System ◽  
Titanium Implants ◽  
Diamond Like Carbon ◽  
Dlc Coating ◽  
13Zr Alloy ◽  
Artificial Plasma ◽  
Modification Of Titanium

Despite high interest in the issues of hemocompatibility of titanium implants, particularly those made of the Ti-13Nb-13Zr alloy, the applied methods of surface modification still do not always guarantee the physicochemical properties required for their safe operation. The factors that reduce the efficiency of the application of titanium alloys in the treatment of conditions of the cardiovascular system include blood coagulation and fibrous proliferation within the vessel’s internal walls. They result from their surfaces’ physicochemical properties not being fully adapted to the specifics of the circulatory system. Until now, the generation and development mechanics of these adverse processes are not fully known. Thus, the fundamental problem in this work is to determine the correlation between the physicochemical properties of the diamond like carbon (DLC) coating (shaped by the technological conditions of the process) applied onto the Ti-13Nb-13Zr alloy designed for contact with blood and its hemocompatibility. In the paper, microscopic metallographic, surface roughness, wettability, free surface energy, hardness, coating adhesion to the substrate, impendence, and potentiodynamic studies in artificial plasma were carried out. The surface layer with the DLC coating ensures the required surface roughness and hydrophobic character and sufficient pitting corrosion resistance in artificial plasma. On the other hand, the proposed CrN interlayer results in better adhesion of the coating to the Ti-13Nb-13Zr alloy. This type of coating is an alternative to the modification of titanium alloy surfaces using various elements to improve the blood environment’s hemocompatibility.

scholarly journals Selected Issues Concerning Degradation of Material in the Production of Injection Molded Plastic Components

2016 ◽  
Vol 10 (3) ◽  
pp. 173-180
Author(s):  
Marek Jałbrzykowski
Keyword(s):  
Thermal Characteristics ◽  
Test Results ◽  
Base Materials ◽  
Plastic Materials ◽  
Technological Quality ◽  
Injection Molded ◽  
Plastic Components ◽  
Injection Molded Plastic ◽  
Selection Of

Abstract This paper presents the problem of thermal degradation of thermoplastic materials processed using the injection method. Attention was paid to the issue of the optimal selection of a dye for modifying the base materials. For the selected materials and dyes, derivatograph tests were performed in order to assess their thermal characteristics and breakdown kinetics. Additionally, tribological tests and microscope observations of selected samples were performed. The obtained test results suggest a diverse level of thermal processes in the analyzed materials. This is crucial for the appropriate selection of dyes for plastic materials. As it turned out, the tribological properties of materials can also influence the technological quality of the injected alloy.

scholarly journals Diamond Like Carbon Films (DLC) Coating Effect on Friction Reducation of Heat-resistant Polymers.

2001 ◽  
Vol 52 (12) ◽  
pp. 878-882 ◽  
Author(s):  
Shojiro MIYAKE ◽  
Tadashi SAITOH ◽  
Shuichi WATANABE ◽  
Eiichi HAYASHI ◽  
Takashi NAKAMARU
Keyword(s):  
Carbon Films ◽  
Diamond Like Carbon ◽  
Heat Resistant ◽  
Dlc Coating

Prediction of crystallinity profile and eject time of injection molded parts using finite element method (FEM)

e-Polymers ◽  
2009 ◽  
Vol 9 (1) ◽  
Author(s):  
Mehdi Mostafaiyan ◽  
Farhad Sharif
Keyword(s):  
Finite Element ◽  
Degree Of Crystallinity ◽  
Element Analysis ◽  
Melt Temperature ◽  
Crystalline Polymers ◽  
Molded Parts ◽  
Time Part ◽  
Injection Molded ◽  
The Subject

AbstractQuality of injection molded parts of semi-crystalline polymers has been the subject of intense interest from both analytical and industrial points of view. Crystallinity profile plays an important role in determining mechanical properties of a part and its quality. Therefore it is important to analyze the effect of injection molding parameters on the crystallinity profile of the molded parts. In this study, finite element analysis has been used to solve the equations of mass, momentum, and energy conservation simultaneously with the equation of crystallization kinetics to predict melt front, its solidification and crystallinity profile. The results from our numerical analysis have been compared with the reported experimental results. Furthermore, progress of the crystallization is proposed to be a proper criterion for estimation of the eject time. Finally, the effects of mold and melt temperature on the eject time; part temperature and average degree of crystallinity, for a specific compound are also presented.

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