Dissertations / Theses on the topic 'Hybrid Injection Molding'
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1
Shelesh-Nezhad, Karim. "Developing a hybrid expert system program to aid in the design of plastic injection molding process." Thesis, Queensland University of Technology, 1997. https://eprints.qut.edu.au/36048/7/36048_Digitised_Thesis.pdf.
Full textAbstract:
Experts in injection molding often refer to previous solutions to find a mold design
similar to the current mold and use previous successful molding process parameters
with intuitive adjustment and modification as a start for the new molding application.
This approach saves a substantial amount of time and cost in experimental based
corrective actions which are required in order to reach optimum molding conditions.
A Case-Based Reasoning (CBR) System can perform the same task by retrieving a
similar case which is applied to the new case from the case library and uses the
modification rules to adapt a solution to the new case. Therefore, a CBR System can
simulate human e~pertise in injection molding process design.
This research is aimed at developing an interactive Hybrid Expert System to
reduce expert dependency needed on the production floor. The Hybrid Expert
System (HES) is comprised of CBR, flow analysis, post-processor and trouble
shooting systems. The HES can provide the first set of operating parameters in order
to achieve moldability condition and producing moldings free of stress cracks and
warpage. In this work C++ programming language is used to implement the expert
system.
The Case-Based Reasoning sub-system is constructed to derive the optimum
magnitude of process parameters in the cavity. Toward this end the Flow Analysis
sub-system is employed to calculate the pressure drop and temperature difference in
the feed system to determine the required magnitude of parameters at the nozzle. The
Post-Processor is implemented to convert the molding parameters to machine setting
parameters. The parameters designed by HES are implemented using the injection
molding machine. In the presence of any molding defect, a trouble shooting subsystem
can determine which combination of process parameters must be changed
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during the process to deal with possible variations. Constraints in relation to the
application of this HES are as follows.
- flow length (L) constraint: 40 mm < L < I 00 mm,
- flow thickness (Th) constraint:
-flow type:
- material types:
I mm < Th < 4 mm,
unidirectional flow,
High Impact Polystyrene (HIPS) and Acrylic.
In order to test the HES, experiments were conducted and satisfactory results
were obtained.
2
Nugay, Isik Isil. "POLYURETHANES in RIGID and FLEXIBLE ELECTRONICSNOVEL HYBRID PROCESSING TECHNIQUES and REAL-TIME MONITORING OF MATERIAL PROPERTIES." University of Akron / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=akron1406633847.
Full text
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Rohne, Clemens, Michael Schreiter, Jens Sumpf, Klaus Nendel, and Lothar Kroll. "Hybrid Conveyor Chains – Calculation, Design and Manufacturing." Universitätsbibliothek Chemnitz, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-231781.
Full textAbstract:
The following paper will illustrate the development of a multiflex chain in hybrid construction. The aim of this novel chain variant is to improve the stiffness and strength in comparison to conventional plastic slide chains. A two part multiflex chain with a chain pitch of 33.5 mm and a structural width of 83 mm was used as the basis for the development of the hybrid multiflex chain. The hybrid multiflex chain is supposed to be integrated in already existing layouts of chain conveyors. The load bearing structure of the single chain links is manufactured in the metal die cast procedure while taking the constructive, production related, and operational aspects into consideration and subsequently covered in the injection molding process with plastics commonly used for multiflex chains. The evaluation of the improved stiffness and strength takes place in the course of extensive test seriesIn der folgenden Abhandlung wird die Entwicklung einer Multiflex-Kette in Hybridbauweise erläutert. Mit dieser neuartigen Kettenvariante soll eine Steifigkeits- und Festigkeitssteigerung gegenüber den konventionellen Kunststoffgleitketten erzielt werden. Als Ausgangsbasis für die Entwicklung der hybriden Förderkette dient eine zweiteilig ausgeführte Multiflex-Kette mit der Teilung von 33,5 mm und einer Baubreite von 83 mm. Die hybride Förderkette soll in bestehende Layouts von Kettenförderern integriert werden können. Unter Beachtung konstruktiver, fertigungstechnischer und betrieblicher Aspekte wird die lasttragende Struktur der einzelnen Kettenglieder im Metalldruckgussprozess gefertigt und anschließend mit einem, für Multiflex-Ketten üblichen Kunststoff im Spritzgießprozess ummantelt. Die Evaluierung der Steifigkeits- bzw. Festigkeitssteigerung erfolgt im Rahmen umfangreicher Versuchsreihen
4
Ghoreishi, Rima, and Fatmehsari Mehdi Ehsani. "Mechanical and Thermal Characterizations of Biobased Thermoset Resins from Soybean Oil Reinforced with Natural Fiber Using Vacuum Injection Moulding Technique." Thesis, Högskolan i Borås, Institutionen Ingenjörshögskolan, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-20223.
Full textAbstract:
The aim of this research was to analyze the mechanical and thermal properties of composites andhybrid composites prepared with four types of jute fibers and two different resins; biobased thermosetresins acrylated epoxidized soybean oil (AESO) and mathacrylated anhydride modified soybean oil(MMSO). The processing technique used was vacuum injection molding (VIM). Tensile and, flexuraltestings and dynamic mechanical and thermal analysis (DMTA) were used to characterize thecomposites’ properties. The results showed that the AESO composites have better tensile and flexuralproperties. This may be due to the fact that the curing conditions were quite the same for both AESOand MMSO composites but MMSO composites showed different behavior during curing step. Theywere completely cured in a shorter time compared to AESO composites. Having equal curing time forboth resins’ composites can damage the structure of MMSO composites and hybrids. Tan delta peak forthe MMSO reinforced composites occurs at higher temperatures, compared to AESO reinforcedcomposites, which means better thermal properties for MMSO reinforced composites.
5
Vastesson, Alexander. "Thiol-ene and Thiol-ene-epoxy Based Polymers for Biomedical Microdevices." Doctoral thesis, KTH, Mikro- och nanosystemteknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-215110.
Full textAbstract:
Within healthcare there is a market pull for biomedical devices that can rapidly perform laboratory processes, such as diagnostic testing, in a hand-held format. For this reason, biomedical devices must become smaller, more sophisticated, and easier to use for a reasonable cost. However, despite the accelerating academic research on biomedical microdevices, and especially plastic-based microfluidic chips, there is still a gap between the inventions in academia and their benefit to society. To bridge this gap there is a need for new materials which both exhibit similar properties as industrial thermoplastics, and that enable rapid prototyping in academia. In this thesis, thiol-ene and thiol-ene-epoxy thermosets are evaluated both in terms of their suitability for rapid prototyping of biomedical microdevices and their potential for industrial manufacturing of “lab-on-chips”. The first part of the thesis focuses on material development of thiol-ene and thiol-ene-epoxy thermosets. Chemical and mechanical properties are studied, as well as in vitro biocompatibility with cells. The second part of the thesis focuses on microfabrication methods for both thermosets. This includes reaction injection molding, photostructuring, and surface modification. It is demonstrated how thiol-ene and thiol-ene-epoxy both provide advantageous thermo-mechanical properties and versatile surface modifications via “thiol-click chemistry”. In the end of the thesis, two applications for both polymer platforms are demonstrated. Firstly, thiol-ene is used for constructing nanoliter well arrays for liquid storage and on-demand electrochemical release. Secondly, thiol-ene-epoxy is used to enhance the biocompatibility of neural probes by tuning their flexibility. It is concluded that both thiol-ene and thiol-ene-epoxy thermosets exhibit several properties that are highly suitable for rapid prototyping as well as for scalable manufacturing of biomedical microdevices.QC 20171003
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Imaddahen, Amine. "Étude expérimentale multi-échelle et modélisation hybride prédictive du comportement, de l'endommagement et de la durée de vie en fatigue d’un matériau composite polypropylène / fibres de verre." Thesis, Paris, HESAM, 2020. http://www.theses.fr/2020HESAE063.
Full textAbstract:
L’objectif final de ce travail est de proposer un outil numérique capable de prédire l'endommagement et la durée de vie en fatigue des matériaux et structures en composite à matrice thermoplastique. Pour ce faire, une étude expérimentale multi-échelle du matériaux PPGF40 (polypropylène chargé en fibre de verre à 40% en masse) est réalisée. Une analyse qualitative, mais aussi quantitative des différents mécanismes d’endommagement se produisant lors d’une sollicitation mécanique a été réalisée à travers des essais de flexion trois points in situ MEB, des essais de fatigue interrompus et des observations des faciès de rupture en monotone et en fatigue. A la lumière de ces essais nous avons conclu que la décohésion de l’interface fibre-matrice et la propagation des fissures à travers les interfaces apparait être le phénomène prépondérant menant à la ruine du matériau et cela indépendamment de l’orientation des fibres et du mode de sollicitation monotone ou fatigue. La démarche hybride proposée est basée sur un modèle micromécanique / phénoménologique permettant de prendre en compte l’endommagement à l’interface fibre-matrice et la plasticité de la matrice. Pour ce faire, un critère local statistique d’endommagement à l’interface fibre-matrice est introduit dans un modèle de Mori et Tanaka et la linéarisation du comportement plastique de la matrice est réalisée pas à pas, en utilisant une approche en champs moyens avec une formulation sécante. Le modèle micromécanique utilisé permet alors de prédire le comportement du matériau sous chargement monotone et notamment la première perte de rigidité en fatigue. L’analyse des résultats montre que cette dernière est directement liée à la durée de vie en fatigue du matériau. Ainsi, une méthodologie prédictive de la durée de vie est proposée et validée pour différentes configurations microstructurales. Un critère de rupture en fatigue est proposé en fonction du nombre de cyclesThe main objective of this work, is to provide a numerical tool, capable of predicting the damage and fatigue life of thermoplastic matrix composites materials and structures. To do this, a multi-scale experimental study of the PPGF40 material (polypropylene loaded with 40% by mass of glass fiber) is carried out. A qualitative, but also a quantitative analysis of the various damage mechanisms occurring during mechanical loading was carried out through in-situ three-points SEM bending tests, interrupted fatigue tests and observations of fracture faces in monotonic and cyclic loading. In the light of these tests, we concluded that the decohesion of the fiber-matrix interface, and the propagation of cracks through the interfaces, appears to be, the predominant damage phenomenon leading to the fracture of the material and that, regardless of the orientation of the fibers and the loading mode. The proposed hybrid approach is based on a micromechanical / phenomenological model taking into account the damage at the fiber / matrix interface and the plasticity of the matrix. To do this, a local statistical criterion of damage at the fiber-matrix interface is introduced into a Mori and Tanaka model, and the linearization of the plastic behavior of the matrix is done step by step, using the mean field approach with a secant formulation. The micromechanical model used then, makes it possible to predict the behavior of the material under monotonic loading, and in particular the first stiffness loss during the fatigue. Analysis of the experimental results shows that the latter is directly related to the fatigue life of the material. Thus, a predictive methodology of the fatigue life is proposed and validated for various microstructural configurations. A fatigue failure criterion is proposed according to the number of cycles
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Wang, Chih-hao, and 王志豪. "Research on Hybrid Optical Elements by Vibratile Injection Compression Molding." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/77563941492623190496.
Full textAbstract:
碩士國立臺灣科技大學
機械工程系
98
This research is to develop Vibratile Injection Compression Molding (V-ICM) and integrate the Varithermo Mold Temperature (VMT) technology for increasing the Groove Filling Ratio (GFR) and reduce aspheric form errors of hybrid optical elements. PMMA and COP 480R have been used to investigate the difference in processing, and to understand the residual stress, chromatic aberration (CA) and the Modulation Transfer Function (MTF) graph for comparison. Groove filling ratio (GFR), aspheric form error and the distribution of residual stress have been studied and discussed. Results have shown that the V-ICM can enhance the GFR effectively. In addition, the fixed mold temperature and different trigger time points affect the GFR significantly under the same aspheric form errors. The GFR can achieve nearly 98.09% and aspheric form error is about 7.26μm with high mold temperature in the COP 480R processing with V-ICM and VMT technology. The results of this study can effectively enhance the accuracy of multi-scale hybrid optical elements. In the future, this technology can apply to produce the high accuracy and also have the aspheric form with different multi-scale sizes, or freeform optical elements.
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Lee, Feng-Chi, and 李豐吉. "Research on Multi-Scale Hybrid Optical Elements by Injection Molding." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/60630087523422359384.
Full textAbstract:
碩士國立臺灣科技大學
機械工程系
97
This research is to develop and integrate the in-mold micro compression (IMMC) and varithermo mold temperature (VMT) method in injection molding process for investigating the multi-scale hybrid optical elements including the aspheric form error (Rt) and the replication or groove filling ratio (GFR) of Fresnel diffraction structure. The data acquisition system is used to integrate these two processes. In the IMMC method, piezoelectric actuator and pressure sensor are used to test with different percentages of peak filling pressure. The VMT method is to switch on the compression air to achieve quick mold cooling after sensing the packing phase signal from the injection molding machine. It is to investigate the effect of different cooling setting temperature (CST) on the quality of molded parts. The Rt can be achieved as 1.29 μm when the mold temperature is set as 100 ℃ in the traditional injection molding. Then experimental results show that the Rt can be achieved as 3.32 μm and the GFR as 96.95% when the mold temperature is set as 120 ℃, the CST of varithermo mold temperature as 80 ℃, and the IMMC method with trigger point as 50% of peak filling pressure. Further research focuses on the replication of hybrid lens array optical elements with micro structures to increase the optical performances.
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Lin, Shian-Ming, and 林先明. "Research on μ-Injection Compression Molding of Hybrid Optical Elements." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/54326041383935224691.
Full textAbstract:
碩士國立臺灣科技大學
機械工程系
96
This research conducted a novel micro injection compression molding (μ-ICM) process for fabrication of hybrid optical elements (HOEs). The micro compression motion is triggered by the percentage of peak filling pressure obtained by the data acquisition (DAQ) system. Experiments were implemented with different percentages of peak fill pressure, and the relationship between the trigger time and transfer ratio of the groove (TRG) were investigated. The Moldflow MPI software (Moldflow Co., USA) is used to simulate the filling and packing stages of HOEs. Comparison of short shot is preceded by simulation and experimentation. Results show that (1) the HOEs are fabricated successfully by the μ-ICM with a closed-loop pressure control, (2) the comparison of short shot is similar in simulation and experiment, (3) the TRG has been achieved as 99% when the trigger pressure is 15% of peak filling pressure with mold temperature 90°C and melt temperature 250°C, (4) the comparison of different mold insert materials show that the STAVAX with electroless plated Nickel (ELNi ) has better TRG than that of the oxygen-free copper (OFC) due to higher hardness of ELNi. Further research focuses on the μ-ICM of optical elements with micro structures to increase the optical performances.
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Chen, Pi-Kai, and 陳必凱. "Research on Closed-Loop Micro Injection Compression Molding of Hybrid Optical Elements." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/43370630576400291339.
Full textAbstract:
碩士國立臺灣科技大學
自動化及控制研究所
98
This research is to develop a novel Closed-Loop micro injection compression molding (CLMICM) process for fabricating the multi-scale hybrid optical elements with Fresnel diffraction structure. The research adopts the LabVIEW and PC-Based control system to construct a controller developing platform. In this Study performance analysis, controller design, simulation, and system application have been completed and tested on this platform. The cavity pressure controller uses a mold-based PI controller for closed-loop control scheme. Experimental results have demonstrated the feasibility of the proposed system. Results show that the HOEs can be fabricated successfully by the CLMICM. The cavity pressure response is similar as show in simulation and experiment. Moreover, the groove filling ratio (GFR) has been achieved as 98.27% by CLMICM with mold temperature 100°C. Further research focuses on the CLMICM for optical elements with micro structures and aspheric surface to increase the optical performances.
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Liou, Pen-Hsi, and 劉朋熹. "An optimization system for plastic injection molding process parameters using hybrid algorithms." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/12119435650441651849.
Full textAbstract:
博士中華大學
科技管理博士學位學程
102
The plastic injection molding (PIM) industry offers a variety of products to satisfy diverse consumer needs. Nowadays, the parameter settings for the PIM industry are based on engineers’ experiences and design of experiments (DOE). However, it takes a large amount of time, manpower, and cost to figure out an appropriate combination of process parameters since parameter settings that could have a great impact on products are numerous and there are deep nonlinear relationships between the parameters. This study proposes a system with optimal parameters for the PIM industry in order to solve those problems. Two models are taken along with the research work and each model is a two-stage multiple-objective optimization based on hybrid algorithms. The research starts with the Taguchi method employed for experiment and data analysis. Besides, the signal-to-noise (S/N) ratio and analysis of variance (ANOVA) are used to obtain a combination of parameter settings that is the most significant one in the process. The first model is an optimization based on regression model using hybrid algorithms. With the experimental data gained from the Taguchi’s experiment, a quality regression model (quality predictor) and an S/N ratio regression model (S/N ratio predictor) are created. The first stage is to optimize the multiple-objective S/N ratio. The S/N ratio predictor is associated with genetic algorithm (GA), simulated annealing (SA), and particle swarm optimization (PSO) for universal search to acquire the process parameters and to maximize the S/N ratio of each quality characteristics. This stage intends to minimize the variance in process. The second stage is to optimize the multiple-objective quality. The hybrid algorithms (SA-PSO, GA-PSO, PSO-GA) are associated with the S/N ratio predictor and the quality predictor for universal search. The process parameters gained from the first stage is set for the initial values. The hybrid algorithms are then used to find the optimal parameter settings that tally best with the quality standard and make it most stable in process. The second model is an optimization based on back-propagation neural network (BPNN) using hybrid algorithms. The data gained from the Taguchi experiment are applied to train in BPNN so as to generate an S/N ratio predictor and quality predictor. The first stage is to optimize the S/N ratio. The S/N ratio predictor then works together with GA for universal search to acquire the process parameters and to maximize the S/N ratio of the quality responses. This stage intends to minimize the variance in process. As for the second stage, process optimization of the multiple-objective quality is investigated. Hybrid GA-PSO is associated with the S/N ratio predictor and the quality predictor for universal search. The process parameters gained from the first stage is set for the initial values. The Hybrid GA-PSO is then used to find the optimal parameter settings that tally best with the quality standard and make it most stable in process. The confirmation results show that the second model can create the best performance. The best process parameter settings which not only enhance the stability in the whole injection molding process but also meet the length specification, reduce the parts’ warpage and effectively improve the PIM product quality.
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Chen, Szu-Ting, and 陳思婷. "Study on Progressive Injection Compression Molding for Hybrid Prism with Sub-wavelength Micro Structures." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/92056688307271984954.
Full textAbstract:
碩士國立臺灣科技大學
機械工程系
101
This research is to design a progressive injection compression molding (PICM) for hybrid prism with micro structures to obtain better surface uniformity for improving optical quality. The compression stroke is based on the different part thickness of prism and the mold cavity pressure has been observed by two sets of pressure sensor modules to acquire the relationship of pressure and compression effects. In this research, three kinds of molding process including injection molding (IM), injection compression molding (ICM) and progressive injection compression molding (PICM) have been investigated to discuss the parameters of injection velocity, mold temperature, and compression time based on performance of non-uniformity (NU) and sub-wavelength micro structures (SWMS) of filling ratio (SFR) by experimental design. The SWMS is replicated by a silicon mold insert with nano or sub-micro structures of porous anodic alumina (PAA). Residual stress has been measured by photoelastic instrument and discussed. Experimental results show that the PICM could effectively improve the incident surface uniformity 46.34% as compared with IM process and also improve the SFR from 82% to 92%, The contact angle incident surfaces of prism by IM and PICM increased from 83.3ﾟto 118.7 ﾟ, as increased by 42.50%. The hybrid prism with best SFR can improve the illumination 80.8 % as compared with prism without sub-microstructure. Further study can apply on injection molding of the hybrid thickness of prism aspheric elements.
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Chen, Te-Ning, and 陳德寧. "Optimization of the Plastic Injection Molding Process Using Taguchi method, RSM, and Hybrid GA-PSO." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/t637s2.
Full textAbstract:
碩士中華大學
工業管理學系碩士班
101
In a rapidly changing world, the plastic injection molding (PIM) industry is trying to make the product various. At present, the parameter settings for plastic injection molding often rely on engineers’ experiences and design of experiments. However, since many different parameters could influence a finished product and a high level nonlinear relationship stands between each parameter, it takes a large number of manpower, devices, and other expenses to figure out a better combination of process parameters. This study proposes three optimization models of process parameters in plastic injection molding in order to solve those problems. Three optimal models are taken along with the research methodologies. In the first model, the Taguchi method is employed for experiment and data analysis in which the quality characteristics for the plastic injection product are length and warpage. Besides, the control factors for the process are melt temperature, injection velocity, packing pressure, packing time, and cooling time. Moreover, the signal-to-noise (S/N) ratio and analysis of variance (ANOVA) are used to obtain a combination of parameter settings that is the most significant parameters in the process. In the second model, experimental data are set for the response surface methodology (RSM) to analyze and create a quality regression model (quality predictor). The quality predictor is associated with genetic algorithm (GA) to derive an optimal combination of process parameters that meets multiple-objective quality characteristics. The third model is a two-stage multiple-objective optimization. The first stage is to optimize the S/N ratio. The data gained from the Taguchi experiment are adopted to generate an S/N ratio predictor. The S/N ratio predictor then works together with GA for universal search to acquire the process parameters and to maximize the S/N ratio of the quality responses. This stage intends to decrease the variance in process to minimum. As for the second stage, process optimization is investigated. Hybrid GA-PSO is used with the quality predictor and the S/N ratio predictor for search. The process parameters gained from the first stage is set for the initial values to find the optimal parameter settings that tally best with the quality standard and make it most stable in process. The confirmation results show that two-stage optimization system turns out with the best performance. The approach not only enhances the stability in the whole injection molding process including the quality in length and warpage but also saves the cost and time spent from the mold design to manufacturing.
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Yeh, Ching-Hsien, and 葉敬賢. "Research on Residual Stress and Optical Quality in Hybrid Optical Elements by Vibratile Injection Compression Molding Process." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/ke9whj.
Full textAbstract:
碩士國立臺灣科技大學
機械工程系
99
This research is to explore the formation model of the residual stress, molecular orientation during injection molding of hybrid optical lens and finally to study aspheric form error, groove filling rate(GFR) and residual stress on optical quality. The research methods discuss the forming of residual stress from gate to filling end by in-mold annealing. Further, the Raman intensity ratio is defined to discuss the molecular orientation on different injection velocity and thickness. It also discusses the factors of injection velocity, mold temperature and PZT vibration frequency to the effects of aspheric form error, GFR and residual stress by experiment design finally. Experimental results will be compared with those of simulation analysis. From experimental results, the residual stress reduces gradually once the time of holding temperature is getting longer by in-mold annealing. The molded parts near the mold wall can have higher molecular orientation with higher injection velocity.The molecular orientation reduces in this in-mold annealing experiment. The aspheric form error, GFR and residual stress are mainly affected by mold temperature. Finally, the optical quality is mostly affected by aspheric form error.
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Kurniawan, Denni, and 丹尼Denni Kurniawan. "An Integrated Optimization System for Plastic Injection Molding Using Taguchi Method, BPNN, GA, and Hybrid PSO-GA." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/gh8fbp.
Full textAbstract:
博士中華大學
科技管理博士學位學程
102
Applications of polymer material in injection molding application are growing very fast in last decades. Moreover, several advantages, such as short cycle time production, light weight of products, and high surface quality, make plastic injection molding (PIM) work as a solution for industries to survive in competitive world. Besides these advantages, PIM is a more complex process than it is previously thought. Inappropriate material selection, process parameters, part and mold designs can affect the quality of plastic products. Therefore, investigation to improve product quality still becomes an important issue to be conducted. A well-controlled parameter setting is one of the solutions to avoid or reduce defect in plastic products. Previously, process parameters in PIM relied on the technician's experience using trial-and-error approach. However, this approach is not effective and unsuitable for complex manufacturing processes. This study presents a two- stage optimization system to find optimal process parameters of multiple quality characteristics in the PIM process. The Taguchi method, back-propagation neural network (BPNN), genetic algorithms (GA), and combination of particle swarm optimization and genetic algorithms (PSO-GA) are used to find optimum parameter settings. Melt temperature, injection velocity, packing pressure, packing time, and cooling time are selected as initial process parameters. Length and warpage are employed as the product quality. The experimental work is conducted using the Taguchi orthogonal array. According to the result from the Taguchi experiment, S/N ratio is calculated to find the best combination settings for product quality. Then, analysis of variance (ANOVA) is used to determine significant factors of the control parameters. Moreover, the S/N ratio predictor and quality predictor are constructed using BPNN. In the first stage optimization, S/N ratio predictor and GA are used to reduce variance of quality characteristic. In the second stage optimization, the S/N ratio predictor and quality predictor with hybrid PSO-GA are used to find optimal parameter settings for quality characteristic and stability of the process. Finally, three confirmation experiments are conducted to assess the effectiveness of the proposed system. Experimental results show that the proposed system not only improves the quality of plastic parts, but also reduces variability of process effectively.
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Chen, X., Yee Cheong Lam, Michael K. C. Tam, and S. C. M. Yu. "Particle Migration of Quasi-Steady Flow in Concentrated Suspension for Powder Injection Molding." 2002. http://hdl.handle.net/1721.1/4035.
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A hybrid FEM/FDM algorithm for particle migration of quasi-steady flow in concentrated suspension materials is proposed in this study. This hybrid FEM/FDM algorithm in which the planar variables, such as pressure field, are described in terms of finite element method, and gapwise variables of temperature, density concentration and time derivatives are expressed by finite difference method. The particle concentration inhomogeneities can be predicted, which is ignored by the existing injection molding simulation packages. Simulation results indicated that powder concentration variation could be significant in practical processing in PIM.Singapore-MIT Alliance (SMA)
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Dai, Tsai-lun, and 戴采綸. "Research of Injection Compression Molding and Photoelasticity Compensator Method on Residual Stress and Optical Quality of Hybrid Prism." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/02982195926061773011.
Full textAbstract:
碩士國立臺灣科技大學
機械工程系
102
This study aims to design a Photoelastic Stress Image Analysis System (PSIAS) based on circular polarization theory, which includes two calibration and analysis methods of (I) PSIAS combined with a LWC Compensator Method or named as PSIAS_LWC_md and (II) Photoelastic Stress Analysis Software (PSAS) modified from previous study. Experimental verification has been performed by mechanical force compression on a benchmark Psm-1 disk for comparison of both methods with theoretical optical-stress coefficient method (C_md) from reference. The average stress error by PSIAS_LWC_md is 0.140MPa or 4.6%. Another results of PSAS is lesser than 0.312MPa or 10.3%. Then a PMMA disk by injection molding (IM) is used for estimating the stress-optical coefficients of test materials by PSIAS_LWC_md. Therefore a light-guide prism has been fabricated by IM and injection compression molding with thermal annealing (ICM-ANL) processes to investigate effects of parameters on prism’s residual stress, formability and optical quality. Result of the average residual stress of prism by ICM-ANL process is reduced 24.5% with that of IM process. Similarly, the minimum average non-uniformity (ANU) of prism by ICM-ANL process is 11?慆 or improved 74% and the illumination is promoted as 4% with that of IM process. Verification results of Raman intensity measurement have revealed that the molecular orientation of skin, shear and core layers in filling direction of prisms is much reduced for ICM-ANL process. Final test of hybrid prism with sub-wavelength structure, an Anodic Alumina Oxide (AAO) process is applied to fabricate six inch sub-wavelength structure (6”Al_SWS), and electroforming process is conducted to make 6”Ni_SWS of diameter 93nm and height 360nm. The sub-wavelength structures of hybrid prism are difficult to be demolded because the Ni_SWS of nano-columns are not totally vertically duplicated. Results of this study have been tested and verified for residual stress estimation of light-guide prism with different thickness by PSIAS_LWC_md. Future study can focus on applying the PSIAS_LWC_md and ICM-ANL technique as residual stress estimation on optical elements with different thickness and sub-wavelength structure.
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Lo, Wen-Tuan, and 羅文端. "Design and Fabrication of a Self-Powered Wireless Sensing Module and Corresponding Temperature/Pressure-Hybrid Micro-Sensor for Injection-Molding Monitoring." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/74975270808652712896.
Full textAbstract:
碩士國立交通大學
機械工程系所
102
Recently, energy-harvester-powered (i.e., self-powered) wireless sensors network for environmental, medical, mechanical, and civil structural monitoring applications are rapidly developed. In this thesis, an energy-harvester-powered (i.e., self-powered) wireless sensing module for injection-molding monitoring is reported. Thermoelectric generators connected in series are used to harness a thermal energy from the injection-molding process and subsequently convert the thermal energy to the electrical output. The electrical output is consequently modulated/rectified to power a customized wireless temperature-sensing module which consists of wireless RF components, central controlling unit, RTD temperature sensor (embedded inside a mold cavity to detect the process temperature of injection-molding), and corresponding circuits. Due to this, a self-powered wireless temperature sensing module for injection-molding monitoring is achieved. The experimental results show the module successfully monitors the process temperature of the injection-molding. In addition, a smart MEMS temperature/pressure-hybrid sensor is fabricated and integrated with the module toward an intelligent injection-molding monitoring module. The testing results indicate the intelligent module is capable of sensing the temperature and pressure in the injection-molding process.
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Sardashti, Amirpouyan. "Wheat Straw-Clay-Polypropylene Hybrid Composites." Thesis, 2009. http://hdl.handle.net/10012/4712.
Full textAbstract:
The preparation of polymeric hybrid composite consisting of organic and inorganic fillers is of interest for industries like automotive, construction and packaging. In order to understand and predict the physical and chemical properties of these hybrid composites, it is necessary to fully understand the nature and properties of the employed fillers. In this study, the preparation of polypropylene hybrid composite consisting of wheat straw and clay was investigated. A detailed study was performed on wheat straw from South Western Ontario region. The effect of grinding the straw and compounding it with polypropylene was investigated. Experiments were carried out to identify the thermal stability of the ground wheat straw with respect to their size and composition. It was important to identify a correlation between these properties in order to minimize the straw degradation by processing and also to improve the final properties of the hybrid composite. The composite samples were prepared through melt blending method using a co-rotating twin-screw extruder. Sample test bars were prepared by injection moulding. The composition of the constituents of the hybrid composite; percentages of wheat straw, clay and coupling agent, were varied in order to investigate their influence on thermal stability, water resistance and mechanical properties.
The results of the study indicated that grinding the wheat straw with a hammer mill produced particles with different sizes and shapes. It was found that through the grinding system all particles, regardless of their size, had a multi-layered structure similar to the plant structure. Further hammer milling did not produce plant particles with long aspect ratios that would be expected in a defibrillation process. Analysis of the chemical composition of wheat straw particles of different sizes and shapes was used to measure the ratio of hemicelluloses: lignin and the ash content. It was found that the large particles contained more amount of lignin whereas smaller particles had larger amount of ash content. The thermal stability of the particles was found to be a function of particle size rather than the lignin content. Particle size analysis on the wheat straw particles after the extrusion process indicated a reduction in the particle length and aspect ratio.
The thermal stability of the composites was found to be enhanced by the addition of clay particles at higher temperature and the addition of coupling agent at lower temperatures. Increasing the amount of wheat straw and clay content increased the flexural modulus and reduced the resistance for water absorption. Increasing the amount of coupling agent also increased the flexural modulus and resistance for water absorption. The morphological study by scanning electron microscopy revealed that coupling agent increased the interfacial interaction between the particles and the polymer matrix.