• Title/Summary/Keyword: Glass mold

Search Result 298, Processing Time 0.023 seconds

A Study of Laser Joining for Polymer 2D Camber Compensation (폴리머 2D 캠버 보상을 위한 레이저용접 기술)

  • Lee, Young-Min;Yoon, Jin-Young;Song, Chi-Hun;Choi, Hae-Woon
    • Laser Solutions
    • /
    • v.15 no.2
    • /
    • pp.15-20
    • /
    • 2012
  • A novel joining technology was developed to compensate the camber in polymers. The preheating laser beam circulates on the joining location and the accumulated heat serves to increase the flexibility of neighboring polymers. The temperature rises up to the glass transient temperature of the polymers and continually loading spring force closes the gap of camber. The irradiated laser was 808nm central wavelength and the power varied between 2Watt and 5Watt. The laps were adjusted between 3 and 10 and the optimum process parameters were 3Watt and 5 laps for the specific application. An FEM analysis was introduced to understand the mechanism of joining by the transient temperature distribution on the polymers. Thermocouples experiments were also tried to correlate the numerical analysis results and it showed the trend of heat accumulation in experiments.

  • PDF

Effect of Manufacturing Accuracy of Flexible Propeller on the Open Water Performance (유연 프로펠러의 제작 정도가 단독성능에 미치는 영향)

  • Lee, Kun-Hwa;Jang, Hyun-Gil;Lee, Chang-Sup;Nho, In-Sik;Lee, Sang-Gab;Hyun, Beom-Soo
    • Journal of the Society of Naval Architects of Korea
    • /
    • v.50 no.5
    • /
    • pp.349-354
    • /
    • 2013
  • The blades of flexible propellers are formed by overlaying and adhering many layers of thin glass-fiber fabric sheets, are compressed and dried in the rigid mold. The current manufacturing process can not avoid the rather irregular deformation of the blades composed of non-isotropic non-uniform fabric structures, and inevitably introduces the different shape-forming errors between blades. In this paper, several flexible model propellers are precisely measured with three-dimensional optical instrument and compared with the original design geometry. The model propellers with the as-measured geometry are evaluated with the lifting-surface-theory-based propeller analysis code. The open-water performance are presented and discussed. The importance of the manufacturing accuracy is addressed to be able to apply the flexible propellers for propulsion of marine vehicles.

Heat & Cool Injection Molded Fresnel Lens Solar Concentrators (가열-냉각 사출성형 방식을 적용한 집광형 프레넬렌즈)

  • Jeong, Byeong-Ho;Min, Wan-Ki;Lee, Kang-Yeon
    • The Transactions of the Korean Institute of Electrical Engineers P
    • /
    • v.63 no.4
    • /
    • pp.283-289
    • /
    • 2014
  • A Fresnel lens is an optical component which can be used as a cost-effective, lightweight alternative to conventional continuous surface optics. Fresnel lens solar concentrators continue to fulfill a market requirement as a system component in high volume cost effective Concentrating Photovoltaic (CPV) electricity generation. The basic principles of the fresnel lens are reviewed and some practical examples are described. To investigate the performance space of the Fresnel lens, a fast simulation method which is a hybrid between raytracing and analytical computation is employed to generate a cache of simulation data. Injection molders are warming up to the idea of cycling their tool surface temperature during the molding cycle rather than keeping it constant. Heat and cool process are now also finding that raising the mold wall temperature above the resin's glass-transition or crystalline melting temperature during the filling stage and product performance in applications from automotive to packaging to optics. This paper deals with the suitability of Fresnel lenses of imaging and non-imaging designs for solar energy concentration. The concentration fresnel lens confirmed machinability and optical transmittance and roughness measure through manufactured the prototype.

A Basic Study on the Manufacture of UHPC 3D stereoscopic panels using 3D Printer (3D 프린터를 활용한 UHPC 3D 입체패널 제작에 관한 기초적 연구)

  • Kim, Tae-Ik;Yoon, Ju-Yong;Choi, Byung-Keol;Park, Yong-Kyu;Lee, Dae Seek;Yoon, Gi-Won
    • Proceedings of the Korean Institute of Building Construction Conference
    • /
    • 2021.11a
    • /
    • pp.154-155
    • /
    • 2021
  • Appearance finish is important for amorphous buildings to maximize amorphousness, and GFRC, glass, and metal are mostly used as exterior materials for amorphous buildings currently applied. However, the existing exterior materials showed limitations in amorphous expression, texture, and color expression. In this study, a 3D stereoscopic panel mold was manufactured using the FDM method, one of the 3D printing technologies, and 3D stereoscopic panel production was reviewed using Ultra High Performance Concrete (UHPC), which has excellent physical and mechanical performance and expression. In order to overcome the limitations of unstructured expression, a UHPC 3D stereoscopic panel using the FDM method, one of the 3D printing technologies, was manufactured. Unlike steel molds, FRP molds, and EPS molds, the FDM method can be applied to various materials, and complex shapes are implemented. If it is used using recyclable materials as well as PLA filaments used in the FDM method, it will overcome the limitations of amorphous expression and activate the production of 3D stereoscopic panels that have secured eco-friendliness.

  • PDF

A Study on Injection Condition Optimization and Deformation Improvement using Taguchi Design of Experiments (다구찌 실험계획법을 이용한 사출 조건 최적화와 변형 개선에 대한 연구)

  • Young-Tae Yu;Sung-Min Mun;Sung-Young Jun;Kyoung-A Kim
    • Design & Manufacturing
    • /
    • v.17 no.2
    • /
    • pp.62-69
    • /
    • 2023
  • In this study, we conducted a study on the optimization of injection molding conditions to minimize deformation of plastic product. The charging management system housing of the vehicle was selected as the research subject. Melting temperature, cooling temperature, packing time, and packing pressure were selected as the main factors expected to affect the deformation of molded products. Each main factor was divided into 5 levels. Optimization of injection molding conditions to minimize deformation was performed using the Taguchi Method. We performed an analysis of variance (ANOVA) to identify significant factors affecting the deformation of plastic product. In order to select injection molding conditions that minimize deformation of plastic products, injection molding analysis was additionally performed for insignificant factors. We then compared the deformation of the molded part before and after optimization. As a result of comparing the injection analysis results of the basic conditions and the injection analysis results of the optimal conditions, it was confirmed that the amount of deformation after optimization was improved by about 10.9%.

Numerical Analysis of Warpage and Reliability of Fan-out Wafer Level Package (수치해석을 이용한 팬 아웃 웨이퍼 레벨 패키지의 휨 경향 및 신뢰성 연구)

  • Lee, Mi Kyoung;Jeoung, Jin Wook;Ock, Jin Young;Choa, Sung-Hoon
    • Journal of the Microelectronics and Packaging Society
    • /
    • v.21 no.1
    • /
    • pp.31-39
    • /
    • 2014
  • For mobile application, semiconductor packages are increasingly moving toward high density, miniaturization, lighter and multi-functions. Typical wafer level packages (WLP) is fan-in design, it can not meet high I/O requirement. The fan-out wafer level packages (FOWLPs) with reconfiguration technology have recently emerged as a new WLP technology. In FOWLP, warpage is one of the most critical issues since the thickness of FOWLP is thinner than traditional IC package and warpage of WLP is much larger than the die level package. Warpage affects the throughput and yield of the next manufacturing process as well as wafer handling and fabrication processability. In this study, we investigated the characteristics of warpage and main parameters which affect the warpage deformation of FOWLP using the finite element numerical simulation. In order to minimize the warpage, the characteristics of warpage for various epoxy mold compounds (EMCs) and carrier materials are investigated, and DOE optimization is also performed. In particular, warpage after EMC molding and after carrier detachment process were analyzed respectively. The simulation results indicate that the most influential factor on warpage is CTE of EMC after molding process. EMC material of low CTE and high Tg (glass transition temperature) will reduce the warpage. For carrier material, Alloy42 shows the lowest warpage. Therefore, considering the cost, oxidation and thermal conductivity, Alloy42 or SUS304 is recommend for a carrier material.

A Study on the Compression Moldablity for Continuous Fiber-Reinforced Polymeric Composites ―Part 1 : The Mechanical Propertis and the Cup-type Compression Moldability for Numbers of Needling― (연속섬유강화 플라스틱 복합재료의 압축성형에 관한 연구 -제I보 : 니들펀칭횟수에 따른 물성치 및 컵형 압축성형성-)

  • 오영준;김형철;김이곤
    • Composites Research
    • /
    • v.12 no.5
    • /
    • pp.31-39
    • /
    • 1999
  • Glass-fiber reinforced polymeric composites provide the desitable properties of high stiffness and strength as well as specific weight. Hence, they have become some of the most important materials in several industries. These composites can be grouped into thermoplastic and thermoset composites, with thermoplastic composites having several advantages over thermoset composites in mechanical properties and processing. As a result, the study of the material behavior and forming techniques of such composites has attracted considerable attention in recent years. When the continuous fiber-reinforced polymeric composites are molded by flow molding, the molded parts leads to be nonhomogeneity and anisotropic because of the separation and orientation of fibers. As the characteristics of the products are greatly dependent on the separation, it is very important to clarify the separation in relarion to molding conditions, fiber mat structures and mold geometry. In this study, the effects of the mold geometry and the fiber mat structure on the compression moldability are studied using the cup-type molding.

  • PDF

Fabrication of Radar Absorbing Shells Made of Hybrid Composites and Evaluation of Radar Cross Section (하이브리드 복합재를 이용한 레이더 흡수 쉘의 제작 및 레이더 단면적 평가)

  • Jung, Woo-Kyun;Ahn, Sung-Hoon;Ahn, Bierng-Chearl;Park, Seoung-Bae;Won, Myung-Shik
    • Composites Research
    • /
    • v.19 no.1
    • /
    • pp.29-35
    • /
    • 2006
  • The avoidance of enemy's radar detection is very important issue in the modem electronic weapon system. Researchers have studied to minimize reflected signals of radar. In this research, two types of radar absorbing structure (RAS), 'C'-type shell and 'U'-type shell, were fabricated using fiber-reinforced composite materials and their radar cross section (RCS) were evaluated. The absorption layer was composed of glass fiber reinforced epoxy and nano size carbon-black, and the reflection layer was fabricated with carbon fiber reinforced epoxy. During their manufacturing process, undesired thermal deformation (so called spring-back) was observed. In order to reduce spring-back, the bending angle of mold was controlled by a series of experiments. The spring-back of parts fabricated by using compensated mold was predicted by finite element analysis (ANSYS). The RCS of RAS shells were measured by compact range and predicted by physical optics method. The measured RCS data was well matched with the predicted data.

The evaluation of surface roughness and polishing time between polishing systems (연마시스템에 따른 복합레진의 표면거칠기와 연마시간에 대한 평가)

  • Kim, Ye-Mi;Shin, Su-Jung;Song, Min-Ju;Park, Jeong-Won
    • Restorative Dentistry and Endodontics
    • /
    • v.36 no.2
    • /
    • pp.119-124
    • /
    • 2011
  • Objectives: The purpose of this experiment was to evaluate four different polishing systems of their polishability and polishing time. Materials and Methods: 4 mm diameter and 2 mm thickness Teflon mold was made. Z-250 (3M ESPE) hybrid composite resin was slightly overfilled and pressed with slide glass and cured with Optilux 501 for 40 sec each side. Then the surface roughness (glass pressed: control group) was measured with profilometer. One surface of the specimen was roughened by #320 grit sand paper and polished with one of the following polishing systems; Sof-Lex (3M ESPE), Jiffy (Ultradent), Enhance (Dentsply/Caulk), or Pogo (Dentsply/Caulk). The surface roughness and the total polishing time were measured. The results were analyzed with one-way ANOVA and Duncan's multiple range test. Results: The surface roughness was lowest in Pogo, and highest in Sof-Lex. Polishing times were shortest with Pogo, and followed by the Sof-Lex, Enhance and Jiffy. Conclusions: One-step polishing system (Pogo) is very effective to get the smooth surface in a short time, therefore it can be recommended for final polishing system of the restoration.

Identification of the microstructural components of crumb rubber modified asphalt binder (CRMA) and the feasibility of using environmental scanning electron microscopy (ESEM) coupled with energy dispersive X-Ray spectroscopy (EDX) (ESEM과 EDX를 사용한 CRM 바인더의 미세구조 성분 분석)

  • Kim, Hyun Hwan;Mithil, Mazumder;Lee, Moon Sup;Lee, Soon Jae
    • International Journal of Highway Engineering
    • /
    • v.18 no.6
    • /
    • pp.41-50
    • /
    • 2016
  • OBJECTIVES : In this study, microstructural components of crumb rubber modified asphalt (CRMA) binder were investigated using environmental scanning electron microscope (ESEM). To clearly understand the elemental composition of the CRMA binder, energy dispersive X-ray spectroscopy (EDX) was employed on the ESEM samples. METHODS : CRMA binders were produced using open blade mixers at $177^{\circ}C$ for 30 min. The binders were artificially aged through a series of accelerated aging processes. Sample preparation was done by making a mold shape on the glass slide. Thereafter, the morphology of the CRMA binder was observed using the ESEM coupled with the EDX. RESULTS : The images captured from the ESEM indicate that the unaged CRMA binder appears to have a single-phase continuous nonuniform structure after the addition of crumb rubber particles, whereas the artificially aged CRMA binder was observed to have two different phases. ESEM coupled with EDX shows detailed internal structure of the modified binders compared to other technologies (i.e., optical microscopy, atomic force microscopy, and conventional scanning electron microscope). CONCLUSIONS : The captured images resemble the internal structures such as the viscous properties of the unaged CRMA binder and the interaction between the rubber particles and the base binder at aged condition. ESEM is a powerful instrument and with the introduction of EDX, it provided more details of the network microstructure of the asphalt binder. ESEM coupled with EDX is recommended for use in future investigation of microstructure of asphalt binders.