• Title, Summary, Keyword: Packing Time

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A study on monitoring for process time and process properties by measuring vibration signals transmitted to the mold during injection molding (사출성형공정에서 금형에 전달되는 진동 신호 측정을 이용한 성형 단계별 공정시간과 공정특성의 모니터링에 대한 연구)

  • Lee, Jun-han;Kim, Jong-Sun
    • Journal of the Korea Society of Die & Mold Engineering
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    • v.14 no.3
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    • pp.8-16
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    • 2020
  • In this study, the vibration signal of the mold was measured and analyzed to monitoring the process time and characteristics during injection molding. A 5 inch light guide plate mold was used to injection molding and the vibration signal was measured by MPU6050 acceleration sensor module attached the surface of fixed mold base. Conditions except for injection speed and packing pressure were set to the same value and the change of the vibration signal of the mold according to injection speed and packing pressure was analyzed. As a result, the vibration signal had a large change at three points: "Injection start", "V/P switchover", and "Packing end". The time difference between "injection start" and "V/P switchover" means the injection time in the injection molding process, and the time difference between "V/P switchover" and "Packing end" means the packing time. When the injection time and packing time obtained from the vibration signal of the mold are compared with the time recorded in the injection molding machine, the error of the injection time was 2.19±0.69% and the error of the packing time was 1.39±0.83%, which was the same level as the actual value. Additionally, the amplitude at the time of "injection start" increased as the injection speed increased. In "V/P switchover", the amplitude tended to be proportional to the pressure difference between the maximum injection pressure and the packing pressure and the amplitude at the "packing end" tended to the pressure difference between the packing pressure and the back pressure. Therefore, based on the result of this study, the injection time and packing time of each cycle can be monitored by measuring the vibration signal of the mold. Also, it was confirmed that the level and trend of process variables such as the injection speed, maximum injection pressure, and packing pressure can be evaluated as the change of the mold vibration during injection molding.

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Investigation on Characteristics of Various Mold Packing Materials in Lost Foam Casting of Aluminum Alloy (알루미늄 합금 소실모형주조 시의 주형충전재에 따른 특성변화)

  • Kim, Ki-Young;Lee, Kyung-Whoan;Rim, Kyung-Hwa
    • Journal of Korea Foundry Society
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    • v.22 no.3
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    • pp.137-143
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    • 2002
  • Silica sand, zircon sand, and steel shots were used as mold packing materials in lost foam casting of the aluminum alloy bar. Vibration acceleration in three directions and temperatures in the casting and mold were measured, and packing and cooling characteristics of these materials were investigated. Packing densities increased with increase in vibration magnitude and time, and were $1.41{\sim}1.49g/cm^2$ for silica sand, $2.54{\sim}2.86g/cm^2$ for zircon sand, and $3.92{\sim}4.52g/cm^2$ for steel shots. Sound castings were obtained only without evacuation of the flask during pouring. Solidification time became faster in order of silica sand, zircon sand and steel shot packing because steel shot has the highest cooling capacity of them. Solidification time of steel shot packing was shortened to about 1/2 of silica sand packing. Cooling capacity of sand mold was generally evaluated by heat diffusivity of the mold, however could be simply evaluated with specific heat per unit volume of the packing material in lost foam casting.

The Physical Properties and Warmth retaining of Bedspread Jacquard Fabrics Using Filling Batt Yarn (충전 솜사를 이용한 Bedspread Jaquard 직물의 물성과 보온성)

  • Park, Myung-Soo
    • Fashion & Textile Research Journal
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    • v.9 no.4
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    • pp.445-449
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    • 2007
  • The results of warmth retaining, heat transfer and compressive elastic recovery of the five kinds of bedspread fabrics, which were produced from packing weft of 2700 denier and 3600 denier batt yarn treated with raw material of Polyester $150^D$/48 DTY, are as follows: 1) 3600 denier packing weft showed lover count in compressive elastic recovery than 2700d packing weft, so it took longer time to recover. 2) When packing weft of the same count is used, a sample of packing weft with higher density showed lower recovery. 3) It took 2700d packing weft 30min to get approximately 98% recovery in temperature $30^{\circ}C$. But, 3600d packing weft stayed under 98% recovery in the same temperature. Considering only the result of compressive elastic recovery, we should use 2700d packing weft. 4) The higher the density of packing weft is, the higher warmth retaining becomes. Although sharp increase appeared until 5min, equilibrium was kept without any increase after that time. 5) When 2700d packing weft was used, the maximum warmth retaining was approximately 60% and 64% in the conditions of density 12(thread/in) and 22(thread/in) respectively.

Development of Automatic Packing System of One Station for Fasteners(II) : Packing System Manufacture and Performance Test (원 스테이션 파스너 자동포장기 개발(II) : 제작 및 성능검증)

  • Kim, Yong-Seok;Jeong, Chan-Se;Yang, Soon-Young
    • Journal of The Korean Society of Manufacturing Technology Engineers
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    • v.20 no.5
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    • pp.653-658
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    • 2011
  • In general, the purpose of packaging fasteners is a series of management activities to maintain the condition at the time of production until they get delivered to the end user. An automatic packing system for fasteners is consisted of bucket conveyor, slide feeder, vision inspection system, box-magazine conveyor system and automatic packing machine. Also, the automatic packing machine is consisted of six modules including charging device, clamping/opening device, sealing/cutting device, feeding/air-shower device, supplying/adjusting device and device frame, etc. In this paper, we proposed an automatic packing mechanism of the one station concept for packing work of fastener objects where the continuous batch work is performed in a finite space. The proposed one-station packing mechanism has been optimized through mechanical, dynamical, structural and fluid analyses. And it had been manufactured as the prototype of automatic packing machine. The field test for validation of performance was performed directly at the production line of bolt and screw. In the field test, this packing machine showed an efficiency of about 4.5 times the manual operation. It also showed 30% reduction in the consumption of packing materials compared to the manual operation. This automatic packing machine for fastener objects will be commercialized soon.

Numerical Analysis of Residual Stresses and Birefringence in Injection/Compression Molded Center-gated Disks (II) - Effects of Processing Conditions - (사출/압축 성형 Center-gated 터스크에서의 잔류 응력과 복굴절의 수치 해석 (II) - 공정조건의 영향 -)

  • Lee, Young-Bok;Kwon, Tai-Hun;Yoon, Kyung-Hwan
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.26 no.11
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    • pp.2355-2363
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    • 2002
  • The accompanying paper, Part 1, has presented the physical modeling and basic numerical analysis results of both the flow-induced and thermally-induced residual stress and birefringence in injection molded center gated disks. The present paper, Part II, has attempted to investigate the effects of various processing conditions of injection/compression molding process on the residual stress and birefringence. The birefringence is significantly affected by injection melt temperature, packing pressure and packing time. Birefringence in the shell layer increases as melt temperature gets lower. The inner peak of birefringence increases with packing time and packing pressure. On the other hand, packing pressure, packing time and mold wall temperature affect the thermally-induced residual stress rather significantly in the shell layer, but insignificantly in the core region. Injection/compression molding has been found to reduce the birefringence in comparison with the conventional injection molding process. In particular, mold closing velocity and initial opening thickness in the compression stage of injection/compression molding process have significant effect on the flow-induced birefringence, but not on tile thermal residual stress and the thermally induced birefringence.

Effect of Glass Fiber Contents on the Tensile Strength in Injection Molding Process (사출성형공정에서 유리섬유함유량이 인장강도에 미치는 영향)

  • 김영수;김인관
    • Journal of the Korean Society for Precision Engineering
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    • v.17 no.5
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    • pp.63-69
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    • 2000
  • The main target of this research is investigating the relations between mechanical properties and injection conditions, like injection pressure, packing pressure and packing time for various contents ratio of glass fiber and resin. In general idea, high injection pressure produces high strength of molded parts as a monotonic function. but it was revealed that high pressure does not make high strength directly through various experiments of injection molding. In this experiments, PA66 was selected as resin and Glass Fiber was selected as reinforcing fiber Fiber reinforcement was controlled, as 14%, 25%, 33%, 44% of total volume and packing pressure was divided 55%, 65%, 75%, 85% of reference pressure, i.e. 100% equal to 1400kgf/$\textrm{cm}^2$. Finally, tensile testing was executed for injected test specimen. Optimum results based on authors' experiments have been obtained under conditions of 25% and 33% of glass fiber contents. Tensile strength rather depends on the packing pressure and packing time than injection pressure. Especially almost equal value of tensile strength was obtained for various percentage of packing and injection pressure as 65%, 75% and 85% of reference pressure.

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Pressure distributions in the cavity in injection molding for various operational conditions (사출성형조건에 따른 캐비티의 압력분포)

  • Kim J. M.;Jun J. H.;Lyu M. Y.;Hwang H. S.;Lee J. W.;Lee S. H.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • pp.214-219
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    • 2005
  • Pressure distribution in the cavity during injection molding affects part quality. In this study pressure distributions in the runner, near gate in the cavity, and end of ail in the cavity have been measured using direct pressure sensors for various molding conditions. Molding conditions were injection speed, injection pressure, packing time from filing stage, and packing pressure. Through experiments it was realized that the packing time from filling stage and packing pressure are the dominant factors on the part quality such as part shrinkage. Experimental results have been compared with computer simulations.

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Efficacy and Safety of Guardcel Nasal Packing After Endoscopic Sinus Surgery: A Prospective, Single-Blind, Randomized Controlled Study

  • Kang, Byungjin;Kim, Jeong-Rok;Shin, Jae-Min;Park, Il-Ho;Lee, Heung-Man
    • Clinical and Experimental Otorhinolaryngology
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    • v.10 no.3
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    • pp.248-253
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    • 2017
  • Objectives. Nasal packing after endoscopic sinus surgery is frequently used to control postoperative bleeding, enhance the wound healing process, and prevent lateralization of the middle turbinate, which causes insufficient ventilation. Many biodegradable materials have been developed to reduce pain and mucosal damage during packing removal. The purpose of this study was to compare the efficacy of Guardcel (Genewel Co.) middle meatal packing with a traditional nonabsorbable middle meatal packing, Merocel (Medtronic Xomed), on wound healing and patient satisfaction. Methods. In this prospective, single-blind, randomized controlled study, we enrolled 32 consecutive patients (64 nostrils) undergoing bilateral endoscopic sinus surgery at Korea University Guro Hospital from February 2015 to August 2015. Guardcel and Merocel were inserted postoperatively into a randomly assigned side. Objective findings about bleeding, hemostasis, adhesion, and infection were evaluated with nasal endoscopy. Patients' symptoms including pain and nasal obstruction were evaluated with a visual analog scale. Each evaluation was done at 2-3 days, 1 week, 2 weeks, and 4 weeks after surgery. Results. At 2-3 days after endoscopic sinus surgery, the Guardcel side had a significantly less hemostasis time than the Merocel side (P=0.001). During this period, the pain during packing removal was significantly lower on the Guardcel-inserted side than the Merocel-inserted side (P=0.002). At two weeks after surgery, the adhesion score on the Guardcel side was significantly lower than that of the Merocel side (P=0.011). Other parameters during the study follow-up periods were not statistically significant. There were no severe adverse reactions. Conclusion. Guardcel, a newly developed packing material, appeared to shorten the hemostasis time and reduce pain sensation at 2-3 days after surgery; it also prevented adhesion formation 2 weeks after surgery when compared with the control. Guardcel can be an effective and safe candidate to replace conventional packing materials after endoscopic sinus surgery.

Hydration and time-dependent rheology changes of cement paste containing ground fly ash

  • Chen, Wei;Huang, Hao
    • Computers and Concrete
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    • v.11 no.1
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    • pp.39-49
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    • 2013
  • The use of ground fly ash in concrete can increase the risk of slump loss due to the drastic surface change of the particles after the grinding treatment and the accelerated reaction compared to the untreated ash. This study is aimed at the early age hydration and time-dependent rheology changes of cement paste containing ground fly ash. An original fly ash is ground into different fineness and the hydration of cement paste containing the ground fly ash is monitored with the ultrasound propagation method. The zeta potentials of the solid particles are measured and the changes of rheological parameters of the cement pastes with time are analyzed with a rheometer. A particle packing model is used to probe packing of the solid particles. The results show that the early age hydration of the paste is strongly promoted by replacing Portland cement with fly ash up to 30 percent (by mass), causing increase of the yield stress of the paste. The viscosity of a paste containing ground fly ash is lower than that containing the untreated ash, which is explained by the denser packing of the solid particles.

Parallel Simulation of Bounded Petri Nets using Data Packing Scheme (데이터 중첩을 통한 페트리네트의 병렬 시뮬레이션)

  • 김영찬;김탁곤
    • Journal of the Korea Society for Simulation
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    • v.11 no.2
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    • pp.67-75
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    • 2002
  • This paper proposes a parallel simulation algorithm for bounded Petri nets in a single processor, which exploits the SIMD(Single Instruction Multiple Data)-type parallelism. The proposed algorithm is based on a data packing scheme which packs multiple bytes data in a single register, thereby being manipulated simultaneously. The parallelism can reduce simulation time of bounded Petri nets in a single processor environment. The effectiveness of the algorithm is demonstrated by presenting speed-up of simulation time for two bounded Petri nets.

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