• Title/Summary/Keyword: Manufacturing pressure

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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
    • Design & Manufacturing
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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.

Dry Etching of PMMA and Polycarbonate in a Diffusion Pump-based Capacitively Coupled O2 Plasma (확산펌프 기반의 O2 축전결합 플라즈마를 이용한 PMMA와 폴리카보네이트의 건식 식각)

  • Park, Ju-Hong;Lee, Seong-Hyun;Choi, Jyoung-Hoon;Noh, Ho-Sub;Lee, Je-Won
    • Korean Journal of Materials Research
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    • v.19 no.8
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    • pp.421-426
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    • 2009
  • We report on the capacitively coupled O2 plasma etching of PMMA and polycarbonate (PC) with a diffusion pump. Plasma process variables were process pressure and CCP power at 5 sccm $O_2$ gas flow rate. Characterization was done in order to analyze etch rate, etch selectivity, surface roughness, and morphology using stylus surface profilometry and scanning electron microscopy. Self bias decreased with increase of process pressure in the range of 25$\sim$180 mTorr. We found an important result for optimum pressure for the highest etch rate of PMMA and PC, which was 60 mTorr. PMMA and PC had etch rates of 0.46 and 0.28 ${\mu}m$/min under pressure conditions, respectively. More specifically, etch rates of the materials increased when the pressure changed from 25 mTorr to 60 mTorr. However, they reduced when the pressure increased further after 60 mTorr. RMS roughnesses of the etched surfaces were in the range of 2.2$\sim$2.9 nm. Etch selectivity of PMMA to a photoresist was $\sim$1.5:1 and that of PC was $\sim$0.9:1. Etch rate constant was about 0.04 ${\mu}m$/minW and 0.02 ${\mu}m$/minW for PMMA and PC, respectively, with the CCP power change at 5 sccm $O_2$ and 40 mTorr process pressure. PC had more erosion on the etched sidewall than PMMA did. The OES data showed that the intensity of the oxygen atomic peak (777.196 nm) proportionally increased with the CCP power.

Impact of Indoor Green in Rest Space on Fatigue Recovery Among Manufacturing Workers (휴게공간에서의 식물 도입이 생산직 근로자의 피로 회복에 미치는 효과)

  • ChoHye Youn;LeeBom Chung;Minji Kang;Juyoung Lee
    • Journal of Environmental Science International
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    • v.33 no.3
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    • pp.217-226
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    • 2024
  • Manufacturing workers face increased fatigue and stress due to environmental factors in workplace such as noise and vibration. Addressing this issue requires creating conducive rest spaces; however, the existing conditions of rest spaces in manufacturing workplace are subpar and lack sufficient scholarly evidence. This study investigated the effect of nature-based rest spaces on the physical and emotional recovery from fatigue on manufacturing workers. Three manufacturing complexes with nature-friendly rest spaces were selected, and 63 manufacturing workers participated in the study. The measurement tools included the Multidimensional Fatigue Scale (MFS) for fatigue levels, physiological indicators (blood pressure and heart rate), and emotional indicators (Zuckerman Inventory of Personal Reaction Scale; ZIPERS, Perceived Restorativeness Scale; PRS, Profile of Mood States; POMS and State-Trait Anxiety Inventory; STAI). The study compared recovery levels during a 7-minute rest between a space without plants and a space with natural elements. The results indicated a significant reduction in systolic and diastolic blood pressure of participants in green rest spaces compared with those in conventional rest spaces. Regarding fatigue levels, green rest spaces showed a decrease in systolic blood pressure in the middle-fatigue and high-fatigue groups. Positive feelings increased in green spaces, whereas negative emotions decreased, suggesting that short breaks in nature-friendly environments effectively promote workers' physical and emotional recovery. Furthermore, this study emphasizes the importance of green space in various work environments to promote well-being in workers.

Dynamic Respeonse of Hydraulic Pipe Lines with a Relative Small Diameter (직경이 작은 유압관로에서의 동특성)

  • 유영태
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.8 no.4
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    • pp.38-44
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    • 1999
  • This paper primarily directed toward analyzing the frequency response in hydraulic pipe lines with a small diameter. The exact solution to the frequency response is obtained by using the complicated transfer function. The discrepancy with the exact and the approximate is small so the approximation solution is adopted to compare the experimental results with the theoretical analysis. In this experiment the input frequency was generated by the frequency generator with the ball valve and speed controller. In order to compare the theoretical were forms with the experimental ones the trace obtained from the oscilloscope is photographed, The diameter the length of lines and input pressure amplitude are varied to investigate their effects,. the experiment results show that th values of dimensionless parameter are very affected to the phase delay and guide response time in the design of pressure manifold to measure the pressure of hydraulic pipelines.

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FEM Analysis of Caliper Housing Cut Inside Upper Face for Unbalance Wear Prevention of Disk Brake Pad (디스크 브레이크의 편마모 방지를 위한 finger 안쪽면 윗 부분이 가공된 캘리퍼 하우징의 유한 요소 해석)

  • Kim, Nam-Kyung;Kang, Jong-Pyo
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.1 no.1
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    • pp.89-100
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    • 2002
  • The purpose if this research was to improve the pressure distribution on the disk brake pad Not uniform pressure distribution on the disk brake pad generate the unbalance wear of it and the unbalance wear of disk brake pad generate vibration, noise, heat and reduce the braking capacity. For improve the pressure distribution on the pad in this research, upper face of caliper housing finger was cut. Two kinds of caliper which uncut and cut of finger face were compared the stress distribution by FEM analysis and real experiment. Also natural frequency and deforming displacement ware calculated. It was understood that pressure distribution could Improve by cut inside upper face of caliper housing finger.

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Optimal Design of Mold Layout and Packing Pressure for Automobile TCU Connector Cover Based on Injection Molding Analysis and Desirability Function Method (사출성형 해석과 선호함수법에 기초한 자동차 TCU 커넥터 커버의 금형 레이아웃 및 보압의 최적 설계)

  • Park, Jong-Cheon;Yu, Man-Jun
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.19 no.9
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    • pp.1-8
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    • 2020
  • In this study, the optimal design of the multi-cavity mold layout and packing pressure for the automobile TCU connector cover is determined based on the injection molding analysis and the desirability function method for multi-characteristic optimization. The design characteristics to be optimized are the warpage and sink marks of the product, the scrap of the feed system, and the clamping force. The optimal design is determined by performing injection molding analysis and desirability analysis for design alternatives defined by a complete combination of five mold layouts and six-level packing pressure. The optimal design shows that the desirability values for individual characteristics are quite high and balanced, and the resulting values of individual characteristics are satisfactorily low.

Performance Investigation of Cylindrical-Type ER Valves With Different Electrode Length (전극길이 변화에 따른 실린더 형태 ER밸브의 성능고찰)

  • Jeon, Young-Sik
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.7 no.6
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    • pp.1-11
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    • 1998
  • This paper presents performance analyses of three types of the cylindrical-type ER(electro-rheo-logical) valves, which have different electrode length and width but same electrode area. Following the composition of silicone oil-based ER fluid, the field-dependent yield stresses are obtained from experimental investigation on the Bingham property of the ER fluid. The ER valve which is dependent on the applied electric field is devised and its theoretical model is derived. On the basis of the pressure-drop analysis, three types of the ER valves are designed and manufactured. After experimentally evaluation field-dependent pressure drops, PI controller is formulated to achieve tracking control on desired pressure drop. The controller is then experimentally implemented and tracking control performance is presented in order to demonstrate superior controllability of the ER valve. In addition, the response characteristic of the ER valve with respect to the excitation frequency of the electric fiedls is provided to show the feasibility of practical application.

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Muffler Design Using Transmission Loss Prediction Considering Heat and Flow (열과 유동을 고려한 음장해석을 통한 머플러의 설계)

  • Kim, Hyunsu;Kang, Sang-Kyu;Lim, Yun-Soo
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.24 no.8
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    • pp.600-605
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    • 2014
  • Two mufflers for a large-size sedan are suggested aiming (1) sporty-sound and (2) quiet-sound as well as both satisfying low back-pressure and low manufacturing cost. Transmission loss prediction considering heat and flow may increase the accuracy and reduce the development cost in muffler design; thus, GT-power prediction considering heat, flow, and acoustics is utilized. By understanding the fundamentals of flow-acoustic theory in small orifice(hole), an effective muffler design concept is proposed. Vehicle tests show the consistence with predictions for sound; also a back-pressure test bench confirms the advantage in pressure drop for both suggested mufflers. Those suggested mufflers also have advantages in manufacturing cost due to simplicity of the design.

Development of FEA Custom Application System for Thermal Stress Evaluation of Skirt Type Joint Pressure Vessel (압력용기 Skirt부의 열응력 평가를 위한 유한요소해석 전문가시스템 개발)

  • Ye, Gyoo-Hyeon;Park, Dong-Sung;Choi, Kyeong-Ho
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.2 no.1
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    • pp.51-56
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    • 2003
  • A custom application system, which was based on the finite element analysis, for stress on the head-skirt junction of a hot pressure vessel was developed. This is useful computer-based analysis system which designed to provide an analysis technique and knowledge conveniently available to other people. It was found the evaluation of thermal stress of several typed skirt joint of a pressure vessel could be performed early using this system.

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Bonding of Electric Wire by Ultrasonic Welding (초음파 용접을 이용한 전선의 접합)

  • 이철구
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.9 no.4
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    • pp.41-47
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    • 2000
  • In this study, the purpose finds out the best welding conditions for bonding of electric wire by ultrasonic welding. The material was plastic-insulating low-voltage-cabels for automobiles. The experiment varied the values of welding time and welding pressure and fixed the values of amplitude and energy. With the facts, the best condition for ultrasonic welding to achieve bonding exactly is gained according to the size of the cross-sectional area of the cable, and the adhesive intensity is greatly influenced by the variables of welding time and welding pressure. Also when the welding time and welding time and welding pressure increase as the cross-sectional areas of the cable increase the welding result in gained exactly.

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