엔지니어링 플라스틱 材料의 再活用 混合比가 成形品 收縮에 미치는 영향

김인관 한국자원리싸이클링학회 2004 資源 리싸이클링 Vol.13 No.3

플라스틱 재료는 재생이 가능한 열가소성 플라스틱과 재생이 거의 불가능한 열경화성 플라스틱으로 분류 할 수 있고, 본 연구에서는 재생이 가능한 열가소성 플라스틱 중 산업 및 생활 전반에 널리 사용되고 있는 PP, PA6, PC 및 PBT 재료의 재생 방안에 대한 기초 연구로서 재생 재료의 혼합비가 증가함에 따라 치수 정밀도에 미치는 영향을 고찰 하였다. In this study, an experimental work was performed to mold tensile specimens by using the injection molding machine. Melt temperature, mold temperature and the mixed ratio of recycled resin were selected as processing parameters for studying the effect of those conditions on the shrinkage and weight of molded parts. As a result, the shrinkage was increased with the higher mold and melt temperature and it was more sensitive to the change of mold temperature. On the other hand, the weight of molded parts was decreased with the increment of mold and melt temperature.

금형온도제어에 대한 실천공학모형 연구

신주경 한국실천공학교육학회 2018 실천공학교육논문지 Vol.10 No.2

In injection molding, the tool temperature has a great influence on the quality of the molded article. The appropriate temperature is determined by the molding material and the quality required for the molded part, and the important point is that the temperature should be stable. First, the tool temperature should be set in accordance with the quality required by the molded article within the range of the tool temperature conditions suitable for the material. That is, the tool temperature changes depending on the importance of the surface gloss of the molded article, shortening of the molding cycle, prevention of deformation, degree of shrinkage, ease of resin flow and the like. In order to improve practical tool technology, we propose a training model of the difficult process of tool temperature control which can be utilized in industry that design and manufacture injection mold. 사출 성형에서 금형 온도는 성형품의 품질에 큰 영향을 준다. 어느 정도의 온도가 적정한가는 성형 재료, 성형품에서 요구되는 품질에 의해서 결정되고 중요한 것은 그 온도가 안정적이어야 한다. 먼저 그 수지에 적합한 금형 온도 조건 범위 내에서 성형품이 요구하는 품질에 맞는 금형 온도를 설정해야 한다. 즉, 성형품의 표면 광택, 성형 사이클의 단축, 변형 방지, 수축 및 수지 흐름의 용이성 등의 중요성에 의해서 금형 온도는 변화한다. 실질적인 금형 기술 향상을 위해서 사출 금형을 설계하고 제작하는산업체에서 적용할 수 있는 온도 제어에 대한 애로 기술 과정의 훈련 모형을 제시하고자 한다.

Effects of Molding Pressure and Sintering Temperature on Properties of Foamed Glass without Blowing Agent

EunSeok Kim,Kwangbae Kim,Hyeryeong Lee,Ikgyu Kim,송오성 한국세라믹학회 2019 한국세라믹학회지 Vol.56 No.2

A process of fabricating the foamed glass that has closed pores with 8 ~ 580 μm sizes without a blowing agent by sintering 10 μm boron-free glass powder composed of CaO, MgO, SO3, Al2O3–83 wt% SiO2 at a molding pressure of 0 ~ 120 MPa and a sintering temperature of 750 ~ 1000oC was investigated. To analyze the glass transition temperature of glass powder, thermogravimetric analysis–differential thermal analysis (TGA-DTA) method were used. The microstructure and pore size of foamed glass were examined using the optical microscopy and field emission scanning electron microscopy (FE-SEM). For the thermal diffusivity and color of the fabricated samples, a heat flow meter and ultraviolet–visible–near-infrared (UV–VIS–NIR)-colormetry were used, respectively. In the TGA-DTA result, the glass transition temperature of glass powder was confirmed to be 626oC. In the microstructure result, closed pores of 7 ~ 20 μm were formed at 750 ~ 900oC, and they were not affected by the molding pressure and sintering temperature. However, at 1,000oC, when there was 0 MPa molding pressure, closed pores of 580 μm were confirmed, and the pore size decreased as the molding pressure increased. Moreover, at a molding pressure of 30 MPa or higher, closed pores of approximately 400 μm were formed. The porosity showed an increasing trend of smaller molding pressure and larger sintering temperature, and it was controllable in the range of 5.69 ~ 68.45%. In the thermal diffusivity result, there was no change according to the molding pressure, and, by increasing the sintering temperature, up to 0.115 W/m·K could be obtained. The Lab color index (CIE-Lab) results all showed a similar translucent white color regardless of molding pressure and sintering temperature. Therefore, based on the foamed glass without boron and blowing agent, it was confirmed that white foamed glass, which has closed pores of 8 ~ 580 μm and a thermal diffusivity characteristic of 0.115 W/m·K, can be fabricated by changing the molding pressure and sintering temperature.

사출성형 열가소성 폴리우레탄의 물리적 성질에 미치는 금형 온도 영향

김성근 ( Seong Geun Kim ),구엔빈칸 ( Vinh Khanh Nguyen ),이명걸 ( Ming Ji Lee ),방수진 ( Su Jin Pang ),이대수 ( Dai Soo Lee ) 한국고무학회 2004 엘라스토머 및 콤포지트 Vol.39 No.4

경도를 달리하는 에스테르계 및 에테르계 열가소성 폴리우레탄(thermoplastic polyurethane: TPU)의 사출에서 금형 온도가 물리적 성질에 미치는 영향을 조사하였다 TPU의 연질부 유리전이온도는 금형 온도 변화에 따라 거의 변화하지 않았으며, 연질부와 경질부의 상분리는 금형온도의 영향을 별로 받지 않는 것으로 판단되었다. 그러나 에스테르계와 에테르계 TPU는 종류에 관계없이 공통적으로 경도가 높은 TPU들은 금형온도를 높이는 경우 결정성, 고무상 평탄 온도영역, 인장강도가 감소하였으나, 경도가 낯은 TPU들은 오히려 결정성, 고무상 평탄 온도영역, 인장강도의 증가를 보였다. TPU의 사출 성형 금형 온도에 따른 물리적 성질의 차이를 결정성경질부의 결정화와 물리적 가교효과 차이로 해석하였다. Ester- and ether-based thermoplastic polyurethanes of different hardness were injection molded at different mold temperatures and effects of mold temperature on the physical properties of TPUs were investigated. Glass transition temperatures of soft segments of TPUs were hardly changed by mold temperatures. The phase separation of soft and hard segments of injection molded TPUs were affected little by mold temperatures. However, crystallinity of hard segments, temperature range of rubbery plateau, and tensile strength of injection molded TPUs decreased with increasing mold temperatures for TPUs of high hardness. However, injection molded TPUs of low hardness showed increases of crystallinity of hard segments, temperature range of rubbery plateau, and tensile strength with increasing mold temperatures. Different physical properties of injection molded TPUs depending on mold temperatures were attributed to different crystallization and physical crosslinking effects of hard segments.

Effects of Molding Pressure and Sintering Temperature on Properties of Foamed Glass without Blowing Agent

Kim, EunSeok,Kim, Kwangbae,Lee, Hyeryeong,Kim, Ikgyu,Song, Ohsung The Korean Ceramic Society 2019 한국세라믹학회지 Vol.56 No.2

A process of fabricating the foamed glass that has closed pores with 8 ~ 580 ㎛ sizes without a blowing agent by sintering 10 ㎛ boron-free glass powder composed of CaO, MgO, SO₃, Al₂O₃-83 wt% SiO₂ at a molding pressure of 0 ~ 120 MPa and a sintering temperature of 750 ~ 1000℃ was investigated. To analyze the glass transition temperature of glass powder, thermogravimetric analysis-differential thermal analysis (TGA-DTA) method were used. The microstructure and pore size of foamed glass were examined using the optical microscopy and field emission scanning electron microscopy (FE-SEM). For the thermal diffusivity and color of the fabricated samples, a heat flow meter and ultraviolet-visible-near-infrared (UV-VIS-NIR)-colormetry were used, respectively. In the TGA-DTA result, the glass transition temperature of glass powder was confirmed to be 626℃. In the microstructure result, closed pores of 7 ~ 20 ㎛ were formed at 750 ~ 900℃, and they were not affected by the molding pressure and sintering temperature. However, at 1,000℃, when there was 0 MPa molding pressure, closed pores of 580 ㎛ were confirmed, and the pore size decreased as the molding pressure increased. Moreover, at a molding pressure of 30 MPa or higher, closed pores of approximately 400 ㎛ were formed. The porosity showed an increasing trend of smaller molding pressure and larger sintering temperature, and it was controllable in the range of 5.69 ~ 68.45%. In the thermal diffusivity result, there was no change according to the molding pressure, and, by increasing the sintering temperature, up to 0.115 W/m·K could be obtained. The Lab color index (CIE-Lab) results all showed a similar translucent white color regardless of molding pressure and sintering temperature. Therefore, based on the foamed glass without boron and blowing agent, it was confirmed that white foamed glass, which has closed pores of 8 ~ 580 ㎛ and a thermal diffusivity characteristic of 0.115 W/m·K, can be fabricated by changing the molding pressure and sintering temperature.

사출성형조건이 용융수지의 유동선단에 미치는 영향의 수치해석적 연구

유민지,김경아,한성열 한국기계기술학회 2021 한국기계기술학회지 Vol.23 No.3

In this study, we used a numerical analysis program to study the molding conditions that affect the flow rate at the time of injection, using a spiral mold, which is mainly used for the evaluation of the flow rate of plastic resin. The mold temperature, melt temperature, and flow rate are composed of experimental factors. The three plastic forming factors were divided into five to six levels each. Since then, changes in the flow rate temperature were analyzed as the level of each forming factor increased. Experiments showed that all three forming factors increased the filling length of the spiral mold and the temperature of the flow front by a total of 34.53°C, melt temperatures increased the temperature of the flow front by a total of 34.53°C, the temperature increased by the flow rate was 23.5°C, and the temperature increased by the mold temperature was 1.99°C. It was shown that the melt temperature was the largest, followed by the flow rate and mold temperature. It was also possible to check the effect of plastic forming factors on the speed of the flow front.

섬유강화 플라스틱 복합재료의 압축성형에서 리브 성형품의 휨에 미치는 성형조건의 영향

김진우 ( Jin-woo Kim ),이정훈 ( Jung-hoon Lee ),이동기 ( Dong-gi Lee ) 조선대학교 공학기술연구원 2017 공학기술논문지 Vol.10 No.3

Molding of body with ribs is the most difficult during flow molding process. The rib area is easy to be deformed at the rear side due to wall thickness variation. In this study, relationships between molding condition and deflection of rib-shaped part is investigated during the compression molding of fiber reinforced plastic composites , and the following results are derived. Polypropylene(PP), Polystyrene(PS), and stampable sheet(SS 40wt%) show the increment of deflection along with releasing temperature. For the correlation between incremental holding pressure load and deflection, stampable sheet exhibits lower deflection along with higher holding pressure, while PS shows significant increase of deflection with higher holding pressure, PP shows completely different characteristic, significant reduction of deflection along with higher holding pressure. Regarding to mold temperature and deflection, deflection amount of SS is the biggest, and PS shows the smallest. In addition, all three kinds shows the highest amount of deflection at 173C. Deflection is reduced when mold closing speed is increased. Amount of deflection in SS is larger and is not highly dependent on molding conditions like holding pressure and cooling parameters, compared with single component material like PP. This can be elucidated by anisotropic and inhomogeneous characteristics of glass fiber during filling process of stampable sheet composite.

사출성형의 냉각 파라미터가 플라스틱 롤러의 수축에 미치는 영향

조성기,한성렬 한국금형공학회 2021 한국금형공학회지 Vol.15 No.4

A plastic roller for opening and closing the safety door of the injection molding machine was molded. Thedimensional change of the measurement position of the roller was studied when the cooling time was applied differentlyamong the molding conditions, and when the temperature of the coolant applied for mold cooling was also applieddifferently. Cooling times of 300 seconds and 400 seconds, hot and low-temperature coolant were applied. When thelow-temperature coolant was applied, the measuring point of the roller shrank by 0.03 mm. However, when thehigh-temperature coolant was applied, the measuring point shrank by 0.3 mm. It was found that the application oflow-temperature coolant among coolants was more suitable for the reference dimension of the molded article comparedto the application of high-temperature coolant. Among the cooling water applied for the molding of plastic rollers, whenhigh-temperature coolant is applied, the shrinkage rate measured immediately after ejection was smaller than whenlow-temperature coolant is applied. However, it was found that post shrinkage, which occurs over time, occurs muchlarger when high-temperature coolant is applied.

사출성형공정 모니터링용 엣지 디바이스 개발 및 평가

김종선,이준한,Kim, Jong-Sun,Lee, Jun-Han 한국금형공학회 2020 한국금형공학회지 Vol.14 No.4

In this study, an edge device that monitors the injection molding process by measuring the mold vibration(acceleration) signal and the mold surface temperature was developed and evaluated its performance. During injection molding, signals of the injection start, V/P switchover, and packing end sections were obtained through the measurement of the mold vibration and the injection time and packing time were calculated by using the difference between the times of the sections. Then, the mold closed and mold open signals were obtained using a magnetic hall sensor, and cycle time was calculated by using the time difference between the mold closed time each process. As a result of evaluating the performance by comparing the process data monitored by the edge device with the shot data recorded on the injection molding machine, the cycle time, injection time, and packing time showed very small error of 0.70±0.38%, 1.40±1.17%, and 0.69±0.82%, respectively, and the values close to the actual were monitored and the accuracy and reliability of the edge device were confirmed. In addition, it was confirmed that the mold surface temperature measured by the edge device was similar to the actual mold surface temperature.

고성능 사출성형을 위한 고효율 금형시스템 개발

강형선 ( Hyung-sun Kang ),이홍래 ( Hong-lae Lee ),백종진 ( Jong-jin Baek ) 조선대학교 공학기술연구원 2018 공학기술논문지 Vol.11 No.3

This is a study to solve the problems that occur in plastic injection molding. Temperature control of the mold in injection molding is very important because it is a heating and cooling operation and has a decisive influence on the productivity and merchantability of the product. We have developed a technology to uniform the resin density of the injection molding products by heating the mold temperature to high temperature within a short time and to develop the cooling speed and cooling temperature control system. A small test bed was made to test the heating and cooling performance, and the heating and cooling performance was tested by thermo-imaging the heating and cooling performance. It was applied to development molds and general molds. In the developed molds, there were no flowmark and weld lines that we wanted to improve.