DSI 성형을 이용한 금속/플라스틱 복합 부품 제조에 관한 연구

하석재,차백순,고영배,Ha, Seok-Jae,Cha, Baeg-Soon,Ko, Young-Bae 한국금형공학회 2020 한국금형공학회지 Vol.14 No.4

Various manufacturing technologies, including over-molding and insert-injection molding, are used to produce hybrid plastics and metals. However, there are disadvantages to these technologies, as they require several steps in manufacturing and are limited to what can be reasonably achieved within the complexities of part geometry. This study aims to determine a practical approach for producing metal/plastic hybrid components by combining plastic injection molding and metal die casting to create a new hybrid metal/plastic molding process. The integrated metal/plastic hybrid injection molding process developed in this study uses the proven method of multi-component technology as a basis to combine plastic injection molding with metal die casting into one integrated process. In this study, the electrical conductivity and ampacity were verified to qualify the new process for the production of parts used in electronic devices. The electrical conductivity was measured, contacting both sides of the test sample with constant pressure, and the resistivity was measured using a micro ohmmeter. Also, the specific conductivity was subsequently calculated from the resistivity and contact surface of the conductor path. The ampacity defines the maximum amount of current a conductive path can carry before sustaining immediate or progressive deterioration. The manufactured hybrid multi-components were loaded with increasing currents, while the temperature was recorded with an infrared camera. To compare the measured infrared images, an electro-thermal simulation was conducted using commercial CAE software to predict the maximum temperature of the power loaded parts. Overall, during the injection molding process, it was demonstrated that multifunctional parts can be produced for electric and electronic applications.

균일 냉각을 고려한 Thick-Wall 형상의 플라스틱 렌즈 쾌속 금형 제작

박형필,차백순,이상용,최재혁,이병옥,Park, Hyung-Pil,Cha, Baeg-soon,Lee, Sang-Yong,Choi, Jae-Hyuk,Lee, Byung-Ok 한국금형공학회 2007 한국금형공학회지 Vol.1 No.1

In the optical application demand for high quality lens is increasing. Plastics lenses are demanded more than glass lenses for large size lenses as well as micro-size lenses. It is difficult to apply typical straight cooling channels of injection mold to lens molding due to its non-uniform temperature distribution. In this study, we manufactured molds for plastic lenses with the conventional cooling channels and conformal cooling channels produced by the DMLS process. We evaluated cooling performance for the 2 molds by injection molding experiment. Also, uniformity of the temperature distribution was tested by infrared camera and temperature monitoring. We confirmed that the cooling performance and temperature uniformity with the conformal cooling channels is much improved from the ones with the conventional. The cooling time with the conformal cooling channels was reduced 30% compared with the conventional cooling channels.

방수 커넥터용 LSR Seal의 균일 경화를 위한 사출 금형 히터의 최적 설계

송민재(Min-Jae Song),차백순(Baeg-Soon Cha),홍석관(Seok-Kwan Hong),고영배(Young-Bae Ko) 한국산학기술학회 2017 한국산학기술학회논문지 Vol.18 No.7

자동차용 방수커넥터는 외부로부터 방수가 필요한 전장부품인 와이어 하네스(Wire Harness)에 연결되어 있는 핵심 기능부품이며 특히 와이어씰(Wire Seal) 부품은 고온, 다습, 저온, 먼지, 약품 등의 복합적 환경에서도 체결부 기밀성이 확보되어야 한다. 이러한 와이어씰은 최근 기존의 고상실리콘고무(Heat Cure Rubber)대신 친환경 소재이며 기계적 특성이 우수한 액상실리콘고무(LSR)를 적용하고 있다. 그리고 LSR용 와이어씰을 액상사출성형(Liquid Injection Molding)공정으로 제조할 경우 고상실리콘고무를 제조 하긴 위한 압축성형방식에 비해 사이클타임이 10배이상 빠르고 스크랩이 발생하지 않아 재료의 손실이 없으며 가류 및 생산을 위한 전후처리 과정이 필요 없기 때문에 원가 절감효과가 큰 이점이 있다. 하지만, 방수커넥터를 제조하기 위한 LSR 다캐비티 사출성형공정에서는 일정한 품질의 제품을 확보하기 위하여 캐비티간 균일한 경화온도를 유지하는 것이 중요하다. 본 연구에서는 캐비티간 온도 편차를 최소화 하기 위하여 카트리지 히터의 용량을 위치마다 다르게 설계한 후 열전달 해석과 최적화 모듈을 연계하여 최적의 카트리지 히터 용량을 빠르고 효율적으로 도출하였다. 최적화 해석결과 일정한 히터 용량을 적용한 경우에 비하여 캐비티간 온도 편차는 13.1℃에서 8.1℃로 감소 시켜 균일 경화를 위한 온도 편차 10℃ 이내인 설계 기준을 만족시킬 수 있었다. Automotive waterproof connectors are highly functional parts that must be air-tight in a complex environment. In the LSR multi-cavity injection molding process for manufacturing waterproof connectors, it is important to maintain a uniform curing temperature between the cavities in order to obtain a quality product.For this purpose, we designed the capacity of the cartridge heater differently for each position, and then linked the heat transfer analysis and optimization module to obtain the optimal cartridge heater capacity.As a result of the optimization analysis, the temperature deviation between cavities was decreased from 13.1℃ to 8.1℃ compared with the case in which constant heater capacity was applied, so that the design criterion could be satisfied within a temperature deviation of 10℃ for uniform curing.This study suggests that this method can be applied efficiently to the design of a large area multi-cavity LSR mold heater.

사출성형기 실린더와 금형 캐비티의 실시간 모니터링을 이용한 사출성형공정 비교 분석

박형필(Hyung Pil Park),차백순(Baeg Soon Cha),태준성(Jun Sung Tae),최재혁(Jae Hyuk Choi),이병옥(Byung Ohk Rhee) 대한기계학회 2010 大韓機械學會論文集A Vol.34 No.10

최근 고품질 제품 생산을 위한 방법으로 센서를 이용한 사출공정모니터링 시스템이 적용되고 있다. 그러나 마이크로 금형, 광학용 금형 및 구조가 복잡한 금형에는 센서 설치가 어렵기 때문에, 공정 모니터링 시스템이 적용되기 어려운 단점이 있다. 본 연구에서는 금형과 사출성형기 노즐의 압력 을 측정하여 공정 모니터링 데이터의 정량적 지수를 정의하고, 성형품 중량에 대한 상관분석을 수행하여 노즐에 설치된 압력센서의 공정모니터링 적용성을 알아보았다. 또한 공정모니터링 데이터를 분석하여 다단사출속도, 보압 및 제한 사출 압력의 영향에 따른 사출성형기의 공정 제어 특성도 알아보았다. Recently, on-line process monitoring systems using sensors are being extensively used to produce highquality products. However, the difficulty in installing the sensors within the mold in the cases of micro-molds, optical molds, and molds with complex structures is a serious disadvantage of such process monitoring systems. In this study, the quantitative index of a process monitoring system was evaluated with the mold cavity pressure and the nozzle pressure for the injection molding machine. In order to evaluate the effect of the nozzle pressure, we performed correlation analysis for the weight of the molded product. We also examined the control characteristics of the injection molding machine by analyzing the effect of multistage injection speed, holding pressure, and injection pressure limit on the process monitoring data.

가변러너를 이용한 LDPE/ABS/PA66 수지의 충전균형에 관한 연구

박형필(Hyung-Pil Park),차백순(Baeg-Soon Cha),강중근(Jung-Geun Kang),이병옥(Byung-Ohk Rhee) 대한기계학회 2006 대한기계학회 춘추학술대회 Vol.2006 No.11

During the injection molding process an excessive packing can occur in the smaller-volume cavity because of volumetric difference of the family-mold. It causes warpages by increased residual stress in the product and flashes by over packing. In this study, we developed a variable-runner system for the filling balance of the cavities by changing the cross-sectional area of a runner, and confirmed the filling imbalance by temperature and pressure sensors. We carried out experiments to examine the influence of types of resins such as LDPE/ABS/PA66 on the balancing-capability of the system, in order to help mold designers, who can easily adopt the variable -runner system to their design. We also confirmed the filling imbalance in the system with CAE analysis.

Film In-mold 성형 시 발생되는 Wash-Out 현상에 관한 연구

박형필(Hyung Pil Park),차백순(Baeg Soon Cha),김동한(Dong Han Kim),정민화(Min Hwa Jung),이화원(Hwa Won Lee) 대한기계학회 2011 대한기계학회 춘추학술대회 Vol.2011 No.6

LSR 사출성형의 공정조건 변화가 캐비티 압력 및 성형품의 기계적 강도에 미치는 영향

박형필(Hyung Pil Park),차백순(Baeg Soon Cha),이정원(Jeong Won Lee),고영배(Young Bae Ko),김상권(Sang Gweon Kim),정태성(Tae Sung Jung),김동한(Dong Han Kim),이병옥(Byung Ohk Rhee) 한국생산제조학회 2014 한국생산제조학회지 Vol.23 No.2

Liquid silicone rubber (LSR) has been widely used in automotive, electrical, and medical components. Thus, research on the use of LSR in the injection molding process is required to obtain high-quality and high-performance products. In this study, a mold was fabricated to examine the effects of the process parameters on the molding and mechanical properties of LSR parts. A computer-aided engineering analysis was used to optimize the air vent depth and curing temperature to decrease the flash at the air vents caused by the low viscosity of LSR. Temperature and pressure sensors were mounted in the mold to determine the effects of the process parameters on the temperature and pressure in the cavity. The tensile strength of the LSR parts was also examined in relation to the process parameters.

멤브레인 주름의 응력거동에 관한 수치적 연구

김청균(Chung Kyun Kim),이영숙(Young Suck Lee),차백순(Baeg Soon Cha),김영규(Young Gyu Kim),윤인수(In Soo Yoon),홍성호(Seung Ho Hong) 한국가스학회 1997 한국가스학회 학술대회논문집 Vol.1997 No.9

자동차용 방수커넥터의 밀봉특성에 관한 연구

고영배(Ko, Young-Bae),박형필(Park, Hyung-Pil),이정원(Lee, Jeong-Weon),차백순(Cha, Baeg-Soon) 한국산학기술학회 2014 한국산학기술학회논문지 Vol.15 No.4

본 액화 실리콘 고무는 내열성 및 내화학적 우수성으로 전자 제품 및 다양한 제품에서 활용되고 있다. 하지만 초탄성 재료는 일반 금속재료와 다른 특성을 보인다. 초탄성 재료는 하중과 변형이 비선형 관계를 보이는 대변형 범위에서도 탄성거 동을 나타내는 특성을 지니며, 비선형, 비압축성 및 대형의 특성을 지니고 있다. 이러한 특성 때문에 제품을 설계 및 생산 하기위해는 기능적 측면을 고려한 소재의 특성에 대한 물성 확보가 반드시 필요하기 때문에 현장에서 많은 어려움이 있다. 본 논문에서는 자동차용 방수커넥터 설계를 위해 소재의 인장, 압축 시험으로부터 구한 하중-변형관계를 이용하여 이를 유한 요소 해석에 적용한 결과를 비교하였으며, 해석결과와 제품의 성능 테스트 결과를 비교하여 방수커넥터용 씰의 경우 어떠한 소재특성을 적용할 경우 유용한 결과를 도출할 수 있는지를 확인하였으며, 이를 통해 제품 개발에 유용성을 확인하였다. Liquid silicone rubber(LSR) has been applied to various products such as electronic devices owing to its excellent thermal and chemical resistance. Hyperelastic materials, however, have properties distinguished from general metal materials. Hyperelastic materials show elastic behaviors in the range of large deformation in which load has the nonlinear relation with deformation. In addition, they have characteristics of nonlinearity, incompressibility, in large scale. On account of such characteristics, there are many difficulties in design and production using these materials. In this study, the load-deformation relation obtained from tension and compression tests was applied to finite element analysis in order to design waterproof connectors for automobiles. Furthermore, the effectiveness of the finite element analysis was confirmed by comparing the results of analysis with those of performance tests.

A Study on Thermal and Flow Characteristics of an Injection Mold Using a Detachable Core Module with Embedded Heating

오승아(Seung-Ah Oh),고영배(Young-Bae Ko),차백순(Baeg-Soon Cha),박근(Keun Park) Korean Society for Precision Engineering 2020 한국정밀공학회지 Vol.37 No.5

The purpose of this study was to develop an efficient mold heating technology by an embedded heating unit. To localize the heating effect in the mold core and prevent heat transfer to surrounding mold plates, the core module with embedded heating unit was assembled to a mold plate in a detachable manner. The detachable core module was then separated from the mold plate when the mold was opened, and thus could be rapidly heated by the embedded heater. The heated core contacted with the mold plate when the mold was closed, and could be cooled by heat conduction to the mold plate of which thermal inertia was much larger than that of the core module. To verify thermal efficiency of the proposed structure, heat transfer simulation was performed with an experimental validation. Mold filling simulation was also performed to investigate the effect of mold heating on improving flow characteristics through a thin and narrow channel. Injection molding experiments were also conducted by adopting the proposed embedded heating module.