자동차 암레스트의 인몰드코팅에 관한 실험적 연구

박종락(Jong-Rak Park),이호상(Ho-Sang Lee) 대한기계학회 2014 대한기계학회 춘추학술대회 Vol.2014 No.11

Mold design for in-mold coating were carried out in order to achieve simultaneous coating and injection molding of an automotive armrest. The developed mold consists of two molds and one sliding plate. The first mold includes a movable mold piece and a first fixed mold piece for injection molding of a substrate. On the substrate surface near a parting line, sealing edges were considered for forming a seal projection. The second mold includes the movable mold piece and a second fixed mold piece for forming the coating. The mold enables coating on the substrate surface after injection molding. The materials used were PC/ABS for substrate and 2-component Polyurethane for coating. The experiments were conducted by changing the flow rate in order to investigate mixing characteristics. As the flow rate increased, the mixing was more improved. And the bubbles appeared over the substrate surface decreased with an increase of the weight of injected coating material.

컴퓨터 해석을 통한 사출압축성형의 성형특성에 관한 연구

천용호 ( Y. H. Chun ),안형광 ( H. G. An ),류민영 ( M. Y. Lyu ) 한국고무학회 2012 엘라스토머 및 콤포지트 Vol.47 No.4

사출성형은 고분자성형법 중에서 가장 광범위하게 활용되고 있다. 사출성형은 전형적인 사출성형 외에 가스사출, 물사출, 그리고 사출압축성형 등과 같이 특수한 사출성형방법들이 쓰인다. 사출압축성형은 사출과 압축공정이 합쳐진 것으로 균일한 물성 및 성형의 정밀도를 향상시키기 위하여 사용된다. 또한 사출압축은 잔류응력을 줄이는데도 효과적으로 사용되고 있다. 본 연구에서는 성형품의 형상에 따라 다양하게 나타나는 사출압축성형의 특성에 대해서 컴퓨터 해석을 통해 분석하였다. 성형품에 벽이 있는 제품은 벽의 두께가 압축의 방향과 직각이므로 압축효과가 작게 나타났다. 사출압축성형을 일반사출성형과 비교하였을 때 수축의 균일성 및 수축량 또는 성형수축률이 작게 나타나서 정밀성형에 유리하게 나타났다. 실험계획법을 통해 실제로 제작되고 있는 렌즈에 대해서 최적 사출압축조건을 구하고 이의 결과를 사출성형의 결과와 비교분석하였다. Injection molding is one of the widely used polymer processing operations. It is being used for not only conventional injection molding but gas injection molding, water injection molding, and injection compression molding. Injection compression molding involves injection and compression operation, and it gives uniform physical property and high dimensional quality of product. In this study, injection compression characteristics for various product shapes have been investigated by computer simulation. Product containing side wall showed not much effective in injection compression molding since wall thickness direction was perpendicular to the compression direction. Uniform and low shrinkage was observed in injection compression molding comparing conventional injection molding. Subsequently injection compression molding can be used for molding precise product. Optimal injection compression molding condition was obtained using design of experiment for plastic lens and the results were compared with conventional injection molding.

사출성형공정에서 금형에 전달되는 진동 신호 측정을 이용한 성형 단계별 공정시간과 공정특성의 모니터링에 대한 연구

이준한,김종선,Lee, Jun-han,Kim, Jong-Sun 한국금형공학회 2020 한국금형공학회지 Vol.14 No.3

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.

高麗中期壓出陽刻 靑瓷의 性格

장남원(Chang Nam-won) 한국미술사학회 2004 美術史學硏究 Vol.- No.242·243

고려 중기(11세기 말-13세기 전반) 청자의 제작에서 사용된 문양장식 방법은 음각, 상감, 압출양각, 철화. 투각 등 매우 다양하나 지금까지 주로 상감기법을 대표적인 것으로 중요하게 인식해 왔고 연구해 왔다. 그러나 실제로 청자에 문양을 장식하는 작업이 보편화되는 고려 중기 요지와 소비유적에서는 압출양각 기법을 사용한 청자가 음각문 청자 다음으로, 또는 지역에 따라 더 많은 비율로 생산되었음이 밝혀졌다. 예로서 왕실과 관공서, 주요사찰 등에 용품을 납품하던 강진지역의 용운리 10호 가마에서는 문양이 있는 접시 가운데 50% 이상에 압출양각 기법이 사용되었으며, 부안 유천리 7구역의 경우는 문양 있는 청자의 40% 이상에서 압출양각 기법이 사용된 것으로 집계되었다. 나아가 지방에서 소규모로 운영되었던 대전 구완동이나 음성 생리 같은 곳에서는 다른 기법보다 압출양각이 월등하게 많은 비중을 차지하고 있는 것으로 조사되었다. 압출양각 기법은 주로 鉢이나 접시처럼 형태상 내면보다 구연이 넓고 벌어져 문양틀〔陶範〕을 사용하기 편리한 기종에서 사용되는 것이 일반적인데, 고려 중기에는 이처럼 일정한 규격의 틀을 사용함으로써 크기와 문양이 일정한 제품을 전국 각지에서 대량으로 생산할 수 있는 압출양각 기법이 최적의 공예기법으로 채택되었다. 압출양각 기법은 같은 규격의 문양틀만 있으면 시도할 수 있는 기법이므로 강진이나 부안만큼 숙련된 장인이 상주할 여건이 마련되지 않은 지역에서도 그들 지역과 조형적으로 유사한 청자를 생산할 수 있는 공예적 장점을 가지고 있다. 따라서 국내 수공업품 생산 확대와 청자의 수요가 증가되는 과정에서 국가 공납품을 생산하던 최고급 가마인 康津지역의 생산 모델이 다른 지역 가마에 영향을 미치는 과정에서 위와 같은 현상이 나타났던 것으로 파악된다. 압출양각 청자의 대부분이 내면 전체나, 내측면 등에 공통적으로 화려하고 섬세한 花文을 시문하였으므로 그 문양을 살리기 위해서 燔造時에 그릇 위에 다른 그릇을 포개는 疊燒방법을 사용하지 않았으며, 문양이 없는 기물의 위쪽에 놓거나 다른 그릇들보다 가장 위쪽에 놓게 됨으로써 문양이 없는 청자에 비해 같은 가마 내에서나 또는 서로 다른 지역의 생산품 간에서도 비교적 일정하게 고급한 質을 유지하고 있는 것으로 파악되었다. 이 기법은 중국 북송 후반부터 남송대에 걸쳐 耀州窯(Yaozhou Yao)系나 定窯(Ding Yao)系에서 주로 사용되어 중국에서도 남북방에 걸쳐 기장 광범하게 나타나는 장식이다. 국내에서는 강진 용운리 10호 생산품을 기준으로 10-Ⅱ층위에 해당하며, 국내외 유적들의 고고학적 층위 관계와 동반 유물의 편년으로 보아 대개 11세기 말경부터 13세기 전반에 집중되어 있다. 이른바 ‘한국식 퇴화해무리굽’ 碗의 생산이 끝나는 시점, 즉 宋과의 관계가 정상화되고 중국의 새로운 문물을 받아들이는 시기가 우리나라 압출양각의 개시 시기일 것으로 본다. 그러나 이 기법은 국내에 정착한 이후 중국과는 다른 독자적인 문양을 개발하여 고려의 고유한 양식을 이끌어 갔던 것으로 파악되었고, 상감기법 같은 고급 장식기법을 실현할 수 없었던 지방요지에서는 더 오래 동안 지속했던 것으로 볼 수 있다. 본고에서는 압출양각 기법이 고려 중기에 청자 제작이 전국각지로 확대되어 생산량이 늘어나는 과정에서 국가 공납품을 생산하던 요장이나 지방수요를 감당하던 요장 모두에서 나타나는 현상에 주목하여 다각적인 검토를 시도하였다. 그리고 태토와 유약, 번조기술 등에서 다소 격차가 있는 요지들에서도 당시 최고급품을 생산했던 康津청자의 형식과 조형에 가장 근접하게 생산되고 있었음을 확인할 수 있었다. 고려 중기의 청자생산에서 압출양각 기법이 공예적 특성의 하나인 대량생산을 위한 ‘複製’에 가장 적합한 기법으로 채택되고 있었음을 상기하면서 압출양각 청자의 공예적 위상에 대해 새롭게 주목해야 할 것으로 생각한다. During the mid-Goryeo period (late 11th century-first half of the 13th century) when decoration on celadons became commonplace, relief design created by molds or molded design, was employed most frequently on celadons after the incision of decoration. This was not just the case of the major kilns in areas such as Gangjin (康津) and Buan (扶安), but the small local kilns also revealed that molded design was the most popular among decoration methods. More than 50% of the plates from kiln no. 10 at Yongun-ri (龍雲里) in Gangjin, and more than 40% of the decorated celadons from kiln no. 7 at Yuchon-ri (柳川里) in Buan, comprise the molded design. Moreover, it has been reported that celadons with molded design constitute a considerable portion among those from kiln sites in Guwan-dong (舊莞洞). Taejon, and in Saeng-ri (筬里), Umseong. Molded design was used on vessels with a wide, open mouth so that the design mold could easily be impressed. The use of a standard mold enabled the mass-production of the same shape and style. This preference for celadons with molded design appeared as the celadon from Gangjin kiln celadons were established as a standard model for other regions. It appears that the craft-like characteristic of this type enabled potters who were not as those of capable as the Gangjin and Buan kilns, to use the same standard design mold, and thus to produce a similar decorative effect. Celadons with molded design presented the decoration either on the entire inside or on the internal walls. Other pieces were not stacked on this type, but instead this type was placed on top of stacks. Therefore, the objects were able to maintain higher quality than other objects from this kiln or those from other kilns. Used extensively among Yaozhou-ware (耀州窯) and Ding-ware (定窯), this method was particularly popular in the 10-Ⅱ stratum kiln no. 10 at Yongun-ri in Gangjin. From the archaeological evidence and chronological comparison with the firds from other sites, the stratum appears to belong to the period between the late 11th century and the first half of the 13th century. Thus, when the production of the tea bowls with pi-shaped foot ring came to a dose, and when the normalized relationship with Song China brought forth a new cultural wave. Korean celadons began to be decorated using molds. Once established in the peninsula, this decorative method, developed independently as a distinctive Korean design. Celadon with molded design made use of the craft-like quality of repeated impressing and mass-producing as celadon production spread throughout the Korean peninsula. The craft-like quality of the celadon with molded design enabled the maintenance of the Gangjin kiln shape and style despite the low quality of the day body and glaze, and the imperfect kiln technology of other local kilns.

CO2 냉각모듈을 적용한 고곡률 성형품의 사출금형 급속냉각

이세호,이호상 한국금형공학회 2022 한국금형공학회지 Vol.16 No.4

Injection molding is a cyclic process comprising of cooling phase as the largest part of this cycle. Providing efficient cooling in lesser cycle times is of significant importance in the molding industry. Recently, lots of researches have been done for rapid cooling of a hot-spot area using CO2 in injection molding. The CO2 flows under high pressure through small, flexible capillary tubes to the point of use, where it expands to create a snow and gas mixture at a temperature of -79°C. The gaseous CO2  removes heat from the mold and releases it into the atmosphere. In this paper, a CO2 cooling module was applied to an injection mold in order to cool a large area cavity uniformly and quickly, and the cooling performance of the injection mold was investigated. The product was a high-curvature molded part with a molding area of ​​300x100mm. Heat cartridges were installed in a stationary mold, and CO2 cooling module was inserted inside a movable mold. Through structural analysis, it was confirmed that the maximum deformation of mold with CO2 cooling module was 0.09mm. A CO2 feed system with a heat exchanger was used for cooling experiments. The CO2 was injected into the holes on both sides of the supply pipe of the cooling module and discharged through hexagon blocks to cool the mold. It took 5.8 seconds to cool the mold from an average temperature of 140°C to 70°C. Through the experiment using CO2 cooling module, it was found that a cooling rate of up to 12.98℃/s and an average of 10.18℃/s could be achieved.

Injection molding of a nanostructured plate and measurement "Injection molding of a nanostructured plate and measurement of its surface properties"

Y.E. Yoo,T.H. Kim,D.S. Choi,S.M. Hyun,H.J. Lee,김선경,B.H. Kim,Y.H. Seo,H.G. Lee,J.S. Lee 한국물리학회 2009 Current Applied Physics Vol.9 No.2

This paper highlights recent research on the injection molding of a surface nanostructured substrate with super-hydrophobicity or dry adhesiveness. An anodic aluminum oxidation (AAO) membrane or layer on an Si wafer is used as a molding master for surface nanostructures. The AAO membrane or layer has closely packed nanoholes; depending on the AAO membrane used, the nanoholes have a diameter of around 200 nm and a depth that varies from a few hundred nanometers to 60 ㎛. This AAO master is installed directly in the injection molding tool, or the AAO holes are replicated on the nickel stamper by an electroforming process and installed in the injection molding tool. Either a high temperature (>Tg of the molding material) mold or a rapid heating (up to 200 ℃) and cooling (<70 ℃) mold is used to fill the high aspect ratio nanoholes with thermoplastic melt for the injection molding. These high aspect ratio nanoholes are extremely difficult to fill with melt in a conventional injection molding process. This paper proposes a new simple and efficient rapid heating and cooling method that heats the stamper by means of the electrical resistance of the stamper itself. Depending on the aspect ratio of the structures and the type of master, a chemical etching or mechanical ejecting process is used to release the molded surface nanostructures. With the use of an AAO membrane and a high temperature mold, some polypropylene disks with a nanohairy surface and some polycarbonate plates with a nanopillar on the surface are injection molded at several different mold temperatures for the purpose of studying the replication of the surface nanostructures. In addition, the contact angle of the water and the adhesion force on the molded surfaces are measured to investigate the effect of the surface nanostructures on the hydrophobicity or dry adhesiveness.

사출 성형품의 수지에 따른 최적의 온도에 대한 연구

조성기,한성렬 한국금형공학회 2019 한국금형공학회지 Vol.13 No.2

For optimal injection molding, various molding conditions should be combined well. Therefore, engineers should be thoroughly familiar with mold design, fabrication, and injection molding. The choice of resin among the various molding conditions is closely related to the productivity of the molded part and the deformation after molding, so the engineer must select the appropriate resin. Engineers work on the basis of data provided by resin manufacturers during molding. However, in actual molding work, it is necessary to apply values slightly different from those provided to obtain molded articles of desired performance. In this study, various deformations of molded products were compared with respect to crystalline resin and amorphous resin when molded according to the data provided by the resin maker and molded at the changed values at the work site.

Characterization of SUS Molds for Light Guide Plates by Electro-Chemical Fabrication (ECF) Method

Min-Soo Cho,Si-Hyeong Cho,Nam-Goo Cha,Hyun-Woo Lim,Jin-Goo Park,Jae-Seung Jo 대한금속재료학회(구 대한금속학회) 2007 ELECTRONIC MATERIALS LETTERS Vol.3 No.2

A new micro fabrication method termed electro chemical fabrication (ECF) is introduced to overcome conventional problems of electrochemical machining (ECM), such as low reliability and reproducibility. This ECF process defines micro patterns using a conventional photolithography, allowing it to produce micro-scale patterns with an excellent surface profile and of excellent quality. In this paper, four-inch 304 SUS and Ni molds were fabricated by using ECF and FeCl3 wet etching processes, respectively. The etch rate of stainless steel was measured at nearly 0.27 μm/min at optimized ECF conditions and that of Ni was 0.77 μm/min with FeCl3 dipping. To ensure a uniform depth profile of 10 μm, the process time for the SUS and the Ni mold were determined to be 36 minutes and 13 minutes, respectively. After the fabrications of SUS and Ni molds, the ECF-SUS mold showed two times better surface roughness values than the FeCl3-Ni mold. To evaluate the ECF-SUS process, light guide plates (LGP) were made using an injection molding method. The LGP using the FeCl3-Ni mold showed a hazy area when tilting the plate. This haze effect is believed to have formed from poor surface roughness. An LGP made with an ECF-SUS mold showed a 25% higher brightness and a 15% higher light uniformity compared to a FeCl3-Ni mold.

CNT 필름 히터 적용 곡면형 금형의 균일 가열기법 연구

오서현,전은지,이현민,고영배,박근 한국정밀공학회 2022 한국정밀공학회지 Vol.39 No.7

Injection molding is one of most widely-used polymer processing technologies in which hot polymer fills a mold cavity, and is solidified during the subsequent cooling process. In the mold filling stage, the mold temperature should be high to improve flow characteristics, and low to reduce cooling time during the cooling stage. To fulfill these objectives, rapid mold heating technology has been developed to raise mold temperature, without significant increase in cycle time. While the conventional rapid heating technologies required dedicated facilities such as steam heating or high-frequency induction heating system and has a limitation in uniform heating, the purpose of this study was to develop a facile and conformal mold heating unit that uses a carbon nanotube (CNT) film heater. The CNT film heater was used to heat a curved mold with high temperature uniformity, by maintaining uniform distance from the mold surface. The developed conformal heating technology was then applied to a singly curved mold and a multiply curved mold. Considering that the resulting temperature uniformity is superior to the conventional oil heating, the conformal mold heating technology using the CNT film heater can be used to improve part quality and productivity in various molding processes.

다수 캐비티를 갖는 3매 구성 사출금형에서의 충전 불균형

제덕근(Deok Keun Je),정영득(Yeong Deug Jeong) Korean Society for Precision Engineering 2004 한국정밀공학회지 Vol.21 No.6

Injection molding is the one of the most important processes for mass production of plastic parts. Usually injection molds for mass production are constituted to multi-cavity runner system to manufacture the more parts at a time. Multi-cavity molds are designed to geometrically balanced runner system to uniformly fill to each cavity.But,when injection molding is performed using a mold with balanced runner system filling imbalances are occurred between the cavity to cavity. The previous studies by Beaumount at.al reported that filling imbalance occurred by thermal unbalance on the mold and viscosity variation of resins and so on. In this study, we conducted experiments in order to know the causes of filling imbalance for 3 plate type mold with 8 cavities. And we exhibited a new so called 4BF mold (4 plate type Balanced Filling Mold) to be possible filling balance. We conducted a experimental injection molding to verify the efficiency of the 4BF mold. In the results of the experiment, we could confirmed the balanced filling possibility of the 4BF mold.