Warpage of injection molded product is caused by non-uniform shrinkage and residual stress. A method of removing uneven molding shrinkage and residual stress is to remove the defective factor to Uniform cooling of products. Warpages for part designs have been investigated in this study according to the injection molding conditions for amorphous ABS and crystalline PP by the rapid cooling and heating system. Experimental results showed that the crystalline resin was more warped than amorphous resin, Warpages have been observed in the regions of the part, near gate region and flow direction region.

This study was developed the rapid heating and cooling device using peltier module for uniform cooling. make the rapid heating and cooling device(RCHD), for traditional water cooling device(TWCD) method and the rapid heating and cooling method warpage were compared and were analyzed and the materials used crystalline PP polymer. various warpage were compared for the process parameters such as packing pressure, packing time, mold temperature. in the crystalline PP polymer, TWCD method has higher warpage than RCHD method and show the result to be a bit more uniform cooling. RCHD method has higher warpage than TWCD method as cooling time and packing time increases and TWCD method has higher warpage than RCHD method as mold temperature increases.

Molding trouble in injection-molded parts is caused by change of complexed molding product and molding process condition, etc. Warpage, which is one of the molding trouble, acts as possible factor which results in defect in assembly. In this study, a mold was designed to produce specimens with rib parallel to flow direction, specimens with rib perpendicular to flow direction and specimens without rib. This work researched change of warpage according to injection molding condition such as packing pressure, packing time, resin temperature in crystalline polymers(PP). Flat shape with ribs showed higher warpage than flat shape without ribs. The Specimens with ribs that are located perpendicular to the flow direction.

Most of the plastics products have been manufactured by injection molding. Molding trouble in injection-molded parts is caused by changing a molding product and molding process condition, etc. In this study, warpage in the injection molded part have been studied. specimens are rectangular flat shape with and without ribs. Non-crystalline resins (PC) and crystalline resins (PA66) were used for material and 30% glass fiber reinforced-resins(PC, PA66). Flat shape ribs showed higher warpage than flat shape without rib by 10 to 41%. the specimens with ribs that are located parallel to flow direction has higher warpage than the specimens with rib that are located perpendicular to flow direction by 11 to 50%. crystalline resins have higher warpage than non-crystalline resins by 22 to 78%.

배 경: 콘택트렌즈 착용으로 인한 각박 변형은 콘텍트렌즈 착용자에게 하나의 증요 한 문제로 인식되고 있는데， 특히나 PMMA 렌즈 착용 후에 시력이 일정하지 않고， 불량한 시략이 되기도 한다 또한 RGP 렌즈나 소프트렌즈도 각막변형의 유판하는데 주요한 역 할을 하고 있다. 방 법: Pubmed에서 키워드 검색을 통해 기존 간행된 저널을 기본으로 하였으며. 최 근 저덜의 Oπho-K 에 대한 각막 형상에 대한 기전에 대해 언급을 하였다. 결 과: 본 저널은 각막 변형의 원인과 증상 및 징후， 다른 진단파 각기 다른 종류에 대한 각막변형에 따른 처지 관리 요령에 대해 서숨하였다 산소결핍， 렌즈의 디자인， 눈과 콘택트 렌즈간의 피팅 관계와 눈물막 두께， 각막 상피의 작용， 각막경직도의 개 별적 차이， 그리고 각막 형상에 악영향을 주는 요소룹 서술하였다. 결 론: 콘택트렌즈 작용에 의해 받생되는 대부분의 각막변형은 렌즈 작용 중지 흑 은 고산소 투과도의 재질을 가진 렌즈로 변경， 재 피팅， 그리고 렌즈 착용 시간의 갑 소 등으로 조섣 관리 되어 질 수 있다