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%.

Abstract
 1. 서론
 2. 실험 및 방법
  2.1 실험모델
  2.2 실험 조건 및 장비
  2.3. 휨의 측정
 3. 결과 및 고찰
  3.1 결정성 수지에 따른 휨
  3.2 비결정성 수지에 따른 휨
 4. 결론
 참고문헌

• 이민(영남이공대학 기계자동차공학부) | M. Lee