Composites Research

The Korean Society for Composite Materials (한국복합재료학회)
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Effects of Molding Condition on Surface Unevenness of GMT-Sheet Moldings

GMT-Sheet 성형품의 표면요철에 미치는 성형조건의 영향

  • Published : 2010.10.30
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Abstract

Observing of GMT-Sheet in molding conditions, we have investigated unexpected phenomenons of moldings surface. In microscope investigation, we observe that there exist deficiencies on the surface of GMT-Sheet moldings, such as the spherulite, fiber projection, crack, fiber exposure, micro-weldline, pinhole and winding. They are caused to arise unevenness and phenomenons influence polish on surface. Especially, the major cause of the unevenness, effected to surface roughness, is a shrinking of matrix in the process of holding pressure and cooling temperature. The higher holding pressure load in a molding process and the lower demolding temperature in an annealing experiment, the better GMT-Sheet moldings improved its appearance.

성형조건에 따른 GMT-Sheet를 관찰하여, 성형품 표면의 불량원인을 조사했다. 현미경 관찰 결과, GMT-Sheet 성형품의 표면에서 구정, 섬유돌출, 크랙, 섬유노출, 마이크로 웰드라인, 핀홀, 여파굴곡곡선 등의 결함을 발견했다. 이 결함들은 요철의 발생원인이고, 표면 광택에 영향을 주는 현상이다. 그리고 표면거칠기에 영향을 주는 요철의 가장 주요한 발생원인은 보압 냉각 과정에서 발생하는 모재의 수축이었다. 성형 시의 보압하중이 높을수록 GMT-Sheet 성형품 표면은 좋아졌다. 또한 서냉실험에서는 탈형온도가 낮을수록 성형품의 표면이 좋아졌다.

Keywords

References

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  1. Impact of Fiber Projection from GMT-Sheet Moldings on Surface Unevenness vol.24, pp.6, 2011, https://doi.org/10.7234/kscm.2011.24.6.031