Cloth Prepreg Weft Loosening Control for Texture Defects
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Solution Overview
Problem
Fiber reinforced resin molded articles manufactured from cloth prepregs often exhibit visible texture defects due to local fiber meandering, which impairs their aesthetic appearance and is not suitable for high-productivity industrial manufacturing, particularly in automotive applications.
Innovation Solution
A cloth prepreg with a woven fabric structure where the loosening rate of the weft fibers is controlled between 0.0% to 0.2%, and the fiber basis weight is 240 g/m² or more, combined with a method involving stretching in the weft direction to reduce fiber meandering, and compression molding with a resin film layer or foamed core layer to enhance appearance and productivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If compression molding is used to manufacture fiber reinforced resin molded articles from cloth prepregs, then productivity is improved due to short molding cycle, but the aesthetic appearance deteriorates due to visible texture defects and fiber meandering
Solution Approach 1:
The patent applies preliminary action by controlling the loosening rate of weft during the prepreg manufacturing process itself. By adjusting the weaving tension and loom settings before molding, the fiber arrangement is optimized in advance to prevent meandering during compression molding, thereby achieving both high productivity and good surface appearance.
Solution Approach 2:
The patent changes physical parameters by controlling the loosening rate of weft within a specific range (0.0% to 0.2%) and adjusting the fiber basis weight (240 g/m² or more). These parameter optimizations ensure that the woven fabric maintains its texture visibility while preventing excessive fiber movement during compression molding.
2Manufacturing precision
If autoclave molding is used to manufacture fiber reinforced resin molded articles from cloth prepregs, then the aesthetic appearance is improved by maintaining visible woven fabric texture, but productivity deteriorates due to long molding time
Solution Approach 1:
The patent applies preliminary action by optimizing the cloth prepreg structure before molding. By controlling the loosening rate of weft and fiber basis weight in advance, the material is pre-conditioned to maintain texture visibility during faster compression molding processes, eliminating the need for time-consuming autoclave molding.
3Ease of manufacture
If the loosening rate of weft is increased to improve fabric drape and formability, then ease of manufacture is improved, but the aesthetic appearance deteriorates due to increased fiber meandering and texture defects
Solution Approach 1:
The patent optimizes the loosening rate of weft within a narrow range (0.0% to 0.2%) to balance formability and surface quality. This parameter optimization allows sufficient fabric drape for manufacturing while preventing excessive fiber movement that would cause meandering and texture defects in the final product.
Data Source
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AI summary
Provided are a cloth prepreg for a fiber reinforced resin molded article having a surface through which a texture of a woven fabric formed of reinforcing fiber bundles is visible, in which a molded article having an improved appearance in a case of being compression molded is obtained; a method for manufacturing the cloth prepreg; a fiber reinforced resin molded article having a surface through which a texture of a woven fabric formed of reinforcing fiber bundles is visible, and having improved industrial producibility and an improved appearance; and a method for manufacturing the molded article. The cloth prepreg has a surface through which a texture of a woven fabric made of a reinforcing fiber bundle as a warp and a weft is visible, in which a loosening rate of weft is 0.0% to 0.2%; and the method for manufacturing a fiber reinforced resin molded article includes compression-molding the cloth prepreg or a prepreg laminate having one or more of the cloth prepregs and obtaining a compression molded article having a surface through which a texture of a woven fabric is visible.