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 หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Characterization of Fiber Length Distribution in Short andLong-Glass-Fiber Reinforced Polypropylene during Injection Molding Process) ผู้เขียน: สมเจตน์ พัชรพันธ์ สื่อสิ่งพิมพ์:pdf AbstractThe reduction in fiber length during injection molding of two commercial glass-fiber reinforced polypropylene (PP) granules was studied. The first containing 20 percent by weight (wt%) of shortglass- fibers with the average fiber length around 350 ?m and the other filled with 40 wt% of relatively much longer fibers mostly around 7,000 mm. The fiber length distribution (FLD) was measured along the screw channels and after the molten composite was injected through a nozzle of an injection unit. The results indicated that the FLD moved to shorter fiber lengths along the screw channels further from the hopper. In both cases, fiber attrition occurred predominately in the feed and the compression zones, particularly in long-glass-fiber reinforced polypropylene. More severe fiber attrition in this finding can be assumed due to higher fiber concentration and longer fiber length which result in a higher degree of fiber-fiber interaction and increased fiber-wall contacts. |
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 หัวเรื่อง:Prediction of Weldline Strength for Push-Pull Injection Molded Short-Glass-Fiber Reinforced Thermoplastic Composites |
ที่มา:การประชุมทางวิชาการของมหาวิทยาลัยเกษตรศาสตร์ ครั้งที่ 46หัวเรื่อง:การวิเคราะห์ความยาวของเส้นใยแก้วในระหว่างกระบวนการฉีดขึ้นรูปชิ้นงานเทอร์โมพลาสติกคอมโพสิต |
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หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Properties Enhancement of Short-Glass-Fiber Reinforced
Thermoplastics by Sandwich Injection Molding Technique) ผู้เขียน:สมเจตน์ พัชรพันธ์, G?nter Mennig สื่อสิ่งพิมพ์:pdf AbstractThis article demonstrates the possibility of using sandwich injection molding in order to improve
the mechanical properties of short-glass-fiber-reinforced thermoplastic by investigating the effect of fiber
orientation, compared with conventional injection molding. The effects of short-glass-fiber content
within skin and core materials, in the present case PP, varying from 0 to 40 wt % were studied. The results
showed an increase in the maximum tensile stress and impact strength as the concentration of the shortglass-
fiber was increased. The mechanical properties of sandwich moldings were observed to be slightly
higher than conventional injection moldings, which is attributed to the higher fiber orientation and lesser
voids within the core layer. The effect of different processing types on the phase distribution of shortglass-
fibers showed no significant phase separation effects between sandwich and conventional injection
molding processes, except when using of sandwich injection process with different materials. The results
obtained by analyzing the fiber attrition inside the skin and core regions in the longitude direction of
tensile specimens showed that the degree of fiber degradation inside the skin layers were higher than the
core layers and there are only minor differences in fiber length inside skin regions observed between
sandwich and conventional injection molding processes, whilst this effect being more pronounced in the
core regions and for the higher fiber volume fraction. The theoretically calculated values of the ultimate
tensile stress (UTS) were found to be considerably higher than the experimental values. However, a more
realistic estimation of UTS can be achieved by using measured values for fiber length within skin and core
layers. |