Study of Monitoring Method and Melt Flow Behavior in Compression Molding Process Using Thermoplastic Sheets Reinforced with Discontinuous Long-Fibers

In compression molding using glass-fiber-mat-reinforced thermoplastic (GMT) sheets, a slightly longer compression waiting time from sheet placement on a lower mold to the start of sheet compression by an upper mold can cause incomplete filling due to a decrease in the sheet temperature. However, pre...

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Main Author: Masatoshi Kobayashi
Format: Article
Language:English
Published: MDPI AG 2021-02-01
Series:Journal of Composites Science
Subjects:
Online Access:https://www.mdpi.com/2504-477X/5/2/50
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author Masatoshi Kobayashi
author_facet Masatoshi Kobayashi
author_sort Masatoshi Kobayashi
collection DOAJ
description In compression molding using glass-fiber-mat-reinforced thermoplastic (GMT) sheets, a slightly longer compression waiting time from sheet placement on a lower mold to the start of sheet compression by an upper mold can cause incomplete filling due to a decrease in the sheet temperature. However, precise measurement techniques for compression waiting time have not been sufficiently established. A monitoring system was produced that includes pressure—temperature sensors mounted in a compression mold that can simultaneously measure the pressure and temperature of one local surface. Two types of distance sensors were also used to measure upper mold motion widely and precisely. Determination of compression waiting time was attempted by measuring the moment when the lower mold temperature slightly increases in response to contact with the melted GMT sheet and the moment when the melt pressure increases in response to compression by an upper mold. The results showed that compression waiting time could be precisely calculated using the profile data obtained. Moreover, it was also possible to observe the melt pressure overshoot that occurs depending on sheet stacking patterns and mold cavity shape, although in some cases, the overshoot was not observed. In conclusion, this study has demonstrated that the system is effective in monitoring the compression molding process widely and precisely.
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spelling doaj.art-64e760393bac42cc85e572ae28d20fb82023-12-03T12:40:07ZengMDPI AGJournal of Composites Science2504-477X2021-02-01525010.3390/jcs5020050Study of Monitoring Method and Melt Flow Behavior in Compression Molding Process Using Thermoplastic Sheets Reinforced with Discontinuous Long-FibersMasatoshi Kobayashi0Innovative Research Excellence, Honda R&D Co., Ltd., Tochigi 321-3321, JapanIn compression molding using glass-fiber-mat-reinforced thermoplastic (GMT) sheets, a slightly longer compression waiting time from sheet placement on a lower mold to the start of sheet compression by an upper mold can cause incomplete filling due to a decrease in the sheet temperature. However, precise measurement techniques for compression waiting time have not been sufficiently established. A monitoring system was produced that includes pressure—temperature sensors mounted in a compression mold that can simultaneously measure the pressure and temperature of one local surface. Two types of distance sensors were also used to measure upper mold motion widely and precisely. Determination of compression waiting time was attempted by measuring the moment when the lower mold temperature slightly increases in response to contact with the melted GMT sheet and the moment when the melt pressure increases in response to compression by an upper mold. The results showed that compression waiting time could be precisely calculated using the profile data obtained. Moreover, it was also possible to observe the melt pressure overshoot that occurs depending on sheet stacking patterns and mold cavity shape, although in some cases, the overshoot was not observed. In conclusion, this study has demonstrated that the system is effective in monitoring the compression molding process widely and precisely.https://www.mdpi.com/2504-477X/5/2/50glass-fiber-mat-reinforced thermoplasticpolyamide 6stacked sheetcompression moldingmelt flowin-mold measurement
spellingShingle Masatoshi Kobayashi
Study of Monitoring Method and Melt Flow Behavior in Compression Molding Process Using Thermoplastic Sheets Reinforced with Discontinuous Long-Fibers
Journal of Composites Science
glass-fiber-mat-reinforced thermoplastic
polyamide 6
stacked sheet
compression molding
melt flow
in-mold measurement
title Study of Monitoring Method and Melt Flow Behavior in Compression Molding Process Using Thermoplastic Sheets Reinforced with Discontinuous Long-Fibers
title_full Study of Monitoring Method and Melt Flow Behavior in Compression Molding Process Using Thermoplastic Sheets Reinforced with Discontinuous Long-Fibers
title_fullStr Study of Monitoring Method and Melt Flow Behavior in Compression Molding Process Using Thermoplastic Sheets Reinforced with Discontinuous Long-Fibers
title_full_unstemmed Study of Monitoring Method and Melt Flow Behavior in Compression Molding Process Using Thermoplastic Sheets Reinforced with Discontinuous Long-Fibers
title_short Study of Monitoring Method and Melt Flow Behavior in Compression Molding Process Using Thermoplastic Sheets Reinforced with Discontinuous Long-Fibers
title_sort study of monitoring method and melt flow behavior in compression molding process using thermoplastic sheets reinforced with discontinuous long fibers
topic glass-fiber-mat-reinforced thermoplastic
polyamide 6
stacked sheet
compression molding
melt flow
in-mold measurement
url https://www.mdpi.com/2504-477X/5/2/50
work_keys_str_mv AT masatoshikobayashi studyofmonitoringmethodandmeltflowbehaviorincompressionmoldingprocessusingthermoplasticsheetsreinforcedwithdiscontinuouslongfibers