書誌事項
- タイトル別名
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- Development of Precision Injection Molding by Cooling Rate Control Part III Study on Shrinkage Mechanisms of Cylindrical Parts Based on a Viscoelastic Model
- レイキャク ソクド セイギョ ニ ヨル セイミツ シャシュツ セイケイホウ ノ カイハツ(ダイ3ポウ)ネンダンセイ モデル ニ ヨル エントウ ケイジョウ ブヒン ノ シュウシュク メカニズム ノ カイメイ
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抄録
In this study, we applied our precision injection molding method, which enhances molding precision by controlling cooling rate, to cylindrical parts and reviewed the shrinkage mechanisms of PPS, PBT, and POM. Using a viscoelastic model, we calculated elastic strain after demolding, taking into account the generation and relaxation of thermal stress during the cooling process. We then added thermal strain after demolding to this to analyze the total shrinkage strain, and investigated the changes in the shrinkage strain in respect to the initial mold temperature (TM). The results showed that for PPS and PBT, whose glass transition temperature (Tg) is higher than room temperature, their shrinkage characteristics were found to change around Tg as the borderline. When TM was higher than Tg, the shrinkage strain increased gradually in normal cooling. The shrinkage strain at this time was dependent on the thermal strain in the case of PPS, and dependent on both the elastic and thermal strain in the case of PBT. However, with PBT, as strain relaxed gradually, the elastic strain decreased with longer cooling time, resulting in reduced shrinkage strain. On the other hand, when TM was below Tg, both resin materials showed a balanced relation between the thermal and elastic strain because the elastic strain increased with greater control of the thermal strain, resulting in a more or less uniform shrinkage strain. The same results were observed when the molded product was rapidly cooled. In the case of POM, whose Tg is lower than room temperature, no balanced relation was seen between the thermal and elastic strain. When TM was higher, the thermal strain was dominant, resulting in a gradual increase in the shrinkage strain during normal cooling. These results show that the shrinkage characteristics obtained in experiments were reproduced well by the analysis, and that the shrinkage mechanisms of the various resins can be explained by the correlation between thermal and elastic strain.
収録刊行物
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- 成形加工
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成形加工 25 (10), 493-503, 2013
一般社団法人 プラスチック成形加工学会
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詳細情報 詳細情報について
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- CRID
- 1390282679439562752
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- NII論文ID
- 130006646982
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- NII書誌ID
- AN10278882
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- ISSN
- 18837417
- 09154027
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- NDL書誌ID
- 024931852
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- 本文言語コード
- ja
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- データソース種別
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- JaLC
- NDL
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- 抄録ライセンスフラグ
- 使用不可