ひび割れはプラスチック製品の一般的な欠陥です, これは主に応力と変形によって引き起こされます. 主に残留応力が含まれます, 外部応力および外部環境による応力変形.
(NS) 残留応力によるひび割れ
The residual stress is mainly caused by the following three conditions, PMMAプラスチック射出成形プロセス. overfilling, demoulding and pushing out and metal inlay. As the cracks produced in the case of excess filling, the solution can be mainly in the following aspects:
(1) since the pressure loss of the gate is the smallest, if the cracks are mainly near the gate, the multi-point distribution point gate, side gate and handle gate can be considered.
(2) on the premise that the resin does not decompose or degrade, properly increasing the resin temperature can reduce the melt viscosity, improve the fluidity, and also reduce the injection pressure to reduce the stress.
(3) 一般的, when the mold temperature is low, it is easy to produce stress, so the temperature should be increased appropriately. But when the injection speed is higher, even if the mold temperature is lower, the stress can be reduced.
(4) too long time of injection and holding pressure will also produce stress, so it is better to shorten it properly or switch holding pressure for th time.
(5) non crystalline resin, such as as as resin, ABS樹脂, PMMA resin and so on, is more likely to produce residual stress than crystalline resin, such as polyethylene, polyformaldehyde and so on. When demoulding and pushing out, due to the small demoulding inclination, rough mold glue and punch, the pushing out force is too large, resulting in stress, and sometimes even whitening or cracking around the pushing rod. As long as the location of crazing is carefully observed, the cause can be determined.
It is easy to produce stress and crack after a period of time when the metal parts are embedded at the same time of injection molding. This is mainly due to the great difference between the thermal expansion coefficient of metal and resin, which leads to stress, and with the passage of time, the stress exceeds the strength of the resin material which is gradually deteriorated, resulting in cracks. To prevent the resulting cracking, as an experience, the wall thickness is 7 “with the outside diameter of the embedded metal part
一般に, polystyrene is not suitable for inlay, but inlay has the least effect on nylon. Because the coefficient of thermal expansion of glass fiber reinforced resin material is small, it is suitable for embedded parts.
加えて, preheating the metal insert before forming has better effect.
(Ⅱ) cracks caused by external stress
The external stress here is mainly caused by the unreasonable design, especially at the sharp corner. According to figure 2-2, NS / 7 “- 0.5 ～ 0.7 can be taken.
(Ⅲ) external environment
Chemicals, water degradation caused by moisture absorption, and excessive use of recycled materials will degrade physical properties and produce cracks.
JasonMould Industrial CompanyLimitedについて
ジェイソンモールドは 中国の金型メーカー プラスチック金型の- 射出成形金型, ダイカスト金型, プラスチックブロー成形, 回転成形, 医療 プラスチック射出成形, ツーショット プラスチック射出成形, インサート成形, オーバーモールド, 金属射出成形, マイクロ射出成形, 粉末射出成形, セラミック射出成形, 液体射出成形, ハスキーインジェクションモールディング, 家庭用カビ, 鋳造金型, ダイモールドツール, カスタムモールド, 中国のカビ, ラピッドプロトタイピングツール, プラスチックプロトタイピングツーリング, パンチプレス工具, 携帯電話/携帯電話部品用の金型と工具, 自動車部品, 掃除機, 充電式ツール, 電話, コピー機, コンピューター, マルチメディアスピーカー, および他の多くの電子製品および家電製品. また、プラスチック製品メーカー, 金型メーカー中国- プラスチックの部品, プラスチック製の水タンク, プラスチックボール, プラスチック容器, プラスチックバックル, プラスチックアンカー, プラスチックハンガー, プラスチックスプーン, プラスチックパイプフィッティング, プラスチックタンブル, プラスチック製食器, プラスチックのコップ, ペットボトル, プラスチックトレイ, プラスチック化粧品容器, プラスチックケース, プラスチック製の食品容器, プラスチック製の椅子, プラスチックキャップ, プラスチックキャップクロージャー, プラスチックチューブ, プラスチック製の水道管, プラスチック製のノブ, プラスチックチューブ, プラスチック製ユーティリティボックス, プラスチックラックなど.
連絡先:
人: ジェームズ・ユアン
会社: JasonMould Industrial Company Limited
追加: 竜崗村,Long西町,博羅県,恵州市,広東省, 中国
電話: 86-752-6682869
Eメール: [email protected]
