欧美色图片玖玖视频

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中文English

塑料焊接原理

常用塑料基本知識點

塑料的定义：塑料指的是以合成树脂为主要成分，加入填料、增塑剂和一起其他助剂（如着色剂、防老剂、调节剂等），在一定条件下塑制而成的材料及其制品。

塑料的分類、特點
1、塑料的分类：按加热性质不同来分，分为热固性塑料和热塑性塑料；按用途不同来分，分为通用塑料和工程塑料。

2、热固性塑料一旦成形，化学结构上即不可变，无法通过再次加热加压来软化和塑变。温度过高，就会发生分解。

3、熱塑性塑料成形後，通過加熱加壓，可以再次軟化和塑變。

熱塑性塑料的分類

1、無定形塑料：具有隨機的分子結構。其軟化溫度範圍寬廣（Tg，玻璃態轉變溫度），軟化緩慢，在熔化和流動過程中不會過早的固化。這些高聚物通常就傳遞超聲振動來說是非常高效的，可以在寬廣的壓力和振幅範圍內焊接。

2、半結晶型塑料：局部具有規則的分子結構。它們具有尖聳的熔化點和固化點（Tm）。該高聚物的分子，固態時，形似彈簧，能夠吸收一定的高頻機械振動能。這樣，將超聲波能量傳遞至接口界面就變得困難些了。所以，焊接半結晶型塑料通常需要較大的振幅。尖聳的熔化點也需要非常高的能量來破壞半結晶型塑料的結構，使得塑料得以流動。一旦熔融材料離開加熱區域，溫度只要下降一點，這些材料就快速固化。這些特性使得必須考慮一些特殊因素（如：更高的振幅、謹慎設計接口、遠近區焊接和夾具）以獲得理想的結果。

温度比热图.webp

塑膠熔接常見的熔接方式（一）

热塑性塑料超聲波焊接的相容性情况

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