[中文]包封

一、注塑件缺陷的特征

可以容易地在透明注塑件的“空气阱”内见到但也可出现在不透明的塑料中， 这与厚度有关，而且常因塑料收缩离开注塑件中心而引起。

二、可能出现问题的原因

(1).模具未充分填充。

(2).止流阀的不正常运行。

(3).塑料未彻底干燥。

(4).预塑或注射速度过快。

(5).某些特殊材料应用特殊的设备生产。

三、补救方法

(1).增加射料量。

(2).增加注塑压力。

(3).增加螺杆向前时间。

(4).降低熔融温度。

(5).降低或增加注塑速度。（例如对非结晶体类的塑料要增 加45%速度）。

(6).检查止逆阀是否裂开或无法运作。

(7).应根据塑料的特性改善干燥条件，让塑料彻底干燥。

(8).适当降低螺杆转速和增大背压，或降低注射速度。

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[外文]Envelope

I. Features of injection molding defects

Easily found in the air trap in transparent injection molding, sometimes also found in non-transparent plastics. It bears reference to thickness and is usually resulted from deviating from the center of injection molding.

II. Possible Causes

(1) Insufficient injection of materials into the mold.

(2) Stop valve malfunctions

(3) The materials have not been dried sufficiently.

(4) Too high preplasticizing and injection speed.

(5) Where some special materials are processed by special equipment

III. Remedies

(1) Increase the injection amount

(2) Increase the injection pressure

(3) Increase the forward time of screw.

(4) Decrease the melt temperature.

(5) Decrease or increase the injection speed. (e.g. for uncrystalline plastic, the speed shall be increased by 45%)

(6) Check the stop valve to see whether it has been broken or unserviceable.

(7) The drying condition shall be improved depending on the feature of plastic to ensure thorough drying .

(8) Properly decrease the screw speed and increase the back pressure , or decrease the injection speed.

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