日期:2022-05-25 10:53:40 / 人气:426 / 来源:本站


  PE double-wall bellows in the actual production process, will encounter the problem of poor expansion, below we will analyze in detail.


  (1) The causes of inner blowing are generally excessive air pressure in the inner layer, poor toughness of raw materials, too thin inner layer, late start-up of the flared exhaust port or blockage of the flared exhaust pipe, impurities in raw materials, poor plasticization of materials, etc.



  (2) The inner and outer layers of the flame do not adhere well. If this phenomenon occurs at the beginning, it is because the internal air blast starts late or the corresponding cross-section pressure is too small; if it occurs at the end, it is because the internal thrust is too early or the combustion and exhaust is too early, or because the pressure at the corresponding part is too small. If the cementing is not good from beginning to end, it may be due to the performance or temperature of raw materials.


  (3) The end-face enlargement is incomplete and can not be jammed by adjusting the enlargement in any case. The reason is that the internal air rushes to an earlier end-face; the end of the enlargement and exhaust is ahead of schedule.



  (4) There is a concave phenomenon in the inner cavity of the front end, which is generally caused by the premature start of internal air; the deviation of the middle line of the water jacket from the middle line of the model module (the position of the forming machine is different from that of the water jacket); the thin inner wall; and the premature stop of the internal vacuum.


  (5) The inner layer of the flame end accumulates, which often causes the flame to enter concave shape. The reason is that the inner layer of the expanding end is too thick. In this section, the deceleration of the injection moulding machine is too large; in the first few sections, the thrust is too large; the temperature of the inner material is too high, and the blank is too soft. This part of the outer blank is too thick.

  6. 扩口的内层末端有凹形,其原因一般是扩口后波和第二波压力过小;波和第二波的内壁厚度过厚。内真空度小或内真空度启动太晚;原材料的韧性较差。

  6. There is concave shape at the inner end of the enlargement. The reason is that the pressure of the first wave and the second wave after the enlargement is too small, and the thickness of the inner wall of the first wave and the second wave is too thick. The internal vacuum is small or the internal vacuum starts too late; the toughness of raw materials is poor.



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