Injection Molding
6 مشاهدة
Unstable screw back in general-purpose polyethylene '2079851475616104452
ظاهرة المشكلة
The screw jumps during the plasticizing back process, the back speed is uneven or the back is not in place, and the pre-plasticizing position fluctuates greatly.
Unstable screw back leads to inconsistent injection amounts each time, directly affecting the product weight and dimensional stability.
تحليل الأسباب
（1）The back pressure is set too high or unstable, and the plasticizing resistance is large
（2）The barrel temperature is uneven, and the melting section temperature is low, resulting in plasticizing difficulties
（3）The screw is severely worn, and the plasticizing efficiency decreases
（4）The raw material particles are uneven in size or contain too much powder, and the feeding is uneven
（5）The screw speed and back pressure are improperly matched
الحل
（1）Appropriately reduce the back pressure to 3-8MPa to ensure stable back pressure
（2）Check the temperature of each section of the barrel to ensure that the melting section temperature is at a reasonable value within the range of 160-260°C
（3）Check the screw wear, and replace the screw if the thread clearance exceeds 0.2mm
（4）Screen the raw material and control the powder ratio to not exceed 5%
（5）Adjust the matching relationship between the screw speed and the back pressure, speed 40-100rpm
الخلاصة الأساسية
Unstable screw back is caused by large plasticizing resistance or equipment wear, and the back pressure, temperature, and screw condition need to be optimized.
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