Cause analysis of plasticizing failure in extruder

one

Scorched

1. Scorching phenomenon

(1) The temperature is too high, or the instrument controlling the temperature is out of order, causing the plastic to scorch due to high temperature.

(2) The rubber outlet of the machine head has large smoke, strong irritating smell and crackling sound.

(3) Granular scorched matter appears on the plastic surface.

(4) There are continuous air holes at the glue joint.

2. Causes of scorching

(1) Super high temperature control causes scorching of plastics.

(2) The screw has been used for a long time without cleaning, and burnt materials are accumulated and extruded with plastic.

(3) If the heating time is too long, the plastic deposits will be heated for a long time, and the plastic will be aged and burnt.

(4) The parking time is too long, and the machine head and screw are not cleaned, resulting in the decomposition and burning of plastic.

(5) The plastic is decomposed and burnt due to repeated mold or color change.

(6) The head gland is not pressed tightly, and the plastic is aged and decomposed inside.

(7) The instrument for controlling the temperature is out of order, resulting in scorching after ultra-high temperature.

3. Methods to eliminate scorching

(1) Frequently check whether the heating system is normal.

(2) Clean the screw or head regularly and thoroughly.

(3) The heating shall be conducted according to the requirements of process regulations. The heating time shall not be too long. If there is any problem in the heating system, it shall be solved by relevant personnel in time.

(4) Mold change or color change shall be timely and clean to prevent mottled or burnt glue.

(5) After the mold is adjusted, the mold sleeve gland shall be pressed tightly to prevent glue from entering.

(6) If scorching is found, the head and screw shall be cleaned immediately.

two

Poor plasticization

1. Poor plasticization

 (1) There is a skin like phenomenon on the surface of the plastic layer.

(2) The temperature control is low, the temperature reflected by the instrument pointer is low, and the actual measured temperature is also low.

(3) The plastic surface is dark, and there are tiny cracks or small particles that are not plasticized well.

(4) The plastic glue is not sewn well, and there is an obvious trace.

2. Causes of poor plasticization

(1) The temperature control is too low or inappropriate.

(2) There are difficult to plasticize resin particles in the plastic.

(3) The operation method is improper, the screw and traction speed are too fast, and the plastic is not fully plasticized.

(4) The mixing of plastics during granulation is not uniform or the plastics themselves have quality problems.

3. Methods for eliminating poor plasticization

(1) Control the temperature according to the process regulations. If the temperature is low, adjust the temperature appropriately.

(2) The speed of screw and traction shall be properly reduced to increase the time of plastic heating and plasticizing, so as to improve the plasticizing effect of plastic.

(3) The screw cooling water is used to strengthen the plasticization and tightness of plastics.

(4) When selecting the mold, the mold sleeve should be appropriately small to strengthen the pressure of the rubber outlet.