How to solve the yellowing of the extruded products of the twin-screw extruder?


1. Check whether the thermocouple in each area of the b […]

1. Check whether the thermocouple in each area of the barrel is working normally, and whether the fan in each area is operating normally. If there is a problem with the thermocouple or the fan, it will cause the screw barrel to overheat locally and cause the product to turn yellow.

2. Check whether the heat transfer oil of the screw is sufficient, whether the oil pump is working normally, and whether the oil pipe is blocked. If the oil path is blocked, the frictional heat of the screw cannot be effectively discharged, which will cause the screw to overheat and cause the material to decompose and turn yellow.

3. Check and adjust the screw clearance or replace the screw. In the case of severe screw wear, the gap between the screw and the barrel will become larger, and the screw's ability to push the material will become poor, which will cause the material to flow back in the barrel, so that the heating time inside the barrel will be longer, resulting in yellowing .

4. Check the mixing device, whether the mixing time is normal, whether the cooling water circulation is normal, and whether the cooling water temperature is normal. If the hot mixing time is too long or the cold mixing cannot cool the material to normal temperature, the material will consume the stabilizer in the formula during the mixing or storage process.