What causes the yellowing and blackening of the product produced by the screw of the injection molding machine?

Screws are mostly used in plastic molding equipment, such as plastic profile extruders, injection molding machines, etc. Screw and barrel are the core components of plastic molding equipment. It is the part that is heated, extruded and plasticized. It is the core of plastic machinery. Screws are widely used in machining centers, CNC machines, CNC lathes, injection molding machines, wire cutting, grinders, milling machines, slow wire feeding, fast wire feeding, PCB drilling machines, engraving machines, engraving and milling machines, spark discharge machines, tooth biting machines , Planer, large vertical lathe gantry milling, etc.
Injection molding machine, also known as injection molding machine or injection machine. It is the main molding equipment that uses plastic molding dies to make thermoplastic or thermoset plastics into various shapes of plastic products. The injection molding machine can heat the plastic and apply high pressure to the molten plastic to make it eject and fill the mold cavity. According to the arrangement of the injection device and the clamping device, it can be divided into vertical, horizontal and composite vertical and horizontal.
Abnormal analysis and treatment of black spots and macula in injection molded products
Anomaly analysis:
1. There is char on the surface of the nitroflon screw
2. The screw, barrel and auxiliary machine (suction machine) of the injection molding machine are not clean
3. The check ring, thrust ring, screw head, front barrel, etc. are dirty or corroded
4. Flanges and nozzles have burnt material
5. The temperature is too high and the back pressure of the melt is too large
6. Unclean raw materials
7. The finish of the screw of the injection molding machine is not enough
8. There is a problem with the material of the nitroflon screw itself, and the steel has impurities.
Solution:
1. Check the Neflon screw: clean and polish the screw
2. Check whether there is dust in the hopper, polishing the barrel and cleaning auxiliary equipment
3. Check whether it is dirty or corroded; clean and polish or replace
4. Check flanges and nozzles; clean and polish or replace
5. Check the temperature settings of each section; cool down and reduce back pressure
6. Check the raw materials for impurities; replace the raw materials

web:https://www.jzjxc.cn