First, the reasons for the mold
1. Prenatal degreasing full inspection, can effectively prevent contaminated oil and rust stains of the product and the flow of material mixed with crushed material to be used (especially in the production process rather than the initial trial);
2. Mold gate is too small or too rough, will result in a lot of friction heat, if the mold is not good, it will cause the gas combustion obvious black stripes (dark spots).
Second, the reasons for the equipment
3. Dryer motor long-term operation, filthy dirt, to be regularly cleaned;
4. Dryer filter should be regularly cleaned, replaced, otherwise it will enter the foreign body or due to poor ventilation and material discoloration, caking;
5. Dryer due to negligence or lack of equipment and other operating equipment caused by the cartridge is not (completely) sealed, resulting in dust in the air to enter; or dust fly, polluting the surrounding products and crusher material; or barrel is too large, easy to operate , Ignoring the angle (feeding pipe and its interface) and other factors, resulting in refueling process, the barrel is not completely clean.
6. Long-term production and operation, usually did not make good protection, resulting in mixed dust scattered equipment;
7. Shredder shading is not in place, resulting in pollution and pollution of other materials;
8. Shredder as far as black and white isolation use;
9. If the nozzle aperture is too small or the inner surface is rough, a lot of friction heat will be generated. If the mold is not well vented, the gas will burn to produce obvious black stripes (dark spots);
10. Barrel or plastic head wear, crack bending, the polymer part of the overheating and black lines (dark spots);
11. When the sealant wear, the melt can not move smoothly forward squeezing material phenomenon, will cause excessive gas in the material pipe, when the injection is smooth, due to the rapid friction resulting black lines;
12. The outer diameter of the rubber ring and the tolerance of the cylinder wall clearance is too small to make the screw melt have a greater resistance surface, resulting in heat generated by friction caused by black stripes (can remove the outer diameter of the ring a few small grinding or replacement of larger tolerances new , The screw smooth melt glue);
13. Eccentric screw and tube produce a very large friction heat;
14. Screw compression ratio is too large, the feed part of the shallow groove and the barrel wall and raw materials have a greater friction between the decomposition of raw materials resulting from overheating black spots (dark spots);
15. The temperature is not correct, the actual temperature thermistor and thermometer error is too large, a section of the temperature is too hot and not easy to intuitive, need to use the measuring instrument view.
Third, the material
16. Raw material itself with black spots, and the proportion of black spots exceed the allowable range of customer incoming inspection or finished product allowed standards;
17. Raw material bags are damaged or contaminated during transport, handling and storage, and foreign materials are mixed in.
18. Materials in the mix or material mixed with debris;
19. Some raw materials need to add a lubricant, if less than added, it will seriously produce friction heat, exhaust too much exclusion is not timely, resulting in gas combustion black lines (dark spots);
20. The lack of heat resistance of the raw material itself, can not afford the operating temperature, raw materials (additives) thermal cracking;
21. Material bag or keep the bag at the Department of unclean, when used again, causing foreign matter mixed.
Fourth, other reasons
22. Long time barrel production of different materials, due to temperature changes, oxidation, degradation, and a variety of materials on the metal surface adhesion and other related factors, over time, resulting in the screw surface, the wall, the nozzle and so on, The formation of carbonation gradually met the higher viscosity material is separated, and gradually brought out.In addition, the screw and the pipe wall and other parts, if there are scars or gaps, it will be easier for the molten material retention, and stop the machine frequently , Will make the above problems worse;
23. People who do not understand the material smash bad products, resulting in material confusion;
24. Bad products identified by the technician is crushed or abandoned;
25. The replacement of materials, the map for the convenience of operation, blowing away only residual air gun residual material, this method can not be completely clean cylinder; or air gun in the scene of indiscriminate bombing, resulting in the dust filled the entire workshop;
26. Floor products or flow material directly into the grinder;
27. Bad products just blow a few times with a wind gun smashed;
28. When dealing with the products in the red box, pour it directly into the crusher;
29. When dealing with foreign matter mixed, only found a reason that found all the real reason;
30. Crusher blade phenomenon, there is no timely adjustment and control of materials;
31. Special materials such as PP, PMMA, ABS control method of inaccurate;
32. Wrong feeding method, such as adding black material directly to add white material, may be due to static electricity or other reasons that black fell into the white material;
33. When the washing machine is not completely replaced original low-temperature material used in the discharge tube, when the operating temperature increases, resulting in low temperature materials (fire retardant, additives, etc.) can not withstand this temperature, thermal degradation, which usually occurs at the nozzle Especially in the production process rather than during the initial trial).