one. The reason for the black strip of the injection molded product
1, the thermal decomposition of materials
2, the injection molding machine screw damage
3, due to friction and air compression of the material carbonization

Second, the associated knowledge
1, the decomposition of the material residue residue re-injection molding machine barrel produced by the most common black bars.
2, in the plunger injection molding machine, easy to remain in the various parts of the residue.
3, a valve injection nozzle injection molding machine, in the valve control part is also easy to residual residue.
4, in the barrel of air is compressed into high temperature, this high temperature gas coupled with the shear heat in the gate, it is easy to become black bars.

three. Solution
1, Immediate: in the material replacement, reduce the injection pressure, reduce the heating cylinder temperature.
2, short-term: heating cylinder cleaning (using copper brush).
3, long-term: barrel repair.

four. Due to material differences
1, the mixed resin in the paint, paint, lubricants, UV absorbers, live anti-agent in the barrel overheating, long time to stay when the thermal decomposition of these materials is also the reason for the emergence of black bars. Especially when certain types of additives are poor heat resistance, this tendency will become more pronounced.
2, with polycarbonate (PC) molding, with a valve nozzle is also easy to produce black bars.
3, with a counter-current to prevent the gasket is also easy to bring the scorched residue.

Fives. Reference matter
When the material is replaced with a special cleaning material, it is necessary to use ordinary soft polystyrene