How to solve the black strip problem of injection molded products?

1. Thermal decomposition of materials

2. Damage to the screw of the injection molding machine

3. Carbonization of materials due to friction and compression of air

Second, the associated knowledge

1. The residue of the material decomposition remains the most common in the barrel of the injection molding machine.

2. In the plunger type injection molding machine, it is easy to remain in the residue of each part.

3. The injection molding machine with valve-controlled nozzle is also prone to residue in the valve control part.

4. The air is compressed into a high temperature in the barrel. This high temperature gas, together with the shear heat at the gate, tends to become a black strip.

three. Solution

1. Immediate: When the material is replaced, reduce the injection pressure and reduce the temperature of the heating barrel.

2. Short-term: cleaning of the heating cylinder (using a copper wire brush).

3. Long-term: repair of the barrel.

four. Due to material differences

1. The pigments, paints, lubricants, ultraviolet absorbers, and anti-static agents in the mixed resin are overheated in the cylinder, and the thermal decomposition of these materials is also the cause of the purlins during long-term retention. Especially when certain types of additives have poor heat resistance, this tendency will become more pronounced.

2. When molded with polycarbonate (PC), it is easy to produce purlins with valve-controlled nozzles.

3. Screws with backflow prevention washers are also prone to charred residue.

Fives. Reference matter

If you do not use special cleaning materials when replacing materials, use ordinary soft polystyrene.