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Talking About The Probability Of Black Spot Discoloration In Injection Mould
Apr 12, 2018

1, machine side:

(1) The operation of the heating control system on the machine is malfunctioning, which causes the inside of the cylinder to overheat and decompose black.

(2) Because the defects of the screw and barrel cause the melt to stick and accumulate, the plastic is decomposed after the machine has been fixed and heated for a long time. At this time, the worker needs to check whether the rubber head kit is worn and whether there are metal foreign objects inside.

(3) Some plastics will cross-link and coke due to high heat while maintaining almost the original particle shape. These plastics are difficult to melt, so that they are finally entrained into the parts after being broken by screw pressure.

2, mold:

(1) Generally, the mold on the mold is easy to scorch if the exhaust gas is not smooth, and the size of the gating system of the mold is too small, or the coking caused by excessive shearing.

(2) The use of anger-appropriate oil-based lubricants, mold release agents, etc., can also cause black spots.

3. Plastics:

Excessive plastic volatiles, excessive humidity, excessive impurities, too much recycled material, and contamination.

4, processing:

(1) The pressure is too high, the speed is too high, the back pressure is too large, and the speed is too fast to decompose the material temperature.

(2) The barrel should be cleaned regularly to remove additives that are inferior to plastics.

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