Plastic bottle caps in the injection molding process, due to molds, materials and equipment and other reasons will lead to parts flashing, lack of material and so on, which will increase the failure rate of parts. Next, let us take a look at some common quality analysis problems!
Question 1: There is a shortage of material. The lack of material generally refers to the fact that during the plastic processing process, due to the cavity filling of the mold being unsatisfied, the appearance of the part does not conform to the design.
Equipment reasons: The main reason for the lack of material is the nozzle part, which is generally blocked by the nozzle; the quick solution is to clear the nozzle. In addition, nozzle leakage may also result in missing material, but such failures generally require the replacement of a new nozzle.
Mold reasons: Generally caused by the internal exhaust of the mold is not smooth. As the air accumulated in the cavity cannot be discharged, the plastic filling amount will be insufficient, resulting in shortage of material. The solution is to reduce the filling speed of the plastic or add a corresponding exhaust hole to the mold.
Problem 2: When the flash problem is not solved in time, it will cause the flash edge to expand; and the flash produced by the insert side gap and the push rod hole will cause the plastic parts to get stuck on the mold and affect the mold division.
Equipment reasons: The machine's own mold clamping force is not enough, which will result in the mold can not be pressed normally. Generally, when selecting the model of the injection molding machine, the rated clamping force of the machine must generally be greater than the tension formed by the injection molding part in the axial cross-sectional area during injection, otherwise the mold release will be caused and the flash will be formed.
Mold reason: Generally caused by the irrationality of the mold design, this kind of problem is more difficult to solve, and it needs to redesign the mold.
Problem 3: Plastic shrinkage occurs. Shrinkage is the most common phenomenon occurring on the surface of the finished product, most of which occurs at the dry wall thickness.
The reason of the equipment: Injection molding machine injection speed and holding time are less, making the plastic parts of the lack of fluidity. The plastic part that causes the first to enter the cavity of the mold cools quickly, and there is not enough time for holding pressure to perform the feeding. To solve this problem, a higher injection pressure is used.
Mold reason: The exhaust inside the plastic bottle cap mold is not smooth, it can also lead to excess air in the cavity can not be ruled out. The solution is to maintain the mold and increase the exhaust port.

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