Why are there bubbles in the injection mold?

2021-03-23 12:47:52 admin

Why are there bubbles in the injection mold?


Causes and solutions of bubbles in the injection mold.


First of all, defects in the mold design cause bubbles in the injection mold


For example: Poor gate position of injection mold, too small gate, asymmetric gate arrangement of multi-gate parts, small runners, unreasonable mold cooling system, so that the mold temperature difference is too large, etc., causing the melt to be in the mold cavity The flow is discontinuous, blocking the air passage.



Secondly, the mold parting surface lacks the necessary vents or the vents are insufficient, blocked, poorly positioned, and there is no processing gap such as inserts, thimble, etc. to exhaust, resulting in the air in the cavity not being able to enter the plastic at the same time Leave. These reasons can also cause bubbles to appear in the injection mold.


Finally, if the surface roughness of the injection mold is poor, the frictional resistance is large, causing local hot spots, and the decomposition of the passing plastic will also cause the appearance of bubbles.


Of course, in addition to mold reasons, there will also be equipment, technology, raw materials and other reasons; therefore, every process in the injection mold manufacturing process needs to be very careful, try to avoid the phenomenon of bubbles in the injection mold, and reduce product production. The defect rate in the process can increase the competitiveness of injection mold manufacturers in the increasingly competitive mold industry.