During the production of injection molds, there may be failures in the injection parts, which are mostly caused by the injection and molding stages of the injection mold, and sometimes due to unreasonable designs. The influencing factors include injection mode, number of cavities, location and size, cold/hot runner system design, and product structure. Therefore, to avoid failures caused by mold design, we need to trial the mold during its production. Let us understand why injection molds need to be trialed.
After obtaining the mold trial results, operators usually need to reassess the condition of the mold to avoid unnecessary costs and time during the trial process. In most cases, to compensate for the shortcomings in mold design, operators may make incorrect settings without their awareness. Since the range of parameter settings required to produce qualified products is small, any deviation in parameter settings would result in product quality that exceeds the allowable error range.
The trial of injection molds is for finding the best process parameters to carry out mold design. It is not just about obtaining a good sample. This issue is crucial as it ensures stable and uninterrupted mass production even when factors such as materials, machinery, and environment change.
Improper adjustment of the clamping device of the injection machine or an inappropriate toggle mechanism can prevent the mold from achieving the required parallelism. As a result, one side of the mold seals tightly while the other side seals poorly, making it easy to overflow during the injection process.
The injection machine itself has a problem with parallelism, and uneven distribution of the tie bars can also cause the mold to not fasten properly, resulting in overflow.
Serious wear of the fixed ring of the injection machine, insufficient injection dosage in the barrel due to excessive wear, and small buffering pads can also result in overflow.
The accuracy of the parting surface of the injection mold is not high, and the active template (such as the middle plate) is deformed and warped. Obvious sliding burrs exist around the groove on the parting surface and the mold seat, all of which can cause overflow during injection molding.
Improper mold design. If the opening position of the mold cavity is too far off, the tension of the mold cavity during injection molding will be too large, resulting in burrs.
The above are the five main reasons for overflow during the production process of injection molds. If we find that the injection mold is overflowing, we need to process the problem as soon as possible, otherwise it may cause partial collapse or even damage of the injection mold. In severe cases, the gap between the blades and the overflow of the top pin can cause the finished product to stick to the mold, affecting the demolding process.