What problems may occur in the process of injection molding of household appliances?

There may be many problems such as appearance, size and performance in the process of injection molding of household appliances. The following are specific introductions:

Appearance problem

Lack of material: the plastic melt does not completely fill the mold cavity, which leads to the phenomenon of partial incompleteness and lack of meat on the product surface. This may be caused by insufficient injection pressure, poor plastic fluidity, unreasonable mold gate design or insufficient material supply.

Bubble: Bubbles appear inside or on the surface of the product, which affects the appearance and product quality. The reason may be that plastic raw materials are not sufficiently dried and contain moisture; In the process of injection molding, the mold filling speed is too fast and air is involved; Or poor exhaust of the mold.

Weld marks: During the injection molding process, two or more plastic melts fail to completely merge at the meeting place, forming obvious marks. This is usually caused by complex product structure, too long melt flow path or uneven die temperature.

Flow mark: When the plastic melt flows on the surface of the mold cavity, it leaves wavy or striped marks on the surface of the product due to uneven cooling or unstable flow. It may be caused by too low mold temperature, unstable injection speed or too high plastic melt temperature.

Size problem

Size deviation: the actual size of the product does not match the design size, which is beyond the tolerance range. It may be caused by insufficient mold design and manufacturing accuracy, unstable injection process parameters, and changes in plastic shrinkage.

Warp deformation: The whole or part of the product is warped and twisted after demoulding, which affects the assembly and use performance of the product. This is mainly caused by uneven cooling and uneven distribution of internal stress in various parts of the product during injection molding, which is related to factors such as mold structure, injection molding process and product structure design.

Performance problem

Insufficient strength: the mechanical strength of the product can not meet the design requirements, and it is easy to crack and damage during use. It may be that the poor performance of plastic raw materials, improper injection molding process lead to internal defects in the product, or the unreasonable structural design of the product can not meet the strength requirements.

Poor toughness: the product is easy to break when it is impacted, and its toughness is insufficient. This may be due to the problem of raw material formula, such as insufficient addition of toughening agent; Or the cooling speed during injection molding is too fast, which leads to unreasonable molecular chain orientation and affects the toughness of the product.

Poor aging resistance: after a period of use, household appliances appear aging phenomena such as discoloration, embrittlement and performance degradation. It may be that the content of additives such as anti-aging agent in plastic raw materials is insufficient, or the processing temperature is too high and the time is too long in the production process, which leads to the aging of raw materials.

Other issues

Poor ejection: When the product is demoulded, the product cannot be ejected from the mold smoothly due to unreasonable design of ejection mechanism or uneven ejection force, which may cause product deformation, damage or surface scratch.

Odor: Injection molded products have pungent smell, which may be due to the smell of plastic raw materials, the volatilization of additives, or the odor caused by overheating and decomposition of plastics during injection molding. These odors not only affect the user experience, but also may cause harm to human health.