Three temperature settings for injection molding
TIME：2021-10-20
01 barrel temperature
Each material has its own melting temperature range. If the temperature is low, the material will not melt well, and if the temperature is high, it will decompose, so the corresponding appropriate temperature must be selected. However, there are some differences in the temperature control system of injection molding machine, so we should learn to watch the rubber head and analyze whether the temperature is appropriate.
There is abnormal sound during gluing, and there are obvious granular particles of incompletely melted material on the beaten material. When the fluidity is not very good, it indicates that the temperature is too low and needs to be increased.
The gluing is very smooth. The materials produced are very liquid like water, indicating that the temperature is too high and needs to be reduced.
Material temperature is very important. If it is too high and slightly decomposed, it will seriously affect the strength and quality of products. Therefore, the change of material temperature is generally not considered in production.
02 mold temperature
The mold temperature directly affects the product size. Generally, it is set according to the material category in the mold trial stage, and slightly adjusted according to the product quality. It is better not to consider the change in mass production.
When the mold temperature is high, the melt fluidity is good, which is conducive to molding, but the product shrinkage increases and the size will be smaller accordingly.
When the mold temperature is low, the melt fluidity is poor, which is not conducive to molding, but the product shrinkage is reduced, and the size is correspondingly larger.
Mold temperature not only affects the product size, but also determines its crystallinity. When the mold temperature is high, the crystallinity is large, and when the mold temperature is low, the crystallinity is small.
The mold temperature also has a certain impact on the product strength. When the mold temperature is low, the product fluidity becomes poor, then the position fusion of the bonding line will be affected, and the strength of the bonding line will be significantly reduced. Moreover, when the mold temperature is low, its crystallinity is low, and its strength is correspondingly low.
03 drying temperature
Some materials have trace water molecules, which will accelerate the decomposition of polymers, such as PC, PBT, etc., so they must be fully dried before forming.
If some dryness is not in place, it will not only accelerate the decomposition of the material and produce a large number of bubbles, but also make the fluidity very good and easy to produce defects such as flapping front. Therefore, it must be dried before forming.
