Filling knowledge of injection molding

Injection molding is a step that many molds need to go through. This step is divided into four stages, and filling is the first stage. Here is not to say that filling is more important in the injection molding process. No one can leave who in the four stages. The following is mainly about filling.

First of all, we need to understand that filling is the first step of injection molding. It needs to work at the beginning of mold closure. Generally, it can be filled to about 95%. Another saying is that the shorter the filling time is, the higher the molding efficiency will be, but the injection molding time is affected by many factors. The filling is also divided into high-speed filling and low-speed filling. See the following for the specific differences.

(1) High speed: when filling at high speed, the shear rate is high. Due to the effect of shear thinning, the viscosity of plastic is reduced and the overall flow resistance is reduced; The local viscous heating effect will also make the thickness of the cured layer thinner. Therefore, in the flow control stage, the filling behavior often depends on the volume to be filled. That is, in the flow control stage, due to high-speed filling, the shear thinning effect of melt is often great, and the cooling effect of thin wall is not obvious, so the utility of rate is the main.

(2) Low speed: when the thermal conductivity is low, the shear rate is reduced, the local viscosity is relatively high, and the flow resistance is large. Because the thermoplastic replenishment speed is slow and the flow speed is slow, the effect of heat conduction is very good, and the heat is taken away quickly from the cold mold wall. A small amount of viscous heating phenomenon and a thicker curing layer are added to further increase the flow resistance in the thin-walled part.

Generally, the strength of the weld line in the high-temperature zone is relatively good, because in the case of high temperature, the activity of polymers is relatively active and can be intertwined with each other. In addition, the melt temperature in the high-temperature melt zone is similar, so the thermal properties are almost the same, and it can increase the strength of the weld zone. If it is in the low-temperature zone, the strength will become worse.


About Huizhou Dj Molding Co., Ltd

Dj Mold is a China mold maker of plastic molds- injection mold, die casting moulds, plastic blow molding, rotational molding, medical plastic injection molding, two shot plastic injection molding, insert molding, overmolding, metal injection molding, micro injection molding, powder injection molding, ceramic injection molding, liquid injection molding, husky injection molding, household mold, casting mold, die mold tool, custom molds, china moulds, rapid prototyping tooling, plastic prototyping tooling, punch press tooling, die and tooling for mobile/ cell phone parts, automotive parts, vacuum cleaners, rechargeable tools, telephones, copiers, computers, multimedia speakers, and many other electronic products and household appliances. And also a plastic product manufacturer, mold manufacturer China– plastic parts, plastic water tank, plastic balls, plastic containers, plastic buckle, plastic anchor, plastic hanger, plastic spoon, plastic pipe fitting, plastic tumble, plastic tableware, plastic cups, plastic bottles, plastic tray, plastic cosmetic container, plastic case, plastic food container, plastic chairs, plastic caps, plastic cap closure, plastic tubes, plastic water pipes, plastic knobs, plastic tubing, plastic utility boxes, plastic racks and so on.

Person: James Yuan
Company: Huizhou Dj Molding Company Limited
Add:  LongGang Village,LongXi Town,BoLuo County,HuiZhou City,GuangDong Province, China
Tel: 86-752-6682869
Email: [email protected]


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