Side gate of plastic injection mold runner system design
In order to get the best injection quality, the gate type must be selected carefully, the coommon gate tyeps are: direct gate, side gate, pin-point gate, sub gate,valve gate of hot runner etc. Among them, the side gate is divided into tab gate, ear protection gate, fan gate, thin gate and so on, the sub gate is divided into sub gate, banana gate, downturning gate and so on.
According to the production automation, it is divided into manual removal and automatic removal, the side gate and direct gate are need to be manually removed after production,but the sub gate and pin-point gate and valve gate of hot runner are automatic removed.
Edge gate: generally make in parting surface of mold, feeding from the edge of the plastic part, the gate cross-section is generally rectangular, as shown in picture 1. The depth of the side gate determines the condensing elbow of the gate, the gate thickness depth is generally 0.5-0.75 times then the wall thickness, and some have the same thickness as the wall thickness, which is generally determined according to the injection volume of the plastic part.
The side gate is the most widely used gate, suitable for various shapes of products, but not suitable for thin and long cylindrical products.
Advantages of side gate:
1. The gate is easy to separate from the part, it is generally in the non-critical surface of part, because the gate thickness is thinner than the wall thickness of the product, so it is more convenient to remove, when the part take out from the mold nand not cooled enought, it can be removed by hand or pliers;
2. It can prevent the plastic from flowing backward, the size and thickness of the side gate are relatively small, after the pressure is maintained during injection molding, the gate position is faster to solidify, so the plastic in the thicker glue position in the product is not easy to flow back through the gate;
3. Frictional heat is generated at the gate, which can raise the temperature of the plastic again and promote filling;
4. The tab gate (as shown in picture 2) can effectively prevent product flow marks;
5. Fan gate (as shown in picture 3) can be filled evenly to prevent product deformation, the plastic melt flows smoothly into the cavity without flow marks and weld marks, and the molding quality is good;
6. It is convenient to process the gate, the side gate can generally be processed by CNC directly, EDM can be used for high mold cavity and core.
Disadvantages of side gate:
1. Pressure loss too much, the plastic pass from the main runner, the runner, and the sub- runner before reaching to the gate area, the injection pressure loss too much, due to the side gate is normally make in side of part;
2. Plastic with insufficient fluidity is easy to cause insufficient filling or shutting down;
3. The gate needs to be removed manually, which cannot realize fully automated production;
4. There will be a mark on the edge of the part after moving the gate, which is not suitable for products with high appearance requirements.
What is Ejection Molding?
Dec 28, 2021The process to get injection molded products is called injection molding, or called injection. Injection molding is an important method in polymer molding processing, it is characterized by a short...viewInsert pin of vengting design for molded parts
Mar 20, 2022Insert pin of venting: It is difficult to make exhaust slot when end runner is not in parting surface during injection, and there is no matching gap available, but we could make the venting pin at end...viewParting surface venting of runner system
Mar 10, 2022There are a large amount of gas in the main and sub channel, these gas are discharged through the pull rod (push rod) during injection processing, a part of gas come out from exhaust slot on parting...viewVenting of parting surface
Mar 7, 2022The exhaust slot on the parting surface is easy to clean and processing, also not easy to be blocked, and has a good exhaust effect, it is the main area where the gas is exhausted, so the exhaust from...viewMain application of gas-assisted molding technology
Apr 7, 2022Gas-assisted molding has a particularly obvious effect on the material saving of tubular and rod-shaped plastic parts, such as car handles, seat armrests, window frames, and wood-like furniture, the...viewConformal cooing channel of plastic injection mold
Feb 23, 2022The conformal cooling gate is a new type of mold cooling gate based on 3D printing technolog, because of its processing characteristics, the conformal cooling gate can fit the shape of the product...view