Working Principle: After plastic is molten, it enters mold cavity through injection molding machine's nozzle under high temperature, high pressure, and high speed via gating system. After holding pressure for a period and then cooling for a period of time, allowing molded product to harden to a certain degree, moving mold section retracts under action of injection molding machine, causing mold to separate at PL1. Then, ejector pins of injection molding machine push ejector plate through K.O. hole, driving ejector pins to eject molded product. Finally, moving mold section of mold closes under action of injection molding machine, ejector pin fixing plate is reset by return rod, driving ejector pins and other components back to their original positions.
Precautions: K.O. hole must not be smaller than ejector pin diameter of injection molding machine; Ejection stroke L must ensure that ribs and holes of injection molded product can be completely ejected; When automatic injection is required, ensure that injection molded product can be completely ejected from mold cavity; in semi-automatic or manual operation, ensure that injection molded product can be easily removed; Sprue bushing radius SR is greater than injection molding machine nozzle radius: R = r + (1～2); Sprue bushing inlet must be larger than orifice diameter at the front end of injection molding machine nozzle: D = d + (0.5～1).

 

Working principle: After plastic is molten, it enters mold cavity through injection molding machine nozzle under high temperature, high pressure, high speed, and is held under pressure for a period of time. After a period of cooling, injection molded product hardens to a certain degree. Moving mold then retracts under action of injection molding machine, causing mold to separate at PL1. Next, ejector pin of injection molding machine pushes ejector pin pad through K.O. hole, driving ejector pin and other components to eject injection molded product. Finally, moving mold part of mold closes under action of injection molding machine. Ejector pin fixing plate is reset by return rod, driving ejector pins and other parts back to their original positions.
Precautions: Applicable to large products, plastics such as ABS, PP, GP, etc.; Wires of heating element on hot runner must be inside groove, and it is connected to power supply outside mold through mold (see standard); Cooling water must pass through vicinity of hot runner; Impact of thermal expansion must be considered in design; Other precautions are same as for two-plate molds;

 

Working principle: When mold opens, fixed mold base plate and stripper plate do not separate temporarily because pull rod holds runner; Since plates A and B are held in place by mold locking buckle, mold opens first at PL1, separating runner from injection molded product. At the same time, bent pin drives fixed mold slider to open, completing side core pulling. After stroke B, stroke screw 1 drives stripper plate, causing fixed mold base plate and stripper plate to open for second time, and main runner disengages from sprue bushing. After stroke A, under action of stroke screws 1 and 2, plates A and B complete third mold opening.
Precautions: Following relationships must be ensured during design: ①. B≥S1＋S2＋5; ②. B≥75; ③. L≥A＋B＋C＋20; ④. A≥S1. A - Stroke of stroke screw (1); B - Stroke of stroke screw (2); C - Height difference between upper and lower molds; S1 - Length of main runner; S2 - Length of branch runner; Other precautions are same as for two-plate molds.

 

Working principle: When mold opens, runner is held in place by sprue sleeve, fixed mold base plate and stripper plate are fixed in place, plates A and B are fixed by mold lock buckle and do not open. Therefore, mold opens first at PL1 to separate branch runner from injection molded product. After stroke B, stroke screw 1 drives sprue plate, causing fixed mold base plate and sprue plate to open for second time, and main runner disengages from sprue bushing. After stroke A, under action of stroke screws 1 and 2, plates A and B complete third mold opening.
Precautions:
1. Following relationships must be ensured during design: ①. B≥S1＋S2＋5; ②. B≥75; ③. L≥A＋B＋C＋20; ④. A≥S1.
B – Stroke of stroke screw (2); A – Stroke of stroke screw (1); S1 – Length of main runner; S2 – Length of branch runner; C – Height difference between upper and lower molds;
2. Other precautions are same as for two-plate molds.

 

Working Principle: During mold opening, stripper plate and B plate are fixed in place by nylon hooks (or other mechanisms). Mold opens first at PL1. After stroke A, injection molded product detaches from stationary mold insert. Stroke screw drives stripper plate to open at PL2, leaving injection molded product in lower mold. Then, injection molding machine's ejector pin pushes ejector pin pad through K.O. hole, causing ejector pins to eject injection molded product. Moving mold part closes under action of injection molding machine. Ejector pin plate is reset by return rod, causing ejector pins to return to their original positions.
Precautions: Sprue bushing and inserts have a 5°-10° ejection angle with stationary mold stripper plate; Angle at point A depends on product, generally 10-20 mm; Other precautions are same as for a two-plate mold.

 

Working Principle: After plastic is molten, it passes through nozzle of injection molding machine under high temperature, high pressure, and high speed, through sprue, hot runner plate, and then through hot nozzle into mold cavity. After holding pressure for a period of time, followed by a cooling period, molded product hardens to a certain degree. Then, moving mold retracts under action of injection molding machine, causing mold to separate at PL1. Next, ejector pins of injection molding machine push ejector pin pad through K.O. hole, driving ejector pins and other components to eject molded product. Finally, moving mold part of mold closes under action of injection molding machine. Ejector pin retainer plate is reset by return rod, driving ejector pins and other components back to their original positions.
Precautions: Suitable for large products, single-cavity or multi-cavity molds. To better fill cavities and reduce warping, multi-gate feeding is typically used; Hot runner is equipped with heating devices; Wiring for heating devices on hot runner nozzles must be recessed and connected to a power source outside mold via mold (see standard); Cooling water must flow near hot runner nozzles; Effects of thermal expansion must be considered in design; Other precautions are same as for two-plate molds.