Molds used for plastic injection molding are called injection molding molds, or injection molds for short. Injection molding molds can form plastic products with complex shape, high precision and inserts at one time.
"Seven-point mold, three-point craft". For injection processing, mold has a great influence on quality of molded product like injection molding machine. It can even be said that mold plays a greater role than injection molding machine; if mold is not fully understood during injection molding, it is difficult to obtain excellent molded products.

Injection mold structure is determined by type of injection molding machine and structural characteristics of plastic parts. Each mold is composed of a movable mold and a fixed mold. Movable mold is installed on moving plate of injection molding machine, and fixed mold is installed on fixed plate of injection molding machine. During injection, movable mold and fixed mold are closed to form a gating system and a cavity. When mold is separated, plastic part is left on the side of moving mold, and then plastic part is ejected by demoulding mechanism provided in moving mold. According to different functions of each part in mold, a set of injection molding molds can be divided into following parts:

Parts that give shape, structure, and size to molding materials, and they are usually made up of cores (plugs), concave mold cavities, threaded cores, and inserts.

It is a channel that leads molten plastic from nozzle of injection machine to closed mold cavity, usually composed of main runner, branch runner, gate and cold material well.

In order to ensure that movable mold and fixed mold can be accurately aligned when they are closed, guide parts are provided for guiding and positioning. It is composed of guide posts and guide sleeves, some molds are also provided with guide parts on ejection plate to ensure smooth and reliable movement of demoulding mechanism.

Device for realizing demoulding of plastic parts and casting system, it has many structural forms. The most commonly used demoulding mechanism are ejector pins, ejector tubes, ejector plates and pneumatic ejectors. They are generally composed of ejector rods, reset levers, slingshots, ejector rod fixing plates, ejector plates (ejector rings) and ejector guide columns / guide sleeves.

In order to meet mold temperature requirements of injection molding process, a mold temperature adjustment system heating rod is required to adjust mold temperature.

In order to expel gas in mold cavity smoothly, an exhaust groove is often set at matching part of mold parting surface and insert.

Refers to parts (such as: fixed plate, moving / fixing template, support column, support plate and connecting screw, etc.) set to meet structural requirements of mold.

 

1. Upper fixing plate: It is used to fix mold when machine table is opened and closed, indispensable part of front mold part is formed.
2. Stripping plate: fixed pulling nozzle plate.
3. Magnet: mold is opened and closed by magnetic control.
4. Square iron: cooperate with magnet to control mold opening and closing.
5. Male template: fixed male mold core and mold core bearing plate.
6. Template bearing plate: fix male template and install heating rod at the same time.
7. Material guide pin: fixed material belt.
8. Limiting column: limit ejection height of guide pin.
9. Mold angle: fixed function, at the same time give ejector plate enough height movement stroke
10. Upper ejector plate: fixed ejector pin.
11. Lower ejector plate: Fix upper ejector plate.
12. Lower fixing plate: fix mold feet and garbage nails, at the same time give lower mold a basic fixation and a fixed mold for opening and closing mold of machine table.
13. Garbage nail: limit height, make lower ejector plate cooperate with lower fixing plate smoothly, prevent miscellaneous flow into the two plates, and make ejector pin and guide pin eject uneven.
14. Top stick column (K.O column): It is used to eject ejector pin and guide pin of machine.
15. Small ejector plate: fixed guide pin.
16. Small ejector plate: fixed guide pin.
17. Ejector pin: eject material belt to make material belt separate from mold.
18. External pull rod: used to pull line cavity and limit mold cavity opening distance.
19. Heating rod: heat up mold.
20. Mold core bearing plate: fixed rear mold core and rear mold inserts.
21. Male mold core: fix insert and sleeve, mainly used for product molding.
22. Runner: part of injection molding.
23. Female mold core: fixed front mold insert, mainly used for product molding.
24. Female template: fixed female mold core.
25. Small tie rod: Fix opening stroke of fixed plate and stripping plate.
26. Female mold core pad: fix female mold core, press and insert heating rod at the same time.
27. Material-fixing plate: Fix material-pulling needle to prevent mold from pushing material-pulling insert out during injection process.
28. Chirp: main entrance for injection molding of machine nozzles.
29. Pulling plate: pull up pulling pin.
30. Pull material nozzle plate: fixed pull needle.
31. Front mold insert: fixed runner plate and female mold core.
32. Rear mold inserts and inserts: mainly used for product cup forming.
33. Pull insert: pull nozzle.

(1) Injection molding molds: mold used on injection machine. It is mainly used for molding thermoplastics. A few varieties of thermosetting plastics are suitable for this mold.
(2) Compression mold: a mold that uses compression technology to form plastic parts on a hydraulic press. It is mainly used for molding thermosetting plastics.
(3) Injection molding: a mold that uses injection molding to form plastic parts on a hydraulic press. It is suitable for molding thermosetting plastics.

(1) Single cavity mold
It is a mold with only one cavity, forming one plastic part at a time.
(2) Multi cavity mold
A mold with two or more cavities can mold multiple plastic parts in one mold.

 

Single cavity mold

 

Multi-cavity mold

Determine combination form of mold base according to structure required for forming plastic parts.

Obtain cavity wall thickness dimension by referring to Table or related wall thickness formula.

 

Length of cavity template:
L = S + A + t + A + S
Cavity template width:
N = S + B + t + B + S
4) Select standard perimeter size of cavity mold plate
5) Determine thickness of mold plate
6) Selected mold base
7) Check relationship between mold base and injection machine