dispensing cup molds


The three-plate mold is an injection molding mold that uses a cold runner system. The runners are arranged on two planes. When opening the mold, there is a clearance to take out the runner and the other to remove the finished part separately. So, the three-plate mold structure is larger and more complicated than its two-plate cousin. It is suitable for manufacturing large products or multi-cavity molds requiring multiple nozzles.

The three main parts or plates which make up this type of mold are

  • The fixed plate. It is attached to the moving or fixed platen.
  • The center or floating plate. It links to two other main plates.
  • The moving plate or front cavity plate. It is attached to the moving platen of the machine.

three plate mold

1 Upper fixing plate 2 Stripping plate
3 Magnet 4 Square iron
5 Male template 6 Template bearing plate
7 Material guide pin 8 Limiting column
9 Mold angle 10 Upper ejector plate
11 Lower ejector plate 12 Lower fixing plate
13 Garbage nail 14 Top stick colum
15 Small ejector plate 16 Small ejector plate
17 Ejector pin 18 External pull rod
19 Heating rod 20 Mold core bearing plate
21 Male mold core 22 Runner
23 Female mold core 24 Female template
25 Small tie rod 26 Female mold core pad
27 Material-fixing plate 28 Chirp
29 Pulling plate 30 Pull material nozzle plate
31 Front mold insert 32 Rear mold inserts and inserts
33 Pull insert

Operating Principle

The plastic injection three-plate molding process still includes common steps such as injection, colling, opening, and product removal. However, the opening process will be a bit complex.

Three-plate mold opening sequence:

There are three opening types in 3 plate mold base.

+ Runner opening

+ Runner stripper plate opening

+ Product opening.

Runner opening

This opening will cut the runner from the product. When the mold opens, the fixed side (cavity plate) will slide on the support pin thanks to the gate cut spring fore. The gate cut spring assembles between the runner stripper plate and cavity plate. The product will attach to the core plate. The runner lock pin skips the runner on the runner stripper plate. Three-plate mold usually uses a pinpoint gate so it can cut easily. Mold will move continuously.

Runner stripper opening

After the cavity plate moves to the end of the puller bolts, the puller bolts will move following the cavity plate. It pushes the runner stripper plate moving, so the runner stripper will push the runner out of the runner lock pin. Spring pin will push runner out of runner stripper.

Product opening

After the side parting lock is opened, the core plate and cavity plate are separated. The cavity plate will stop, and the core plate will move continuously. It will create a distance to remove the product.

Advantages and disadvantages of Three-plate mold

Three-plate mold VS Two-plate Mold

+       Easy to select gate location.

+       The 3-plate mold usually uses metal plugs, so it is easy to disassemble.

+       The product and runner can remove separately, so it is suitable for automation.

+       Be able to produce complex products.


+       Higher manufacturing cost

+       Long injection molding cycle.

+       The injection machine needs a large stroke.

+       More complex structure mold.

+       Less durable than the two-plate mold.

Three-plate mold VS Hot runner mold

+       Cheaper manufacturing cost.

+       Less likely to break down than a hot-runner mold.

+       Heat-sensitive materials are less likely to degrade.

+       Easy to change plastic materials.


+       Longer cycle time.

+       Waste more plastic material.

+       Require greater injection pressure to fill the mold.

Three-plate mold at Duy Tan Precision Mold CO., LTD

Duy Tan Precision Mold company has more than 20 years of experience in manufacturing plastic injection molds and processing medical plastic products. We apply three-plate mold technology for cosmetic and medical button lid molds, helping businesses optimize costs and labor in post-pressing operations.

Here are some three-plate molds Duy Tan Precision Mold Company has made.

Three-plate mold for functional food containers Three-plate mold industrial application Three-plate mold for producing test tube caps
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Duy Tan Precision Mold Co., Ltd
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