THREE-PLATE MOLD, STRUCTURE AND PRINCIPLE OF OPERATION THREE-PLATE MOLD
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.
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 | |
Advantages:
+ 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. |
Disadvantages:
+ 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 | |
Advantages:
+ 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. |
Disadvantages:
+ 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 |
![]() |
![]() |
![]() |
Contact :
Duy Tan Precision Mold Co., Ltd
Hotline: +84 28 3754 5418 (ext 728) | Fax: +84 28 37 54 54 16
Info@duytanmold.com | Facebook: https://www.facebook.com/KhuonChinhXacDuyTan