pfmold.com

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There are two main types of plastic injection mold:

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Two plate Mold and Three plate Mold

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A. Two plate Mold

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Two plate mold is the mold with sprue, runners, gates, and cavities are all on the same side of the mold as shown in Fig. 1-22 , divided by the parting line into moving half and fixed half.

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The features for two plate mold are:

1.Simple structure, easy to operate, and satisllietory to have the plastic part to drop off freely.

2.Minimal operational probIems, long lifespan, and shortened molding cycle.

3.Inexpensive mold cost.

4.Easier to choose gate shape and location for the two pate mould.

5.Other than direct gates, gate location is limited to the side of the plastic part with certain exceptions.

6.After molding, there is need to cut off the gate from the part.

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Fig. 1-22 Two plate mold

1.sprue bush 2.guide pin 3.cavity retainer plate
4.core 5.core-retainer plate 6.support plate
7.sleeve 8.stop pin 9.spacer block I0.core
11.screw 12.clamping plate of the moving half
13.ejector-retainer plate 14 sprue puller pin
15.ejeclor support plate 16.return pin

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Fig. 1-23 two plate mould

Fig. 1-23 is the photos of two plate mould with one cavily for a plastic ear rack of Bluetooth product which has been installed on a plastic injection molding machine.

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B. Three plate Mold

Three plate mould is a mold which has a runner plate in between moving half and fixed half. The runner exists between the runner plate and the fixed half as shown in Fig.24. The cavity is located in between the runner plate and moving half of the mold. Pin-point gates typically locate at the middle of the plastic part, away from its edge. satisfying the aesthetic requirement and eliminating the process tot cutting off the gates.

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A three plate mold has the following features:

1.Its gates can be located at the middle of the plastic part.

2.It allows pin point gates.

3.It may eliminate cutting off the gates manually, when pin-point gates or submarine gates are used.

4.It has to take out both tile part and the runner respectively.

5.The injection molding machine should have sufficient mold opening distance.

6.It has a complex structure, more problematic and less durable.

7.It carries a higher mold cost than two plate mould.

8.It has a longer molding cycle than two plate mould.

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Fig. 1-24 Three plate mould

1.sprue bush 2.guide pin
3.clamping plate of the fixed half
4.cavity -retainer plate 5.spring 6.stop Pin
7.core 8.core retainer plate 9 suport plate
10.spacer block 11.screw 12.return pin 13.ejector pin l4 clamping plate of the moving half
15.ejeclor-retainer plate~ 16.ejectore-support plate

 

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Fig. 1-25 is the photos of three plate mould with two cavities for a plastic cover of Bluetooth product which has heen installed on a plastic injection molding machine.

 

Fig. 1-25 three plate mould - a ) Fig. 1-25 three plate mold - b )

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