Plastic Washer Outside Ring Molding

Plastic mold base selection principle

When selecting a mold base, multifaceted aspects, e.g., part structure, mold parting requirements, and economy, should be considered.

The mold base selection principles are shown as follows:

1. Side gate mold base

* Simple structure, not-very-strict requirements for surface finish, allowing gate marks on the side, and no other special structures.

* When the side gate mold bases are applicable, don’t select the pinpoint gate mold base. The side gate mold base applies to the one-step parting mold.

2. Point gate mold base

* When the single-cavity and the molded part have a large projection area on the parting surface, requiring multipoint feeding, the pinpoint gate mold bases are usually selected.

* For a multi-cavity mold, in which some individual parts require feeding on the inside.

* For a multi-cavity mold, the sizes of some individual cavities vary a lot. When using an edge gate, the gate bushing should be away from the center of the mold.

* Gear mold, and multi-cavity tire mold, etc.

* High barrel, or shell-shaped products.

* For molds of high precision products or those with smaller dimensional tolerances and higher requirements on service life, select the pinpoint gate mold base.

3. Simplified point gate mold base

* When there are large-size core-pulling mechanisms (slides, cylinders) on both sides, it will take a long time to select the pinpoint gate mold base. In this case, the simplified pinpoint gate mold base is a better option.

* The side gate mold with a cavity slide usually adopts the GAI and GCI series of the simplified pinpoint gate mold base.

The calculation method for mold base selection

The form of the mold base is determined first, followed by the size, which depends mainly on the size of the mold core. The larger the size of the mold core, the larger the size of the mold bases are. The relationship between the two is proportional.

1. Determine the width of the mold base

The width of the mold base ejector pin should be the same as the width of the mold core. The difference between the two should be kept within 5-10 mm.

2. Determine the length of the mold base

The distance between the long side of the mold core to the outer edge of the return pin should be greater than 10-15mm, and the mold bases of over 40mm should adopt a length of 15mm.

3. Determine the height of the mold base

The height of a mold base mainly refers to the height of Plate A, Plate B, and the spacer plate. The thicknesses between other plates are all standard. So, adjustment is not required when selecting or calculating the mold base.