As an important part of injection molds, standard mold bases for injection molds have many types and a wide range of choices. According to different classification standards, these mold bases can be divided into multiple types to meet different production needs. Next, we will explore in depth diverse types of standard mold bases for injection molds and their selection points.

2. Fine sprue standard mold base
3. Simplified fine sprue standard mold base
Injection mold standard mold bases are usually composed of key components such as mold plates, guide pins and guide sleeves, return pins and fastening screws. Mold plates play a vital role in mold bases. They are not only divided into two categories: main mold plates (such as A plates, B plates) and structural mold plates (such as panels, bottom plates, support plates, push plates, square irons, sprue plates, etc.), but any set of mold bases is composed of A and B plates, specific structural mold plates in a specific order. In addition, we also need to understand common large sprue standard mold base models so that we can choose according to actual needs.
1. Structural features of large sprue standard mold base (take AI type as an example)

 

Large sprue standard mold base covers 12 different models, as shown in figure:

 

Structural features of slim sprue standard mold base are as follows:

 

Slim sprue standard mold base covers 16 different models, as shown in figure:

 

3. Simplification of slim sprue standard mold base structure (take FAI type as an example)

Simplification of slim sprue standard mold base covers 8 different models, as follows:

 

So, under what circumstances will large sprue mold base, slim sprue mold base and simplified slim sprue mold base be selected respectively? Of course, when choosing a mold base, we need to comprehensively consider multiple factors such as structural characteristics of parts, parting requirements of mold, and economic cost. Following are some commonly used standard mold base selection principles for your reference:

1. For parts with simple structure, less strict appearance requirements and gate marks on the side, if there are no other special structural restrictions, large sprue mold bases can usually be selected. When large sprue mold bases can be used, their use should be given priority, especially for molds with one-time parting.
Next, we discuss selection conditions for fine sprue mold bases.
1. When projection area of a single cavity or molded part on parting surface is large and multiple points of glue are required, a fine sprue mold base is often used.
2. For the case of one mold with multiple cavities, if customer specifies that a certain part must use center glue feeding method, then fine sprue mold base becomes a suitable choice.
3. If size of some cavities in one mold with multiple cavities is significantly different, use of a large sprue mold base will cause gate bushing to deviate from center of mold. At this time, a fine sprue mold base is more suitable.
4. Special molds such as gear molds and multi-cavity tire blow molds usually also require a pinhole mold base.
5. For products with large height dimensions such as barrels and shells, pinhole mold bases can better meet their molding needs.
6. When product has high precision requirements, small dimensional tolerances, and service life of mold is critical, pinhole mold base should be given priority.
Next, we will take a closer look at specific selection conditions of pinhole mold base.
1. If mold is equipped with large side extraction mechanisms on both sides, such as sliders or cylinders, and pinhole mold base is expected to be used for a long time, a simplified pinhole mold base can be considered to improve efficiency.
2. For large-gate molds with sliders on female mold side, it is usually recommended to use a simplified pinhole mold base, such as GAI and GCI series, to adapt to its special structure.

 

Warm reminder
When selecting a pinhole mold base, you need to make a wise choice based on specific structure of mold and expected use time. If mold is equipped with a large side draw mechanism and pinhole mold base is expected to be used for a long time, then a simplified pinhole mold base will be a good choice, which can ensure functionality while improving production efficiency. At the same time, for large-gate molds with sliders on female mold side, simplified pinhole mold bases such as GAI and GCI series are usually recommended because they can fit special structure of this type of mold.
1. For mold bases with an overall size of 250mm or less, it is recommended to use an I-shaped mold base. When mold base size is between 250~350mm, a straight mold base with panel (T-type) will be a suitable choice. If mold base size exceeds 400mm and there is a slider, continue to use a straight mold base with panel (T-type); if there is no slider, use a straight mold base without panel (H-type).
2. If A-plate frame opening depth is large, usually more than 60mm, you can consider using a mold base design with an open frame or no panel. It should be noted that for mold bases with sliders or female mold sliders, A-plate should not have an open frame. When A-plate opening depth is deep, panel can also be omitted.
3. Ensure that push plate mold base does not conflict with female mold guide pin and rear mold guide sleeve.
4. When mold core is round, it is recommended to use a mold base with a support plate.
5. In the case of a slider or a female mold slider, guide pin must be inserted into oblique guide pin 10~15mm first, then pushed into slider. If guide pin is particularly long, female mold guide pin should be matched with male mold guide sleeve to facilitate operation of lengthening guide pin.