Injection Mold Components

Injection Mold Components

Injection mold becomes one of the most common tools that been used in the production among various industries. The products from the injection mold nowadays could be design in sophisticate details but still in acceptable budget range. Injection mold in general would consist of different components as following:

1) The fixed half and moving half

The fixed half would be the part that been attached to the unmoving part of the injection machine. On the other hand, the moving half is the part that attach to the moving part of the injection machine.

2) Impression

Basically, injection mold would stand for parts of steel attached together while leaving space in the middle known as impression which would be space that allow plastic resin to be injected to the area and form up as solid part as the impression area of the mold. The impression area would be the area between 2 parts of the injection mold which are cavity side, the part that reflect the external or surface part of the parts or products, and core side, the part of the mold that reflect the internal side of the plastic parts or products.

3) Cavity and Core

The main parts that form up the impression of the mold are the core and cavity of the mold. The manufacturing method of mold normally could be separate into 2 types which are single piece manufacturing and using inserts.

4) Insert Bolster

The are 5 types of bolster that often been used consists of:

Solid bolster which suitable for mold that have rectangle or round shape

Strip type bolster which suitable for rectangle shape mold

Frame type bolster would suitable for cylinder shape

Chase bolster which suitable with split insert

Bolster plate which would be design based on special shape

5) Guide pin and bush

The main objective of the guide pin is to ensure the accuracy when articulate the mold. The usage methods of these pin are by installing the pin onto 1 side of the mold while on the same location on the other side would be install with the bush. During the mold movement and operation, the pin should work together with the bush to ensure that the mold close accuracy is correct.

6) Sprue Bush

A channel to transfer molten plastics ejected from the nozzle. It is a cylindrical part that is mounted in a mold. It is composed of a sprue hole with a taper and a base to adhere of the nozzle of an injection molding machine.
The entrance R must be 1 to 2 mm larger than the nozzle tip, and the diameter for the entrance of a sprue must be 0.5 to 1.0mm larger than the diameter of the nozzle; otherwise, the molten plastics may leak, making pulling out the sprue difficult.

7) Runner

A channel through which molten plastic is guided from the sprue bush into the cavity of the mold. Its size or shape is determined by the type of molding material.
A large runner allows better flow of the molding material; however, cooling takes longer. Thus, a runner is normally made smaller than the section of a part and gradually made bigger while testing. In any case, a runner should be basically smaller than the thickest area of the part.

8) Ejector System

After the plastic resin liquid form up as solid part in the impression of the mold, it needs to be ejected from the mold. The mold would have the ejector system to work on this part. There are many several types of ejector systems that could be used which it would leave different shape mark on the products. Normally, the ejector system would be attached to the back of the mold on the moving half.

The information above is just some basic about injection molding. If there is any questions or problems towards the mold, or incase that there are any ideas on products development, We at Jaje are welcome to co-develop along with our customers. Please do not hesitate to contact us at jajemold@gmail.com