Plastic Injection Mold Development

Plastic injection mold development is the process of designing and manufacturing the molds used in plastic injection molding. Plastic injection molding is a widely used manufacturing process for producing plastic parts in large volumes. The mold is a critical component in this process as it determines the shape, size, and quality of the final plastic part.

Here are the key steps involved in plastic injection mold development:

Mold Design

The mold design process is a crucial step in plastic injection mold development. It involves creating a detailed design for the mold that will be used to manufacture plastic parts through injection molding. Here are the key steps in the mold design process:

Custom Metal Stamping

1.Understand the Requirements

The first step is to thoroughly understand the requirements of the plastic part that will be produced. This includes studying the product design, specifications, and any specific features or constraints.

2.Determine Mold Type

Based on the product requirements, decide on the appropriate mold type. The most common types are two-plate molds and three-plate molds. Two-plate molds have a single parting line, while three-plate molds have two parting lines and allow for more complex part geometries.

3. Design Mold Cavity

Determine the number of cavities required in the mold. This depends on the desired production volume and efficiency. Design the cavity layout within the mold, ensuring proper spacing, gating systems, and runner configurations.

4. Gate Design

Determine the location and type of gates through which molten plastic will enter the mold cavity. The gate design affects the part quality, including its appearance and integrity. Common gate types include sprue gates, edge gates, and hot runner systems.

5. Cooling System Design

Efficient cooling is crucial to ensure proper part solidification and cycle time optimization. Design an effective cooling system within the mold, including cooling channels or inserts, to control temperature and achieve uniform cooling across the mold.

6. Ejector System Design

Determine the appropriate ejector system to remove the solidified parts from the mold after each cycle. This includes designing ejector pins, sleeves, or plates that will push the parts out of the mold.

7. Venting and Air Traps

Ensure proper venting within the mold to allow for the escape of air and gases during the injection molding process. Proper venting helps prevent defects such as gas traps and burn marks on the parts.

8. Mold Material Selection

Choose the appropriate material for the mold based on factors such as expected production volume, part complexity, and budget. Common mold materials include steel alloys, aluminum alloys, and hardened tool steels.

9. Moldflow Analysis

Conduct moldflow analysis using specialized software to simulate the plastic flow, cooling, and filling behavior within the mold. This helps identify potential issues and optimize the mold design for better part quality and process efficiency.

Material Selection

The choice of mold material is crucial as it affects the mold’s durability, heat resistance, and ability to withstand the injection molding process. Common mold materials include steel alloys, aluminum alloys, and hardened tool steels. Factors such as expected production volume, part complexity, and budget influence the material selection.

Here are some commonly used plastic materials in injection:


1. Polypropylene (PP)

PP is a versatile thermoplastic with excellent chemical resistance, low density, and good impact strength. It is commonly used in packaging, automotive parts, and consumer products.

2. Acrylonitrile Butadiene Styrene (ABS)

ABS is a tough and rigid thermoplastic with good impact resistance and high heat resistance. It is widely used in automotive components, electronics, and household appliances.

3. Polyethylene (PE)

PE is a lightweight and flexible thermoplastic with good chemical resistance. It comes in various forms, such as high-density polyethylene (HDPE) and low-density polyethylene (LDPE), and is used in packaging, pipes, and containers.

Mold Manufacturing

Automotive Sector

Once the mold design is finalized and approved, the mold manufacturing process begins. This involves machining the mold components from the chosen materials using CNC (Computer Numerical Control) machines. The mold’s cavities and other features are precisely machined based on the design specifications.


Mold Assembly and Testing:

Modern Construction

After the individual mold components are manufactured, they are assembled to create the complete mold. The mold is then tested to ensure proper functionality, including checking for accuracy, dimensional precision, and smooth operation. Any necessary adjustments or modifications are made at this stage.


It’s worth noting that plastic injection mold development is a complex and iterative process that requires expertise in mold design, material properties, and injection molding principles. Experienced mold designers and manufacturers work closely with product designers and engineers to ensure the successful development and production of high-quality plastic parts.