Five Factors Affecting the Cost of Injection Molding

5 factors affecting the cost of injection molding

Due to its ability to produce a large quantity of identical parts, injection molding is a very popular manufacturing process. This technology can be used for many different plastics processing, which are melted by the application of heat and pressure. The molten plastic is then injected into the mold to form the desired component.

The cost of injection molding can vary greatly and is usually affected by the following five factors.

1. Product design

The more complex the product, the more complex the mold must be. The complex and customized injection molded parts are usually more expensive because they require more molds than simple parts.

Machining complex parts may require auxiliary EDM programs to achieve undercut features, which requires more production time. In addition, larger parts require more material, which also increases costs.

2. The material used for plastic product

The type of resin used also greatly affects the cost of injection molding. When choosing a resin, the number of parts, additives, ingredients and molding temperature, resin availability, grade and color should be considered at the same time. The choice of resin may also affect the maintenance requirements of the mold, resulting in higher costs.

Each type of thermoplastic requires a different temperature. High temperature resin will increase mold cost, as described below. Thermoplastics that provide lower cost include polypropylene, polyethylene and polystyrene, while liquid crystal polymers, polysulfone and polyphenylene sulfide are usually accompanied by higher temperatures and higher costs.

3. The steel used for molds

A variety of steels can be used for mold making, but the specific type required for the job depends on the type of plastic used for injection molding. High-temperature thermoplastics require higher hardness steel or steel-plated molds. When selecting mold steel, please consider the required mold maintenance and the need for mold replacement.

Different mold steel can provide different service life. Molds with longer service life have higher value. But they are made of the more durable steel, which increases the cost of the mold. When choosing the mold steel, please consider the cycle time, surface finish and output. Because all these factors will affect the service life of the mold. Tool steel is usually chosen to improve its toughness and durability, although cheaper materials (such as aluminum) may be suitable for molds, especially when lower yields are required.

4. Volume and number of cavities

The more cavities required to form a part, the longer the production time. Long production time limits the ability to quickly produce parts, thereby increasing costs. Producing a large number of parts that require a large number of cavities will also involve higher production costs.

5. Location of mold maker

The location of the mold maker will affect the overall cost of injection molding. That depends on the transportation and handling costs required to transport the mold to the processing location. For example, when using a mold maker in China, please consider the minimum wage in each province. Proximity to the seaport will also affect transportation costs.

Planning an injection molding project

Before starting an injection molding project, please consider various factors that may affect the final cost of the plastic product.

Smart design, optimal material selection and careful manufacturer selection can greatly improve the quality of parts while controlling costs.

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