Tips to Reduce Plastic Injection Molding Cost

As a professional engineer with over 8 years of experience, I have overseen many injection molding projects. I frequently find the beauty and intricacy of transforming raw materials into precisely molded plastic components fascinating. One thing that really stands out is producing quality parts at the lowest possible cost. For any project to be successful, cost-effectiveness is always a top priority.

In this article, I will share valuable strategies and industry-recognized best practices to help you save on the cost of injection molding without compromising the quality of your products.

How much does injection molding cost?

Injection molding process

It is impossible to tell exactly how much injection molding costs without specific details about insert molding part size and the project. I have seen low-volume jobs involving simple product designs cost as little as $100, while high-volume jobs where the part’s geometry is complex cost $100,000 and above.

When determining the final cost amount of an injection molding project, we first look at your design and then consider the various types of costs associated with producing the parts before giving you a quote.

The molding or tooling cost is the main factor that determines the overall cost of an injection molding project.

Injection molding tooling cost

Post-mold Machining

This is the initial cost of creating the mold or tooling that will be used in the process of injection molding. The molds need to be made with high precision to form the molten plastic into the desired product design. More time and accuracy will be needed to make complex molds with complicated features, undercuts, or many cavities, which will increase tooling costs.

Injection molded parts cost

This is the initial cost of creating the mold or tooling that will be used in the process of injection molding. The molds need to be made with high precision to form the molten plastic into the desired product design. More time and accuracy will be needed to make complex molds with complicated features, undercuts, or many cavities, which will increase tooling costs.

5 Factors That Affect Cost of Injection Molds

Multiple factors influence the cost of injection molds. I will discuss five of them that play a huge role in determining the cost of injection molds.

#1 Mold Size

The size of the part to be produced considerably impacts the price of the plastic injection molding costs. Larger and more robust molds are needed for larger parts. More materials are needed to make the large molds, which typically results in higher material prices and longer machining times.

Additionally, larger molds need more powerful and expensive injection molding equipment, raising operating expenses.

#2 Parts Materials

ABS Plastic Materials

The type of material used for the injection-molded component greatly influences the injection mold cost. Certain materials may require particular mold features, cooling channels, or surface treatments because of their unique qualities and requirements.

Some plastic materials, particularly those that are high-temperature or abrasive, wear down injection molds and reduce tool life. To overcome this challenge, harder molds built from particular grades of steel are used, which increases the plastic injection molds cost more.

#3 Part Complexity

Custom Plastic Injection Molding

Simple, single-cavity molds and 3D prints made at home in low volumes are examples of relatively uncomplicated parts that are typically less expensive to make. These components often just need simple tooling and mold design, have simple designs, and have few functionalities. As a result, the fabrication of the mold is simpler, and the cost of making it is lower. 

The cost of injection molds rises when parts are more complicated, have more features, or have more mold cavities. If parts have many cavities, more parts may be created during each injection cycle. This enables greater production rates. However, making molds with several cavities requires more engineering, machining, and accuracy to guarantee that each cavity is accurately reproduced. The costs of making such molds are greater as a result of their complexity.

#4 Part Finishing

In my many years of experience manufacturing specialized injection-molded components for luxury consumer gadgets, I have found that the amount of finishing needed for these pieces always has a big influence on the cost of the plastic injection molding itself.

The process of injection molding gets increasingly difficult as part finishing complexity rises. For the process to be optimized, finishing needs must be properly taken into consideration in mold design and production planning. To consistently achieve the desired finish, appropriate tooling materials and the insertion of cutting-edge mold features are required. These call for additional costs in mold-making.

#5 Part Quantities

We can never overemphasize the importance of part quantities when determining injection mold costs. The volume of objects to be produced through injection molding influences the manufacturing process and material selections for the mold. 

3D-printed or lower-grade machined aluminum molds may be appropriate for small-scale applications because they are more affordable. High production quantities, on the other hand, call for using several molds or high-grade steel molds to control the process without compromising the quality of the products produced. However, high-volume molds yield a reduced cost per component because the extra expense is split among more pieces.

8 Tips to Reduce Plastic Injection Molding Cost

Here are some invaluable tips that I always apply to have cost-effective injection molding projects.

injection molding cost

#1 Eliminate undercuts

Avoiding or limiting undercuts makes the design and ejection of the mold easier, which speeds up production and lowers costs. Undercuts make a part’s design complex. They also make it more difficult to remove it from the mold.

When undercuts are present, the mold must include elaborate mechanisms, such as slides or lifters, to release the item from the mold cavity, which increases the complexity and length of the mold design and production process.

For a simpler plastic injection mold build, another option would be to use sliding shutoffs and pass-through cores or to modify the parting line and draft angles. This saves on tooling expenses because the need for extra mold components, which raise production costs, is avoided.

#2 Reduce cosmetic finishes

Although glossy or shiny surfaces are attractive, are they necessary for your project? You could think about getting rid of them if they don’t result in more sales.

Selecting less complicated surface treatments can reduce post-processing and injection mold tooling complexity, which lowers costs. Although attractive components are desirable, improving their visual appeal frequently necessitates bead blasting, EDM, or high mold polishing, which raises tooling costs.

#3 Use a core cavity approach

Core cavity approach is whereby sophisticated interior parts of a device enclosure are machined into a solid core. The final part is subsequently formed by shaping the mold material around this core.

The core cavity method maintains consistency throughout the production process and enables accurate duplication of intricate interior features. Furthermore, it eliminates the need for excessively steep draft angles and makes it easier to achieve smoother surface finishes, proper venting, and enhanced ejection.

#4 Stick to a Lean Design

Lean design is an approach to product design that emphasizes waste reduction, efficiency, and simplicity throughout the whole product development process. It aims to reduce needless complexity and cost while creating products that meet client expectations.

Focus on efficiency and simplicity while designing the component. Reduce complications and extraneous features that can call for specialized tooling to save money on both materials and production expenses.

#5 Apply DFM Analysis

Design for Manufacturability assists in locating any design flaws that could raise the complexity of the plastic injection molding process and the manufacturing cost. Addressing these issues can ultimately result in time and cost savings.

#6 Remove unnecessary features

Examine the part’s design and note any elements that would not significantly improve the product’s usefulness or appearance. Mold design may be made more straightforward, and production costs can be reduced by removing extraneous elements.

Some features and unutilized functionalities, such as unnecessary surface textures, non-functional ribs, and embossed patterns or logos, might not be necessary for the part to operate. Such characteristics can be eliminated to simplify the mold design and save on tooling expenses.

#7 Family Mold/Multi-Cavity Molds

A family mold, often called a multi-cavity mold, is a kind of mold design that enables the production of several identical or related pieces within a single molding cycle. A Family Mold combines many cavities inside the same mold base, allowing for the simultaneous manufacture of multiple parts as opposed to utilizing separate molds for each part.

This approach reduces tooling and labor costs, and increases production efficiency, resulting in lower unit costs.

#8 Use Over molding

PE Overmolding

Over molding may be a cost-effective alternative for sections that need new materials or other functionalities. The use of over-molding eliminates the need for separate assembly procedures by allowing you to integrate numerous materials or components in a single mold.

Please feel free to contact us so that we guide you on how to effectively apply these cost-saving tips for an optimized injection molding process.


Gavin Leo is a technical writer at Aria with 8 years of experience in Engineering, He proficient in machining characteristics and surface finish process of various materials. and participated in the development of more than 100complex injection molding and CNC machining projects. He is passionate about sharing his knowledge and experience.