Tips to Lower your Plastic Injection Molding Costs

Plastic injection molding is one of the most widely used manufacturing processes, enabling the production of durable, precise, and high-quality parts. However, achieving these benefits often comes with significant costs that can impact a project’s overall budget. For manufacturers, especially those working on tight margins, finding ways to reduce these costs without compromising quality is essential.

The good news is that you don’t need to cut corners to lower plastic injection molding costs. From simplifying part designs to optimizing material selection and mold efficiency, there are practical strategies that can help you achieve significant savings while maintaining the performance and aesthetics of your products.

In this blog, we’ll explore effective tips to lower your plastic injection molding costs. Whether you're designing a new part or looking to improve your existing processes, these insights will help you strike the perfect balance between quality and cost-efficiency.

Optimize Part Design

Let’s start off with something very basic, if your design is flawed, your part will not only perform poorly but also end up being more expensive to produce. This is because the design of a part plays a pivotal role in determining the overall cost of plastic injection molding. While complex designs may seem appealing, they often lead to higher mold costs, increased scrap, and longer cycle times, all of which drive up costs. By focusing on design optimization, you can reduce expenses while maintaining the functionality and aesthetic appeal of your product. These reduced expenses are not just for the plastic part but also the investment for tooling. 

To optimize part design, start by minimizing unnecessary features such as undercuts, sharp corners, and intricate geometries that require complex tooling. Simplified designs not only reduce the time and resources needed to create tools but also lead to shorter cycle times during production. For instance, incorporating draft angles can make parts easier to eject from tools, cutting down on wear and tear as well as production delays.

Additionally, consider consolidating multiple parts into a single tooled component when possible. This reduces the need for assembly, lowers material waste, and simplifies the manufacturing process. Working closely with your manufacturing partner to implement Design for Manufacturing (DFM) principles can ensure that your design is cost-effective while meeting all performance requirements.

By optimizing part design, you can reduce your costs and set the foundation for a more efficient and profitable production process.

Refine Material Selection

The materials you choose for your plastic part can impact both the cost and functionality of the part. Selecting the right material doesn’t always mean choosing the cheapest option, it’s about finding a balance between affordability, durability, and functionality.

Start by evaluating the specific requirements of your product. Does it need to withstand high temperatures, endure heavy loads, or meet stringent aesthetic standards? By clearly defining these criteria, you can avoid overpaying for materials with properties your application doesn’t require.

For cost-conscious projects, consider alternatives to high-performance engineering plastics. Many standard-grade plastics offer excellent durability and strength at a fraction of the cost. Collaborating with your supplier to understand the trade-offs between different resins can help you identify more economical options that still meet your needs.

Another way to reduce material costs is by minimizing waste. Design your parts with uniform wall thicknesses to prevent excess material use and ensure a smoother molding process. Recyclable or regrind materials may also be an option for non-aesthetic or hidden parts, further driving down expenses without sacrificing quality.

By refining your material selection process, you can effectively manage costs while ensuring your product performs as intended.

When selecting materials for plastic injection molding, understanding the properties of each option is crucial to balancing performance and cost. The chart below highlights some of the most commonly used plastics, their key characteristics, and typical applications to help guide your decision-making process.

Material	Key Characteristics	Typical Applications	Cost
ABS (Acrylonitrile Butadiene Styrene)	Tough, impact-resistant, good dimensional stability, easy to process, moderate cost.	Automotive parts, electronics housings, toys (e.g., LEGO bricks).	Moderate
PC (Polycarbonate)	High impact strength, transparent, good heat resistance, excellent dimensional stability.	Safety glasses, electronic components, automotive lighting.	Expensive
Nylon (Polyamide)	High strength, wear-resistant, good chemical resistance, absorbs moisture (can affect properties).	Gears, bearings, automotive parts, industrial components.	Moderate to Expensive
PP (Polypropylene)	Lightweight, chemical-resistant, fatigue-resistant, flexible, low cost.	Food containers, automotive interiors, medical devices.	Cheap
PE (Polyethylene)	Excellent chemical resistance, flexible, tough, moisture-resistant, low cost.	Bottles, plastic bags, storage containers.	Cheap
POM (Polyoxymethylene/Acetal)	High stiffness, low friction, excellent dimensional stability, wear-resistant.	Gears, fasteners, automotive components.	Moderate
PVC (Polyvinyl Chloride)	Flame-resistant, good chemical resistance, rigid or flexible options, low cost.	Pipes, medical tubing, window frames.	Cheap
PMMA (Polymethyl Methacrylate/Acrylic)	Transparent, UV-resistant, weather-resistant, good optical properties.	Light covers, display panels, signage.	Moderate to Expensive
PET (Polyethylene Terephthalate)	Excellent mechanical strength, chemical resistance, recyclable, moisture barrier.	Beverage bottles, food packaging, electrical components.	Cheap to Moderate
TPU (Thermoplastic Polyurethane)	Flexible, abrasion-resistant, impact-resistant, good elasticity.	Footwear, seals, protective casings, industrial components.	Expensive

Focus on Efficient Tool Design

The design of the tool is a critical factor in determining the overall cost of injection molding. A well-designed tool not only ensures high-quality parts but also minimizes waste, reduces cycle times, and optimizes production efficiency, all of which contribute to cost savings.

To start, consider simplifying the tool design. Avoid overly complex features like multiple cavities or complex gating systems unless they are absolutely necessary. A simpler tool design reduces upfront tooling costs and shortens production lead times. Additionally, optimizing gate placement and runner systems ensures a more even material flow, reducing the risk of defects and minimizing material waste.

Cooling systems within the tool also play a vital role in cost efficiency. Properly designed cooling channels can significantly shorten cycle times by allowing parts to cool and solidify more quickly, boosting production throughput. Investing in the proper tool materials like hardened steel can also improve durability, reducing long-term maintenance and extending the tool lifespan.

Collaborating closely with your manufacturing partner is key to achieving an efficient mold design. Their expertise can help identify potential cost-saving opportunities while ensuring the mold meets all performance and quality requirements. By prioritizing efficiency in mold design, manufacturers can lower production costs and improve overall profitability.

Consider Alternative Surface Finishes

Surface finishes play an essential role in the appearance, functionality, and cost of plastic injection molded parts. While high-quality finishes can enhance aesthetics or meet specific functional requirements, they often increase tool complexity and production costs. Exploring alternative surface finishes can help strike a balance between achieving the desired look and controlling expenses.

Highly polished or textured surfaces often require additional machining and precision work during mold creation, driving up tooling costs. If your part’s application doesn’t demand a premium finish, such as internal components or industrial parts, consider opting for simpler or more standard surface treatments. These alternatives can significantly reduce mold costs while still maintaining acceptable functionality and appearance.

In some cases, secondary processes, like painting or coating, might offer a cost-effective way to achieve specific visual or tactile effects without requiring intricate mold work. Additionally, certain applications may benefit from no finish at all, especially if the part’s function is unaffected by surface texture.

By carefully assessing the end-use requirements of your part and consulting with your manufacturer, you can identify cost-saving opportunities with surface finishes that align with both your budget and project goals.

Conclusion - Lower Plastic Injection Molding Costs

Reducing the cost of plastic injection parts doesn’t always require compromising on quality or functionality. By carrying out strategies such as optimizing part and tool designs, refining material selection, and considering alternative surface finishes, manufacturers can achieve savings while maintaining high standards.

Collaboration with experienced manufacturing partners, such as EPower Corp, is key to identifying opportunities for efficiency and cost reduction at every stage of the process. With careful planning and a focus on smart decision-making, businesses can maximize the value of their injection molding projects, improve profitability, and gain a competitive edge in their industry.

If you’re looking for expert guidance on reducing plastic injection costs, reach out to us, we’re here to help you bring your ideas to life efficiently and affordably.