How to select the right injection molding materials and control mass production costs
- How to select the right injection molding materials and control mass production costs
- How to make the right material selection for your custom plastic product project?
- Key points to analyze when selecting suitable raw materials for injection molding
- Common Injection Molding Materials
- Before choosing injection molding: Not suitable for producing low-volume products
- Injection Molding Technology Selection
- Make the right choice for your goals
- cost analysis of injection molding production of plastic parts
- Thermoforming is a lower-cost alternative to injection molding.
- Elimold can help you balance the precision and cost of custom injection molded parts.
- in conclusion
- FAQ
Plastics play an extremely important role in our lives. And most of these plastic products likely benefit from the successful injection molding process. Injection molding is a versatile process that can meet a wide variety of product needs. However, this flexibility alone is not enough to guarantee its success. Many steps need to be completed before the part is removed from the mold and delivered.
In this blog post, we will discuss some of the steps that need to be taken before mass-producing custom plastic products , with a focus on the most important step : material selection.
How to make the right material selection for your custom plastic product project?
Plastic material selection is one of the most critical stages in injection molding process design. Correct material selection not only determines the final performance of the product but also affects process parameters, production costs, and the durability of the finished product. In the modern plastics processing industry, there are dozens of different material groups, each offering a unique combination of mechanical, thermal, and chemical properties.
However, selecting materials that align with product performance design and are suitable for injection molding for customized product projects is a systematic process. This requires analyzing application needs to match appropriate plastic materials, ensuring all functional, economic, and technical requirements are met. This process necessitates understanding the inherent properties of the material, the characteristics of the injection molding process, and the intended use of the finished product.
Choosing the right plastic material requires considering several factors: mechanical load, operating temperature range, chemical exposure, aesthetic requirements, industry standards, and cost-effectiveness. Today, engineering plastics offer a wide range of options, from inexpensive bulk materials to high-end specialty polymers with superior performance.
Key points to analyze when selecting suitable raw materials for injection molding
Every material is unique, with vastly different properties. Therefore, the choice of material affects the quality and performance of the final product, determining whether it will sell well or whether the company will have to painstakingly recall it from the market. Thus, when choosing materials for injection molding for your custom plastic product project, you need to analyze several factors.
| Material supply situation | Raw material shortages can severely disrupt your production processes and impact your profits. No business wants to be caught in a supply chain crisis due to raw material shortages or supply issues. Therefore, ensuring material supply is crucial. |
| Component Application | Different plastic parts need to meet unique performance design requirements for their respective applications. Therefore, you may need to select a raw material that matches the performance design of your product. |
| cost | It’s best to fully consider costs before initial product testing. Ensure raw material prices are reasonable so that the company can still profit from the final product’s selling price after deducting all other production costs. |
| performance | You must consider the performance requirements of the product, understand all the conditions your project will face once it is in use, and then try to find a plastic component that can withstand those conditions without performance degradation. |
| Aesthetically pleasing | The appearance of a component is also important and will be affected by the materials you choose. Therefore, be sure to consider its appearance before finalizing the materials. |
| Environmental impact | Choose environmentally friendly plastic parts to reduce their ecological footprint and leverage this as a marketing and sales advantage. For applications with lower tolerance for high ecological footprints, consider using recyclable or biodegradable plastics. |
| Compliance | Choose raw materials that comply with product sales regulations and standards. Not all types of plastics meet stringent guidelines, and if the wrong materials are used to manufacture parts, you may need to recall those parts. |
| Easy to process | Choose plastics that are easy to process whenever possible. Even if easy-to-process plastics are slightly more expensive, the initial cost can be offset by saving production resources and shortening the production cycle. |
Common Injection Molding Materials
The injection molding materials market offers dozens of different thermoplastic polymers. In industrial practice, the most commonly used are 10-12 major families of plastics, which can be divided into three categories: standard, engineering, and high-performance. Each category differs significantly in mechanical properties, thermal properties, and price.
Standard plastics (PP, PE, PS)
Standard plastics account for about half of the global consumption of injection-molded thermoplastics, which is 70%. They are characterized by good processability, low cost, and a wide range of applications.
Engineering plastics (ABS, PC, PA, POM)
Engineering plastics offer significantly superior mechanical and thermal properties compared to standard plastics. They are suitable for applications requiring high strength, dimensional stability, and high-temperature resistance.
High-performance plastics (PEEK, PPS)
High-performance plastics are an elite group of polymers with superior thermal and mechanical properties. They are used in the most demanding industrial applications where standard materials cannot meet the requirements.
Main characteristics of various injection molding materials
| Material | Main features |
| ABS | Tough, high strength, impact and scratch resistant |
| Acrylic | Hardness, weather resistance, and chemical resistance |
| Dellin (acetal, polyacetal) | Durable, high strength, wear-resistant, creep-resistant and non-deformable |
| HDPE (High-density polyethylene) | Lightweight, high strength, and good ductility, suitable for heavy construction. |
| LDPE (Low-density polyethylene) | Soft, lightweight, translucent, stress-resistant |
| Polyamide 6 (Nylon 6) | Tough, abrasion-resistant, and chemical-resistant. Suitable for moving and sliding parts. |
| Polyamide 66 (Nylon 6/6) | Rigid, wear-resistant, and resistant to hydrocarbon compounds, suitable for high-intensity applications. |
| PBT (Polybutylene terephthalate) | Wear-resistant, creep-resistant, and with low moisture absorption. |
| PC (Polycarbonate) | Transparent, durable, and shatter-resistant, suitable for applications requiring both transparency and high strength. |
| PC – ABS | Rigid, heat-resistant, and with high impact strength |
| PC – PBT | Tough and dimensionally stable, suitable for applications requiring corrosion resistance. |
| PEEK | Hardness, rigidity, chemical resistance and fatigue resistance |
| PEI (polyetherimide resin) | It is hard and strong with low moisture absorption. |
| PET (Polyethylene terephthalate) | Rigid, flame-retardant, heat-resistant, and creep-resistant. Suitable for engine components. |
| PLA (polylactic acid) | Low glass transition temperature |
| PPE – PS | Good ductility, impact resistance and high strength |
| PPS (polyphenylene sulfide) | Brittle, UV resistant, and chemical resistant. Suitable for automotive parts. |
| PSU (polysulfone) | Good thermal stability, chemical resistance and high strength |
| PVC (Polyvinyl chloride) | Weather resistance, chemical resistance, corrosion resistance and impact resistance |
| PE (Polyethylene) | It is chemically resistant, waterproof, and has good electrical insulation properties. |
| PP (Polypropylene) | Excellent impact strength, elasticity, and moisture resistance. |
| PS (Polystyrene) | Transparent, hard, and brittle. Suitable for household products. |
| TPE (elastomer) | High strength, tear resistance and abrasion resistance |
| TPV (Thermoplastic EPDM Dynamic Vulcanizing Elastomer) | Durable, lightweight and highly resistant to certain solvents |
Before choosing injection molding: Not suitable for producing low-volume products
To fully appreciate the advantages of injection molding, it is crucial to understand its limitations. These trade-offs make it a specialized tool, not a universal solution.
High initial investment
The main drawback is the huge upfront cost associated with creating the mold. This mold is a complex engineered component that must be machined from high-strength steel, which is both time-consuming and expensive.
Not suitable for small-batch production
Injection molding is economically impractical for prototyping or small-batch production due to the high cost of initial molds. If spread across only a few hundred units, the cost per part becomes prohibitively high. Processes like 3D printing are more suitable for this stage.
Design changes are costly.
Once the steel mold is created, changing the part design becomes difficult and expensive. This often requires reworking the mold or creating a completely new mold, which significantly increases the project’s time and cost.
Injection Molding Technology Selection
Today, plastic parts manufacturers have access to a variety of injection molding technologies. Each technology has its own characteristics and can be selected based on project requirements. For example, gas-assisted injection molding might be necessary when producing hollow plastic parts; thin-wall injection molding is required for parts with high precision requirements. The choice of raw materials also influences mold design, as different materials exhibit different properties when flowing, cooling, and solidifying in the mold. Therefore, once the material is determined, mold development can begin. Injection molds are typically made from aluminum alloys and steel alloys. Some companies offer in-house mold development services, which can help shorten production cycles.
Make the right choice for your goals
Your decision must be based entirely on your anticipated production volume. Ultimately, the profitability of injection molding is a strategic calculation of scale.
| If your primary focus is prototyping or very small batches (less than approximately 1,000 units) | Injection molding is almost certainly unprofitable; consider alternatives such as 3D printing or polyurethane casting. |
| If your primary focus is on early production (1,000 – 10,000 units) | This is a critical area where you must conduct a careful break-even analysis to determine whether the investment is worthwhile. |
| If your primary focus is on large-scale production (10,000+ units) | Injection molding is an industry standard and has become exceptionally profitable, offering the lowest possible unit cost. |
cost analysis of injection molding production of plastic parts
Injection molding has become one of the most sophisticated and widely used manufacturing processes in the world. From plastic parts smaller than a fingernail to car doors, injection molding enables the mass production of high-quality components. The key to this process lies in creating a precise mold, thereby enabling stable, large-scale production. Because industries worldwide rely on injection molding to produce plastic products, cost control is a primary concern for most companies.
However, a thorough analysis of the manufacturing costs of each part is more important for accurately calculating the cost of injection-molded parts. This calculation comprehensively considers material costs, labor costs, and administrative expenses, each of which affects the final unit cost. Below is a basic cost reference for injection molding of plastic parts provided by Elimold.
| standard | Estimated cost range for each part (USD) |
| Cost of injection molding materials (plastics and additives) | 0.10 – 2.00 |
| Injection mold cost | 0.50 – 5.00 |
| Tools and setup costs | 0.20 – 1.00 |
| Equipment costs | 0.15 – 0.75 |
| Labor costs in injection molding | 0.25 – 1.50 |
| Inspection and post-processing costs | 0.10 – 0.50 |
| Packaging and shipping costs | 0.05 – 0.30 |
| Estimated total cost per part | 1.35 – 11.05 |
Thermoforming is a lower-cost alternative to injection molding.
Thermoforming is a basic and simpler process that avoids the high pressure and complexity of injection molding, thus greatly saving on mold costs.
The working principle of thermoforming
In thermoforming, a sheet of plastic is heated until it softens. It is then stretched onto or inside a single-sided mold and cooled to its final shape. Air pressure or vacuum is typically used to draw the plastic sheet tightly onto the mold for better detail.
Mold advantages
Because the process does not involve extreme pressure, the molds do not need to be made of hardened steel. Thermoforming molds are often machined from inexpensive aluminum or even composite materials. This significantly reduces costs and delivery times, making the initial investment only a fraction of the cost required for injection molding.
Unit cost dynamics
Although the initial costs are lower, the unit cost of thermoforming is generally higher than that of injection molding. The cycle time is longer, and the process starts from a single sheet of plastic from which the final part must be trimmed, resulting in more material waste.
Elimold can help you balance the precision and cost of custom injection molded parts.
Achieving the perfect balance between precision and cost in injection molding is one of Elimold’s core competencies. We understand that maintaining high-quality standards while managing costs is crucial for our customers. We focus on delivering precise, high-quality injection-molded parts within budget constraints.
We achieve this balance by utilizing advanced technology and efficient production methods. Our team of experts uses state-of-the-art injection molding machines and employs rigorous quality control measures. This ensures that every part we produce meets stringent precision requirements, minimizing costly rework or material waste.
In addition, Elimold’s injection molding services encompass product market strategy, continuous design optimization, and cost analysis. By regularly evaluating our production methods and material usage, we can identify areas for cost reduction without compromising accuracy. Our commitment to innovation and efficiency enables us to provide our customers with cost-effective injection molding solutions without sacrificing the quality or accuracy of the final product.
in conclusion
Plastic injection molding is widely considered one of the most flexible and cost-effective methods for mass-producing plastic parts. However, proper material selection and pre-production processes are crucial to its success. Before determining raw materials, consider the intended use of the parts. Additionally , don’t forget first-article inspection before mass production; once approved and mass production begins, continue inspecting different batches of products. In short, a comprehensive understanding of injection molding costs is essential for efficient and economical manufacturing. Plastic product manufacturers can improve production efficiency and ensure high-quality output within budget requirements by carefully analyzing each cost element and implementing sensible cost-saving strategies.
FAQ
Is injection molding expensive?
There’s no simple, straightforward answer to this. While injection molding can be expensive, it’s not always the case. Factors such as production volume and the complexity of the parts being manufactured play a crucial role in determining the final cost of injection molding. When producing products in large quantities, injection molding proves to be an inexpensive process.
How much does injection molding cost?
It can range from a few thousand to hundreds of thousands of dollars. Consider the wide range of applications for injection molding. The products made with it are almost limitless. In this context, it’s difficult to specify an exact figure in terms of injection molding costs.
What are the main factors affecting injection molding costs?
The main factors include material costs, mold design and production costs, and operating expenses.
How can injection mold costs be reduced?
Choose simpler mold designs, use cost-effective materials, and maximize the lifespan of the mold.
What factors affect the cost of injection molding materials?
The type of material, its availability, and specific properties such as durability and heat resistance affect the cost of injection molding materials.
Does the complexity of the part design affect injection molding costs?
Yes, more complex designs typically require more complex molds, thus increasing costs.
Is it possible to accurately estimate injection molding costs?
Considering all variables, including production volume and part complexity, an accurate estimate can be made.
What strategies can be used to save on injection molding costs?
Implement design optimization, select economical materials, and streamline the manufacturing process.
Is injection molding environmentally friendly?
Yes, injection molding can not only prove to be a cost-effective solution for manufacturing large quantities of plastic products, but it can also be environmentally friendly, just like 3D printing.