Key Considerations for Choosing the Right Polymer in Injection Molding

Injection molding manufacturing is a manufacturing process primarily used in mass production. The molten polymer is precisely injected into molds, and the product comes to life after the polymer cools down. 

Injection molding is used to mass-produce parts due to its high levels of accuracy, affordability, and short lead times. From engineering to automotive parts, even everyday consumer products are created using injection moulding services.

What to check in selecting the polymers?

Before diving into the vast world of materials, it’s essential to define the objectives of your injection-molded components clearly. Understanding what you want to achieve with your product guides your material selection.

Consider factors such as your product’s intended function, its environment, and the desired lifespan. If your product frequently experiences extreme temperatures, select a material with high thermal resistance. If your product needs to be lightweight yet durable, consider high-strength plastics. By defining your objectives, injection molding becomes easier, which fulfils your current needs and anticipates future demands.

6 Tips for selecting the right polymer in injection molding

There are more than 80k different polymers and finishes to select from. In selecting polymers, there are many options to consider, such as budget, design, product application, and chemical properties.

1. Product functionality

A product’s functionality must meet the user’s goals and needs, and the best material for the product must be selected. This functionality involves a detailed analysis of how to use your product and the various conditions it will experience. For instance, a consumer product such as a kitchen utensil endures high temperatures and requires a food-safe, heat-resistant plastic. 

Polymer selection for injection molding, ensuring the material complies with all necessary standards for specific fields, such as medical or aerospace. This careful alignment of product functionality and material properties optimises your final product’s performance, safety, and longevity, leading to a successful injection molding project.

2. Material costs

Material costs vary significantly, from inexpensive, commonly used plastics to higher-cost, specialised resins. Understanding that the cheapest material may not necessarily be the most cost-effective in the long run is essential.

A material may be inexpensive to purchase, but if it doesn’t align with your product’s functionality and durability requirements, it could lead to product failure and increased costs. Conversely, a more expensive material might provide superior performance and longevity, offsetting its initial higher cost over the product’s lifespan. 

Plastic injection molding manufacturers consider both initial cost and long-term value when assessing material costs to offer the best product at an affordable price.

3. Product design

A product’s structural integrity and functionality are crucial; you shouldn’t undermine aesthetics. In the world of product design, the look and feel of a product play a vital role in its market appeal. The choice of material significantly influences the product’s aesthetic elements, including colour, texture, and gloss, especially in consumer products and automobiles.

Engineering plastics for custom molding of the material’s aesthetic potential enhances the product’s appeal and helps you choose the best material for plastic injection molding.

4. Environmental impact 

In the era of increasing environmental concerns, you shouldn’t overlook the ecological impact of injection molding material selection. Determining the sustainability of a material involves considering its life cycle from extraction, production, and usage to eventual disposal. Choosing the sustainability path or recycling the product for packaging purposes. Such initiatives create a bigger environmental impact. 

    5.  Product properties

Material flexibility is another crucial factor to consider. There is a common misconception that all soft materials are flexible and that all hard materials are stiff. However, there is a difference between softness and flexibility when it comes to materials used in mass production. A material’s flexibility refers to its ability to bend under stress without breaking easily.

    6. Weight 

Weight is the final consideration when choosing the best polymers for injection moulding. This is because the polymer's density determines not only the weight of the moulded part but also the end product. Often, moulded parts are used in lightweight consumer products, and weight can be a determining factor.

Each material has unique properties, including strength, flexibility, resistance to heat and chemicals, and cost.

Common mistakes in material selection

Avoiding the most common industry mistakes is essential to making the best choice when selecting the right polymer.

1. Cost

One of the most common mistakes in material selection is neglecting to consider the full range of a material’s properties and focusing solely on cost. This neglect leads some manufacturers to select a material that is ill-suited to the product’s functionality or durability requirements.

2. Materials

Another error is failing to consider the material’s impact on manufacturing. Materials behave differently during industrial plastic molding, with varying melt flow rates, cooling times, and pressure needs. Neglecting these aspects leads to inefficiencies in production or unexpected costs.

Conclusion

In conclusion, selecting the right material for your injection molding mold components requires a thorough understanding of its properties. Avoid common mistakes and examine how the chosen material may affect the final product. Every decision made in the material selection process has a profound impact.

At Dalal Plastics, we specialise in custom mould manufacturing. We have expert knowledge in choosing the right polymer for your project. Let's connect today to discuss reliable, high-quality industrial plastic molding solutions that deliver results.

FAQ

How to choose material for injection molding?

Common thermoplastics include Polypropylene (PP), Acrylonitrile Butadiene Styrene (ABS), Polyethene (PE), and Nylon.

What are the three categories of polymers?

There are 3 principal classes of polymers: thermoplastics, thermosets, and elastomers.

What type of polymer does not melt?

When heated, thermosetting polymers do not melt.