Everything you need to know about EVA Injection molding

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EVA injection molding is a process widely used to create products out of plastic. The process involves pouring molten plastic into an injection mold, then allowing it to cool and harden. The process can be used to make a wide variety of products, including toys, medical devices,, and auto parts.

To produce high-quality products using the EVA injection molding process, it is important to understand the key factors that affect the results. This blog post will discuss several of these factors and provide tips for achieving the best results.

1. What is the EVA injection molding process?

EVA injection molding is an advanced plastic molding technique used to manufacture products of different shapes asizes. EVA, short for ethylene-vinyl acetate, is a polyethylene foam-based thermoplastic material that is injection molded from EVA to give spectacular results.

EVA injection molding takes place in a specialized injection molding machine capable of precisely mixing EVA with other thermoplastic materials and inserting it into a single mold at precise temperatures.

This method has many advantages over traditional metal stamping or other processes, as EVA can be easily shaped and produces smooth surfaces, as well as sharp details and intricate features.

Due to the versatility and excellent effect of EVA injection molding products, it has been widely used in various industries. EVA is also cost-effective and fast to produce compared to other common plastic products currently on the market.

Due to the unique combination of advantages of EVA injection molding, it has become an increasingly popular choice for manufacturing some products in several industries. Therefore, EVA injection molding is undoubtedly one of the most reliable methods available today to manufacture strong plastic parts quickly and cost-effectively.


The performance of EVA:

EVA is an amorphous plastic, non-toxic, with a specific gravity of 0.95g/cm3 (lighter than water). Its products have poor surface gloss, good elasticity, softness and lightweight, low mechanical strength, good fluidity, and are easy to process and shape. The shrinkage rate is relatively large (2%), and EVA can be used as a carrier for color masterbatch.

Process characteristics of EVA:

EVA injection molding processing temperature is low (160-200°C), the range is wide, and its mold temperature is low (20-45°C), and the material should be dried before processing (drying temperature 65°C).

When EVA is processed, the mold temperature and material temperature should not be too high, otherwise, the surface will be rough (unsmooth). EVA products are easy to stick to the front injection mold cavity, and the cold material hole in the main channel of the nozzle should be made into a buckle type.

It is easy to decompose when the temperature exceeds 250°C. EVA should adopt the process conditions of “low temperature, medium pressure, and medium speed” to process products.

2. What are the advantages of EVA injection molding process?

The EVA injection molding process offers several advantages over other processes when it comes to producing polyethylene parts. First, the cycle time is much faster than other methods.

This speed allows producers to manufacture products quickly and efficiently without sacrificing quality. Additionally, the technology produces parts that are consistent in size and shape, requiring little additional machining or trimming; this means fewer labor costs associated with product completion.

In addition, due to the lower pressure required for the EVA injection molding process, relatively less energy is required compared to other processes, resulting in significant cost savings over time.

Finally, due to the simplicity and low maintenance of the process, it can be easily and reliably operated with minimal technical skills or specialized training. These advantages, therefore, make the EVA injection molding process an attractive option for producers looking for high-quality results at a lower cost in today’s competitive market.

3. Application of EVA injection molding process

EVA injection molding is a versatile process with a variety of applications. EVA injection molding is used in many industries, including the mass production of sporting goods and toys. In the sports industry, EVA injection molding is used to make everything from shoes to helmets.

This process offers a cost-effective solution for manufacturing highly complex parts with complex geometries and sharp angles. Additionally, this type of injection moulding provides excellent part detail and excellent alignment accuracy. In addition, it has excellent impact resistance, which makes it suitable for use in products where durability and robustness are important factors.

EVA injection molding is also often used to make safety and protective equipment due to its excellent strength-to-weight ratio. Finally, this process can be combined with other manufacturing techniques, such as 3D printing for greater part complexity, or 3D printing foam for cushioning materials that require greater shock absorption.

In addition to these common uses, EVA injection molding is ideal for the production of countless other products, enabling companies to take advantage of its many benefits in their own specific applications.

4. How to choose the right EVA grade for your application

When selecting an elastomeric material, such as vinyl acetate (EVA), selecting the proper hardness grade is critical to ensuring successful performance. How do I determine which hardness grade is right for an application?

The needs of each specific application determine the optimum rubber compound type and thickness; however, certain criteria should be considered when selecting the appropriate EVA grade. Rubber needs to resist aging and degradation, so it is important to choose a product that is oxidatively and thermally stable.

In addition, resistance to oils and chemicals must comply with current standards and any additional requirements of the end-use environment. Coil and sheet products made from ethyl acetate have a Shore durometer category of A to D and a rating of zero to seventy (0-70).

Knowing how your product will be used will allow you to select the hardness grade that matches its performance and longevity requirements. With this information, you can choose an EVA grade that meets or exceeds your needs for performance and durability. Making the right decision can ensure your application is cost-effective, durable, and of long-life quality in its specific environment and usage conditions.

5. Factors to consider when designing EVA molded parts

Designing EVA injection moldings can be a complex and challenging process. Several factors must be considered to ensure the successful creation of a final product of the required quality. The 5 main factors to consider when designing these parts are dimensional tolerances, wall thickness, material selection, part geometry and surface treatment.

The constraints imposed by each factor must be kept in mind when making decisions on design parameters. For example, if a product requires tighter tolerances, thicker walls may be required to prevent exceeding allowed tolerances.

Likewise, the shape of a part may need to be altered to minimize the amount of material required to create stress or instability during fabrication. Ultimately, thorough planning during the part design phase can lead to better-performing and more cost-effective end products. As long as all 5 design factors of EVA molded parts are carefully considered, it is possible to create high-quality products that meet customer needs.

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