Factors That Aids Selecting Injection Molding Materials

Plastic injection molding is a large-scale manufacturing process that involves making plastic parts of various dimensions. In the operation steps, choosing the right injection molding materials is one important part of the process. Choosing the right plastics for injection molding is important because it affects operations and product performance.  

injection molding machine

Currently, there are many injection molding plastics in the market. Therefore, choosing the right one can be a very hard process. To choose the right injection molding plastic materials, you must consider many properties. For example, the top properties considered are strength, flexibility, weight, and cost.

This article will introduce the common injection molding materials you can use in your work. It will also introduce the factors used in selecting injection molding plastic types. Read on!

What Are the Common Materials for Plastic Injection Molding?

Do not be surprised that common injection molding materials come before factors that can aid you in their selection. This is because it removes the stress of knowing the best material to use. The market is full of these materials, and getting a summary can help you quickly decide on a suitable one. Below are eight common plastic injection molding materials.

1. Acrylonitrile Butadiene Styrene (ABS)

abs material for injection molding

Acrylonitrile Butadiene Styrene is a very popular injection molding material used majorly in making commercial products.

Properties and Applications

  • It is very rigid. with impact resistance.
  • ABS is dimensionally stable and easy to form after cooling.
  • There is a wide support temperature range.
  • ABS has resistance to chemicals such as acids and bases.

Acrylonitrile Butadiene Styrene is used in making toys, electronics, tools, and home repair equipment.

Price: 5 stars

2. Nylon

nylon injection molding material

Nylon, also known chemically as Polyamide, is one of the strong injection molding materials used in different industrial capabilities.

Properties and Applications

  • Nylon has low friction.
  • Nylon is very versatile evident in its compatibility with other materials.
  • It has a high melting temperature.
  • Nylon is scratch and chemical resistant.

Nylon is one of the favorite plastics for injection molding used in making strong mechanical parts. This is due to its toughness. For example, the automotive sector uses it in making bushings, gears, and bearings. Its scratch-resistance and elastic properties allow it to be useful in the clothing industry. The ability to use Nylon with other materials also improves its applications in different industrial settings.

Price: 5 stars

3. Polycarbonate (PC)

polycarbonate injection molding material

Polycarbonate is one of the common plastics for injection molding used commercially. It is similar to Acrylic, with both materials exhibiting much likeness in properties. However, it is stronger and contains Bisphenol-A.

Properties and Applications

  • Polycarbonate is a highly rigid injection molding material.
  • It is UV ray resistant.
  • Polycarbonate is transparent.
  • The material is chemical resistant.

Polycarbonate is applicable in situations that require strength that Acrylic cannot provide. However, unlike Acrylic, it is not useful in making food-related product since it contains Bisphenol-A. Polycarbonate is also applicable in making eyewear material, windows, compact disks, and led pipes.

Price: 4 stars

4. Acrylic (PMMA)

PMMA raw material resins

Acrylic is one of the most popular injection molding materials used in different industrial sectors. Also known as Plexiglas, Acrylic is an alternative to glass because of the properties listed below.

Properties and Applications

  • It is odorless and tasteless.
  • Acrylic has a very high tensile strength, evident in its rigidity and surface hardness.
  • It is weather and scratch-resistant, which makes it usable despite moisture and UV ray.
  • Acrylic is one of the most transparent plastics used in injection molding
  • Acrylic is chemical resistant. Therefore, solutions of weak acid and alkali
  • It can be colored.

Acrylic is a common plastic used in making electronics parts. For example, plastic materials seen in the refrigerator are mostly Acrylic. Unlike other injection molding materials, Acrylic does not contain Bisphenol-A. This makes it ideal for making material used in storing foods. The automotive industry also uses it in making windows and lighting components.

Price: 5 stars

5. Polystyrene (PS)

PS raw material resins

Polystyrene is one of the injection molding materials widely needed in the plastic and foam industry.

Properties and Applications

  • Polystyrene is transparent.
  • It is very stable and rigid.
  • There is an absence of Bisphenol-A.
  • It is flexible.

Polystyrene is used in making see-through plastics. In the food packaging niche, it is employed in making food containers and bottles. It is also useful in making foam insulation and laminating floors. 

Price: 3 stars

6. Polyethylene (PE)

PE raw material resins

Polyethylene is one of the common hard injection molding plastics. It is a common plastic ideal for products that need glass material without the shattering effect.

Properties and Applications

  • Polyethylene is lightweight.
  • The material is strong and durable.
  • PP has a huge chemical resistance.
  • Polyethylene can act as an electrical insulator.

Polyethylene is one of the commercially-used plastic injection molding materials used in making children’s toys, medicine containers, plastic bags, and trashcans.

Price: 4 stars

7. Polypropylene (PP)

polypropylene injection molding material

Polypropylene is one of the glossy and elastic injection molding materials with a wide range of industrial application.

Properties and Applications

  • It is strong and durable.
  • Polypropylene has elastic properties.
  • PP has insulating properties.
  • Polypropylene is resistant to chemicals such as acids and bases.

Due to its properties, Polypropylene is used in making kitchenware, storage containers, and safe plates. It is also used commercially in making toys, luggage containers and some car parts.

Price: 4 stars

8. Polyoxymethylene (POM)

polyoxymethylene injection molding material

Polyoxymethylene is one of the plastics for injection molding capable of replacing metal in making some products. As expected, it has unique properties responsible for its applications. 

Properties and Applications

  • Polyoxymethylene is a tough, rigid and strong material.
  • It has a glossy surface.
  • Polyoxymethylene is resistant to chemical solvents such as alcohols, gasoline, detergents and oils. However, it is not resistant to acids.

Polyoxymethylene has many industrial applications because of its glossy surface and resistance to many chemical solvents. It is used in making strong mechanical parts employed in automotive, household appliances and electronic products.

Price: 4 stars

At Rapid Direct, you can get the above injection molding materials. That is not all. We also offer other materials unique to your process.

How to Choose Material for Your Injection Molding Project

There are thousands of injection molding materials available to choose from for your work. While this ensures you are exposed to many materials, it makes an outright selection of a material a problem. However, do not worry. There is a way to choose the material for your project.

This is by understanding what you want the end product to be like and where it will be employed. Armed with such knowledge, you can choose a material with the right properties to give you what you want. Below are material properties you should know that will aid in your selection.

· Material Hardness

Material hardness is a property that you must consider when choosing an injection molding material. Every material is ranked based on Shore hardness developed by Albert Shore. According to Albert’s durometer scale, plastics are grouped based into type A and type D.

Type A is for soft plastic, while Type D is for hard plastics. Each scale also runs from zero to 100. Material hardness is important because it indicates the material’s compatibility with the environment and its abrasion resistance.

· Material Flexibility

This is a misconception between material flexibility and hardness. Most people think that soft materials are flexible, and hard materials should be stiff. However, this is not true. Plastic materials can be soft and flexible. They can also be hard and flexible.

Stiffness is the ability to resist bending stress. For example, let’s compare ABS and Nylon materials. ABS is a harder material, yet it is more flexible than Nylon.

· Material Weight

Material weight is a property that determines the end product’s heaviness and lightness. For example, if you need a light material, polyethylene is ideal. However, if you need a heavy material, Nylon is one hard injection molding material to try.

· Chemical Resistance

Chemical resistance is a property you should check if you need a product that can function under different environmental conditions. Such materials must be resistant to conditions such as moisture, acids, and alkalis. The top materials that have this property are Acrylic, polycarbonate, and Nylon.

·  Miscellaneous

Another factor you should consider when choosing a material is the presence of other chemical components. For example, if the plastic contains Bisphenol-A, it is not ideal for food-related purposes. Also, other materials exhibit transparency, coloring, and the ability to combine with other materials.   

· Material Cost

The most important thing to look out for in selecting injection molding materials is their cost. However, while you should consider cost, you shouldn’t make it more important than other properties. Of the common injection molding materials discussed above, Nylon is costly, while polyethylene is less costly.

Rapid Direct Turnkey Injection Molding Services

Do you worry about the right injection molding plastic types to use for your plastic products? Or you are not familiar with the process, and you want the best. With us at Rapid Direct, you have the chance of using our foolproof injection molding manufacturing process.

With us, you can enjoy an almost instant quotation. Within 12 hours, you can get a quotation, DfM analysis, and Mold Flow analysis. All these design feedbacks are FREE.

In terms of manufacturing, Rapid Direct has inbuilt in-time progress feedback and coordination. Therefore, there is an assurance of high quality and on-time delivery of the requested products for you.


Selecting the right injection molding materials is not an easy process. It comes with an understanding of many factors. This article introduces the common injection molding materials and factors that can help you select the right plastic. After going through it, there is no doubt you will get to know two things. One is the common plastics for injection molding. The other is how to select the right one. We hope you learned a new thing about injection molding.


What Materials Are Used in Injection Molding?

The two major groups of materials used in injection molding are plastics and metals. Of the two, the most common one is the injection molding plastics because they are easier to use.

What Is Injection Molding Used For?

Injection molding is a manufacturing process used in making metallic or plastic materials needed in large masses.

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