When you’re developing a plastic product, it’s easy to focus on the design, dimensions and appearance. But there’s another decision that can make or break the finished product: choosing the right plastic material.

The plastic you select affects almost everything, from how strong your product will be to how well it handles heat, moisture, chemicals and everyday wear. It also influences manufacturing costs, production efficiency and how long the finished component will last.

And with so many materials available, where do you start?

Should you choose ABS or Polycarbonate? Is Nylon better for moving parts? Could Polypropylene provide the performance you need without stretching your budget?

These are common questions for Australian businesses developing injection moulded products.

At AC Plastics (ACP), understanding the relationship between material selection, product design and manufacturing is an important part of achieving reliable injection moulding results.

In this guide, we’ll explore the most commonly used Plastic injection moulding materials, compare their strengths and limitations, and help you understand which plastic might be right for your next project.

Why Does Plastic Material Selection Matter?

Not all plastics behave the same way.

Some are incredibly tough but can be sensitive to certain chemicals. Others offer excellent flexibility but aren’t suitable for applications involving high temperatures. A material that works beautifully for an electronic housing might be completely unsuitable for an industrial gear.

Choosing the wrong plastic can lead to problems such as cracking, warping, premature wear or components that don’t fit together properly.

It can also increase production costs.

For example, selecting an expensive engineering-grade plastic when a standard thermoplastic would do the job means paying more than necessary. On the other hand, choosing a cheaper material that cannot withstand the working environment may lead to product failures and costly replacements.

The goal isn’t to choose the strongest or most expensive plastic.

It’s to find the material that delivers the right performance at a sensible cost.

That’s why understanding the properties of different engineering plastics in Australia is such an important starting point.

1. ABS Plastic: A Reliable All-Rounder

Acrylonitrile Butadiene Styrene, better known as ABS, is one of the most widely used materials in plastic injection moulding.

There’s a good reason for its popularity. ABS offers a practical balance of toughness, rigidity, appearance and affordability.

If you’ve handled a computer keyboard, appliance casing or automotive interior component, you’ve probably encountered ABS.

What makes ABS a good choice?

ABS is particularly useful for products that need to look good while standing up to everyday handling.

Its main advantages include:

• Good impact resistance and mechanical strength
• Smooth surface finish suitable for painting and decorative treatments
• Good dimensional stability
• Relatively straightforward injection moulding
• Competitive cost compared with many higher-performance engineering plastics

ABS is commonly used for electronic enclosures, appliance housings, automotive interior trim, consumer products and protective covers.

Where does ABS fall short?

Although ABS is tough, it isn’t ideal for every environment.

Standard ABS grades have limited resistance to prolonged UV exposure, which can cause discolouration and deterioration outdoors. They also have lower heat resistance than materials such as Polycarbonate and may be affected by certain solvents.

Best suited for: Indoor products, consumer electronics, appliance components and applications requiring a quality surface finish.

2. Polycarbonate (PC): Built for Tougher Applications

When impact resistance is a major concern, Polycarbonate often enters the conversation.

Polycarbonate is a high-performance engineering thermoplastic known for its exceptional toughness, useful heat resistance and ability to be manufactured in transparent grades.

It’s commonly considered for applications where components need to withstand knocks, impacts or demanding operating conditions.

Why choose Polycarbonate?

One of Polycarbonate’s biggest advantages is its ability to absorb significant impact without breaking.

It also offers:

• Excellent impact resistance
• Higher heat resistance than standard ABS
• Good dimensional stability
• Optical transparency in suitable grades
• Strong performance in demanding mechanical applications

Typical applications include protective guards, transparent machine covers, lighting components, electrical housings and durable equipment enclosures.

What should you consider?

Polycarbonate generally costs more than ABS and requires careful processing, including appropriate material drying.

It can also be susceptible to scratching and stress cracking when exposed to certain chemicals.

For outdoor applications, UV-stabilised grades or protective treatments may be necessary.

Best suited for: High-impact components, transparent covers, protective equipment and applications requiring greater heat resistance.

3. ABS vs Polycarbonate: Which Is Better?

One of the most common material selection questions is ABS vs Polycarbonate.

Both are widely used in injection moulding, but they offer different benefits.

Here’s a straightforward comparison.

Feature	ABS	Polycarbonate (PC)
Impact resistance	Good	Excellent
Heat resistance	Moderate	Higher
Surface finish	Excellent	Very good
Transparency	Generally opaque	Clear grades available
Material cost	Generally lower	Generally higher
Processing	Relatively straightforward	More demanding
Common uses	Housings, covers, trims	Guards, lenses, tough enclosures

So, which should you choose?

If you’re manufacturing an attractive, durable housing for an indoor electronic product, ABS may offer everything you need at a lower cost.

However, if you’re producing a protective cover exposed to repeated impacts or higher temperatures, Polycarbonate could be the better investment.

There’s also a middle ground.

PC/ABS blends combine useful characteristics of both materials, offering a balance of impact resistance, heat performance and processability.

These blends are often considered for automotive and electronic applications.

Ultimately, the right choice depends on how your finished product will be used, not simply which material appears stronger on paper.

4. Nylon (Polyamide): Strength for Moving and Mechanical Parts

Nylon, also known as Polyamide (PA), is a popular engineering plastic for components that need to handle mechanical loads, friction and repeated movement.

Unlike plastics chosen mainly for appearance, Nylon is frequently selected for its functional performance.

It’s particularly useful for industrial and mechanical components.

Key benefits of Nylon

Nylon offers a combination of strength, toughness and wear resistance.

Its advantages include:

• Good mechanical strength and stiffness
• Excellent wear resistance in suitable applications
• Good fatigue performance
• Resistance to many oils and greases
• Useful performance at elevated temperatures, depending on the grade

Common applications include gears, bearings, bushings, brackets, clips, automotive components and industrial machine parts.

Nylon 6 and Nylon 66 are two widely used grades, each with different processing and performance characteristics.

Glass-fibre-reinforced Nylon can provide additional stiffness and strength where required.

What are the limitations?

Nylon absorbs moisture from its surroundings.

This can affect its dimensions, stiffness and mechanical properties, making careful material selection important for precision components.

It also requires proper drying before injection moulding.

Best suited for: Gears, mechanical components, automotive parts and applications involving friction or repeated loading.

5. Polypropylene (PP): Lightweight, Flexible and Cost-Effective

Not every injection moulded product needs a premium engineering plastic.

Sometimes, a lightweight, affordable material with excellent chemical resistance is exactly what’s required.

That’s where Polypropylene comes in.

Polypropylene, or PP, is widely used across packaging, consumer goods, automotive components and industrial applications.

Why is Polypropylene so popular?

PP offers several practical advantages:

• Low material density
• Good resistance to many chemicals
• Excellent moisture resistance
• Good flexibility and fatigue resistance
• Competitive material cost
• Suitability for high-volume production

One of its standout characteristics is its ability to form living hinges.

These are thin, flexible sections moulded into a component that can bend repeatedly without requiring a separate hinge mechanism.

Think of a flip-top container lid.

With the right design and material grade, Polypropylene can handle repeated opening and closing extremely well.

When might PP not be suitable?

Polypropylene is generally less rigid than materials such as ABS, Polycarbonate or reinforced Nylon.

It can also experience greater mould shrinkage, which needs to be considered during product and tooling design.

Standard grades may require UV stabilisation for prolonged outdoor use.

Best suited for: Containers, hinged lids, packaging components, automotive parts and lightweight chemical-resistant products.

6. Other Engineering Plastics Worth Considering

ABS, Nylon, Polycarbonate and Polypropylene cover a wide range of applications, but they’re far from the only options.

Depending on your product’s requirements, other engineering plastics may deliver better results.

Acetal (POM)

Acetal is known for its low friction, wear resistance and good dimensional stability.

It’s commonly used for precision gears, sliding components, clips and mechanical assemblies.

For components requiring consistent movement and accurate dimensions, POM can be an excellent candidate.

Polybutylene Terephthalate (PBT)

PBT is an engineering thermoplastic valued for its electrical insulating properties, dimensional stability and resistance to many chemicals.

It’s frequently used in electrical connectors, automotive components and technical housings.

Polyethylene (PE)

Polyethylene offers good chemical resistance, toughness and moisture resistance.

Different grades, including HDPE, are used for containers, caps, fittings and various industrial products.

PEEK and PPS

For highly demanding applications involving elevated temperatures, chemicals or significant mechanical stresses, specialised materials such as PEEK and PPS may be considered.

These materials generally cost considerably more than standard thermoplastics, so their use should be justified by the operating requirements.

7. How to Choose the Right Injection Moulding Material

With so many options, how do you narrow down your choices?

Rather than starting with a particular plastic, start with the job your product needs to perform.

Here are six questions worth asking before committing to a material.

1. How much strength does the product need?

Will the component carry weight, absorb impacts or experience repeated movement?

A decorative cover has very different mechanical requirements from an industrial gear or load-bearing bracket.

2. Will it be exposed to heat?

Consider the temperatures your product will experience during normal operation, storage and transportation.

A component installed near a motor may require a different material from one used in a climate-controlled office.

3. Will chemicals or moisture be present?

Cleaning agents, oils, fuels and moisture can affect plastics differently.

Polypropylene may be suitable for many chemical-resistant applications, while Nylon or specialised engineering polymers may be preferable for certain mechanical environments.

4. Does appearance matter?

If your product needs a smooth, attractive finish, ABS may be a strong starting point.

If transparency is essential, Polycarbonate or acrylic could be worth exploring.

5. What is your production budget?

Material price is only part of the equation.

Processing temperatures, cycle times, mould design, production volume and potential rejection rates all contribute to the final cost per component.

A slightly more expensive material may sometimes deliver better value through improved performance or manufacturing reliability.

6. Are there industry-specific requirements?

Products intended for food contact, electrical applications, healthcare or other regulated uses may need materials with specific certifications or documented compliance.

It’s important to check the exact material grade rather than assuming an entire plastic family meets those requirements.

8. Why Material Selection and Mould Design Go Hand in Hand

Here’s something that can easily be overlooked: choosing the right plastic isn’t separate from designing the mould.

Different plastics flow, cool and shrink differently during injection moulding.

A component designed around ABS may require adjustments if the material changes to Polypropylene or glass-filled Nylon.

Wall thickness, gate placement, cooling arrangements, draft angles and dimensional tolerances all influence the finished result.

That’s why it’s worth reviewing material choices early in product development, ideally before committing to production tooling.

Making the right decision at this stage can help reduce unnecessary tooling modifications, manufacturing defects and production delays.

For Australian manufacturers, this is especially important when balancing product quality, production efficiency and long-term costs.

9. Choosing Engineering Plastics in Australia: Why Local Manufacturing Knowledge Matters

Selecting engineering plastics in Australia involves more than comparing material datasheets.

You also need to consider supply availability, manufacturing capabilities, quality requirements and the conditions your product will face once it’s in use.

For example, outdoor products may need additional UV protection, while industrial components might require resistance to heat, oils or repeated mechanical stress.

Working with an experienced injection moulding manufacturer can help you assess these requirements before production begins.

AC Plastics (ACP) provides plastic injection moulding solutions for Australian manufacturing applications, working with a range of engineering plastics to support different product requirements.

Understanding material behaviour alongside practical manufacturing considerations can make the development process more efficient and help businesses avoid expensive mistakes.

Final Thoughts: The Best Plastic Is the One That Fits Your Product

There’s no single plastic material that’s perfect for every injection moulded product.

ABS offers an excellent balance of toughness, appearance and affordability. Polycarbonate is a strong choice for demanding impact-resistant applications. Nylon performs well in mechanical and wear-related environments, while Polypropylene delivers lightweight flexibility and cost efficiency.

Other engineering plastics, including POM, PBT and high-performance polymers, offer specialised properties for more technical applications.

The key is understanding what your product actually needs.

Think about strength, temperature, chemical exposure, appearance, production volume and long-term performance before making your decision.

Planning a new injection moulded product?

Whether you’re comparing ABS vs Polycarbonate or exploring other engineering plastics in Australia, making an informed material choice early can save time, reduce costs and improve product reliability.

Visit AC Plastics (ACP) to learn more about plastic injection moulding solutions and discuss the requirements of your next manufacturing project.

Frequently Asked Questions

What is the best plastic for injection moulding?

There is no single best material. ABS is a popular choice for housings, Polycarbonate for impact-resistant components, Nylon for mechanical parts and Polypropylene for flexible, cost-effective products. The right material depends on the application.

Is ABS cheaper than Polycarbonate?

Generally, yes. ABS typically has a lower material cost and is easier to process. However, Polycarbonate may provide better value when higher impact or heat resistance is essential.

Is Nylon stronger than Polypropylene?

Nylon generally offers greater stiffness and mechanical strength, particularly in reinforced grades. Polypropylene is lighter, more flexible and often more economical. Each is suited to different applications.

Which plastic is best for outdoor products in Australia? UV-stabilised Polycarbonate, appropriately formulated Polypropylene and other weather-resistant grades may be suitable. The best choice depends on sunlight exposure, temperature, mechanical loads and expected product lifespan.