Choosing the proper process can significantly impact cost, quality, and turnaround time when manufacturing plastic parts.
Two popular techniques used in product development and low-to-high volume production are vacuum casting and injection moulding. While both produce similar end results, the method you choose depends on factors like your design requirements, budget, materials, and production timeline.
We support Australian businesses in navigating these critical manufacturing decisions. Whether you’re creating a prototype or moving into mass production, understanding the difference between both processes is essential.
In this guide, we’ll explore the pros and cons of both methods, along with the best scenarios for using each method, to help you make an informed decision.
What is Vacuum Casting?
It is a prototyping and low-volume production technique where liquid plastic or rubber is poured into a silicone mould under vacuum. The vacuum ensures the material fills every detail of the mould evenly, without air bubbles or voids. This results in high-precision parts with excellent surface finish.
We provide professional casting services across Australia. This method is ideal for businesses needing fast, cost-effective solutions for product development or short production runs.
Advantages:
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- Short lead times – often within days.
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- Excellent surface detail and smooth finishes.
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- Lower cost for small quantities.
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- Ideal for functional testing and market-ready prototypes.
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- Flexible material choices include transparent, coloured, and rubber-like options.
Limitations of Vacuum Casting:
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- Not suitable for high-volume production.
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- Silicone moulds have a short lifespan (approx. 20–30 uses).
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- Material properties may not match those of thermoplastics used in injection moulding.
What is Injection Moulding?
It is a manufacturing process where melted plastic is injected into a precision-engineered metal mould at high pressure.
Once cooled, the plastic solidifies into the desired shape. This technique is widely used for large-scale production due to its consistency, efficiency, and ability to handle complex geometries.
We help clients transition from prototyping to full-scale moulding production. We also offer design optimisation and printing to support the entire product development cycle.
Advantages:
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- Highly efficient for mass production.
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- Consistent part quality and dimensional accuracy.
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- Wide range of durable thermoplastic materials.
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- Low per-unit cost at high volumes.
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- Strong, heat-resistant, and impact-resistant parts.
Limitations:
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- High initial tooling costs.
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- Longer lead times for mould creation (weeks to months).
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- Not cost-effective for short production runs.
Key Differences
To help you decide which method suits your needs, here’s a side-by-side comparison of both methods:
| Feature | Vacuum Casting | Injection Moulding |
| Production Volume | Low (10–100 parts) | Medium to high (1,000+ parts) |
| Setup Cost | Low | High |
| Per-Unit Cost | High | Low (at scale) |
| Lead Time | Short (days) | Longer (weeks to months) |
| Tooling | Silicone moulds (short lifespan) | Metal moulds (long lifespan) |
| Material Types | Polyurethane resins, rubber-like materials | Durable thermoplastics |
| Detail and Finish | Excellent | Excellent |
| Best Use Case | Prototypes, functional testing, short runs | Mass production, durable product lines |
When to Choose Vacuum Casting
This is the preferred option when you need:
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- Rapid prototypes for form, fit, or function testing.
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- Short-run production before investing in injection moulding.
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- Parts with complex shapes or fine details.
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- Flexible materials, including rubber-like or clear plastics.
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- Faster turnaround for presentations, investor pitches, or testing.
Industries like automotive, medical devices, and consumer electronics often use vacuum casting in early-stage product development.
When to Choose Injection Moulding
Injection moulding is the right choice when your project requires:
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- Large-scale production (hundreds to millions of parts).
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- Durable and consistent components.
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- Long-term use products needing heat or chemical resistance.
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- Precision and repeatability across thousands of parts.
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- Cost efficiency over high production volumes.
This process is commonly used in the manufacture of car parts, household appliances, toys, electronics, packaging, and more.
Combining Both Methods: A Hybrid Approach
Many modern manufacturers, including our clients, take a hybrid approach: They use vacuum casting during product development and injection moulding for full production.
This strategy offers several advantages:
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- Speeds up the development cycle.
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- Allows thorough testing and market validation before committing to tooling.
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- Reduces the risk of expensive design changes during mass production.
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- Optimises budget and resource allocation at each stage.
This flexible approach supports both innovation and scalability, ideal for Australian startups, SMEs, and product-based businesses.
Why We Are Your Trusted Manufacturing Partner
We’re more than just a printing and manufacturing provider. We’re your product development partner. Our team understands the nuanced decisions between both methods and will guide you to the best solution for your needs.
Here’s what we offer:
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- Expert design consultation and prototyping.
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- Local manufacturing support across Australia.
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- End-to-end services, from CAD to final production.
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- Fast turnaround and competitive pricing.
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- Experience across multiple industries, including medical, automotive, and consumer goods.
Whether you’re developing a concept or scaling production, we help Australian innovators bring their products to life.
Ready to Get Started?
Choosing between the two methods isn’t just about the process. It’s about finding the right fit for your budget, timeline, and project goals. With us by your side, you’ll have the tools and expertise you need to make the right call.
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- Need a prototype quickly? Explore our expert vacuum casting services in Australia.
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- Preparing for mass production? Let us help with moulding design and manufacturing.
Contact us today to discuss your project or request a free quote. We’re ready to help you quickly turn your ideas into quality products.
Final Thoughts: Casting vs. Moulding
Both are vital processes in modern manufacturing, each offering unique advantages and disadvantages. The right choice depends on the specific requirements of your project.
Casting is ideal for quick, cost-effective prototypes and short production runs, while moulding is the go-to choice for large-scale, consistent, and durable part production.
Understanding their differences in cost, speed, and material options can help you make informed decisions that save time and money.