Choosing the Right Metal for Your CNC Project: A Guide to Material Selection in Precision Engineering
The success of your project doesn’t start at the cutting tool – it starts with choosing the right material. The type of metal or plastic you select plays a critical role in determining not only how your part performs under pressure, but also how long it lasts, how it reacts to environmental conditions, and what it will ultimately cost to produce.
In Australia’s fast-paced manufacturing industry, engineers and specifiers are under increasing pressure to reduce lead times, lower project costs, and improve reliability – all without compromising on precision. That’s why understanding CNC machining materials and how they perform under different conditions is vital, especially during the early stages of specification.
At Berkeley Engineering, we work closely with clients to guide material selection decisions that align with both performance goals and budget. With over 90 years of experience and a proven BE Assured approach, we help reduce change orders and ensure you’re set up for success from day one. Because the right material decision now can prevent costly redesigns later.
Why Material Selection Matters in CNC Machining
Choosing the right material is one of the most important decisions in any CNC machining project. While factors like geometry and tolerance are essential, it’s the material that determines a component’s strength, performance under load, resistance to wear or corrosion, and overall service life. The wrong choice can lead to premature failure, higher maintenance costs, and missed delivery deadlines – especially when exposed to harsh environmental conditions or high-volume use.
Different applications demand different mechanical properties. For instance, stainless steels offer exceptional corrosion resistance for marine and medical settings, while aluminium alloys are preferred for lightweight materials in aerospace and transport applications. Meanwhile, carbon steels and tool steels provide strength and wear resistance for heavy-duty or high-precision components.
In our experience at Berkeley Engineering, many project delays stem from materials not being properly matched to the application. This often results in multiple rounds of changes, pushing timelines and budgets beyond the original scope. Our team helps you avoid that scenario.
When you partner with Berkeley, you can BE Assured that your project benefits from local expertise, real-world insight, and material recommendations tailored to your performance goals. We don’t just machine components – we help shape the outcome of your product, from the material up.
Common CNC Materials and Their Properties
The performance, lifespan, and cost-efficiency of a CNC machined component hinge on the material used. Each type of material brings its own blend of mechanical properties, machinability, and environmental resilience – and no single option suits every project. Below is a guide to some of the most common CNC materials we work with at Berkeley Engineering, along with their key characteristics.
Stainless Steel
A staple across medical devices, marine applications, and industrial equipment, stainless steels offer high corrosion resistance, solid tensile strength, and excellent performance in extreme environments. Grades such as 304 and 316 are particularly suited to projects requiring chemical resistance or exposure to high temperatures. While more challenging to machine, their durability often outweighs the added production effort.
Aluminium Alloys
Known for being lightweight, cost-effective, and highly machinable, aluminium alloys such as 6061 and 7075 are ideal for aerospace, electrical components, and automotive applications. Their good mechanical properties, resistance to corrosion, and fast machining times make them an industry favourite for achieving tight tolerances and weight reduction goals.
Carbon Steels & Medium Carbon Steel
When strength and wear resistance are required, carbon steels are often the go-to. Medium carbon steel, in particular, offers a balance between toughness and machinability, making it suitable for structural parts, gears, and shafts. However, its susceptibility to corrosion means it’s best used in controlled environments or with added surface protection.
Tool Steels
Designed to hold their edge in high precision and high performance applications, tool steels boast excellent thermal stability and impact resistance. They’re commonly used in cutting tools, dies, and moulds where durability is critical.
Engineering Plastics (e.g. Nylon, ABS, Polycarbonate)
Though not metals, high-grade plastics offer valuable benefits such as electrical insulation, chemical resistance, and suitability for injection moulding or lightweight structural parts. They’re often used in medical, electronics, and custom housings where material options must balance performance and cost.
At Berkeley Engineering, we help clients choose the right material based on their design, budget, and operating environment. When you work with us, you BE Assured that every material we recommend is backed by years of real-world testing and reliable performance across Australia’s manufacturing landscape.
Matching Materials to Industry Applications
Material choice doesn’t just influence the integrity of a part – it directly impacts how well that part performs in its intended environment. Whether it’s resisting corrosion in coastal infrastructure, withstanding the wear and tear of mining operations, or delivering reliable insulation for electrical systems, every industry comes with its own set of demands. That’s why at Berkeley Engineering, material selection is always informed by real-world use – not guesswork.
Mining and Heavy Industry
For abrasive conditions and high load-bearing performance, carbon steels and tool steels are the materials of choice. These metals offer strong wear resistance, excellent mechanical properties, and can tolerate the shocks and high temperatures often encountered in the field. For components like brackets, structural supports, or custom tool assemblies, we favour materials that are robust, heat-treated, and proven under pressure.
Automotive and Transport
Here, aluminium alloys shine thanks to their lightweight nature and adaptability. Reducing component weight helps achieve better fuel efficiency without compromising strength. Parts such as housings, brackets, and panels are often machined from 6061 or 7075 aluminium due to their tensile strength, thermal stability, and clean machinability – all essential for high-speed manufacturing and precision fitment.
Electrical and Energy Systems
In these sectors, the emphasis shifts to electrical insulation, corrosion resistance, and dimensional tolerance. Engineering plastics, stainless steels, and copper-based alloys are ideal for switchgear, terminal blocks, and other electrical components. They maintain integrity under elevated temperatures, provide safety compliance, and deliver long-term stability.
Medical and Scientific Equipment
Precision, hygiene, and repeatability are critical in medical-grade components. That’s why we often rely on stainless steels like 316 and engineering plastics with chemical resistance for lab instruments, surgical tools, and diagnostic housing.
At Berkeley Engineering, our role is to simplify complex choices. We don’t just offer materials – we recommend solutions. And when you choose us, you can BE Assured that each material is chosen for long-term reliability, compliance, and performance in your sector.
Selecting the Right Material: A Step-by-Step Process
Choosing the right material for your CNC machining project isn’t just a matter of ticking boxes—it’s a strategic decision that affects cost, performance, lead time, and compliance. At Berkeley Engineering, we’ve refined a clear and collaborative process to help clients get it right from the start, minimising costly change orders down the track. Here’s how we guide you through it:
1. Define the Functional Requirements
We begin by asking the right questions: What does the part need to do? Will it be under constant stress? Exposed to moisture, heat, or chemicals? Understanding the component’s environment helps us determine whether properties like corrosion resistance, tensile strength, or thermal stability are critical.
2. Identify Key Material Properties
Based on the project’s purpose, we match required traits—such as impact resistance, electrical insulation, or wear resistance—with materials that deliver those outcomes. If the part will be used in marine applications, for example, we may recommend stainless steel grades or specialised plastics with excellent corrosion resistance.
3. Consider Machinability and Cost
Even the best material can become inefficient if it’s difficult to machine or drives up costs. We weigh up the machining tools required, cycle times, and post-processing steps. Aluminium alloys are often chosen for their balance of good mechanical properties and cost efficiency, while medium carbon steel is preferred when high strength is required without blowing out budgets.
4. Factor in Industry Standards and Compliance
For sectors like medical, aerospace, or food-grade manufacturing, strict documentation and traceability are non-negotiable. We ensure the right materials meet all required standards, certifications, and regulatory demands.
5. Validate with Prototyping or FEA (if needed)
When performance is critical, we may recommend Finite Element Analysis (FEA) or a pilot run using CNC prototyping to confirm the material behaves as expected under stress or load.
6. Finalise and Document for Production
Once approved, we lock in your material selection and build it into the part’s CAM programming, ensuring consistency from the first run to the thousandth.
At every step, you can BE Assured you’re working with a team that puts precision, practicality, and partnership first. Our goal is to make material selection not just accurate—but confidently backed by experience.
Beyond Metals: When Plastics or Composites Make Sense
While metals dominate the CNC machining world, there are plenty of applications where plastics or composites offer a better fit—technically and financially. At Berkeley Engineering, we help clients weigh up these options with confidence, especially where properties like chemical resistance, electrical insulation, or weight reduction are top of mind.
High-performance plastics such as polycarbonate, nylon, or PTFE are ideal for components exposed to moisture, corrosive environments, or sensitive electronics. These materials are easy to machine, offer tight dimensional tolerance, and eliminate the risk of rust or conductivity issues. In sectors like medical devices or electrical components, they often outperform metal alternatives.
Composites, meanwhile, bring together the best of both worlds—offering mechanical properties that rival metals while being significantly lighter. For clients needing strength without sacrificing mobility or thermal insulation, composites can be a smart long-term choice.
Choosing non-metallic materials doesn’t mean compromising on performance. With Berkeley’s expertise, you can BE Assured that every part—whether metal, plastic, or composite—is selected for what it needs to do, not just what it’s made from.
How Berkeley Engineering Helps You Choose With Confidence
At Berkeley Engineering, we know that choosing the right material for your CNC machining project isn’t always straightforward. With dozens of options, shifting project requirements, and cost pressures, it’s easy to overlook a better-fit material until after production has started. That’s where we step in.
Our experienced team supports engineers, procurement professionals, and project managers in making informed decisions—right from the start. We don’t just take a drawing and quote; we dive deeper into your project goals, expected operating environments, and tolerances to recommend CNC machining materials that match the performance and commercial outcomes you’re aiming for.
Whether you need materials that offer corrosion resistance for marine applications, wear resistance for mining parts, or lightweight materials for transport components, we can identify suitable alloys or plastics that hit the mark. With over 90 years in the manufacturing industry, we’ve worked across sectors including defence, infrastructure, energy, and medical—so we know what lasts in the real world.
We also offer clarity around availability, lead times, and pricing, helping you avoid material-related delays or surprises. And because all our work is backed by our ISO 9001:2015 certification and the BE Assured standard, you can trust that your component will be made to spec, first time, every time.
When you work with Berkeley, you’re not just getting parts—you’re getting a proactive partner in the design and material selection process.
Conclusion: Start with the Right Material, Finish with the Right Result
Material selection isn’t just a step in the process—it’s a decision that defines the performance, durability, and cost-effectiveness of your CNC machined components. Whether you’re producing high-volume parts or critical one-off components, choosing the right metal or alternative material can be the difference between unexpected failure and long-term reliability.
At Berkeley Engineering, we’ve spent decades helping clients make these decisions with confidence. From tool steels and stainless steel to engineering plastics and composites, we guide every project based on real-world application and performance data—not guesswork.
With in-house expertise, ISO-certified processes, and a deep understanding of CNC machining materials, you can BE Assured that every part we produce is built to perform in the environments you rely on.
Don’t leave your material choice to chance. Work with a team that understands the entire lifecycle of your components—from design through to delivery. Let Berkeley Engineering help you start strong, so you finish stronger.
FAQs Answered:
1. What is the best material for CNC machining?
There’s no single best material—it depends entirely on your project’s requirements. Commonly used materials include aluminium alloys for lightweight strength, stainless steel for corrosion resistance, carbon steels for toughness, and tool steels for applications requiring exceptional wear resistance and tight tolerances.
2. Is aluminium easier to machine than steel?
Yes, aluminium is generally much easier to machine than steel. It’s softer, generates less heat, and is less abrasive on cutting tools, which often results in faster machining speeds and lower tool wear. Steel, while more durable, usually requires slower speeds and more robust tooling.
3. Does aluminium resist corrosion better than steel?
In most environments, aluminium offers better natural corrosion resistance than mild steel. It forms a protective oxide layer, whereas carbon steel typically needs coatings or treatments to prevent rust. Stainless steel, however, is specifically alloyed for high corrosion resistance and can be a better choice in harsher environments.
4. Can plastics be CNC machined instead of metal?
Yes, many plastics can be CNC machined and are ideal for applications that don’t require high structural strength. Materials like polycarbonate, nylon, and PTFE offer excellent electrical insulation, chemical resistance, and dimensional stability, making them suitable for electronics, medical, and prototyping components.
5. What factors should I consider when choosing a CNC material?
When selecting a CNC material, consider mechanical properties (like tensile strength and hardness), corrosion and wear resistance, thermal stability, operating environment, machinability, and cost. Matching these characteristics to your component’s function will ensure optimal performance and longevity.
- written by:
Berkeley Engineering
Berkeley Engineering is one of Australia's leading CNC machining and metal fabrication workshops. With 90+ years of experience in the industry, we're trusted by businesses like yours for all their CNC machining needs, including CNC milling, CNC turning, plasma cutting, welding, assembly and more.Get a QuoteOur Machining Services:
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Berkeley Engineering has a rich history of producing high-quality components since 1931. Our CNC machining operations in Australia offer a comprehensive range of services, including CNC turning, metal fabrication, plasma cutting and more. We are dedicated to delivering custom components of the finest quality for your projects. Whether you require low or high volume production, our manufacturing services are cost-effective and efficient, with turnaround times as fast as one business day.
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