It’s no secret that CNC machining has transformed the manufacturing world accurately and precisely. CNC machining offers raised productivity, reduced waste across countless industries, and works with various materials — metals, wood, plastics, glass, the list goes on.
It’s just as well that CNC machining is so adaptable, as different industries require different materials for specific applications and components. However, brass CNC-turned parts might be the best if you’re looking for durability and ductility.
Why use brass?
Brass is a metal alloy mainly made of copper and zinc, but it can also consist of different quantities of iron, magnesium, lead and other advantageous materials. The quantities of each added material will incorporate specific properties into the grade of brass, making each one better suited to particular applications.
Brass is generally known for being easy to machine due to its excellent ductility and high flexibility. This makes it perfect for crafting a range of quality components for various industries. Its versatility can range from electrical components to decorative items, and its repeatability makes it an ideal match for the high-batch output of CNC machining.
Applications
Brass is a popular material across a range of industries. It can be produced with high precision and various surface finishes, making it ideal for multiple quality components.
Brass-turned parts are commonly found in plumbing and heating applications because they offer durable valves and fittings with excellent heat conductivity. They’re also perfect for aircraft fasteners in aerospace settings and long-lasting automotive components such as electrical connectors or radiator cores. Not to mention how often brass is used to create instruments like trumpets, cornets and trombones.
Other industries that use brass parts well include the electronics and marine sectors. The components these two industries require must resist corrosion and be excellent conductors of electricity — brass ticks both boxes.
Grades
Brass comes in different grades that are defined by their various properties. Some of the most common grades of brass used for CNC machining are CZ106, CZ121 and CZ112.
- CZ106 — Cartridge Brass: This grade exhibits high ductility, workability and strength. It’s best used for deep drawing and forming applications and presents excellent corrosion resistance. It’s not advised for use alongside most ammonia and ammonia compounds or hydrochloric, nitric and acetic acid.
- CZ121 — Free-Cutting Brass: This grade is perfect for high-speed machining. It’s highly machinable, has good tensile strength and formability, and offers excellent corrosion resistance. However, this type of brass has a higher lead content that can make it unsuitable for the medical industry and prone to acid corrosion.
- CZ112 — Naval Brass: This grade contains tin, making it ideal for saltwater and marine environments. It offers the best resistance to corrosion and seawater erosion.
Surface finishes
Since brass doesn’t have a natural coat, you can use brass parts without any extra finish after machining. Their natural gold surface looks good as machined and is ideal for numerous applications, but if you’re looking for something more aesthetically appealing, there are three main types of finish to choose from: polished, powder coated and electroplated.
Polished brass parts are made by removing ruptured metal materials on the surface of the alloy and then honing it to create a cross-hatched pattern. This increases its visual appeal and gives it a smooth surface. Powder-coated brass parts include — you guessed it — a powder coating on the surface that enhances its durability and corrosion resistance. And electroplated parts feature smoother, glossier finishes following electrolysis. This process binds the molecules of another metal to the brass surface, typically chrome, zinc, silver or gold.
Why does brass machining work so well?
Brass and CNC machining combine nicely for several reasons, especially when creating precise and repeatable components.
This is because CNC machines operate on G-code, which are computer-automated instructions. Once the machines have been told what to do, they can quickly and easily create durable products with intricate detailing and complex geometries. This is a fantastic process for machining brass parts.
Since brass offers excellent mechanical properties, such as corrosion resistance, high machinability and low friction points, it’s very well suited for CNC machining processes. Thanks to their potential for speed and detail, these processes — such as turning, milling and drilling — ensure that brass parts are repeatable and will meet any relevant standards or regulations every time.
Advantages of brass machining
Thanks to the inclusion of different materials, brass is an alloy that offers a wide range of advantageous properties. These include the following.
Corrosion resistance
The most popular grades of brass offer good-to-excellent corrosion resistance, making brass machining parts perfect for humid conditions. The quantity of aluminium in brass dictates its degree of corrosion resistance. More aluminium makes brass more resistant, while more iron means less resistance. This is essential for crafting quality parts and components for specific applications.
Electrical and thermal conductivity
Brass is a known conductor of electricity and heat because of the quantity of copper in its makeup, making CNC brass parts ideal for electrical components.
Brass effectively dissipates heat, preventing thermal damage inflicted upon the workpiece and the machine’s cutting tools.
Malleability
Brass is a highly malleable material, especially when compared to similar alloys like bronze. As a result, it’s more workable and suitable for forming intricate shapes during CNC machining processes.
Strength and hardness
Despite being malleable and workable, brass is highly strong and hard. Because of this, brass parts are durable and suitable for applications that require them. That said, brass parts aren’t quite as durable as steel or titanium, so they may not be the perfect choice for long-term use in high-stress environments.
Highly machinable
Due to its lead makeup, brass is highly machinable. This makes CNC brass parts easy to cut and shape using various machines. The low cutting forces required also allow for cost-effective processes, minimal tool wear, detailed designs and plenty of design freedom.
Aesthetic value
Brass is a fantastic option for components and parts that must be durable and aesthetically pleasing. It offers smooth surfaces in bronze, gold and even silver shades if the alloy has a high zinc content.
Recyclability
Since it’s a recyclable material, brass parts can be repurposed and reused. This limits waste and boosts sustainability, ideal for industries and companies aiming to limit their environmental impact.
Disadvantages of brass machining
While brass has plenty of benefits, it also has its faults. This is primarily due to the material’s composition and physical properties, which make it unsuitable for specific scenarios. While there are generally fewer cons than pros, you must ensure brass machining and its parts are the perfect choice for your intended use.
Toxicity
Since some grades of brass include higher amounts of lead, they’re not suitable for use in specific applications such as the creation of medical components.
Susceptible to corrosion
We’ve previously mentioned that brass alloys have excellent corrosion resistance against salt water, but that doesn’t mean they always resist corrosion against other substances like acids or ammonia.
Price
Generally, brass is more expensive than other materials compatible with CNC machining. If you’re looking for a cost-effective option, you might want to consider something else — aluminium, for instance. You can learn all about the pros and cons of aluminium by reading our article.
Getting down to brass tacks
Brass is the perfect fit for many industries needing a durable, ductile, conductive material that is easy to machine and highly repeatable. It’s often used in the plumbing, electrical, aerospace, automotive, and marine sectors.
Brass can be divided into many grades depending on its composition. Typical grades are those with high strength, machinability, or corrosion resistance. It also has several surface finishes, including polished, powder-coated, and electroplated.
Before you go all-in on brass, you should be aware that it has a few setbacks. Namely, its toxicity makes it unsuitable in some industries like healthcare. It can also be vulnerable to certain acids or ammonia. And it’s more expensive than many materials, making some more cost-effective alternatives a better choice.
But if you can afford brass, you’ll be extremely satisfied with its high performance in almost all areas.
Supporting UK businesses
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