The Advantages of CNC Machining Brass
There are numerous benefits of using CNC machining brass over other metal materials. Let us examine some of them.
High-Speed Machining
Brass alloys have one of the best machinability of all metal alloys with high tensile strength.
The shear resistance of the brass alloy is also very high, contributing to the faster machining speeds engineers experience when using brass.
Often referred to as maximum machinability, brass CNC machining speed is higher than other materials by 5 to 20%.
Precision Machining and Dimension Stability
Another advantage is its optimal dimensional stability. This stability is due to high impact resistance and low deformation factor.
The stability of brass makes it ideal for precision machining, making screw machine parts, and manufacturing parts with strict tolerance.
High Workpiece to Tool Compatibility
Chip formation when CNC machining brass is negligible. This results in minimum wear and tear, improving tool durability, reducing friction, and improving CNC machine productivity.
Consequently, engineers prefer brass rod workpieces to those of other metals, as it is most compatible with different machining tools.
Commonly Used Brass Grades for CNC Machining
There are different grades of brass available for the CNC machining process. However, here we will discuss the most commonly used ones.
C230 Brass
Also known as Red brass, C230 is reddish. It contains 84-86% Copper, 15% Zinc, 0.05% Iron, and 0.06% Lead.
This brass is ideal for making valves, castings, water pumps, small gears, meter housing, and valves.
C260 Brass
Also known as Cartridge brass, it is only available in sheets. This type of brass, while common, is not very machinable.
However, C260 brass is ideal for making brass fasteners, ammunition, hardware, and automobiles due to its cold working and good mechanical properties.
What’s more, cartridge brass contains 68.5-71.5% Copper, 28.5-31.5% Zinc, 0.05% (Max) Iron, and 0.07% (Max) Lead.
C272 Brass
Also known as Yellow brass, C272 has both architectural and industrial applications. It contains 65% copper, over 33% Zinc, and smaller percentages of tin, iron, lead, and nickel.
C353 Brass
Due to its excellent machinability, C353 Brass has application in the production parts of precision components.
Also called Clock brass because you often find this type of brass in watch and clock parts, it contains 36.2% Zinc, 62% Copper, 1.8% Lead, and a minute percentage of iron.
C360 Brass – Free Machining Brass
C360 is the most common type of machinable brass. Engineers prefer this brass due to its excellent formability, machinability, and optimal suitability for brazing operations and soldering.
Also known as free machining brass or free cutting brass, you often find this type of brass in fasteners, values, hardware components, and fittings.
This brass owes its high machinability to the presence of a high percentage of lead, 2.5-3.7%. It also contains 35.5% Zinc, 60-63% Copper, and a minimum of 0.35% Iron.
C385 Brass Metal Alloy
Another name for this brass is Architectural bronze. This is due to its architectural and construction applications. T
Besides, this brass contains 2.5-3.5% Lead, 0.35% Iron, 55-59% Copper, and trace amounts of Zinc.
The lead content of this brass makes it ideal for different brass machining processes, including the fabrication of angles, square tubes, handrail molding, channels, etc. Its Lead content makes it quite similar to the free-machining brass.
C464 Brass
This brass has excellent resistance to seawater corrosion across diverse temperatures, giving it the nickname naval brass.
It owes good corrosion resistance to its tin content (between 0.5-1.0%). Naval brass also contains 59-62% Copper, 39.25% Zinc, and a maximum of 0.10% Iron.
Additionally, this brass is also suitable for hot-forming, bending, soldering, welding, bending, and brazing.
C770 Brass
Also known as Nickel silver due to its silvery appearance. Its combination of high formability, solderability, corrosion resistance, and stiffness makes it for a range of spring applications.
This brass contains a high percentage of Zinc (27%), 53.5-56.5% Copper, and 16.5-19.5% Nickel. It also contains a maximum Manganese content of 0.5% and leads content of 0.1%.
Surface Finishes for CNC Machined Brass Parts
Adding a surface finish to CNC-machined brass parts is a form of value addition.
Besides, surface finish improves aesthetics, as well as the mechanical and chemical properties of brass.
Here are major surface finishes for CNC machined brass parts
As Machined
Since brass readily accepts CNC machining, it comes out with an attractive surface without giving the finish added attention. This is why it is sometimes viable to leave the surface of brass as-machined.
However, this surface finish leaves the brass parts without sharp edges while deburring parts cleanly.
Brushing
This type of surface finish is often aesthetic and involves using abrasive belts to draw traces on the surface of brass parts.
Additionally, brushing as a surface finish leaves the surface of brass looking aesthetically pleasing.
Polishing
Engineers use polishing to improve or reduce surface shine depending on brass parts requirements. It involves rubbing an abrasive over the surface of the CNC machined brass.
Bead Blasting
Bead blasting is a type of surface finish used to rid the surface of CNC brass machined parts of impurities and coating layers. Engineers use a high-pressure stream of blast media for this type of surface finish.
Nickel Plating
This surface finish makes brass corrosion-resistant by making it less porous while improving its thermal conductivity. It also improves its appearance, making it shinier and aesthetically pleasing to the eye.
Chrome Plating
Chrome plating brass improves its physical properties. A chrome-plated brass has increased impact corrosion, electrical conductivity, and wear resistance. It also has a shiny appearance, making it beautiful and aesthetically pleasing.
Conclusion
Brass alloys have several beneficial properties ideal for CNC machining. Besides, there are different grades of brass, with each one having its ideal use. If you are looking to produce a CNC machined brass part, it is important you know the properties of these brass grades, their uses, and surface finishes so you make the best decisions.
Machining brass might be difficult, but AT-Machining promises top-notch quality. It specializes in the CNC machining of brass and other materials. With a team of experts and professionals, you’re sure to get high-quality machined brass parts at a fast lead time. Are you looking to get CNC-machined brass parts? Contact AT-Machining today.
