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CapabilitiesCustom Online CNC Machining ServicesBronze for CNC Machining

Bronze for CNC Machining

Bronze, brass, and other copper alloys have a range of important electrical, mechanical, and corrosion-resistant properties. Specifically, bronze has excellent machinability, with an index of 100%. It also has low friction properties that make it ideal for parts that undergo continuous frictional contact.

cnc machined bronze parts

Bronze CNC Machining

Bronze is made by mixing copper with up to approximately 35% tin and up to 8% lead. The inclusion of lead alloy, which is a soft metal, is what makes it so machinable. Bronze is great for applications such as bearings as well as marine applications on pumps and fittings where corrosion resistance against seawater is required. This material’s mechanical properties don’t quite measure up to many other machinable metals, so it is best used on low-stress components made with CNC machining.

Bronze At a Glance

Application

Bronze has a wide range of applications in components such as gears, bearings, and bushings

Advantages

Good corrosion resistance
Highly machinable

Disadvantages

Expensive to manufacture

Lead Time

Minimum 3 days; potentially longer for complex or internationally manufactured parts

Price

$$-$$$

Tolerances

Machining tolerances depend on the exact alloy used. However, a general tolerance of 0.005” is achievable.

Wall Thickness

Minimum 0.80 mm (~0.03”); may vary depending on alloy and wall thickness to planar dimension ratios

Max Part Size

The maximum size of the part is determined by the machines available and the complexity of the part.

Copper 932

Copper 932 is also known as bearing bronze. This alloy has excellent anti-friction properties, making it ideal for bearings, bushings, wear strips, and other light-duty applications.

C932 Properties
Tensile Strength, Yield (MPa)Fatigue Strength (MPa)Elongation at Break (%)Hardness (Brinell)Density (g/cm^3)
Tensile Strength, Yield (MPa)

125

Fatigue Strength (MPa)

110

Elongation at Break (%)

20

Hardness (Brinell)

65

Density (g/cm^3)

8.93

Finishes and Post-Processing Options

Because quality bronze forms only a surface layer of oxidation, it does not corrode the way many other metals do. As such, it does not always have to be coated. Xometry offers a range of surface finishes that work well for bronze. These can include the standard as-milled surface, bead blasting, or chemical coatings to prevent oxidation. To learn more about what surface finish is best for your application, contact us here.

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    Cost-saving Design Tips

    Bronze is a costly material and therefore its use must be optimized as much as possible.

    Design for manufacturing: Following design for manufacturing principles is one of the easiest ways to reduce costs in the machining process. Bronze is more forgiving of complex features due to its machinability, but there is a limit and this needs to be understood before manufacturing begins. A Xometry expert can provide insight into what can be achieved with bronze.

    Tolerancing: Bronze is easy to machine. Do not negate the production savings by over-tolerancing the part. This adds significant extra cost to the machining.

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