CNC Machining Bronze: An Ultimate Guide

Bronze is an element that is used in multiple applications, it is a copper and tin alloy that comprises other elements too. Bronze is known for its corrosion resistance and durability and is used to manufacture multiple components via the CNC machining process.

The guide below offers a detailed insight into bronze machining, its types, advantages, and essential tips, so let's delve in.

What is CNC Machining Bronze?

CNC machining bronze is a process equipped with precision in which the element bronze is machined to achieve the desired mechanical shape of the component for various applications. Bronze is an alloy of copper and tin and is used in industries like aerospace, marine, and many more.

Bronze is opted for the purpose of manufacturing CNC machined components due to its strength and resistance against corrosion which makes it a durable material to choose.

CNC Machining Bronze Process

There are various techniques of CNC machining that are implemented to achieve the bronze components and some of these are discussed below:

CNC Milling

The process of CNC milling consists of a cutting tool that keeps on rotating and removes the excess material from the workpiece of bronze in order to attain the required shape. The process of CNC milling is usually opted for when designs of the bronze components are complex and they need high precision.

The applications that require components consisting of high resistance against corrosion and seamless strength are usually manufactured through CNC milling. It helps generate the exact tolerance in the component.

CNC Turning

The process of CNC turning has a lathe that rotates the workpiece of bronze against the tool which carves the workpiece. It is commonly used for manufacturing components which include valves and shafts.  The CNC turning process ensures that the smooth and uniform surface of the components is achieved.

CNC turning is also very efficient for handling shapes that are either tabular or round offering durability in the components.

CNC Drilling

CNC drilling helps to produce holes and cavities in the bronze components. The process of CNC drilling is usually opted for manufacturing components that are used for the assembling process for the other parts.

The appropriateness of drill selection is very important followed by the speed setting in order to match it with the wear resistance and hardness of the bronze component. The process of CNC drilling is applied mostly to the components that are used in marine environments as they need to offer resistance against water corrosion.

Advantages of Bronze CNC Machining

CNC machining bronze comes with multiple advantages and some of these are as follows:

Resistant Against Wear and Tear: There are various alloys of bronze that offer excellent resistance against wear and tear, like phosphor bronze. This property of bronze makes it suitable for manufacturing various components which comprises gears, bushings, bearings, etc that are subjected to friction during their use.

Improved Machinability: Bronze offers exceptional machinability compared to other types of materials. They are equipped with such a composition that shaping, finishing and cutting them is quite easy and hence CNC machining suits them. Due to the improved machinability, the time and cost associated with the machining process are reduced.

Resistant Against Corrosion: Bronze is known for its seamless resistance against corrosion and therefore is suited for marine environments and also harsh weather exposure.

Hence, the components made using bronze via CNC machining are suitable for moisture-oriented environments as they require less maintenance and have a longer span of life.

Thermal Conductivity: Bronze during the process of CNC machining offers excellent heat conductivity which helps in heat dissipation. Due to the efficiency of heat dissipation, the tools and workpieces do not overheat and the chance of thermal damage also reduces.

Aesthetically Pleasing: Bronze is an attractive-looking material and hence when used for decorative applications it could offer an artistic appeal. The CNC machining process helps to derive such artistic profiles due to its intricate and precision-oriented functionality.

Offers Versatility: Bronze is quite flexible, it can be tailored based on different requirements and hence it can meet the different applications and their diverse requirements.

Disadvantages of Bronze CNC Machining

There are also some disadvantages to consider when machining bronze due to its lower hardness and brittleness, and below you will find the main disadvantages of machining bronze:

High Cost of Material: Bronze is a pricey material being an alloy of tin and copper which leads to an increase in the cost of projects that involve CNC machining of bronze.

Tool Wear: Due to the high strength and lower hardness of bronze, tool wear can be significant during CNC machining, leading to frequent tool replacements and increased maintenance and tooling costs.

Heat-Induced Deformation: Bronze generates heat during the machining process, and its sensitivity to temperature changes can lead to thermal expansion, which may cause deformation and affect the dimensional accuracy of the bronze parts.

Poor Surface Quality: Bronze may have poor cutting properties because it tends to produce cutting chips and cutting vibrations, which can affect the surface quality of the machined parts.

What are the Types of Bronze Available for CNC Machining?

Some of the types of bronze available for CNC machining are as follows:

Bronze 932

Bronze 932 has a high composition of zinc, copper, and tin and is also known as bearing bronze alloy. It is used in manufacturing bearings, bushings, and other precise components that need high wear resistance and strength followed by anti-friction properties.

Bronze 932 is suitable for applications where lubrication is needed because it has a natural coating of lubrication on its surface. It is very easy to drill and mold with the help of CNC machining and components of aerospace and other industries that need high precision use bronze 932.

Phosphor Bronze PB1

PB1 is the phosphor bronze which comprises phosphorus in its composition. It is equipped with seamless resistance against fatigue and due to the content of phosphor it offers stiffness and wear resistance.

PB1 is commonly used in bearings, valve bodies, springs, gears, and bushes due to its seamless formability. It consists of excellent corrosion resistance and high strength and is also suitable for harsh environments.

Silicon Bronze

Silicon bronze comprises silicon along with zinc and copper and the surface polish of silicon bronze is excellent with a good ability to pour. It is used for manufacturing valve parts and pump parts through CNC machining.

Aluminum Bronze

Aluminum bronze also known as bronze 954 comprises aluminum of about 6 percent to 12 percent along with copper and also may contain magnesium, iron, silicon, and nickel. It comprises robust strength and resistance against tarnish.

Aluminum bronze is used in marine applications and also in pumps that carry out the process of transporting corrosive fluids.

Bronze 660

Bronze 660 has a high lead content. It is a suitable alloy of bronze in applications that are low friction and have high wear and tear. It usually helps in manufacturing bearings.

Manganese Bronze

Manganese bronze has manganese followed by zinc, copper, and aluminum. It is known for its shock resistance. It also offers corrosion resistance in salt water. Hence it is commonly integrated into boat propellers, gears, nuts, and pump components.

Surface Finishes for Bronze CNC Machining

Bronze machined parts can undergo various surface finishes techniques to meet specific functional requirements. Here are some common surface treatment processes for bronze:

As-Machined Finish

As-Machined finish refers to the surface condition of bronze after CNC machining (including milling, turning, grinding, etc.). This finish is smooth but typically features tool marks and burrs, making it suitable for applications where appearance or surface quality is not a critical requirement.

Bead Blasting

Bead blasting is a processing technique that involves projecting abrasive materials such as glass beads, ceramic beads, or corundum at high pressure onto the surface of bronze parts. This creates a smooth, matte finish, providing a uniform texture that gives the bronze parts a consistent appearance. It facilitates cleaning, deburring, conceals tool marks, and enhances the corrosion resistance of the components.

Chemical Coating

Chemical coating involves applying a layer of chemical substances to the surface of bronze components to enhance their functionality, longevity, and appearance, providing bronze parts with corrosion resistance and wear resistance.

Polishing

Polishing can reduce surface roughness through physical or chemical methods, making the surface of bronze machined components smoother and more lustrous. This improves the appearance of the object and reduces friction, making it particularly suitable for decorative or precision mechanical parts.

Applications of Bronze CNC Machining

Bronze CNC machining has versatile applications in many industries and some of these are as follows:

Marine: The corrosion resistance of bronze parts makes them suitable for marine applications, including ship parts, propellers, and fittings.

Mechanical Engineering: Bearings and bushings used in various machines require low friction, and bronze is known for its low friction properties, making it adaptable.

Automotive: Machined bronze automotive parts include gears and radiators, which provide enhanced strength and wear resistance.

Construction and Decoration: CNC-machined bronze products, known for their aesthetic appeal and durability, are ideal choices for architectural decorations, door handles, and more.

Cost-saving Design Tips for Bronze CNC Machining

Bronze CNC machining can be achieved with some cost-saving tips and these are given below:

• Design the bronze-based components keeping in mind the post-machining processes that you may need which add to the cost but are necessary for the performance and smoothness of the components.
• Optimize the wall thickness of the components of bronze so that they are neither too thin nor too thick. When too thin, they may distort during CNC machining and when too thick they may lead to material waste.
• There are multiple types of bronze each having its own properties and performance capabilities, always choosing the right type of bronze in order to have durable and strength-oriented parts.
• Try to eliminate the undercuts so that the complexity and the cost of the CNC machining can be minimized.
• Edges and sharp corners create stress concentration which may cause cracks and hene should be avoided.

Conclusion

CNC machining bronze is a versatile process and learning everything about it is very important to choose the right type of bronze for the relevant industry application. As the guide above highlights the minute details on the process of CNC machining of bronze you must have learned a lot of things by now.

If you are looking for Custom CNC machining bronze components  for your specific applications, you can get in touch with DEK. We will help you choose the relevant bronze type and machining process offering high-quality and affordable machined parts for your application.

FAQs

Is Bronze easy to machine?

Bronze offers a high machinability when compared to other elements, among the different types of bronze, 642 has the highest machinability.

What are Common Challenges in Bronze Machining?

Due to the abrasive nature of bronze, tool wear is the most common challenge in its machining.

What are the best grades of bronze for CNC machining?

The best grades of bronze for CNC machining are 642  and PB1. 642 bronze offers the highest machinability and also is ductile. Whereas, PB1 also is known for its free machining.

Is Bronze More Machinable than Brass?

Bronze is harder compared to brass when it comes to machining due to its abrasive and tough nature.