CNC Machining Brass: A Complete Guide to Custom Brass Parts

Brass is a metal that is commonly used in a variety of industries due to its various desirable properties. The alloy contains copper, zinc, and other metals such as magnesium, iron, and lead. These metals all contribute to its properties, while the addition of lead makes it very easy to machine. This is why this metal is perfect for CNC machining brass.

In this guide to CNC machining brass, we will look at the properties of brass and the various brass grades used for custom brass parts. We will also review the applications of brass manufacturing and factors to consider when selecting brass for your machining projects.

1.What are the properties of machining brass?

As mentioned earlier, brass contains primarily copper and zinc. It may also contain other metals such as silicon, iron, lead, or magnesium that give brass additional properties. The difficult thing about brass, however, is that the copper and zinc content can be adjusted to suit any intended use. These different proportions of brass are what really produce the various grades of brass used for machining brass parts.

Let’s review these properties and how they affect the suitability of the CNC machining brass process:

1) Highly Machinable

Brass is one of the easiest metals to machine. This property is due to the presence of lead in its composition. Machining brass is an easy task for most machinists due to its machining properties such as high feed rates, good ductility, and flexibility. The machinability of brass is the main reason why brass manufacturing using CNC processes is quite common.

2) Corrosion Resistance

One of the properties that makes brass suitable for machining is its corrosion resistance. This property is one of the reasons why tools made of brass have a long service life. In addition, it also makes parts made using this material suitable for use in liquid environments. However, its level of corrosion resistance depends on the amount of components such as iron and aluminum.

3) Plasticity

Brass is extremely plastic due to the presence of copper. However, the plasticity of this metal is even stronger than that of copper. Its high plasticity makes it an easy choice for machining projects. This is because machinists can easily machine the metal into different shapes. This is why custom machining brass parts is required.

4) Strength and Hardness

Brass is not only easy to machine, but it is also known for its high strength. Although it is not as strong as steel, it is also quite durable.

5) Aesthetic Appeal

One of the main factors considered in machining is the aesthetics of the finished part. Brass has a bright, golden color and its appearance definitely complements its other characteristics. The beautiful natural finish of brass means that machined brass parts can be used without external finish.

2.Types of Brass Suitable for CNC Machining

Brass comes in different grades, depending on the composition of copper and zinc it contains. These changes in composition also affect the application characteristics of different grades of brass. This section will review several of these brasses and their advantages, disadvantages, and applications.

1) Brass C360

Machinists often refer to this alloy as easy-to-machine brass. It is the most commonly used brass grade in machining. It is known for its high machinability and tensile strength. Its high machinability is attributed to its lead content, which accounts for about 3% of its composition. Machinists use it to machine brass custom parts such as electrical equipment and joints or screws.

Advantages:

1. Easy to machine.
2. Corrosion resistance.
3. Good tensile strength.

Disadvantages:

1. Lead content may cause problems if used for medical purposes.
2. Susceptible to acid.

2) Brass C230

Mechanics refer to this grade as red brass or Nordic brass. It also has moderate strength and good rust resistance. C230 is popular for its resistance to seasonal wear and dezincification. Manufacturers also use it for making plumbing service lines because of its resistance to water corrosion. It is also suitable for custom parts such as rotor bars, J-hose elbows, etc.

Advantages:

1. Resistance to dezincification corrosion.
2. Moderate tensile strength.
3. Corrosion resistance.

Disadvantages:

1. It may not withstand corrosion in harsh environments.

3) Brass C220

Mechanics refer to this alloy as commercial bronze. Despite the name, it is still a brass alloy due to the high copper content in its composition. It has a good machinability grade, strength, and ductility. It is a favorite in the construction industry and is used for machining weather stripping.

Advantages:

1. Excellent corrosion resistance.
2. Good machinability rating.
3. Good ductility and strength.

Disadvantages:

1. Additional annealing may be required after exposure to harsh environments.

3.Finishing Options for CNC Machining Brass

Brass itself has no natural coating. However, its natural golden finish means that you can use machined brass parts as finished products. If the part has cosmetic purposes, you may want to polish it externally.

Here are some compatible polishing options for CNC machining brass:

1) After machining

Due to the natural aesthetic surface of brass, some people prefer to machine brass parts. In most cases, when using this finish, the focus is usually on the functionality of the part rather than the aesthetics. However, such parts can be easily damaged.

2) Polishing

This requires the use of grinding wheels and sanding discs to polish the surface of the custom brass part. The abrasive on the sanding disc helps remove any impurities and make it smooth.

3) Electroplating

This surface treatment method uses an electrolyte to bond another metal molecule to the surface of the brass part. Metals used include aluminum, stainless steel, etc. Electroplating usually produces a shiny or smooth surface.

4) Honing

This surface treatment requires grinding the surface of the finished part with a grinding stone. It creates a crisscross pattern on the surface of the machining brass part.

5) Powder coating

This surface treatment involves using a free-flowing dry powder to coat the surface of the custom brass part. The powder coating surface treatment improves the corrosion and wear resistance of the brass metal.

4.Factors to Consider When Selecting Brass for CNC Machining

Choosing brass for your CNC machining project can be a little trickier than it seems. Since the metal comes in various grades, you need to consider which of these grades have the right properties for your project. Therefore, it would help if you made a list of factors to consider before settling on a specific grade.

We have listed some of the factors you can consider below:

1) Processing Time Required for the Part

Delivery times vary from project to project, which is an important factor in deciding which brass grade to use. Among CNC machined brass, C360 alloy is the best choice for machinability. Therefore, if you need a custom brass part in a hurry, C360 is definitely the material of choice.

However, if you need other characteristics besides machinability, you can evaluate other grades such as C230 or C220.

2) Design for Manufacturability

DfM principles are crucial in any machining process. Although brass is very easy to machine, you must ensure that the part design is not too complex to machine. In addition, it is recommended to minimize the number of machine setups required. This helps to reduce the machining cost of the project.

3) Application of the Finished Part

Brass grades vary in composition, which means that they all have different advantages and disadvantages. This means that where you plan to use the part will affect the brass that is suitable for machining the project. For example, if the part is used for underground pipes, it is best to use C230 grade.

5.Applications of machining brass parts

Applications of CNC machining brass processes include making the following parts:

1. Hinges
2. Knobs
3. Pipes
4. Bells
5. Jewelry
6. Gears
7. Door trims, etc.

6.How do you know if brass is the right choice for your CNC project?

CNC metalworking uses a variety of metals as raw materials for machining. Choosing brass as the right metal for your CNC project means you need to make sure the application of the machined part matches the performance of the brass grade. For example, it is not recommended to use a C220 brass grade for underwater pipes.

If you are looking for an experienced CNC machining manufacturer, Xavier is your ideal choice. The Xavier team is well-equipped to provide high-quality CNC machining solutions. If you need more information or to discuss your machining needs with us, please feel free to contact us.