CNC materials selection process

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Things to keep in mind when choosing CNC machining materials

Are you certain about using CNC machining for your part production? If “yes”, then you’ve made a good choice in terms of options to bring your tailored product to life. To begin with, CNC machining is a highly precise and cyclic manufacturing process used for prototypes and production parts. Also, it is one of the most common manufacturing methods used in the modern era. The computer numerical controls (CNC) allow parts to be produced using a highly automated process, which is way more advanced and efficient than conventional manufacturing methods in terms of speed, accuracy and production rate.

However, like many other manufacturing processes, it is essential to choose the best CNC machining materials. Otherwise, it can cause poor element functionality and excessive production cost. Material versatility can be one of the advantages of CNC machining, but it may prove to be a disadvantage as material selection can become a difficult process.

Key considerations for choosing the right materials

There are numerous factors that should be kept in consideration when picking a material for machining, including strength, weight, workability, corrosion, cost, resistance, and cosmetic appearance. Here are few examples of a memo list of questions you should respond to before picking a CNC material for your project.

Usage of the part

How will the machined part be used? It is an important point to keep in mind while machining the work-piece. Over the passage of time, engineers have analysed what materials are best for what purpose. Their practical application helps to determine the specific properties the CNC material must have. For instance, brass (alloy of copper and zinc) is a soft metal and it has intense workability at room temperature. Hence, it can be machined in products that don’t require great tensile strength. On the other hand, steel can endure high tensile strength and can be machined into high- stress- bearing designs such as bridges.

The operating temperatures of CNC material used

The operating temperature of the surroundings in which CNC material will be functioning is another prime factor to consider before choosing the material. If the melting temperature of the CNC material becomes less than the operating temperature of the environment, then there might be a change in its part structure. On the other hand, the material should also have the ability to withstand extreme and sudden temperature changes. Otherwise, the material could show bending or deformation over a period of time.

The material’s resistance can also be examined through operating temperature since it can be effectively analysed if it can withstand the heat that is released as a by-product from CNC machining operations. The material should be able to endure temperatures without any case of deformation such as bending, breakdown, and distortion over time.

Weight of the material

Right selection should be made when choosing CNC machining materials for weight-sensitive projects. For this purpose, lightweight materials can be used as they are durable and can withstand a considerable amount of stress. For instance, we can implement the use of aluminium over steel or materials such as titanium for aerospace applications. Because steel and titanium can’t bear high loads of stress so they are not suitable for the respective purposes.

CNC material cost and functionality

When picking a CNC machining material many factors will together contribute to the decision. To choose the best material for machining, you need to prioritise the characteristics most essential for your finished part. Choosing material and checkmark all the requirements including profile strength, resistance to stress, temperature fluctuations, and workability is the best thing to do. The CNC materials that have high costs and poor production rates should be eliminated. For instance, platinum is a rare and precious metal so it can’t be used in manufacturing of doors.

Most commonly used materials

There are various types of materials that are commonly used. For instance, stainless Steel is one of the most widely used in various industries due to its enduring properties such as resistance to corrosion, and high tensile strength. It includes several subtypes such as stainless steel (303, 316, 304), and carbon steel 1045. Carbon steel is mostly used CNC machining material pickings. It provides unique features for use in different applications. Typical features include high strength, sound workability, and toughness. Other steel types offer properties that are beneficial for implementation in productions such as tanks, pipes, kitchen accessories, and automotive.

Aluminium is also an important CNC machining material. The non-ferrous metal is easy to machine and has desirable structural and chemical features. The properties of lightweight, non-magnetic, resistant to corrosion, and good electrical and thermal properties makes aluminium a perfect material for rapid prototyping and mass production using CNC machines. As a lightweight and less dense material, machining aluminium parts also can be used in manufacturing of several products such as planes, and automotive.

With the high machinability rates and structured mass production strategies, CNC aluminium machining has been widely used in manufacturing.

Meanwhile brass is a material that has key features such as cost- effectiveness and easy workability, so it is the best CNC machining material that can be used in several precision components manufacturing. It is used in plumbing fitting, home décor, electrical sockets, and musical instruments. Due to its shiny outlook, it is widely used in home furniture and décor. Brass has numerous grades such as C360 and C260, each offers different usage. Another useful factor of using brass is that it is spark-proof so it can be used in potentially explosive environments.


For CNC machining processes, material selection is one of the most vital parts that need to be considered sincerely before the process begins. The selection of material influences almost every phase of product lifecycle, beginning from prototyping to part’s performance to its final application. To ensure you’ve chosen the best material that is most precise and accurate, it’s worth taking advice from your product manufacturer so the process becomes easy.

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