CNC Machining Metal Parts

What is CNC milling?

CNC milling is a manufacturing process that uses a cutting tool mounted on a rotating spindle to selectively remove material from a block of raw substrate. The workpiece is rigidly mounted to a table, and this table moves or rotates on different planes so the tool can work at many angles. Sophisticated CNC milling machines can have 5 or more axes of independent motion to make more complex shapes or to avoid having to move the workpiece to a separate machine.

Metal Alloys Offered

Aluminum for CNC Milling

Aluminum is a lightweight metal with an excellent strength-to-weight ratio, making it ideal for applications in which metallic-level strength is required, but mass is still a concern. There are various alloys for aluminum, each denoted by the first number in their classification. The number indicates the main alloying element(s).

Aluminum is one of the most common materials used in the aerospace, medical, and automotive industries. This is due to its excellent strength-to-weight ratio, formability, and general versatility.

Stainless steel for CNC Milling

What sets stainless steel apart from normal steel is the inclusion of chromium in its alloys. All stainless steel chemical compositions contain at least 10.5% chromium. The inclusion of chromium makes these steels more corrosion resistant. The different grades of this material have various alloying elements that serve to further improve corrosion resistance, heat treatability, and machinability. It should be noted that heat treatment can significantly affect the metal’s mechanical properties.

Stainless steels can be classified based on their crystalline structure. This includes Austenitic, ferritic, martensitic, and duplex:

Austenitic stainless steel, such as 300- and 200-series stainless, are highly formable and do not work harden. They are also non-magnetic in an annealed condition.

Ferritic stainless steels are magnetic and offer better thermal conductivity than austenitic stainless. They cannot be hardened by heat treatment.

Martensitic stainless steel such as grade 416 and 420 can be hardened through multiple methods of aging or heat treatments.

Duplex stainless steel, also known as austenitic-ferritic, are grades of stainless that are highly specialized for improved corrosion resistance. Duplex steels are typical in industrial and architectural structuring. 

Given its versatility, some form of stainless steel is prevalent in every industry.