There are many materials that can be used for CNC machining, and they can be applied across a wide range of industries. Different materials have vastly different machining properties as well as physical and chemical characteristics. The materials we machine include aluminum alloys, stainless steel, alloy steel, titanium alloys, plastics, and more.

Aluminum Alloy

Aluminum alloys commonly used for CNC machining parts:

1. 6061 Aluminum Alloy: Widely used in aerospace, automotive, and construction industries. It offers good mechanical properties, weldability, and strong corrosion resistance.
2. 7075 Aluminum Alloy: Mainly used in aerospace applications due to its high strength, though it has poor weldability and moderate corrosion resistance.
3. 2024 Aluminum Alloy: Suitable for high-strength and fatigue-resistant applications such as aircraft structures and automotive chassis. It has poor weldability but good machinability.
4. 5052 Aluminum Alloy: Often used for manufacturing tanks, pipelines, and marine components, known for its excellent corrosion resistance and weldability.
5. 5083 Aluminum Alloy: Used in shipbuilding and chemical equipment due to its outstanding corrosion resistance in marine environments.
6. 6063 Aluminum Alloy: Commonly used in architectural materials and decorative items, known for its excellent extrusion properties and surface treatment characteristics.

Titanium Alloy

Common titanium alloys which can be used for custom CNC machining parts include: TC4, TC11, TA1, TA2, TA3, TA4, TA5, TA6, TA7, TA9, TA10, TA15, TB2, etc.

Titanium alloys generally have poor machinability, but they are widely used in many industries due to their excellent strength-to-weight ratio and corrosion resistance. These industries include aerospace, medical devices, and chemical engineering, among others.

Titanium alloy has high strength, good corrosion resistance, and thermal stability. It has a lower density than aluminum alloy and is lighter than steel, making it conducive to reducing structural weight. Due to its excellent mechanical properties, titanium alloys are widely used in aerospace, automotive, medical, and other high-end industries.

However, titanium alloy has poor machinability. Due to its high hardness, low elastic modulus, and poor plasticity, it is difficult to process. Titanium alloy has poor cutting performance, which easily leads to severe tool wear. In the machining process, it is also necessary to control the temperature to avoid generating excessively high cutting temperatures, which could cause oxidation on the surface of titanium alloys.

To improve the machinability of titanium alloys, the following measures can be taken: selecting appropriate cutting tool materials and tool geometries, using suitable cutting parameters and cutting lubrication methods, and employing advanced machining techniques such as high-speed cutting and liquid nitrogen cooling. Furthermore, changing alloy chemical composition and heat treatment processes can also enhance the machinability of titanium alloys.

Stainless Steel

Generally speaking, the machinability of stainless steel falls between aluminum alloy and titanium alloy. There are many grades and standards for stainless steel. It is also a very common material used for custom machined parts.

Common stainless steel grades include the following:

1. 304 Stainless Steel: The most common type of stainless steel, with good corrosion resistance and formability, widely used in household appliances, architectural decoration, etc.

2. 316 Stainless Steel: Offers better corrosion resistance than 304, especially in chloride environments, and is commonly used in chemical equipment, marine equipment, and medical instruments.

3. 430 Stainless Steel: A ferritic stainless steel that is more affordable, with lower corrosion resistance but easy to form, commonly used in kitchenware and automotive trims.

4. 201 Stainless Steel: An austenitic stainless steel with higher manganese content and lower cost than 304, but with less corrosion resistance, often used in low-end products and food industry equipment.

5. 310S Stainless Steel: Known for its excellent high-temperature resistance, suitable for heat exchangers, furnace tubes, and other applications in high-temperature environments.

6. 321 Stainless Steel: Contains titanium, providing good resistance to intergranular corrosion, suitable for equipment used in high-temperature environments.

7. 410 Stainless Steel: A martensitic stainless steel with higher strength and wear resistance but relatively lower corrosion resistance, commonly used for knives, pump shafts, and applications requiring hardness.

Plastic

Engineering plastics are also frequently used for machined parts due to their light weight, ease of machining, and in some cases, good lubricity. They are widely used across various industries. With advancements in materials, not only are plastic parts used for decorative purposes, but more and more parts that require strength and transmission capabilities are being utilized in engineering applications.

Common plastic materials used for mechanical parts include

1. Polypropylene (PP): Known for its good wear resistance and chemical stability, often used to manufacture pipes, valves, and pump bodies.
2. Polyethylene (PE): Offers excellent impact resistance and abrasion resistance, suitable for making bearings, gears, and mechanical parts.
3. Polystyrene (PS): Easy to process and mold, used for manufacturing insulation cups, models, and some mechanical parts.
4. Polymethyl methacrylate (PMMA): High transparency and good weather resistance, commonly used for making displays, light fixtures, and lenses.
5. Polyester resin (PET): High strength and good heat resistance, frequently used for making enclosures and structural components of mechanical parts.
6. Nylon (PA): Excellent wear resistance and impact resistance, widely used for manufacturing bearing housings, gears, and bushings.