Numerical control (CNC) processing is a multi-functional, high-precision traditional manufacturing process, which is very suitable for the medium to mass production of complex parts. CNC service machining is a subtractive process, which means that the machine cuts off a solid piece of material to make the finished product, rather than gradually depositing material as in the additive manufacturing method. Through CNC machining, manufacturers can quickly produce prototypes and durable parts for specific applications.
Material selection is an extremely important part of any manufacturing process, but engineers and product teams must be extremely diligent when selecting materials for CNC service processing.
Since this process is compatible with many materials, from metal to fiberglass to wood, it is easy to mistakenly choose a material that is sufficient to meet the needs of the project but is not the most suitable.
Ⅰ. The procedures of selecting materials for CNC service
The following are the basic steps of the material selection process:
Step 1: Define material requirements: These requirements can include mechanical, thermal, or other material requirements, as well as cost and surface finish. Also, it is necessary to consider the environment in which the parts are used and related components.
Step 2: Identify candidate materials: Identify some candidate materials that meet all (or most) of the design requirements.
Step 3: Choose the most suitable material: Here there is usually a trade-off between two or more design requirements (such as mechanical properties and cost).
Ⅱ. Which CNC machining material should you choose for the CNC service?
Any material, metal or plastic is sufficient for CNC service processing and can be used for CNC manufacturing.
(1) Aluminum
Aluminum alloy is easy to process in large quantities, has good strength, weight ratio, and high thermal conductivity and electrical conductivity. They also have natural corrosion resistance. Aluminum 6061 is a general-purpose aluminum alloy and is often used for cheap CNC machining.
It is usually found in car parts, bicycle parts, sporting goods, and other entertainment products. This material is highly workable. However, it may be more expensive than other metals and cannot be maintained well in the presence of saltwater or certain chemicals. Aluminum 7075 is an upgraded version of 6061. And the 7075 is an ideal choice for aviation frames and high-performance entertainment equipment because it is the strongest commercially available aluminum alloy.
(2) Stainless steel
Stainless steel alloy has high strength, resistance to deformation, wear, and corrosion. 303 stainless steel contains sulfur to improve workability, but this material has limitations that many engineers must keep in mind.
303 cannot be cold-formed, heat-treated, or welded. In the CNC manufacturing process, special attention must be paid to the feed and the sharpness of the tool. In other words, 303 can manufacture excellent nuts, bolts, non-marine grade accessories, shafts, and gears.
304 stainless steel is non-magnetic general-purpose steel used for cheap CNC machining and is known for its toughness. It is as easy to process and corrosion resistant as 303, but it can be welded. 304 is very suitable for a wide range of consumer and industrial applications, kitchen accessories, water tanks and pipes, construction, etc.
Due to the addition of molybdenum, 316 stainless steel is more resistant to corrosion than 304 or 303. It is strong and weldable and is one of the few marine-grade stainless steel.
Since stainless steel cannot be distinguished visually, engineers should make sure to test raw materials to confirm the characteristics of the steel they use.
(3) Carbon steel
Carbon steel 1045 is a mild grade carbon steel. Manufacturers often use this material for cheap CNC machining because it is cheaper than most stainless steel, but it is stronger and tougher. The carbon steel 1045 is easy to process, which can be welded, hardened, or heat-treated to achieve various hardnesses.
This material is ideal for nuts, bolts, gears, shafts, connecting rods, and other strong small mechanical parts. 1045 can also be used in construction applications, but it must be surface treated to prevent rust and corrosion.
