Milling is a cutting process which performs a cutting action similar to drilling process, however, the cutting tool moves in 3 or more axis to achieve desired shape in a component. The cutting tool usually rotates about an axis that is perpendicular to the table that holds the material to be cut. A block of material is placed on a moving table below the cutter. While the cutting tool turns, a computer controls the vertical (Z axis) motion of the cutter and the horizontal (X and Y axis) motion of the block of material.
While designing a component for CNC Milling, try to adhere to following points:
Providing corner radius of 10% or more of wall height is ideal.
- Avoid flimsy shapes.
- Provide shapes that are practical to hold during machining.
- As the milling process applies pressure to the material, weak shapes are difficult to machine, such as long thin shapes and thin walls.
- Generates a cut surface with a visible pattern resulting from the rotation and movement of the cutter.
Apart from these general design considerations, following are some technical specifications of CNC Milling which should be taken care of.
Size of components
- Maximum part size (3-axis milling): 10 in. by 7 in. (254mm by 178mm)
- Maximum part size (5-axis milling): 2.6 in. by 2.9 in. by 3.9 in. (66mm by 73mm by 99mm)
- Minimum part size: 0.25 in. by 0.25 in. (6.4mm by 6.4mm)
- Maximum part depth: ranges from 0.75 in. to 3.75 in. (19mm to 95mm). The maximum depth that can milled from either side of the part is 2 in. (51mm).
Tolerance: In general, we can achieve of tolerance of 0.13mm.
There are several advantages to going for CNC Milling for production, such as:
- Cost effective for short runs, i.e, for upto 200 pieces
- Complex shapes and high dimensional tolerances can be achieved
- Wide variety of materials can be CNC Machined, such as Nylon, Steel, Stainless Steel, Aluminum.
- Same designs can be replicated over a good number, maintaining reproducibility.
Some commonly CNC Milled components are shown below:
Typically, the accepted file formats for CNC Milling is STEP or IGES. So to get a quote, for the same, make sure to export your designs in these file formats.