For 3D milling you will need an .stl file of the object you want to mill. In case your object is bigger than the material you have OR bigger than the max thickness we can mill (6 cm), you will need to split up the model into separate pieces. Each piece then becomes a separate .stl file. Make sure to not have too big files that are hard to import (>500 MB)
Since we only have 3-axis machines at Fellesverkstedet, you'll want to avoid undercuts. Undercuts are cavities that the milling bit cannot reach because of the limit of the axes, as shown in the image below.
However, there are ways to split up your 3D model into separate parts which can then be milled and afterwards glued together as shown in the image below.
Depending on the shape or model you are trying to create, this can get quite complex, so if there's the opportunity, try to simplify what you are tying to do as much as possible.
With 3D-milling, things can sometimes get a bit complicated as there's more factors to consider then with 2D/2.5D-milling (though not always). If you're using a ballnose milling bit there's no way to create perfect sharp corners, as shown in the image below. Note: this is only the case for inner corners. Outer corners shouldn't provide an issue.
The diameter of you milling bit will also decide the detailing that you're capable of milling. At the same time, the diameter decides how much time it takes to mill so you need to find a balance between how much detailing you would like and how much time you would like to spend milling. In some cases it is possible to use a smaller diameter milling bit in the areas where the bigger big cannot reach, but this is often hard to get perfect due to a different tool deflection of a different bit.****
