Fused deposition modelling (FDM) is a 3D printing technology that uses melted plastic filament to build up objects layer by layer. FDM parts are typically made from thermoplastic materials such as ABS, PLA, or PC.

Once the object is printed, it can be finished using various methods, such as sanding, painting, or machining. CNC machining is one of the most common ways to finish an FDM part.

It involves using computer-controlled cutting tools to remove material from the surface of the object until it reaches the desired shape and size.

The effects of CNC machining on surface roughness in FDM
In Fused Deposition Modeling (FDM), a layer of melted plastic is deposited onto a build plate in a pre-determined pattern.

Once the layer has cooled and solidified, the build plate is lowered and another layer is deposited on top. This process is repeated until the desired item is complete.

One of the challenges with FDM is that the deposition process can cause surface irregularities, known as surface roughness. CNC machining can be used to smooth out these irregularities and improve the surface finish of an FDM part.

In most cases, CNC machining will involve milling or turning operations. The milling process involves using a rotating cutting tool to remove material from the part.

The turning process also uses a rotating cutting tool, but in this case, the part is rotated while the tool remains stationary.

Both of these processes can yield excellent results in terms of surface roughness. In general, CNC machining is an effective method for improving the surface finish of an FDM part.

However, it should be noted that CNC machining can also introduce new surface irregularities if not performed properly.

This is because the toolpaths generated by the CNC machine can create small “valleys” in the surface of the part. These valleys are typically only a few microns deep, but they can be visible to the naked eye.

Read more: Effects of CNC Machining on Surface Roughness in Fused Deposition Modelling Products