Summary

Prints have separate resolution in the x-y plane (determined by minimum movement of a printing nozzle/laser) and z direction (determined by layer height). This is then separate from minimum feature size which is determined by diameter of the nozzle/laser point.

To help distinguish the various methods of polymer additive manufacturing, the benefits, limitations and usage of each are summarised in the table below.

It is important to note that all additive manufacturing methods struggle to control properties with the precision and variety that traditional methods have. Limited material pool size and printing effects such as the anisotropy in FDM prints prevent additive manufacturing being seen as a better alternative to existing methods. Combined with the fact that additive manufacturing is generally quite slow and unable to produce products in bulk, AM is mostly being used in pre-production for prototyping, to produce parts that are used to make moulds which then allow fast production, and in printing one-off custom objects such as hearing aids (which require specific shapes to fit in the user’s ear).

Looking specifically at FDM, properties are highly anisotropic and can vary greatly depending on variables such as infill percentage, fill pattern used and print direction. How you create a print should be considered when making a product with its purpose in mind so these variables can be chosen appropriately.