Selecting the right technology
When choosing between CNC and Additive Manufacturing (AM), there are a few simple guidelines that can be applied to the decision making process.
As a rule of thumb, all parts that can be manufactured with limited effort through a subtractive process should generally be CNC machined.
CNC machining offers tight tolerance and excellent repeatability. Very large to very small parts can be CNC machined accurately. Due to the shape of the cutting tool, internal corners will always have a radius, but external surfaces can have sharp edges and can be machined very thin.
CNC is mainly used for machining metals. It can also be used for machining thermoplastics, acrylics, softwoods and hardwoods, modeling foams and machining wax.
There are a number of limitations that must be considered when designing parts for CNC machining,