Comparison of Additive Manufacturing & CNC MachiningBoeing and other manufacturers use three primary criteria to measure the
value of additive manufacturing (AM) against CNC Machining: part
performance, cost and lead time (see our blog post on this). In the
past, metal AM processes were expensive and slow. As a result, their use
in production was primarily in applications where the value of improved
part geometries outweighed the sacrifice in speed and cost. For this
reason, the analysis of production cost and schedule efficiency has been
neglected.
With new high speed, low cost AM technologies like Joule Printing™, AM
can now compete with (or augment) machining in speed and cost. This
elevates the importance of a more thorough comparison of these two
manufacturing methods – the purpose of this blog.
cnc precision machining partsMachining is the most common choice for low volume manufacturing because
it is flexible, and can produce strong, accurate parts. Machining
removes material from a workpiece (typically a billet) by cutting it
with rotating tools (milling) or rotating the workpiece itself against a
tool (turning). These cutting processes are very accurate and have
broad capabilities in part geometry and materials. In addition,
machining has low tooling requirements – reducing fixed costs and lead
time. Machining is usually the first choice for rapid, low volume
manufacturing, and is used extensively for prototyping, tool production,
and short-run production of end use parts.
While machining has advantages in low volume manufacturing, it is
expensive and does not scale well for high volume production. Its
shortcomings include: high material waste, expensive machinery, and a
requirement for skilled programming time. In addition, for hard metals
like titanium and tool steel, cutting times and tool wear are very high.
Due to these limitations, manufacturers prefer more cost-effective
processes like casting, stamping, and forging for high volume
production.
