68 MMS December 2017 mmsonline.com
ADDITIVE INSIGHTS
Understanding Industrial 3D Printing
lattice structure on the underside of the part to
improve rigidity while adding only minimal extra
weight. Corey also was able to leverage machining
allowances to add material near the piston rings
in such a way that they were self-supporting. All
combined, the enhanced piston crown design
required zero additional supports to enable addi-
tive manufacture in stainless steel (see Figure 2).
The final piston crown weighed 7.5 percent more
than the original piston crown yet required 11
percent less time to manufacture. It had zero sup-
port structures to remove, and once it was machined
to its final specifications, it was actually 4.1 percent
lighter than the original design yet had 37 percent
more surface area to improve heat transfer. In short,
by designing for AM, we enabled a functional
prototype that could be made in two to three days
with minimal post-processing effort, compared to
two to three weeks via conventional methods.
So why should machine shops care about this?
Those that subsist off making functional prototypes
could find themselves displaced from the supply
chain if their customers decide to leverage AM
technology. It may be in their best interests to
understand how to contribute to AM rather than
be disrupted by it.
Fig. 2. All combined, the enhanced piston crown
design required zero additional supports to enable
additive manufacture in stainless steel.