Page 14 - 3D Metal Printing Summer 2016

3D Insights in Metal Printing
Fig. 4a
Fig. 4b
Fig. 4c
best be described as similar to a sand-cast part. The goal was to produce a much smoother finish, accomplished using a lot of filing and sanding (Fig. 4b), followed by shot-peening with glass beads to give the guitar a soft satin finish (Fig. 4c). This step also took 3 to 4 days, mainly because of the geometric complexity of the guitar. In contrast, the second guitar took less than 2 days to achieve the same level of finish. A lesson learned from this proj- ect is to think of metal AM in the same way as sand-casting—all
surfaces that require a good fin- ish must be machined in a post-processing operation.
Finally, the guitar was assem- bled (Fig. 5) by CNC-machining the wooden inner core and assembling the core into the aluminum body. The neck was attached, the pickups and elec- tronics were installed and wired, and the back plates were laser- cut and engraved.
Lessons Learned
So, what lessons were learned? For one, this project reinforced the strong belief of what is possible with metal AM. It also reinforced the importance of post-processing, and recog- nized the amount of labor required to finish metal-AM parts. This project also demonstrated the need to design specif-
ically for maximiz-
ing the benefits of
metal AM while
minimizing the
amount of required post-processing.
Substantial changes
to the guitar design
have since been made
to reduce the amount
of needed support
structures.
Fig. 5
12 | 3D METAL PRINTING • SUMMER 2016
3DMPmag.com
The best way
to design for AM
is to gain a
deep under-
standing of the
setup and oper-
ation of the AM
system itself.
This means direct
hands-on experience
with the machine (not possi-
ble for this project). Designing the part correctly in the begin- ning lessens the number of decisions to be made by the machine operator, such as where to put support structures, which may affect the quality of the finished product. 3DMP