3D Printing: Rapid Prototyping

Left: Successfully assembled, printed prototype parts. Right: Initial proof-of-concept assembly.
Full prototype designs, mid-print.
Proof-of-concept, mid-print.

What:

  • Overnight production of new prototype designs to check feasibility, perform assembly fitment, and hold tangible parts in hand.

Why:

  • Time: 3D printing allows for concepts to manifest in physical form overnight rather than waiting 3-6 weeks for a traditional machine shop to CNC.
  • Cost: The initial fit-check print (pictured above, in purple) consumed 0.80 kg of PLA filament, at $22.99 / 1kg spool, for a net cost of $18.39. The same parts cost $50-200 in aluminum from a local machine shop, depending on expedite fees.
  • Informed Design: The low risk nature of rapid prototyping gives designers license to create and print concepts that would not be worth paying traditional manufacturers to produce. This is turn, can provide valuable feedback to improve the main design path, in DFMA, highlighting stress concentrations, or even appearance.
  • Value of Physical Parts: There’s simply no replacement for having tangible parts in hand. Despite the impressive capabilities of modern CAD software, physical parts bring a unique benefit to the design process that digital models do not.

How:

  • To check the way the cone, the anti-slip segments, and the retention bands fit together during assembly in a unique, untested geometry (if they would fit, and how difficult it would make assembly), a proof-of-concept model was printed on my home printer (a heavily modified Creality CR-10S).
  • Once we determined that the last anti-slip segment could successfully be in installed in the assembly, I printed the full prototype cone and all 6 segments as designed (pictured above, in red).

My Role:

  • Designed all CAD models
  • Exported STLs, sliced, & printed all parts
  • Assembled all

Challenges and Lessons Learned:

  • Printed part tolerances on consumer-level 3D printers do not compare to CNC machining, and can leave a lot to be desired in critical areas. For this use-case, loose tolerances did not ultimately impact the goal of proving design feasibility.
  • Part orientation, part geometry (like overhangs), and infill % can all affect the print-ability of designs. Intelligent choices must be made to reduce the likelihood of a failed print. These parts were printed successfully on the first attempt.
  • It is as important to understand the benefits of 3D printing as it is to understand the limitations.