RAPDASA 2024 · Additive manufacturing

Helical Pen

The 2024 RAPDASA Design Competition asked entrants to use additive manufacturing to make the most aesthetic, ergonomic and impressive pen they could. Our entry has a helical body and a captive cap. It ranked first in round 1 and reached the multi-material final round.

Helical Pen - Additive manufacturing
Competition
RAPDASA 2024, run by Akhani 3D
Project
BMEC internal R&D
Round 1
SLS nylon - ranked 1st, 21.8 / 25
Final round
DMLS stainless + SLS nylon
Body inlays
BMEC in Morse code
  • Mechanical design
  • Additive manufacturing
  • DfAM

The challenge

Round 1 called for a pen in SLS nylon, under 160 mm long, with three attempts to print and fit the parts. The top 10 entries went through to a final round combining DMLS stainless steel with SLS nylon.

In the final round, each metal part could be at most 80 mm long and had to be self-supporting, and there was one attempt at the metal print. In both rounds the pen had to house an existing refill and use under 25 cc of material. Judges scored aesthetics and design, ergonomics and practicality, and the use of additive manufacturing.

What we did

  1. 01

    A cap that cannot be lost

    The cap has runners that travel in channels along the body, so it stays on the pen. Detents at each end hold it in place. Between the detents it slides freely and can be used as a fidget.

  2. 02

    Fitted by temperature

    The cap is printed separately and has to pass the detents to go on. The cap went on after we warmed the cap and cooled the body. At room temperature the fit is firm.

  3. 03

    Bubble texture and magnet

    The round 1 nylon cap has a bubble texture over a helical form. A magnet in the end of the pen can reach small objects in tight places.

  4. 04

    Redesigned for metal

    The final-round cap is DMLS stainless steel and adds weight to the pen. Akhani 3D flagged overhangs on our first cutouts as too horizontal and too large, so we changed to a hex cap with bobble cutouts and reduced the fillets.

  5. 05

    Morse code inlays

    Stainless steel inlays in the nylon body spell BMEC in Morse code. The inlays rely on the accuracy of the stainless steel and nylon prints.

Gallery

Up close.

1 / 10Final-round pen with stainless steel cap and nylon body.
Final-round parts and pens. The finished pen is on the right.
2 / 10Final-round parts and pens. The finished pen is on the right.
3 / 10The cap sliding along the body.
DMLS stainless steel cap with bobble cutouts.
4 / 10DMLS stainless steel cap with bobble cutouts.
Hex end of the cap.
5 / 10Hex end of the cap.
Stainless steel inlays spelling BMEC in Morse code.
6 / 10Stainless steel inlays spelling BMEC in Morse code.
Finished pen on a notebook.
7 / 10Finished pen on a notebook.
8 / 10Writing with the finished pen.
Round 1 SLS nylon cap with bubble texture.
9 / 10Round 1 SLS nylon cap with bubble texture.
Round 1 parts and pens in SLS nylon.
10 / 10Round 1 parts and pens in SLS nylon.

More work

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