Click Pen V2

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When I got my first taste of CNC machining and CAD/CAM, I was immediately hungry for more. As a hands-on learner, I decided to machine a bespoke ballpoint pen with a custom-designed click mechanism.

Version one was a resounding success, but it wasn't perfect—its premium looks and feel were undermined by poor balance and excessive weight. It's time for round two.

Group

Role

Personal Project

Skills

Design for Manufacturing (DFM) | Test & Validation | CAD/CAM

Year

2024

(L) single-point knurling in Haas ST20Y 4-axis turning center, (R) sorted parts

Process

Exploded view

Squeezing every last bit of functionality out of vanishingly little space and material was a tall order—V1 was compact as is, and I found my "small" 1/8" end mills shockingly unwieldy for such intricate parts.

Using SolidWorks CAD helped me validate the design and check for interference throughout the design process, substantially reducing prototyping time. V2 adopts titanium, reducing mass while retaining the premium feel of steel. However, its tough, springy nature made manufacturability by design all the more critical.  Integrating additional modularity helped; for example, V1's purely aesthetic accent ring now serves as a structural coupler in V2, reducing the grip's overall length by 37% and making it substantially easier to machine.

The final pieces of the puzzle were incorporating custom milled and 3D-printed fixturing while leveraging four-axis machining and automated probing, which ultimately enabled me to crank out six pens in one batch. I had designed more than just a pen—I had established a process to produce them efficiently.

But that's not all. While testing V1's single pen by hand was trivial, V2's batch of six was a more daunting prospect; instead, I designed and coded an automated stepper-driven test bed to do the validation for me.

SolidWorks CAD Renderings: (L) V2 click pen mechanism (T) V1 pen (B) V2 pen

Outcome

Custom designed and 3D printed test fixture. Powered by two NEMA 17 stepper motors & Arduino Uno R4.

V1 was a success, teaching me valuable lessons about designing for manufacturing (DFM) and still going strong to this day.

Now, here, it used to say, "titanium V2, anyone?" Well, now it's a reality, and it's better than ever:

  • It's 27% (7.4g) lighter
  • It's better balanced, with a center of mass 10% (6mm) closer to mid-grip
  • It'll last a lifetime, with every pen surviving 10,000 cycles on the test fixture with no visible wear or reduction in holding force
  • It's smoother than ever—the test fixture serves double duty, with 10,000 cycles of break-in reducing the click resistance by as much as 43%

V2 retains full functionality in nearly all areas and delivers dramatic, numbers-backed improvements in others. And now there are six of them. Now that is continuous improvement.

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