Abstract

For a long time, I’ve wanted to design and manufacture my own pen. I’ve always loved stationary and especially fountain pens. While taking a manufacturing course through the Scientific Instrumentation Facility at Boston University, I got the perfect opportunity!

Design Process

I started the design process by visualizing how I would like my pen to look and function. Drawing inspiration from the Rotring 600 Mechanical Pencil, I decided that I wanted my pen to feature a hexagonal body to prevent it from rolling off tables, be made from brass to provide both stability and a substantial feeling in the hand, and be about 5 inches long. In addition, I wanted my pen to have a a screw mechanism so that the user could retract the nib when not using the pen. I’ve found that pens without retractable nibs are more prone to breaking with continued use. Lastly, I wanted a lofted tip on the end of my pen. In my CAD class we had just learned about lofts and I wanted to understand how to translate a loft from a design onto a manufactured product.

Then, I began research to understand the components of a typical pen and how they interact together. I found that pens have the following basic components: body, attached or separate tip, ink insert, spring, and cap. The body houses the ink refill, the cap keeps the insert within the body of the pen, and the tip provides a housing for the spring and the outlet for the ink refill.

After understanding the desired functionality for my pen and researching the necessary components of such a pen, I began to design my pen within Solidworks. In this project, I actually used Solidworks much earlier in the design process than usual. Rather than comprehensively designing my pen on paper, I visualized my design within Solidworks to see how changing one component would impact the whole pen.

Modelling & Drafting in Solidworks

The final design for my brass pen included five components:

1. hexagonal body
2. lofted tip
3. screw cap
4. Pilot G-2 Ink Refill
5. Pen Spring

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Manufacturing

Drawings

Before I could begin manufacturing my pen, I had to create drawings from the Solidworks models. These drawings contained the specifications of my design to ensure that the manufactured components would fit together in the desired way. For instance, the drawing of the lofted tip highlights the diameter of each hole to ensure that the pen refill and spring will fit properly.

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Machines & Process

To manufacture the hexagonal body, I used the CNC mill to cut a 0.5″ rod of brass into a 0.35″ hexagonal shape. Then, I used the manual lathe to cut the various width holes into the body. Lastly, I used a thread tap to make the threads on the inside of the hexagonal body for the lofted tip and the screw cap respectively.

I turned the outer diameters and bored out the inner holes in the screw cap with the manual lathe. And then, Glenn Thayer, the teacher of the SIF class, helped me cut threads into the outside of the screw cap with the Haas CNC lathe.

Lastly, to manufacture the lofted tip, I used the manual lathe to turn the outer diameter of the tip that would interface with the hexagonal body. Then, we used the 3D milling machine to achieve the loft of the tip.

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