After being encouraged by a co-worker, maker and blogger Angry Monk took on the challenge of 3D printing a working mechanical pencil all in one print. The pencil is fully functional and is rather stylish as well.
The pencil, comprising four independently moving parts, was 3D printed fully assembled on a Stratasys Objet Eden500V in a white polypropylene material with a water soluble gel-like support structure. The holes along the side of the pencil are not strictly decorative, but actually allow the supports to easily be removed. At about 6.5 inches (16.51cm) the pencil is roughly the same size as any other mechanical pencil. It uses standard 0.9 mm lead, 0.7 mm erasers and has a small internal cavity that can hold additional pieces of lead.
Angry Monk found that trying to design a printable object from a standard mechanical pencil design was futile, as they relied too much on an internal spring and tight fitting parts. He essentially had to completely redesign his mechanical pencil from the ground up. Take a look at a video of Angry Monk explaining the design process and showing off the incredibly clever internal mechanism:
His design functions like a screw inside of the hollow pencil. You start by rotating the back of the pencil, turning the screw-shaped mechanism inside that extrudes the lead out 1.2mm at a time. The screw piece has twelve detents that click into place after each successful turn, and if you rotate it in the opposite direction the lead can easily be pushed back inside of the pencil. The lead is prevented from sliding out by three tiny fingers at the front of the pencil inside of the tip.
“I tried to retain all the core functionality of a mechanical pencil with this design. I believe I accomplished that. Moreover, it looks cool and functions well. I am glad with how this project came out.” The design has been placed up on Shapeways, however it is not available for download or sale yet, as Angry Monk is still trying to verify that it can be printed without an industrial 3D printer like the Eden500V. You can find more information about how he made his pencil on his blog, where he has also posted several other awesome 3D printing projects.
