Celebrating the 10th Edition of the Nextruder Fine Point Sharpie Adapter

My Best Adapter Yet - Now Slim

The Fine Point Sharpie lineup of the Nextruder Pen Plotter Adapters have always needed some extra love. For quite some time the fitup hasn't always worked for some of the sharpies in my supplies, so I took some time this weekend to get a sample of measurements to figure out why.

Discovery

It turns out that the dimensional accuracy of fine point sharpies is pretty wide. I measured a sample of 31 pens in 3 critical dimensions, producing a spreadsheet of 93 measurements. The measurement process was pretty mechanical and featured a lot of music, logging, and data entry. It turns out that all 3 critical dimensions have a range of about 0.3mm. Combine this fact with the single sharpie I based my initial prototypes off of being on the smaller side and I had my answer.

Prototyping With New Dimensions

I took what I learned from my measurements, updated my CAD variables, and incrementally printed a few versions. Then at V9 and experiencing better fitups, I wanted to address a long standing problem with wasted space in the depth of the model. I did some fancy boolean union and subtraction operations with the separate parts I use to create the chassis and produced a 4mm smaller part and shaved 29% off the print time bringing it from a 58 minute print down to 43 minutes.

Next Steps

I'm planning on installing the new V10 model onto my printer for further testing in the coming days, but it's already passed torture testing and validated the printer won't eject the pen from the friction of use. I'm looking forward to making more art with this updated version, as it will allow me to use my metallic series of sharpies (which run a bit thicker) on black paper for some pretty striking results.