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3D-printed, plain chopstick in silver (bottom), in 0.3mm draft mode, compared to Japanese chopsticks

Last Updated on 2021 年 01 月 20 日 by 編輯

As hinted in our Mark-and-Go license agreement, we intend to make patent-pending ergonomic and training marcosticks available for everyone to print, for free. During research we made prototypes with a carving knife, epoxy putty, plain chopsticks, and some piano wire. After filing two utility patents, we are now making 3D models, to reproduce these enhanced chopsticks by 3D printing. Once we are happy with these, we’ll make models available.

What you see here are your run-of-the-mill chopsticks, not the enhanced versions. We just received the 3D printer last week. At the moment we are still figuring out how to make good prints. We have printed a few interesting objects so far, including plain chopsticks from model files uploaded by Caracolmaker.

Chopsticks Marcosticks - print M02 palillos-sushi from Caracolmaker - finished chopsticks next to a bunch of interesting test prints
Plain chopsticks from Caracolmaker next to various initial test prints

We printed these chopsticks with SLA at 0.3mm layer height. Since it was just a test print we left the infill at 20% and used draft mode settings.

Chopsticks Marcosticks - print M02 - printing plain chopsticks on the Prusa MK3S at 0.3mm draft mode with 20% infill
Printing plain chopsticks at 0.3mm draft with 20% infill

The STL model from Caracolmaker came with the stick standing on its rear end. This is not the best way to print chopsticks. With a tiny base sitting on the printer bed, and a tall stick flexing at the top, it would not have come out well.

Chopsticks Marcosticks - print M02 - screenshot of PrusaSlicer - chopstick model sitting on its rear end
It is hard to print a thin and tall stick

The challenge here was about how to best print these sticks. A chopstick is tapered at the tip. This creates an extensive overhang which is enemy number one of 3D printing.

Chopsticks Marcosticks - Tip of a chopstick is tapered - it's hard to print on a 3D printer with such extensive overhang
A chopstick is tapered at the tip – it’s hard to print with such extensive overhang

One way to solve this problem is to cut a chopstick in half along its longitudinal axis. The two halves are printed with the cross section facing the print bed, and then glued togeher after printing. That’s too much trouble. Instead, we added support material to prop up tips of the two chopsticks in PrusaSlicer.

Chopsticks Marcosticks - print M02 - screenshot of PrusaSlicer - chopstick model laid on a side, with support material to prop up the tapered tip
Chopstick models laid on a side, with support material to prop up tapered tips

Below is a picture of the print bed after a few layers.

Chopsticks Marcosticks - print M02 - printing plain chopsticks on the Prusa MK3S at 0.3mm draft mode with 20% infill, with brim and support material
Printing plain chopsticks with brim and support material

We are half way there:

Chopsticks Marcosticks - print M02 - printing plain chopsticks on the Prusa MK3S at 0.3mm draft mode with 20% infill, with brim and support material

Just about done:

Chopsticks Marcosticks - print M02 - printing plain chopsticks on the Prusa MK3S at 0.3mm draft mode with 20% infill, with brim and support material
Printing plain chopsticks at 0.3mm draft mode with 20% infill, with brim and support material

They are printed successfully!

Chopsticks Marcosticks - print M02 - printing plain chopsticks on the Prusa MK3S at 0.3mm draft mode with 20% infill, with brim and support material
Chopsticks Marcosticks - print M02 - printing plain chopsticks on the Prusa MK3S at 0.3mm draft mode with 20% infill, with brim and support material

We do not intend to use these printed chopsticks yet. They are printed with PLA at coarse grain and are not sanded. They contain crevices that harbor bacteria, so they are not suitable for actual use. In general one would use PETG for actual use.

Chopsticks Marcosticks - print M02 palillos-sushi from Caracolmaker - finished chopsticks - comparison to Japanese square chopsticks - IMG_7639
3D-printed chopstick in silver (bottom), compared to Japanese chopsticks

In any case, PLA at 20% infill with 0.3mm layer height is too soft for chopsticks. Watch how these sticks bend at medium pressure.

Chopsticks Marcosticks - print M02 - PLA at 20 infill at 0.3mm is too soft for chopsticks - IMG_7637
PLA at 20% infill with 0.3mm layer height is too soft for chopsticks

Well… that’s it for now. We’ll be busy working on 3D models of enhanced chopsticks next. Stay tuned.

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