Category: Free 3D Models

Summary
A ruler designed to mark the filament at 15 cm before feeding and reading off the actual length fed afterwards.
The filament snaps into the bottom and top of the ruler and fits into the grove to make reading off the length easier.
The length of the ruler is 15 cm with a ledge at the top that can be used as a guide for a sharp razor mark or marker line.
The markings on the ruler are in mm of actual fed filament to be read off where the mark lines up after feeding 10 cm of filament through the extruder.
Print Settings
Printer:
TEVO Little Monster Rafts:
Doesn’t Matter Supports:
No Resolution:
0.2 mm layer height Infill:
30%, not critical Notes:
I printed mine with ABS but see no reason why this would not work in PLA.
Print settings
0.2 mm layer height
30% infill, not critical
no support, already included in the model
raft does not matter
Post-Printing
You need to clip off the tiny support holding the end of the clamp at the bottom of the ruler.
How I Designed This
After realizing that the extruder feed accuracy needs to be tested for new filaments I decided to make a ruler designed for the task that allows easy marking and measuring of the extruder filament feed length and does not require three hands to hold the filament in place.
I am new to 3D printing and find Fusion 360 to be the easiest to use when taking an idea to a working model.
I use parameterized dimensions to allow easy tweaking and reducing the model size for faster test prints.

Custom Section
Marking 15 cm before filament feed
Snap the filament into the top and bottom clamps of the ruler and press into the grove along the scale.
With the bottom of the ruler resting on the extruder intake mark off 15 cm using the top of the ruler as a guide. Only the bottom of the mark is relevant so don’t worry about how thin it is.
Reading actual feed length
After feeding 10 cm of the filament with:
G92 E0; reset extruder origin
G1 E100 F120; feed 10 cm of filament at 120 mm/min (adjust this to your usual feed rate
G92 E0; reset extruder origin
Read off the actual length from the bottom of the mark aligning with scale printed on the ruler. Numbers are in mm of actual feed. In the image, I adjusted my extruder steps/mm to compensate for always underfeeding by 5mm on 100mm feed so it is showing 100mm.