The Direct Drive Bowden Extruder V3 BSP Edition was first introduced on Ebay back in March 2013, followed by public release of all the design files in August. So to avoid confusion, this article is the documentation for the above extruder and not a new extruder release. While the bowden extruder continues to be popular it seems important to produce some documentation for it, even if only to provide some sort of version history.
Probably the most important part of the 3d printer direct drive extruder system, at least after the stepper motor, is the filament drive gear pulley. Basically, the choice of drive gear could make or break the quality output of the 3d printer. Without a good drive gear, it will be difficult to begin to troubleshoot or solve hot end issues. So, with the help of the Airtripper Extruder Filament Force Sensor, I’ve reviewed and bench-marked four drive gears and provided graphs for a quick visual comparison.
Here’s the electronics and firmware side of things to support the Airtripper Extruder Filament Force Sensor, which includes the Arduino load cell circuit and the Arduino Sketch. Follow the guides in this edition to obtaining the parts, to calibrate the Arduino load cell circuit and then to calibrate the load cell for accurate weight measuring.
So, to get the best hex nut capture socket fit, I wrote a parametric OpenSCAD script to produce a simple 3d printable test part to fit a configured screw size. Any screw size with either a hex head or a round head can be configured to produce the calibration test part for 3d printing. I’ve made the OpenSCAD file compatible with the Thingiverse Customizer so that the custom STL files can be produced on-line instead of using the OpenSCAD program.
Continuing the Airtripper Extruder Filament Force Sensor series this topic is about getting the plastic parts configured to fit the chosen load cell. Included is a guide to configure the OpenSCAD model file with image references for most of the variables for easy set-up. Be sure to read the section “Choosing A Load Cell” for a guide to getting a load cell to fit the filament force sensor bracket.
To support the Airtripper Extuder Filament Force Sensor and other projects involving load cells, this article will cover some ideas in acquiring load cells and getting them ready for calibration. The article will cover the pros and cons of buying a bare load cell or buying electronic digital scales for the load cell inside. To finish off the article there are three electronic kitchen scale teardowns to reveal the load cells inside, and you will see how the scale enclosure & platform can be re-assembled for calibration purposes. A separate article will follow to cover load cell calibration.
Following the announcement of the Airtripper Extruder Filament force sensor I found a bit of time to run a few tests and to plot a few graphs to find out if the load cell is not just a fancy 3d printer add-on. But before we get into the graphs, we’ll start with the introduction to the Airtripper Extruder Filament Force Sensor; with images to boot.