Paste extruder (clay)

We designed this clay extruder based on a syringe extruder. It's possible to put syringes up to 100 mL with this system.
All the files are designed with OpenSCAD and can be modified parametrically.
The original project has one NEMA17 motor but for heavy duty 2 motors can be driven in parallel (as in the picture).
An housing for two LM8UUs was drawn but tests showed that they weren't necessary.
Take care of the nut and nut coupling and washers at the top. Their positioning should avoid the vertical movement of the axis but a free rotation of the screw must be guaranteed.
The extruder was mounted on a Prusa Mendel i2 and worked successfully. However, due to the design of the printer used, a tube was used to draw the material up to the nozzle. For this reason, a careful experimentation is needed in order to find the proper clay/water ratio and printing speed. The use of an hair-drier pointed close to the nozzle helps to increase the stability of the printed object.
The next step is