Geared Extruder

thingiverse

Geared Extruder I wanted to create a new extruder for my printer that I had converted to a "bowden setup". My goal was to make it simple, strong, and ensure the filament could be pressed firmly against the driver gear. The filament can be guided using an adjustable guide. For now, I retained the gland nut (experimental), but included parts that can be adjusted for regular Teflon tube holders. On the printer shown in the pictures, the gland nut works exceptionally well. This extruder and tube setup has successfully completed a 20-hour print test. However, on another printer of mine, the gland nut does not function as well. This is because one prints at much higher speeds (60mm/s and above), and the gland nut fails to hold securely. I discovered that applying Kapton tape to the tube significantly improves performance. I am still experimenting with alternative tube holder methods. The small filament driver (11mm diameter) is mounted on an M8x50mm bolt that I had available. On the lathe, I turned down the end of this M8 bolt to 5mm so the driver can be securely attached. See pictures for details. This model is designed for 1.75mm Filament. For 2.85mm and 3mm Filament, the holes need to be bored out to the correct size. The small gear has 10 teeth, while the large gear has 43 teeth. If you have any questions or concerns, please feel free to ask. Teflon tube holder upgrade FEB-22-2018 This upgrade focuses on replacing the gland nut with tube holder clips. Refer to pictures for more information. Through experimentation with these clips, I learned that the diameter of the hole where the clip is inserted plays a crucial role. Since not all Teflon tubes are identical in size, this hole can vary in diameter. The Teflon tubing I am using measures between 3 – 4 mm, so for me, it works best to bore out the hole with a 6.5mm diameter. However, I recommend starting with a 6mm diameter and adjusting as necessary. April 8 2018 Spring Update After successfully utilizing this extruder without a spring, I encountered issues with a specific filament. Further investigation revealed that this filament was not uniformly round in its length, causing the extruder to fail when it encountered a thinner section of the filament. The filament would slip on the driver gear, resulting in extruder failure. To resolve this issue, I incorporated a spring into the design. Although I should have done so initially, my goal at the time was to keep the extruder as simple as possible. Now, I understand that a spring makes the system more reliable and reduces the criticality of adjusting pressure on the filament. Please refer to additional pictures for more information. New features include: * A longer pressure bar holder to accommodate the spring * A new knob, M5 bolt, and 8mm x 20mm spring (note: the old bolt was an M6, which took up too much space) * A modified pressure bar for the spring