Anycubic i3 Mega TPU Retract Extruder Mount MOD v2.0

thingiverse

Anycubic i3 Mega TPU Retract Extruder MOD v2.0 ______________________________________________________________________ v2.0 Change log - Smaller and lighter design - Better access to the extruder - Shorter filament tube possible - More stable than v1.0 (no wobbling at high pressure speeds) - Extrinsic drive is accessible for manual feed ______________________________________________________________________ Since the i3 Mega or i3-Mega S comes with no retract feature for soft TPU by default, here's a small modification that makes it work. You can also use a direct extruder. However, the modification offers several advantages over a direct extruder: - No higher weight on the X-axis, which restricts print speed and increases jerk value for the X-axis (a high value improves print quality at TPU significantly) - No worse print image at high print speeds due to additional vibrations - No worse filament distribution since the feed pressure of the filament is still damped - Price The following items are needed for installation: - Printed extruder holder (infill 15%) - Stepper motor A4988 for extruder (only i3 Mega S) - 4 x 150x1.0mm copper cables - 2 x 10mm M3 screws - Filament tube with exactly 2 or 1.9 mm inner diameter (the original tube has about 2.2mm) I use this one: https://www.ebay.de/itm/Teflonschlauch-%C3%98-4x2-natur-1-Meter-PTFE-bis-260-C/290746551165?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649 Installation: 1. Attach printed extruder holder parts to the printer and extruder (see image below) 2. Pull filament tube through the guide of the holder and insert it into the extruder input. Connect extruder and hotend with new filament tube (about 300mm, as short as possible). 3. Cut middle cable of extruder motor and extend each wire with 150 mm cables. Then, stuff all cables like in image below in extruder holder. 4. If you have an i3 Mega S, you need to use the A4988 driver for the extruder. The TMC2208 does not work! Why? -> The i3 Mega S needs about 400 E-steps for 100mm filament instead of 100 E-steps at the i3 Mega, which leads to loss of E-steps at the extruder motor when using TMC2208. 5. With these settings, the TPU Retract works perfectly for me: Filament: TPU Amzon Basic Retraction speed: 100mm/s Retraction length: 15mm Minimum feed before next retraction: 15mm Travel speed: 60 - 80mm/s Print speed: 30 - 45mm/s (higher I haven't tested yet) Bed temperature: 55°C Hotend: 228 °C Flow: 130% Standard hotend and nozzle With a higher jerk value, the print image with TPU becomes even better. My setting is 15 for X and Y at a print speed of 45mm/s (TPU) and 50-60mm/s (PLA). This only works after stabilizing the Z-axis and possibly adjusting play on the linear bearings: https://www.thingiverse.com/thing:3904836