A10M Dual auto-rewind spool holder

thingiverse

Dual filament spool holder for the Geeetech A10M using the rewind mechanism from the Universal Auto-Rewind Spool Holder (https://www.thingiverse.com/thing:3338467) made by Vincent Groenhuis, many thanks to him for making this :)\r\n\r\nI used the v3.3 version of the spring (important to print the spring in .2mm layers), and my prototype has printed 100 plus hours with this spring without any problems. If it starts giving me problems I might make a new spring based on Vincent's 3.4 modular spring. All other parts can be printed in whatever height you like, and no supports are needed for any of the parts.\r\n\r\nThe spring is the only part that has a different model for the left and right side; the right side is just a mirrored version of the left side. For the other parts, both left and right sides are the same.\r\n\r\nNotice that because my printer is underneath a slanted roof I turned the holders around compared to the stock default where the spools are at the back side of the printer. If you take left and right while standing behind the printer, the construction is the same as left and right for me when in front of the printer.\r\n\r\nI started with a bearing-based filament holder after noticing the spool tugging on the extruder. My hope was that a smooth infeed of filament would improve print quality, but to be honest I cannot really tell the difference between the stock holder, a centered spool with bearings, and the centered spool with bearings and auto rewind. (See calicat pictures)\r\n\r\nWhat I did notice though is that with the auto rewind the spool stays much better wound.\r\n\r\nFor the A10M with its mixing nozzle and bowden tubes I use a large retraction setting (18mm) to reduce stringing. After a few hours of printing, the spool would start to become 'messy', not just the coil nearest to the extruder would become loose but multiple coils behind these. (With the low friction spool this was even worse since the tension from the filament was enough to unwind the spool..)\r\n\r\nWith the auto rewind, the spool rotates back on a retract and the filament stays nicely wound round the spool. (Besides it is quite a cool mechanism to play around with :))\r\n\r\nAnother advantage is that the spools shake less with this holder. (Maybe because of the connection between the holders, the spools now being better centered or just because I moved the printer to a more solid table since I started with the holder..) (Btw I can really recommend a solid foundation and some foam packaging pads underneath the printer; the difference in noise is night and day. I did not even try any of the printed feet yet since the foam I had lying around is already making such a difference.)\r\n\r\nThe holder can hold 1KG spools and smaller with an inner diameter between 36 and 89 mm.\r\n\r\nAdditional hardware needed:\r\n+ 1 - M8 threaded rod - 28 cm\r\n+ 4 - 608 bearings like 608ZZ or 608-2RS; I think any 608 bearing would do.\r\n+ 2 - M8 nuts\r\n+ 2 - M8 washers\r\n+ 2 - M8 Lock nuts, I found that tightening normal nuts against the side of the bearing gave too much friction. With the lock nuts you can give the bearings enough space to rotate without the nut unscrewing itself. (I am sure some solution with smaller washers or some spacers would work fine as well)\r\n\r\nI used a bit of deco for the middle part and the holder endstops (thanks to Tokagehideto https://www.thingiverse.com/thing:2454548, Nexnox https://www.thingiverse.com/thing:3002446, IDig3Dprinting https://www.thingiverse.com/thing:1278865, CreativeTools https://www.thingiverse.com/thing:763622) If you don't want this I included the plain models for the middle and endstops as well.\r\n\r\nThe dimensions are based on my printer; my inner diameters tend to be quite thick. I used about 0.3mm tolerance for the nuts and bolts which might be a bit much for other printers. On the other hand since this is for the A10M your print tolerances might be the same as mine :