EIBOS CYCLOPES KINETIC SPOOL DRIVE

OVERVIEW

This is a drive mechanism that will rotate a second spool of filament in the dryer as the printer is drawing filament from the other.  No modification is needed to the original dryer so it can easily be returned to it's standard state.

I am not totally convinced that this modification is necessary, and I would go as far as to say if you are drying PLA at low temperatures it probably isn't, HOWEVER it is a lot of FUN to build and very satisfying to watch in use!

Even better for me is a message I received from the Eiboss Team which was super complimentary, and rather made my day!

It is clear that some people have encountered instances of filament fusing on stationary spools, and it appears that Eibos' official response to that is to rotate the filament from time to time.

This contraption was inspired by many things, but particularly from 
warpster's Cyclops drive mechanism.  which I may build one day anyway and 
Paul's Extension Rollers 

TESTING

UPDATE 9 June - After twelve hours drying time the PETG is beginning to deform. This was not unexpected!   While the size was deliberately as large as I could fit under the lid, this makes changing filament even more fiddly so I've been running without rear wheels and will make a revised version which will be a little lower.    

With the chamber temp set at 45° I measured actual temp on the wheels at 67° so a little more deflector work is underway!

Be warned that at the time of upload  it's only been tested over a six hour period (and I mostly only dry while printing)  and it works as advertised, but I'll happily take any suggestions on board and attempt to develop the idea further if there's any interest.

The weakest links at the moment are that the wheels can tend to wander a bit (hence Paul's grooved design), and my rubber weld has lost traction (once) which didn't affect the print, but it did stop the idle spool from working for ten minutes or so before mysteriously restarting of its own accord.
 

PRINTING

I have printed everything in clear PETG, and eventually will test it all to destruction.  A wiser person would start with ASA or ABS and not do it twice!   This should be fine in the short term for drying PLA and PETG.

I have also used a ridiculous number of Perimeters (7) to effectively print solid.  This was to perhaps minimise the amount of warping at higher temperatures, but should not be necessary with a more sensible filament choice.

All of the wheels are designed with minimal bearing surfaces to minimise friction.

ASSEMBLY

HARDWARE

Apart from the printed pieces, you will need two M2 16-20mm long hex headed screws and nuts, two 608 SKATE bearings and a bit of low friction tape (or rubber band, or bit of bicycle tube or in my case rubberweld tape) to add a bit of friction to the driving wheels.

“REAR” AXLES

The rear axle lift wheels are optional, and if your filament spools are greater than 200mm diameter, the spools won't fit.  (I'll make a “shorter” version if anyone requests it.

Move the standard o-ring to the centre of the Eibos axle and feed a 22mm spacer and a Spool Wheel (and a washer or two to taste) to each side and replace the axle.

“FRONT” (drive) AXLES

Assemble as shown below.   Note if your filament spools are greater than 70mm wide, flip the spool gears on their axles so that the sprocket runs inside the spool.

Centre the o-ring on the original axles and use a 19mm spacer each side.   Use a Spool wheel on the non-drive side.

Apply some non skid material (I used rubberweld tape, but anything from a piece of bicycle tyre to heatshrink will do) on the surface that contacts the spool.

Press 608 bearings into the frame.

Place two M2 nuts in  the axle slots and assemble the drive axle as shown.

Screw the hubcaps into the axles to secure the drive assembly.

Now using three or four hands, locate the original axles and bearings (now attached to the whole wobbly mess) into the original supports.

Next time you start your printer you will be mesmerised by the turning gears!