CW2 filament slipping - Voron 2.4 250mm with Stealthburner - is there different revisions of the CW2?

[Joegeeks]

Hello, I also have experienced my CW2 filament slipping on a initial build, which is getting worse.  I'm using the CW2 version that was modded for the ECRF with TWO run-out switches.

- Rebuilt 4 times and replaced all geared components and motor. Swapped to thicker hinge pin for the Tension Arm.  I'm totally baffled!   Is there an issue with MIXING the CLOCK WORK 2 components from DIFFERENT VERSIONS of the CW2 assembly - Is there a change in arm/guide width or length/size with the CW2 for the ERCF and in the Stock CW2 ?

The first indication I had was when doing my initial checks - a Filament Length Run-out test where I would put my thumb lightly on the filament in hole on-top of the CW2 as I ran a length of filament through it. It would run-out EVERY 20-25 mm in a  constantly frequency before it would vibrate/slip, leaving me to believe it was the large gear that drives on the smaller motor gear. After replacing the gear with new precision grade gear it actually was a steady slip. 10mm then a 10mm slip.

Tightening my grub screw didn't do anything and I checked and  the small screw used to back OFF the tension (mostly used for TPU filament) on the gear arm too.

- I've rebuild the CW2 more than 4 times - I replaced the gear components including a swap to the slightly larger stock Hinge-Pin from the 3mm bolt as the instructions called for (modifying the smaller 3mm hole to file off the material in a manner pushing the gear arm closer to the other gear).  I've ruled out my motor after doing a motor swap to a known good motor from my trident and back, plus pulling through the filament with my CW assembly in hand it's an obvious slip and in the lack of gripping force even with the thumb/grub screw over tightened.

The components I'm talking about are the Gear tension Arm assembly (3 piece assembly with the spring and grub screw). I know there is a difference in the Front and Back housings - (they snap together is different so you cant mistake the two versions), but as for the tension assembly I'm not completely sure. 

My only other direction is to reprint the stock CW2 assembly on my Trident and see if it happens again.

 

[mvdveer]

3 hours ago, Joegeeks said:

My only other direction is to reprint the stock CW2 assembly on my Trident and see if it happens again.

I have not had this issue at all in any of the printers.

May be worth building a CW2 from a single repository, and all parts printed on the same printer. Also important to have your extrusion multiplier tuned in perfectly for the filament you are using. (As example for e-SUn ABS black, mine is 0.926, whilst for Polymer ASA Black is is 0.96). Parts will print to spec and eliminate play or binding. 

How much play do you have between the motor gear and large gear - I have found, that about 0.5mm play works well.

I have replaced the standard CW2 (over 2000h print) with the Filametrix and ERCF (Dual Sensor) CW2 on two printers now and clocked up about 200hours print without a problem. Build a Galileo 2 to replace the clockwork, just to find there is no Filametrix compatibility. Currently installing this on a Triden250 that is in for some maintenance.

[claudermilk]

I believe there was a slight change to the tension arm length in one of the most recent updates. I haven't looked in the repository for a while, so I don't recall for sure. I didn't have any trouble with slipping after changing to a good set of Bondtech gears. However, now I'm on a Galileo 2 and really liking it; I don't know how compatible it is with ERCF.

[mvdveer]

8 hours ago, claudermilk said:

I believe there was a slight change to the tension arm length in one of the most recent updates. I haven't looked in the repository for a while, so I don't recall for sure. I didn't have any trouble with slipping after changing to a good set of Bondtech gears. However, now I'm on a Galileo 2 and really liking it; I don't know how compatible it is with ERCF.

It is fully compatible with ERCF - there is a version with the two runout sensors - just build one. But NOT compatible with Filametrix filament cutter.

[Joegeeks]

Thank you all for the replies, I did my sanity check and reprinted the whole SM and CW2 assemblies with GREAT results.  I'm going with the great advice of sticking with a known good revision and print all at the same time.  It worked.  Although it takes away a filament run-out switch.

Interesting that the switch I installed on my modded CW2 assembly used a ball-bearing that would actuate the micro switch - only. On a separate mod I found later,  the author used a Micro Switch, Ball-bearing and MAGNET, to ensure the ball-bearing would not cause binding on the filament.

I don't think I will give up on the filament run-out sensor just yet though