S5 Extruder tensioner problem and repair

[Geep 2]

After finishing a long print job and starting another, my S5 went somewhat wonky.  Prints were failing right and left.  I cleaned print cores, reset XY settings, and generally tore hair out until I figured out what had happened.  The number 1 extruder tension adjustment bolt had burst through the housing, removing most of the tension from the extruder.  The material was still feeding when loading and unloading, which added to diagnosing the problem.  Finally, when I got smart enough to realize that all the problems I was having were due to under-extrusion, I inspected both extruders.  Number 1 had a bolt head showing that hadn't been there before. Hmmmm.

 

To make along story much shorter, it appears that the bolts holding the extruder together had somehow loosened, allowing the adjuster bolt to leave it's mounting, and release all the tension on the material.  There was just enough for it to move but not enough to extrude properly for a print, though it appeared to do so when loading.  I heard something make a loud noise when this happened, but it wasn't obvious what happened.

 

The solution was to take apart the extruder and reset the bolt.  To do this you need a number 8 Torx driver and a small pair of needle nose pliers.  Unload the print core and remove the material.  Remove the Bowden tube from the extruder by pulling out the horsehoe clamp, pressing on the connector housing and pulling out the tube.  Take the two bolts that hold the assembly to the frame out and carefully remove the housing.  It has a short cable attached.  CAREFULLY pry out the 4 pin connector.  The assembly is now loose and can be pulled completely off.

 

Take the assembly to your work surface and remove the four bolts holding the cover on.  It takes a little wiggling, but eventually you can take it off.  The Bowden tube connector and the metal ring at the bottom will immediately fall out, or at least mine did.  They're meant to do that, just remember where they go and put them back in the correct way.

 

The adjuster bolt sits in a slot just inside the housing.  Inspect the slot on both sides of the enclosure to make sure that it has not broken.  If it has, you are now out $105 plus shipping for a new one.  Mine was OK. 

 

Extend the adjuster to it's minimum setting.  You screw the bolt into the spring assembly to do that.  Turning it counter clockwise increases the tension.  It's easier to get it back in place with most of the tension off.  Make sure the arm is closed. 

 

Make sure the Bowden tube holder and the metal ring are back in place with the assembly still lying on your work surface.  Have your bolts and Torx driver ready.  Place the top cover back on the bottom assembly but don't start bolting yet.  Use the Torx driver to compress the tensioner bolt so you can slip the head into the slot. It won't stay there, so you have to have the rest of the assembly ready to close up for it to stay in place.  It's a little tricky to do. Once you have it aligned and closed -- make sure the two parts that tend to fall out are in the right place, I had to take mine back apart because the bottom ring had shifted -- tighten the bolts and adjust the tension so the indicator is back to the center position, if that was where you had it.  I use Ultimaker materials, so center was right for them.

 

Now you can go back to the machine and reinstall.  You should probably lubricate the gear that drives the extruder now, as shown in the manual.  Then, carefully grab the wiring and connector you took loose and guide the 4 pin connector back into it's socket.  The wires are short, I found the easiest way to do it was to use needle nose pliers to grab the wiring close to the plug, guide it into the jack and then use a small screwdriver to push it in.   Return the assembly to its mounting spot, and put the bottom bolt in first.  Easier to align the top one that way.

 

Re-attached the Bowden tube and don't forget the horseshoe clamp.  Turn the machine back on, reload your material and you should be good to go.

 

I thought I'd share my experience since I couldn't find any comments about this problem on the board.  Spencer with Ultimaker was very helpful and provided a link to maintenance for the UM3 extruders, which are similar but not exactly the same.  It's here:  https://ultimakernasupport.zendesk.com/hc/en-us/articles/115004264626-Feeder-Reassembly-UM2-UM3- if needed.

 

YMMV. 

 

Geep

Lynchburg  VA