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Both the extruders nozzles Clogged after attempt to do dual print on MBot Cube Dual

I have only had the printer about a week and have done a number of successfuly single nozzle prints using the right head and was very happy with the results.

 then I attempted to do the the earth example as described in the manual page 6 in PLA  using the suggested parameters as suggest on page 7. and ended up with a big mess stuck to the hot end.

I clean up the mess and attempted a single nozzle print on each nozzle and  was rewarded only by clicks. I follow the procedure on page 18-19 of the manual no luck . 

I did notice the nuts holding one of the extruders to the bar were loose so I tightened them. 

This was not the first loose nut  I've encountered on this machine the nuts that were supposted the stop the screws spinning when you use the wing nuts to level the bed were all loose.

I removed the nozzles as suggested elsewhere on this site and they are blocked solid,  as its PLA I did not try acetone.  I did manage to remove most of the PLA from the back of each nozzle using a heated sewing needle but could not clear the 0.4mm hole.

I reassemble the heads and tried loading the PLA again no luck (I thought with most of the PLA out of the nozzles pressure might do the rest)

Now I am at a loss as to what to try next apart throm getting new nozzles.

Also I have no idea what  caused this problem and more importantly how to avoid it in the future.

Your help would be greatly apreciated.

Found your fact sheet about nozzles while pricing up replacments so they are now soaking in castic soda.

Found what I suspect may be part of the original problem.
The left fan was not always spining when it should.
There was a foreign object jamed in grill. Turn out to be a silver rivet (same colour as grill which is propably why I didn't spot it) stuck on end of one of the loops near the screws.  Where it wobbled in and out of the path of the fan blades. I am not sure of the effect of the fan stopping while printing but it can't be good.


ran filiment thru with the nozzles off to clean out any gunk.
 replaced both nozzles with new ones.
works for a little while then starts clicking. no hangups or jams found. in filement feed.
As nobody seems to read this forum and as there is no option for mbot under raising a support ticket I'm stuck.
The machine is still unusable.


I cleaned the nozzles and comfirmed the holes were open. when loaded filament the right nozzle would work for a few seconds then start clicking , the left would just click. The left also clicks when I try to unload the filament.
I have no idea what to do next.

basicly the mbot is now unusable after 10 days of  ownership and 6 prints (all from the right nozzle)

Please help

ps it was  purchased from billycnc Order Number 8584

Hi Rickie. 

My (Mbot3ddualcube) machine is a bit like this when printing with PLA, too. 

Extruder works for a few seconds:

My theory is that when the feedrate slows / pauses temporarily (eg for infill or whatever) heat travels up the barrel and  softens the filament. When feeding again new filament presses into this soft material which compresses and forms a plug that is too wide to pass through the barrel. I've since found that when I pull out the stuck filament it has much thicker segment on the end, which seems to support the theory. I had some success printing at a lower temperature, or printing at 100% infill, although that seems a bit waste-full.

Extruder doesn't work at all:

I've had some success with taking it apart and putting it back together, and also with cleaning the gear on the stepper. Lee (from bilbyCNC) told me it could also be the filament curling and missing the entrance to the top of the barrel - that was when I was using ABS, but I don't see why it wouldn't happen with PLA, too. 

These machines are really frustrating, and I suppose it's our punishment for choosing the cheapest printer available-- I think we'll see them become easier to use over the next few years, and our early models will be obsolete. :P

By the way, I know you can raise a support ticket for mbot now, because I did it. Did anyone get back to you?



A fellow mbot3d dual-cuber

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