Printer stops extruding

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lorenolepi
Posts: 13
Joined: Sat Jan 13, 2018 6:54 pm
Location: Connecticut, USA

Printer stops extruding

Postby lorenolepi » Sat Jul 28, 2018 1:40 pm

Hello All,
I have had my printer for about 8 months now and it has been running for the most part flawlessly. As of lately the printer will not get through a print. It always just stops extruding generally within the first couple layers after the raft or even during the raft.
IMG_20180728_085243.jpg

What appears to be working ok =The stepper motor on the extruder is still turning (but it gets very hot), the temperature of the nozzles stay consistent (215), the fans work (using PLA so no covers) and the bed temperature stays consistent (60). The x, y and Z directions all move fine and I'm using the same print parameters as I always do.
When loading material it appears to flow normal with a lot of material coming out of the nozzle.
IMG_20180728_083523.jpg

What I've tried = At first I thought it could have been this particular print file so I re-tried some existing prints that were stored on my machine that I was successful printing in the past but it still stopped extruding = not the print file
I then thought it could be the material, so I swapped out to a brand new roll but it still not extruding = not material
I then thought it might be a jammed hotend, so I used the second hotend (only used once before) by changing the model material to the right extruder in ideamaker. To my surprise it still stopped extruding = not the hotend
I cleaned of the knurled wheel on the stepper motor of the exturder multiple times = not the knurled wheel
I checked the fuses and both were still intact = not the fuses
Right now I'm not sure what to try next. Does anyone in the community have any suggestions?
Loren
Olepi Labs LLC

Jetguy
Posts: 2700
Joined: Tue Mar 22, 2016 1:40 am
Location: In a van, down by the river

Re: Printer stops extruding

Postby Jetguy » Sun Jul 29, 2018 2:18 am

lorenolepi wrote: It always just stops extruding generally within the first couple layers after the raft or even during the raft.
IMG_20180728_085243.jpg

What appears to be working ok =The stepper motor on the extruder is still turning (but it gets very hot), the temperature of the nozzles stay consistent (215), the fans work (using PLA so no covers) and the bed temperature stays consistent (60). Right now I'm not sure what to try next. Does anyone in the community have any suggestions?

First, what you define as OK is not OK.
lorenolepi wrote:The stepper motor on the extruder is still turning (but it gets very hot.)[/quote That motor should not be getting "very hot". That indicates that the setting on the stepper driver for that motor is pushing so much current that it heats the motor to excess. This is the little potentiometer on the stepper driver that adjusts this and sets the motor current, and that is measured and call Vref- AKA Voltage reference, because the potentiometer sets a voltage on the stepper driver current sensing and controlling circuit as a reference voltage. Changing that voltage changes the stepper driver output to current to the motor.
PLA must have cooler temps in the feeding section (the motor drive area and gear gripping area). It does not take much heat to soften PLA.
Second is, you have failed to identify the feeding failure.
Feeding failure either does one of 2 things:
The stepper motor skips and makes a clicking or thumping sound
OR
It slips and grinds the filament.
You did not say which is happening at the point of it stopping to extrude.
I'm betting on it being slipping and grinding the filament and that would grind a divot in the side of the filament and also producing filament dust around the drive gear area.
Since you have worked on the motor and drive gear area, the motor can also be moved slightly in comparison to the V-groove bearing to determine how hard the filament is pressed against the drive gear. Too tight and the extrude binding can cause the motor to grip well, but also skip steps (failure to rototate). Too loose and the filament grind and slips. An example topic talking about methods to adjust and shim viewtopic.php?f=2&t=1805&p=34255&hilit=paper+shim#p34255

lorenolepi wrote:Right now I'm not sure what to try next. Does anyone in the community have any suggestions?

Yes, read a couple of threads on these adjustments and upgrade drive gripping gear modification.
viewtopic.php?f=8&t=8497&p=31049&hilit=paper+shim#p31049
viewtopic.php?f=4&t=8431&p=30796
Note my reply in that topic:
Here's what I know:
#1 the stock feed gear can slip easier, and so upgrading is a really good cheap first fix- you did that already. Upgrading the gear is covered here viewtopic.php?f=4&t=6193&p=24902&hilit=sharp+tooth#p24902
#2 The change to the Bohong brand black motors on all current shipping N series sometime last year, these motors run hotter than the kickstarter motors. This is turn also heats the entire feeder block and extruder head. Despite attempts and discussions to tell Raise 3D to adjust the factory current setting, tech support told people not to adjust and instead, for a small subset of folks who complained sent them a cork gasket to isolate the motor from the aluminum body. So, a whole bunch of you have hot running extruder steppers. This can soften the filament and cause it to grind easier in the feeder section. The fix that Raise 3D tech support tells you not to do, is lower the current to the stepper slightly to reduce this overheating. Yes, lowering current lowers torque, but you already grind instead of skipping steps, so motor torque is not the fault here. Lowering it, within reason, to keep temperature in check. viewtopic.php?f=4&t=2705&p=17780&hilit=hot+motor#p17780
#3 Even with a sharp tooth gear, a user can and should adjust the motor position to adjust the pinch depth of the filament by changing the distance between the drive gear and v-groove bearing. This most basic of adjustments is just not well covered in the FAQ and guides for this printer.
#4 long continuous infill extrusion for base layers (floors) and roofs are know to be one of the most challenging tasks for any extruder. It's simply a natural thing that sustained extrusion, this is pushing the system to the max. The second part is, first layer has a slowdown feed rate modifier, and second layers and beyond run at the infill speed. So you might be seeing your slowed down first layer- the feeder system is within it's speed limits. You get into faster sustained rates- then you find the breaking point.
#5 There is a reason many folks upgrade to the Bondtech. In fact, it's standard on the Pro2 series, so even Raise 3D finally figured this one out.

User avatar
lorenolepi
Posts: 13
Joined: Sat Jan 13, 2018 6:54 pm
Location: Connecticut, USA

Re: Printer stops extruding

Postby lorenolepi » Sun Jul 29, 2018 3:14 pm

Thanks for the reply jetguy! With your help I was able to get it running again.
You were correct it was slipping and grinding. I ended up adjusting the voltage to the stepper motors and they cooled down a ton. I also moved the stepper motor over a little bit and it appears to be gripping the filament better. I'm just couscous why it just started happening out of the blue and why it wasn't happening all along.
I'm strongly considering the BondTech extruders
Loren
Olepi Labs LLC


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