Extruder jump back during print

Hi There!
I'm having this issue, I know it's happened before but I forgot what causes it and how to cure it!
It's like there's too much force on the hot end from the filament.
Could it be my nozzle is impeded or I've got the wrong extrusion rate in my config (currently E414)
Thanks

Jon

Hi Jon, your right about there being to much force, and the nozzle being impeded (blocked off).
Ok here's the things that should help.
1) Heat up the Hotend to 118', then retract the filament totally. That should clear the nozzle of rubbish. Break off the end, as hopefully any rubbish should be stuck to it.
You can check it's clear by disconnecting the Feeder tube from the feeder, and heating up the nozzle to it's normal temperature (say 200'). Then try pushing some filament through by hand. It should go through fairly easily.
2) Pull the filament back out. Discard the end again, as it might have picked something up. Now put the filament through the feeder with the nozzle disconnected. Put a pencil mark on the filament where it comes out of the feeder.
Extrude 100mm put another pencil mark on it, and measure the distance between the marks.
Ok well if that all has been ok, then it has to be your extruder height.
So check your Z zero height. After you've checked it, you can double check it by lifting the Hotend then lowering it on to paper. Lift the Hotend up to 0.1mm and the paper should be at the point of being released when you pull it out.

If the above has all been ok, then you need to check.....
The Z bearings are screwed up ok (The bearing caps break, so look around the screw holes, and the X axis securing screws
Then check the Lower Z axis mount... I recently had this same problem, and it was the Lower Z mount had broken and this then lets the X axis arm sag.
The thing that gave it away when it happend to me was printed flat surfaces where rough and prickly, and feeder jumping back. The Hotend had been dragging on the plastic.

If everything seems ok on the printer, then try altering the Extrusion Multiplier in Slic3r. I use 0.84 normally.
Let us know what you find....
Kim..

Edited 1 time(s). Last edit at 09/11/2015 11:49PM by KimBrown.

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Okay I do not know the story about this case, but could it be that this is caused by more simple things?

• Is the z-axis too low?
• Printing speed too high?
• Extruder temperature too low?
• Bad filament?

What do you mean by jumping back? The gears? You may also try a spring loaded extruder. What do you mean by impeded (for non-English persons)?

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Slicer: Simplify3D 4.0; sometimes CraftWare 1.14 or Cura 2.7
Delta with Duet-WiFi, FW: 1.20.1RC2; mini-sensor board by dc42 for auto-leveling
Ormerod common modifications: Mini-sensor board by dc42, aluminum X-arm, 0.4 mm nozzle E3D like, 2nd fan, Z stepper nut M5 x 15, Herringbone gears, Z-axis bearing at top, spring loaded extruder with pneumatic fitting, Y belt axis tensioner
Ormerod 2: FW: 1.19-dc42 on Duet-WiFi. own build, modifications: GT2-belts, silicone heat-bed, different motors and so on. Printed parts: bed support, (PSU holder) and Y-feet.
Ormerod 1: FW: 1.15c-dc42 on 1k Duet-Board. Modifications: Aluminium bed-support, (nearly) all parts reprinted in PLA/ ABS, and so on.

impede
verb
past tense: impeded; past participle: impeded

Being a non English person on an English speaking forum

Delay or prevent (someone or something) by obstructing them; hinder.
"the sap causes swelling which can impede breathing"
synonyms: hinder, obstruct, hamper, handicap, hold back, hold up, delay, interfere with, disrupt, retard, slow, slow down, brake, put a brake on, restrain, fetter, shackle, hamstring, cramp, cripple; More

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Yes okay I came that far. There is a good page to translate (leo), but what does he exactly mean? Movement? Exit? Entrance? Movement probably not but I cannot get the context of his sentence in this case and I am (mostly) fluent in English.
I think he means blocked but according to leo it also could mean that the filament goes through the nozzle but (much) more force is needed. And that is a big difference. That is way I am asking. Is it blocked or does the filament flows and more force is needed?

Edited 1 time(s). Last edit at 09/12/2015 04:17AM by Treito.

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Slicer: Simplify3D 4.0; sometimes CraftWare 1.14 or Cura 2.7
Delta with Duet-WiFi, FW: 1.20.1RC2; mini-sensor board by dc42 for auto-leveling
Ormerod common modifications: Mini-sensor board by dc42, aluminum X-arm, 0.4 mm nozzle E3D like, 2nd fan, Z stepper nut M5 x 15, Herringbone gears, Z-axis bearing at top, spring loaded extruder with pneumatic fitting, Y belt axis tensioner
Ormerod 2: FW: 1.19-dc42 on Duet-WiFi. own build, modifications: GT2-belts, silicone heat-bed, different motors and so on. Printed parts: bed support, (PSU holder) and Y-feet.
Ormerod 1: FW: 1.15c-dc42 on 1k Duet-Board. Modifications: Aluminium bed-support, (nearly) all parts reprinted in PLA/ ABS, and so on.

Quote
Jon Steward
...I know it's happened before but I forgot what causes it and how to cure it!...

Have you changed some setting in slic3r recently?

The upper limit for the extruder stepper is a combination of nozzle size, viscosity of the filament, nozzle temperature, layer hight, esp. layer width - and drag in the system - 70mm/sec with a 0,5mm nozzle, layer hight 0,24mm and layer width 0,60mm should be OK

The print that gives you trouble, is that your own slice? (do the RepRapPro sliced whisle-coathanger-snowman still print ok?) - did you change the layer hight or width or sliced with lower nozzle temperature than usual?

e.g I have found that I have to lower the print speed to around 50mm/sec if I raise the infill layer width to 150% or else I get that step-missing knocking sound

Erik

Thanks for all your replies. To give more detail..
I've observed that the 'hobbed' nut in the extruder is cutting into the filament. (there's a half moon shape of a few mm in the filament)
The filament then cannot be gripped to extrude. This happens with different filaments and prints.
I've not changed any settings but I have updated to DC's latest though I think that's fine.
I'm going to try the cleaning approach first as it seem more likely to be a blockage. I have used some poor quality black ABS which broke very easily and the problem appeared after that.
Many Thanks
Jon

This hobbed nut is intended to cut into the filament. As I am using a spring loaded extruder you can really some kind of profile into the filament but this gives more grip.
However in your case cleaning would be a good idea but for me it sounds like your filament could have problems with a constant roundness. I would suggest to switch to the spring loaded extruder as soon as you can print again as you alwasy get a constant grip which you can choose by yourself.

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Slicer: Simplify3D 4.0; sometimes CraftWare 1.14 or Cura 2.7
Delta with Duet-WiFi, FW: 1.20.1RC2; mini-sensor board by dc42 for auto-leveling
Ormerod common modifications: Mini-sensor board by dc42, aluminum X-arm, 0.4 mm nozzle E3D like, 2nd fan, Z stepper nut M5 x 15, Herringbone gears, Z-axis bearing at top, spring loaded extruder with pneumatic fitting, Y belt axis tensioner
Ormerod 2: FW: 1.19-dc42 on Duet-WiFi. own build, modifications: GT2-belts, silicone heat-bed, different motors and so on. Printed parts: bed support, (PSU holder) and Y-feet.
Ormerod 1: FW: 1.15c-dc42 on 1k Duet-Board. Modifications: Aluminium bed-support, (nearly) all parts reprinted in PLA/ ABS, and so on.

The hobbed insert will grind into the filament if two conditions are met:

1. There is excessive back pressure. This could be caused by an obstruction in front of the nozzle, or a blockage, or the temperature being too low, or extruding too fast.

And:

2. You have the extruder motor current set too high. It is better to have it low enough so that when there is excessive back pressure, the motor skips before the hobbed insert grinds away the filament. That way, when you have a temporary obstruction in front of the nozzle, extrusion will restart when the obstruction is removed.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Update.
So far I've tried altering the Extruder current (currently working ok at 750) and various nozzle temperatures with PLA and ABS.
Looked at whether the thermistor is at fault. All seems OK.
When extruding with the hot end raised well above the bed I notice that the filament coming out is rough. So I'm thinking that this is the nozzle at fault.
Do I attempt to clean the nozzle, if so how? (maybe soak the whole hot end in acetone?)
Or after 2 and a half years of the printing learning curve (including ramming the hot end into the bed on several occasions) Buy a new nozzle?
Any thoughts much appreciated.

Cheers
Jon

Edited 1 time(s). Last edit at 09/16/2015 12:57AM by Jon Steward.

Did you also try 250°C for ABS and 230°C for PLA?
There is cleaning filament but I have not tested it yet.
You do not mention what Ormerod you have or especially what nozzle. As the old nozzle is not available no more you have to buy an upgrade kit if you own this on So you have to pay a little bit more. But a nozzle should last more than two years I think and hope. You may also consider to switch to cheap chinese replika of E3D. It seems they are good and they do not cost very much but you need another holder so this is no option if you cannot print or you do not have anybody who can print something for you. I will soon test them by myself.

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Slicer: Simplify3D 4.0; sometimes CraftWare 1.14 or Cura 2.7
Delta with Duet-WiFi, FW: 1.20.1RC2; mini-sensor board by dc42 for auto-leveling
Ormerod common modifications: Mini-sensor board by dc42, aluminum X-arm, 0.4 mm nozzle E3D like, 2nd fan, Z stepper nut M5 x 15, Herringbone gears, Z-axis bearing at top, spring loaded extruder with pneumatic fitting, Y belt axis tensioner
Ormerod 2: FW: 1.19-dc42 on Duet-WiFi. own build, modifications: GT2-belts, silicone heat-bed, different motors and so on. Printed parts: bed support, (PSU holder) and Y-feet.
Ormerod 1: FW: 1.15c-dc42 on 1k Duet-Board. Modifications: Aluminium bed-support, (nearly) all parts reprinted in PLA/ ABS, and so on.

I have just had to rebuild my hot end because my filament got jammed. What happened is that the hot end got a little loose, so there was a slight gap between the Bowden brass insert and the brass hot end - the plastic can work its way inside there over time and jam. Make sure that all parts are correctly tightened. The other comments should also cover other eventualities.

Hi All
I've just fitted a new hot end kit from Reprap.
My Ormerod 1 is working fine again.
Nice smooth extraction, filament coming out clean with no blemishes, print quality much improved.
I can only conclude that the nozzle and hotend became contaminated for some unknown reason.
I think I'll bin the cheap black ebay ABS filament just in case it's to do with that.
Thanks
Jon