Extruder not extruding....

[loosemclaren 0]

Hi This will initially sound so obvious.

Ive had my UO+ for several years and it works most of the time.

I finished a print all fine.

next print and the extruder stepper fails to move.

So I change the extruder and stepper to my spare.

no Joy

I checked the extruder by plugging into another output x all worked fine.

I then set the machine up as a dual extrusion and plugged into stepper driver 2 to check for a blown stepper driver. no joy.

I then bought a new PCB assuming that the stepper driver is well and truly fried and has taken something else out on the board.

New PCB and same story.......

 

What the hell is going on????

 

Ideas please

 

[loosemclaren 0]

I have tried every firmware I can get my hands on and no difference

 

[gr5 2,005]

When doing testing it's important to know that the extruder on 90% of printers out there will not move the extruder unless you either enable "cold moves" or heat the nozzle above a certain temperature (I think 170F).

 

This detail made me think my stepper was broken for a while but it was fine.

 

Anyway - assuming that's not the problem - it's probably one of the 4 wires that go to the stepper.  If any of the 4 wires is broken it won't rotate.  Disconnect the stepper from the PCB and measure the resistance of each pair.  Each pair should have a resistance of < 24 ohms.  Quite a bit less.  And the pairs should be isolated from each other so measuring resistance from a while of one pair to either wire of the other pair should be infinite.

 

I suspect there is a broken wire almost certainly at the stepper end or at the PCB end.

 

[loosemclaren 0]

Hi Thanks

all sensible but....

i have 4 steppers none will drive from either extruder output from either of the 2 boards.

also the extruder stepper drives fine from any of the other x y z outputs. 

All very odd.

the only part ive not changed is the ulticontroler

[gr5 2,005]

Did you heat the extruder to 180C before trying to move it?  Or instead did you issue a "cold extrude" or M302?

[loosemclaren 0]

Hi yes 

I’m currently testing no filament.

have tried all temps and doing a print. All is normal but no filament is extruded.

ive tried commanding an extrude and noting happens.

stepper is not powered. It’s free to move.

[loosemclaren 0]

Hi yes 

I’m currently testing no filament.

have tried all temps and doing a print. All is normal but no filament is extruded.

ive tried commanding an extrude and noting happens.

stepper is not powered. It’s free to move.

 

 

ahh just read your message again I’m printing at 160c... and have been for a while.

 

will increase the temp and try again.

[loosemclaren 0]

7 hours ago, gr5 said:

Did you heat the extruder to 180C before trying to move it?  Or instead did you issue a "cold extrude" or M302?

 

 

Yep there you have it Im an idiot. 180c and printing fine.

This all leads back to the fact that my pt100 on my nozzle under reads. So to stop burning filament Ive dropped my print temps.

I couldn't understand why abs kept burning even at 200c printing brown colour.

 

What is odd is that I changed my temps some time ago a month or two and all was fine. I have updated Cura recently and maybe that is the cause of the change in how the G code is written.

 

Thanks V much for your suggestion.

[johnse 31]

Is it possible you made a firmware change? The “no cold extrusion” is handled in firmware on the printer.

[gr5 2,005]

 So now that you know, you can add M302 to the top of all your print jobs and you should be able to print at 160C just fine.