Step Motor of the feeder loss step!

[ieol2015 3]

Hi,

it's a problems that comes out when the machine is still "cold" usually while "brimming" the step motor loss step making a, quite loud, "TOC" noise .

I've filmed it but for some reason audio get stripped off!!

https://www.youtube.com/watch?v=cdNbDgeL2W0

As you can see the feeder knurled wheel suddenly make almost half round backwards ! I've raised the current of the motor from 1250 mA to 1300 mA (the max current set possible) but nothing have changed.

Any suggestions?

[Labern 775]

This is normal and is a safety feature to stop the feeder motor grinding your filament.

It means that there is to much pressure on your feeder motor. This could be on the roll side like a filament tangle or it can be from pressure build up on the other side of the feeder.

Printing to fast.

blocked nozzle.

damaged bowden tube

deformed PTFE coupler

the list goes on.

I would start with an atomic pull and see how it goes then. after that then look more in depth.

[ieol2015 3]

What you call "a safety feature" I call an issue :)I thought it is just point of view... but a stepper motor that loss step for over charge is not a feature....

Questions: I found that by default the current driving the stepper are all at 1300mA except the one of the feeder that was at 1250, a little difference but why?

And another question is why this limit to 1300mA when the stepper are rated up to 1680mA?

p.s.: I think that Atomic pull is overestimated... I use a PTFE rod like this

to clean the hot end, so you can leave it clean without addition of other material inside the hot end...

[IRobertI 521]

It is a feature in the sense that Ultimaker have carefully tuned the amount of current to give the feeder stepper so that it will start loosing steps before grinding the filament. They have also done tests with higher currents then the limit set in the interface and found that it didn't really make much of a difference (since it'll start grinding the filament instead of actually pushing it through).

I'm assuming you're referring to the Z-motor having slightly lower current? Due to a small mistake in the design of the controller board it was found that in some circumstances higher current limits causes the driver to overheat, the temperature protection then kicks in and that causes the platform to drop down slightly before the driver has cooled down and kicked back in. This of course causes issues with the print.

Why they don't run the motors at the limit? Because it's not needed? Why put more strain on the motors and drivers than necessary? More current = more heat for no reason.

As for the Atomic. It's an easy thing to do with materials you already have. Not everyone are willing to buy a PTFE rod and machine it to fit I've been doing Atomics with PLA for over two years now on lots and lots and lots of printers with no complaints.

[IRobertI 521]

Oh, and since it's happening for you during the brim I'm going to guess that your platform is slightly too close to the nozzle.

[ieol2015 3]

Thank you for your answer IRobertI

Well, no issues with the other 3 step motor (X;Y;Z) just the feeder motor have some issues sometimes ...

By the way, as you can see in the end of the video I was printing a test and the issue come out well over the brim level... it was finishing printing at 3mm cube/sec...

I thought that the nozzle is not hot as it should be... even if the temperature was set at 215°C

My thought about limiting current on step motor is that it reflect on the device capability to maintain its force torque... but it's true that it is a way to limit grinding (but I don't think is a nice way to do it )

About the PTFE rod... I will be pleased to sell it to you or anyone else who like the tool

There is someone in the forum that hacked the hardware to get rid of the current limitation?

[Strik9 0]

I actually have the same problem, usually after a few prints. At some point it will do the same thing and now filament will go out of the nozzle.

Even i manually extrude within the option it still do the same thing.

I've tried to factory reset in case someone has changed parameters, print with normal setting in Cura i still have the problem.

[Labern 775]

Manually extruding can be extrude filament way faster then you print. So can be normal for it to "tick"

If it's happening then it's the sign of something wrong in your filament path. Bypassing the tick is just masking another problem. Wouldn't fixing the root cause be the best option?

[Strik9 0]

When i wrote manually extruding, i was referring to the option where you can spin the wheel, to extrude filament, not me pushing

I've tried the atomic cleansing, and it was already clean. Tomorrow i'll try to open the feeder to see if there's nothing wrong here, and make sure the tension is correct.

[Labern 775]

I was also referring to the same method of manual extruding. If you watch the filament Going into the machine when its printing at 10mm/s, the speed is slower than how fast you can manually extrude. If that makes sense

Check the whole filament path. Bowden tube for tight spots, PTFE coupler, tangles in the spool etc.

[Strik9 0]

Thanks i'll try that!