Feeder grinding on startup while plate is leveled up

[DidierKlein 729]

Hi all,

Just noticed something odd.

Since yesterday i'm having a little trouble on the startup of some of my prints.

I just had one print start and the filament was nearly cut in two by the feeder.

I use Robert's design so it's easy to clean.

This is what i noticed.

It's the new startup routine.

The feeder turns like hell while the buildplate is leveled up. It doesn't seem to happen on every print (will have to confirm that).

Any ideas?

Is this gcode related or firmware or hardware??

Thanks

 

[DidierKlein 729]

Just tested 4 or 5 times the startup with the same print. Didn't happen.

Before that i tried to level up and down the bed. Nothing.

So it's not gcode. Startup is ok i guess.

But why did this happen?? I guess it's more hardware related :???:

 

[DidierKlein 729]

Just happened once more it seems random. This is really bothering because i have to be sure to release the pressure in the feeder before starting the print to make sure the filament isn't grinded dead...

Didn't notice this before last firmware update i don't know if it's related

 

[illuminarti 18]

I think it's because it tries to advance the filament 25mm very fast at the start. When a print has aborted, or filament has just been loaded, the filament is already retracted 20mm, so it's not so bad.

However, I don't think the 20mm retraction happens when a print ends normally. So this problem may happen more if you try printing straight after another print, without doing reloading filament, or doing an abort??

 

[braddock 1]

I usually pre-heat the bed and nozzle manually before starting a print, helps to get things going without problems like this.

 

[DidierKlein 729]

It seems to be random as far as i can tell.

I will try to write down the circumstances for the following times this happens.

The thing is that it doesn't happen during the heating up.

It doesn't happen when the nozzle is primed (the 25mm you refer too illuminati i guess)?

It happens when the plate is lifting up before the nozzle is primed. The feeder's wheel turns at the same time. The it stops. And it turns again to prime the nozzle.

So it's a complete unexpected behaviour from my point of view.

 

[takei-naodar 0]

It seems to be random as far as i can tell.

I will try to write down the circumstances for the following times this happens.

The thing is that it doesn't happen during the heating up.

It doesn't happen when the nozzle is primed (the 25mm you refer too illuminati i guess)?

It happens when the plate is lifting up before the nozzle is primed. The feeder's wheel turns at the same time. The it stops. And it turns again to prime the nozzle.

So it's a complete unexpected behaviour from my point of view.

 

You might need a higher force pressing against the knurled wheel. Normally the motor should slip instead of grinding. What happened with you was that the knurls could not grab deep enough into the filament and thus lost traction and grinded the filament away.

 

[DidierKlein 729]

Ok it's possible but i don't understand why it does this at some moments and not at others...

Because it isn't needed, if i snap the guide on (with robert's feeder) after that the print goes without problems. Why would it want to feed so much filament before starting? And mostly why not all the time?

Just go it again, it looks to be related to a strange noise when the bed is leveled up.

Canceled the print restarted again no problem.

 

[illuminarti 18]

What firmware version are you using?

[DidierKlein 729]

14.03 Of April 18 2014 10h15min11

 

[DidierKlein 729]

I adjusted the pression of the wheel.

It happened again but this time the feeder skipped and the filament wasn't grinded so much. I still need to adjust it a bit i guess.

I don't know if it's something that's new or that it happened before the feeder upgrade to robert's design. I guess it could be happening but because the feeder was skipping i didn't pay attention.

Still wondering why the feeder does that occasionnaly...

 

[gothampixel 10]

This is happening to me as well

14.03 Of April 18 2014 10h15min11

It's random enough that I can't figure it out. When I start some prints nothing comes out because the filament has been chewed up. I have to abort, change material, cut out the bad part and start over. Very wasteful...