Extruder stops extruding at higher speeds - rollers slipping

[michaellatif]

Hi all,

I have been playing with speeding up my H-1 by playing with the speeds in Slic3r. I have it working perfectly at 120mm/min travel feedrate (in Slic3r), when I crank it up past 300mm/min, what I think is happening is the extruder feed rollers slip OR maybe the filament is not melted fast enough?

Any suggestions on how to increase the travel feedrate and get consistent extruded filament?
I have a hobbed roller already on the feeder, I think it can be a bit more aggressive because I feel it slips a little even at 120mm/min.

One thing is for sure, the H-1 X/Y/Z axis can run at 3000mm/min! It was very impressive when it shook my desk!

Thanks,

Mike

[guanu]

what are your settings in mach on the motor tuning, I used to do the same to get more speed, but I found I had to really turn slic3r down after I change the motor tuning, now I can crank out prints at 1200mm/min with infil at 2700mm/min... I know everyones mach settings are different, but its a start to look at, I kept the steps, but played with accel and velocity.

Guanu

[michaellatif]

what are your settings in mach on the motor tuning, I used to do the same to get more speed, but I found I had to really turn slic3r down after I change the motor tuning, now I can crank out prints at 1200mm/min with infil at 2700mm/min... I know everyones mach settings are different, but its a start to look at, I kept the steps, but played with accel and velocity.

Guanu

Hey Guanu,

Thanks for the reply, I am not using Mach3, I am using Repetier firmware/host and a Sanguinololu board on my H-1.

I have been experimenting with just extruding filament, here are my findings.
Working extruder speeds (with no slip or issues) 30-~225 mm/min. I can extrude continually with no issue.
Not working extruder ~250+mm/min. When I try crank up the speeds, the extruder will work for some time (different lengths) and then the filament will pop-up or push back up, even with hobbed rollers tightened down. I think the problem is that the teflon tube is not held in place and moves a little up and down.

[Polygonhell]

You might have to increase your temperatures to go faster I was reading a post somewhere I thin probably by nophead on his blog (though I can't find it now) where he finds the minimum temperature for various extrusion speeds on his setup and once you reach the ceiling, the temperature has to increase fairly dramatically to increase it further.
A lot of it i going to have to do with the hot end design it takes time for filament to reach the glass temperature and if the melt zone in the extruder is small it'll have to be hotter.
At extreme speeds, you'll have a case where the extruded filament is dramatically lower in temperature than the hotend is, of course when you stop extruding it's them going to equalize with the hotend temperature which could be bad.

Edit this is actually where I saw it.
http://www.protoparadigm.com/2012/04/th ... oting-mk8/

[kilroyo]

I had alot of trouble with my extruder until I cut keyways into the drive bolt. Now there is no slip and will drive filament into the feeder as fast as you want

[img]http://xa.yimg.com/kq/groups/80652411/s ... r_fix1.jpg[/img]
used a 1/16" broaching bar to cut the slots in the gears

[img]http://xa.yimg.com/kq/groups/80652411/s ... r_fix2.jpg[/img]
flattened the tip of a countersink to cut the two slots into the bolt , didnt have a small enough endmill

[img]http://xa.yimg.com/kq/groups/80652411/s ... r_fix3.jpg[/img]

I know not just everyone has a broaching tool handy, but I thought I would put it out there, how I was able to fix mine