Filament grinding while printig the raft

[Eike]

Hello,

I've pushed my Wanhao i3 Plus more or less to the limit for the extruder while printing PLA.
215°C
0,2mm layer
80mm/s infill
32mm/s for all other underspeeds

This works pretty well without grinding the filament. But as soon as I select the raft option hell is unleashed and the extruder starts grinding my filament.

I don't want to lower the printing speed, but on the other hand I find no option in the raft section that I could adjust to prevent this from happening.

Any ideas are appreciated!

Eike

[brian442]

They cover the common causes for grinding filament here: https://www.simplify3d.com/support/prin ... g-filament

So that gives you the main things to try (increase temp, lower speed, clean nozzle, etc)

[wirlybird]

My guess is for the raft it is trying to extrude at a higher rate than for the rest of the print. Try slowing down or raising the temp for the raft part. Be careful on raising the temp though. You are already at the upper range for PLA and don't want to get a jam.

[Eike]

brian442: I've read many of the sections in the awesome troubleshooting guide. But thanks for the hint. Decreasing the speed is something I don't want as the speed and temp work well for everything except the raft and for bigger sized prints that don't need the best resolution I like the settings like they are.

wirlybird: Okay, so maybe I just try to print it in two processes with a slow print speed for the raft. I thought there is maybe an easier way or option I've overlooked to influence the raft extrusion rate.

[Eike]

Well, apparently there is an option I can use to prevent this in the raft options: "Disable raft base layers"
I've not tried it yet but thought if someone else has the problem I have or maybe had he may stumble upon this thread here.

screenshot_090.png (13.89 KiB) Viewed 4396 times

[dkightley]

Disabling the raft base layer will only help if the filament grinding is taking place on the three layers that make up the base layer...and not on the other raft layers.

On the subject of this....you've not actually stated which layer or layers the grinding is taking place. If it is only on the very first layer, then there is a way of slowing that single layer down...the First layer speed property.

The grinding is due to the extruder feed stepper motor not being able to push the filament through at the speed you have dialled in in the settings. This will be down to one or more of four things.. either feeding excessively fast, the plastic is too viscous...ie not hot enough, the tension spring on the filament clamp is too low or you have a partial blockage in your extruder.