Extruder motor speed and blockage!

[banana97 0]

Hi guys - I just completed the build of my Ultimaker and was going through the initial set up steps. I am using RepG with the Sprinter/Marlin firmware.

When doing the test extrusions the instructions on the website state to put the speed of the extruder to 2000. I did this and to me it was very fast?! Anyway I proceeded with ABS at 250 C and a small amount came out of the nozzle before the filament stopped moving and I had a jam.

I have now cleaned the blockage but I wanted to ask you guys about the speed - at 2000 the feed rate was very fast. Is this correct?

[ian 32]

why are you using RepG and not Cura ?

Bin RepG, start your ultimaker with Cura and go through the initial tests and setups in Cura.

Much better and a much better start with your ultimaker !

Ian

[banana97 0]

Thanks Ian

I will do just that!

[hcpl 0]

I'd like to know the answer to this question also. My extruder also jams at that speed on a newly assembled UM kit. It works fine at much lower speeds like 500 rpm. 1000 rpm was also blocking eventually.

@banana: check if you can push the filament through by hand. If that isn't possible it's more likely caused by the hot end blocking. Make sure to clean the driving bolt once this has happened since it will slip when not clean. I read that we should have just light toothmarks in the filament, that should help getting the right tension. Do you have the V2 or V1 clamp on your driver? There is a wiki page on jams, check the link on the troubleshooting wiki.

@Ian: I don't see how other software can help here? I'm not saying cura isn't better but for running filament at 1000 or 2000 rpm through the hot end the software shouldn't make any difference.

[joergen 2]

I'd like to know the answer to this question also. My extruder also jams at that speed on a newly assembled UM kit. It works fine at much lower speeds like 500 rpm. 1000 rpm was also blocking eventually.

@Ian: I don't see how other software can help here? I'm not saying cura isn't better but for running filament at 1000 or 2000 rpm through the hot end the software shouldn't make any difference.

I am very confused... As a veteran UM user, the last time I have seen the word RPM in context of extrusion with the dreaded netfabb calibration routines, and those values were usually 2 digits (but that was one year ago).

I don't know any current firmware or slicer (cura, kisslicer, slic3r and even the most current netfabb) use RPM anymore, all extrusion is specified as mm of filament, in software, and in he gcode.

I'd love to hear where this very very outdated notion of RPM is coming from, or where it would appear.

[hcpl 0]

Joergen: in ReplicatorG build 0026 you can go to the control screen (the arrows icon) and there you can set the extrusion motor rpm on the top right box. It's at 1000 rpm by default I think.

[banana97 0]

Joergen: in ReplicatorG build 0026 you can go to the control screen (the arrows icon) and there you can set the extrusion motor rpm on the top right box. It's at 1000 rpm by default I think.

The feed rate when using RepG in comparison to Cura is very fast - I think the version of software you are using - which I also used is outdated and the feed rate must be in different units to what the printer is seeing.

Just use Cura and you'll have less issues. I haven't had a blockage since.