Velocity Extrusion - Dips in Velocity

[Dennis]

Dear Machinekit users,

right now we're facing issues with velocity extrusion. Our test system is installed with Debian Stretch and Machinekit in version 0.1.1543327459.gite7 (uname -a output: Linux labor-m2 4.9.0-8-rt-amd64 #1 SMP PREEMPT RT Debian 4.9.144-3.1 (2019-02-19) x86_64 GNU/Linux). We use three axes with one extruder in velocity extrusion mode.

The attached .ngc-file was created with the ngcwriter-plugin for Cura. Stumbling across another post in this forum (https://groups.google.com/forum/#!searchin/machinekit/m67%7Csort:date/machinekit/mRTcGHU4lUc/hSyyGclIPagJ) I also attached the output of the rs274 standalone interpreter. Maybe this helps.

The Problem we have is, when we print the file (with and without filament) we are facing issues with the extruder feedrate. For a short period of time the feedrate seems to halt, although there should be continuous filament output. We think the issue may be related to command M67 (perhaps related to this issue here https://sourceforge.net/p/emc/bugs/437/). 

Has anyone ever observed such a problem? 

Unfortunately I'm not abled right now to post the contents of linuxcnc.log with DEBUG=5 enabled, because our printer has a hardware malfunction.

Best regards

Dennis

[Bas de Bruijn]

On 3 Jun 2019, at 14:26, Dennis <dest...@gmail.com> wrote:

Dear Machinekit users,

right now we're facing issues with velocity extrusion. Our test system is installed with Debian Stretch and Machinekit in version 0.1.1543327459.gite7 (uname -a output: Linux labor-m2 4.9.0-8-rt-amd64 #1 SMP PREEMPT RT Debian 4.9.144-3.1 (2019-02-19) x86_64 GNU/Linux). We use three axes with one extruder in velocity extrusion mode.

The attached .ngc-file was created with the ngcwriter-plugin for Cura. Stumbling across another post in this forum (https://groups.google.com/forum/#!searchin/machinekit/m67%7Csort:date/machinekit/mRTcGHU4lUc/hSyyGclIPagJ) I also attached the output of the rs274 standalone interpreter. Maybe this helps.

The Problem we have is, when we print the file (with and without filament) we are facing issues with the extruder feedrate. For a short period of time the feedrate seems to halt, although there should be continuous filament output. We think the issue may be related to command M67 (perhaps related to this issue here https://sourceforge.net/p/emc/bugs/437/). 

Well, first determine if this is the issue, if so, then my guess is that it had nothing to do with the velocity extruding, but with motion.

Remove the M67’s and see if the problem persists.

Has anyone ever observed such a problem? 

I haven’t, but is has been a few years i printed with machinekit. I’ve lent out my self built printer (it was too big) and i now just use a prusa i3.

Unfortunately I'm not abled right now to post the contents of linuxcnc.log with DEBUG=5 enabled, because our printer has a hardware malfunction.

Best regards

Dennis

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<Rohrtest.ngc>

<Rohrtest.274>

[Daren Schwenke]

I had issues with retraction that sound like this, but mine was built as a linear delta so I just disabled retraction and turned rapids up to 500mm/sec which solved it 95%.  I haven't returned to it, but I probably should now.

I will take a look later.