How to reduce the speed of extrusion

dc42

The firmware applies a minimum movement speed of 0.5mm/sec. The main purpose of this is to prevent users thinking that the Duet has crashed if they accidentally select a very low feed rate.

You could reduce this limit if you recompile the firmware, however if you use a standard slicer then i think you will have another problem. Most slicers appear to output the E parameter to a fixed number of decimal places. So if you try to extrude very small lengths, i think you may find that the resolution is insufficient.

Can you use E values of 100 times the value you actually want, and reduce your E steps/mm by a factor of 100?

frafa

Thanks for the quick response david
30mm / min is a lot if the diameter is large, for example if you want to push clay in a 1000cc syringe is way too much

In my case the syringe is 20cc and 0.5mm / seconds is too fast ...

dc42

Why not make the extrusion speed the speed at which the clay comes out of the nozzle, instead of the speed at which the syringe moves? Alternatively, use volumetric extrusion. Either way, you will have much larger E values, which will avoid the problem.

frafa

ok, humm Simplify3D does not support volumetric extrusion !
I test reduce E steps/mm ...

frafa

hi David,

Full step is possible on Duetwifi ?
i test M350 E1 I0
Console return : M350: Drive E8 does not support 1x microstepping ...

dc42

@frafa, if you use M584 to specify how many extruders you have, instead of letting the firmware assume that all possible additional drivers are extruders, then you won't get that message.

frafa

one extruder on P3
==> M569 P3 S0
please help me ... M584 E????
just send or on config.g ?

dc42

@frafa said in How to reduce the speed of extrusion:

????

M584 E3

Send it to test it, put it in config.g to make it permanent.

frafa

Thank's

Same error on console: M350: Drive E8 does not support 1x microstepping

ok on 16 microstep
but dont works on 1x motor vibrate and dont turn...
Motor: Nema 8 reduct 19:1
leadscrew - M6 metric (1mm per rotation)

ok (16 microstep)
M92 ... E60800 ;
M350 E16 I0 ;
M584 E3;

ko (full step)
M92 ... E3200 ;
M350 E1 I0 ;
M584 E3;

Firmware Name: RepRapFirmware for Duet 2 WiFi/Ethernet
Firmware Electronics: Duet WiFi 1.02 or later
Firmware Version: 1.21RC3 (2018-02-28 build 4)
WiFi Server Version: 1.21RC4(08b3)
Web Interface Version: 1.21-RC4

dc42

The M584 E3 command must come before the M350 E1 I0.

frafa

ok
M584 E3 before M350
test 16x ok
1x 2x 4x 8x ko, motor vibrate, and do not turn
no error on console ...

dc42

@frafa said in How to reduce the speed of extrusion:

ok
M584 E3 before M350
test 16x ok
1x 2x 4x 8x ko, motor vibrate, and do not turn
no error on console ...

That sounds like you have the steps/mm set too high at x8 and below, or the acceleration (M201) set too high. Please confirm that you still have the M92 command before the M350 command, so that the steps/mm will be adjusted automatically.

I still think that it would be much better to make your steps/mm be the steps per mm extrusion from the nozzle, not the steps per mm movement of the plunger.

frafa

Humm....

I tested a lot of steps by decreasing number of steps per mm without success
motor vibrates and does not turn
I only get there in 16x ...

order used:

M92 ... E3200 ;
M566 ... E30 ; Set maximum instantaneous speed changes (mm/min) (jerk)
M203 ... E60 ; Set maximum speeds (mm/min)
M201 ... E5 ; Set accelerations (mm/s^2)
M906 ... E550 I60 ;
M584 E3; assign extrude on motor (P3)
M350 E1 I0 ;

dc42

On my list to test.

frafa

Ok thanks

dc42

I'm sorry, I can't reproduce this issue. I used the settings you posted above, then sent G1 E1 first with x16 microstepping. Then I sent M350 to change the microstepping to 8, then 2, then 1 and repeated the G1 E1 command in each case. The motor moved the same amount every time, but was much noisier with lower microstepping.

I am using the candidate firmware build for 2.02RC4, but I don't think there have been any changes that would account for the problem going away. But I suggest you try upgrading to 2.02RC4 anyway when I release it.