Slow and weird at 140mm/s on curvy/circular path

Hugues · 9 Jul 2016, 07:07

You bit the record ! 50 000 ! Are you slicing a dental model ?
For me motion is now really clean, i waiting my PT100 to get clean print, i installed an old thermistor that i don't all informations and i have wave on my print evry 10mm…

dc42 · 9 Jul 2016, 07:50

@T3P3Tony:

you are right the speed slider on the web interface increases all speeds including extrude and retraction speeds. this can have bad effects on extruders which don't like going 1.5x faster for example, retraction skips and then you get a huge over extrude when the next extrude command is issued. I find the speed slider useful for testing speeds but always re-slice t the faster speed for actual prints to keep my retraction speed constant.

I could modify the code so that moves that only involve extrusion or retraction and possibly Z movement (no X or Y movement) are not affected by the speed slider. Would this be a good idea?

However, there are already two ways round this issue:

1. Even when you use the speed slider, the speed limits set by M203 are respected. So you can set the E parameter in your M203 command to the maximum extrude or retract speed that you want to use. Of course, this will also limit the speed at which you can load or unload filament.

2. Some slicers have a "use firmware retraction" option. If you use this, then you define the retraction amount and speed using M207 and the speed is not affected by the slider. See http://reprap.org/wiki/G-code#M207:_Set_retract_length.

Hugues · 9 Jul 2016, 09:22

It's a good idea to limit this slider effect to XY, but extruder have to follow only while printing and not during retraction. As you described the problem is while retraction or prime extrude for bowden setup and i don't remember if slicer comment those tiny part.

I never used firmware retract but it can be a good solution to manage this slider. Is it better to use it vs slicer ? And is it necessary to use it with pressure advance control M572 ?

Hugues · 12 Jul 2016, 21:55

Hi,
A small update about high speed print, i get this statue in 4h30, 220mm height at 0.12 mm layer height.
I setup the speed near 200 mm/s +-20 % . and 10 % infill, 3 loop.

S3D announced 2h40, quicker than the reality (it surely forget retraction) but the duet handle quite well this speed but on really sharp curve there is some artifacts.

T3P3Tony · 12 Jul 2016, 22:06

Hi Cubexupgrade

can you embed a larger version please!

dc42 · 12 Jul 2016, 22:38

@cubexupgrade:

I never used firmware retract but it can be a good solution to manage this slider. Is it better to use it vs slicer ? And is it necessary to use it with pressure advance control M572 ?

The main reason I added firmware retraction is to handle mixing hot ends such as the Diamond. With these, all the filaments need to be retracted the same amount, regardless of the current mixing ratio. Firmware retraction in RRF does that.

Use of pressure advance is entirely separate. However, if you use a lot of pressure advance then you should reduce retraction, because at high printing speeds pressure advance will already do some retraction at the end of an extruding move that is followed by a non-extruding move.

Hugues · 13 Jul 2016, 06:22

Sorry i'm little newbie with this kind of code…

I will post more picture, the back is clean but the front less cause it have lot of curve.

I will do more print of this with less mesh to have a reference.

Thanks DC42 for your explanation. I will do some test.

Hugues · 14 Jul 2016, 07:28

Some better pictures :

https://drive.google.com/folderview?id=0B3QhjlM2HLWsa0RZbXNnS29tMTA

I didn't setup a minimum layer time for cooling.

Aussiephil · 15 Jul 2016, 15:17

Sorry to butt in on the end of this thread but having just rebuilt my delta to fix an issue (unsuccesfully by the look of it) before swapping over to the DuetWiFi, from the 0.8.5 board, I've got a print running and decided to check for underuns as I to use S3D and have 0.9 steppers.
I got MaxReps: 5, StepErrors: 0. Underruns: 229 over about a 5 minute window.
Sliced with 3.02 of S3D at only 90mm/s.
Only noticed this as I wanted to baseline things before swapping
Copy of the gcode file zipped in dropbox https://dl.dropboxusercontent.com/u/28032744/chatimage/caselid.zip if that helps.

RCarlyle · 15 Jul 2016, 18:43

S3D 3.0.2 is before the "reduce small segments" fix, you should probably update to 3.1. (I'm still running 3.0.2 and not having any big issues since David patched the motion planner queue, but it depends a lot on the STL poly count.)

Aussiephil · 16 Jul 2016, 00:18

@RCarlyle:

S3D 3.0.2 is before the "reduce small segments" fix, you should probably update to 3.1. (I'm still running 3.0.2 and not having any big issues since David patched the motion planner queue, but it depends a lot on the STL poly count.)

Hi RC,
I've been using 3.1 since it was released, went back to 3.0.2 just to back track changes made since this "sloop error" arrived, thought i had found it but appears not. The machine has been pulled apart and rebuilt with careful attention to squareness and spacing. The small 30mm test cubes still lean the same as prior to the rebuild which points to something else.
Checking m122 after the print finished (about 2hrs) i had this…
MaxReps: 6, StepErrors: 0. Underruns: 5504

Guess I'll bite the bullet today and drop the Duet WiFi in place with the latest firmware

dc42 · 16 Jul 2016, 07:36

@Aussiephil:

@RCarlyle:

S3D 3.0.2 is before the "reduce small segments" fix, you should probably update to 3.1. (I'm still running 3.0.2 and not having any big issues since David patched the motion planner queue, but it depends a lot on the STL poly count.)

Hi RC,
I've been using 3.1 since it was released, went back to 3.0.2 just to back track changes made since this "sloop error" arrived, thought i had found it but appears not. The machine has been pulled apart and rebuilt with careful attention to squareness and spacing. The small 30mm test cubes still lean the same as prior to the rebuild which points to something else.
Checking m122 after the print finished (about 2hrs) i had this…
MaxReps: 6, StepErrors: 0. Underruns: 5504

Guess I'll bite the bullet today and drop the Duet WiFi in place with the latest firmware

If you haven't started that yet, you might like to try the 1.15 beta 3 release for the wired Duet that I just put on github.

Aussiephil · 16 Jul 2016, 14:11

@dc42:

If you haven't started that yet, you might like to try the 1.15 beta 3 release for the wired Duet that I just put on github.

sorry David, was sort of warmish today so got on with it, going to update the other thread with some details.

Cheers