Extruder skipping on prime [SOLVED]

Phaedrux

What board is this? DuetWifi?
What firmware version?

I don't see a M350 anywhere in your config to set the microstepping value.

How did you calibrate to get 6250 steps/mm?

If you run M122 after your skipped steps post the results here.

5mm/s is quite fast for 3mm diameter filament. That's a lot of plastic to melt.

How fast are you retracting? You could try reducing the speed of the unretract.

Duke

Yes, sorry. Duet wifi board, I'll have to check on the firmware.
I'm not terribly familiar with microstepping, so if you could give me an example M 350 command to try, I can give it a shot.

To calibrate the steps/mm I marked 50mm on the filament and hit "extrude 50mm" and adjusted the value until the mark stopped at 0.

I'll try that M122 thing as well, I've never tried that before.

I'm also not sure how to check or adjust the retract speed? I'm using kisslicer 1.6.3 and I can't find any settings in there?

Thanks for your help!

Phaedrux

Well the default microstepping is x16 so it's probably using that.

You can send m350 in the gcode console and it will tell you what it's using.

https://duet3d.dozuki.com/Wiki/Gcode#Section_M350_Set_microstepping_mode

50 mm is pretty short distance. Are you measuring the amount coming out of the nozzle of the amount of filament going into the extruder?

This basic calibration guide might help?
https://duet3d.dozuki.com/Guide/Ender+3+Pro+and+Duet+Maestro+Guide+Part+4:+Calibration/40

I'm not very familiar with kisslicer. If you can figure out how to turn on firmware retraction you can configure your retraction settings with a gcode command.

https://duet3d.dozuki.com/Wiki/Gcode#Section_M207_Set_retract_length

droftarts

We had a BFB 3D Touch donated to our hackspace (Bristol, UK) a while ago. We managed to get it printing, and we felt the structure and mechanics were fine (though heavy gantry limits speed), but the extrusion control was poor. I started to look at ways to improve it, including swapping in a Duet, and found quite a few options on Thingiverse for replacing the extruders and hot ends with something more modern and reliable. In no particular order, I liked:
http://matthiasm.com/mods/how-to-upgrade-the-bfb-touch-3d-printer
https://www.thingiverse.com/thing:1378709 - Bits from Bytes 3DTouch rebuild
https://www.thingiverse.com/thing:2012572 - E3d hotend mount for BFB 3D touch

However, at some point the BFB was given away! No one seems to know where it went. If another one ever gets donated, I'm having it!

Ian

timcurtis67

If you are running worm gear you may try reducing the micro stepping to get that 6250 steps/mm lower. Maybe down to 1/8 or 1/4.

Duke

@droftarts
I've been to the Bristol Hackspace! I bought my 3D touch back when I was living in Hereford.
That's an interesting head carriage build, I may have to look into that.
I'm actually running an E3D V6 in mine, and oddly enough that hotend mount you referenced is remixed from one of my designs!
I'm also well acquainted with Matthias' mods, I've followed his recipe for a heated bed, it works great.
But by far the best mod I've done to date is putting the DuetWifi board in, the old firmware was terrible.

Duke

So it was running x16 microstepping
I dropped it to 1/4 steps on the extruder and divided the steps/mm accordingly, but that didn't help.
I'm still trying to work out how to turn on firmware retraction, but here is a video of it not working:
https://www.youtube.com/watch?v=ycUhGt60Hf0

Duke

AHA! I think I've cracked it.
It was kisslicer all along, it must have changed the settings when I updated to 1.6.3
The destring retract was set to 25mm/sec.
Thanks for the help, and sorry to waste everyone's time.

Just out of curiosity, what slicer is everyone using and why do you like it?

Phaedrux

I try and keep up to date with the Cura and Prusa Slicer releases. I like and dislike things about both of them. I like Cura for the control you can have over lots of little details which comes in handy for a detailed challenging print. I like Prusa because it's fast and the settings are generally easy to understand and tune. But it lacks some of the control you can get in Cura.

Nothing wrong with kisslicer. I've never been able to get the hang of it. The GUI is really offputting and confusing and I've never been able to get good prints out of it. I keep meaning to give it another good try but haven't had the time.

Duke

@Phaedrux
That's funny, the last time I used Cura was years ago. I didn't feel I had enough control over the prints and switched to kisslicer. Perhaps I should give it another try.
With the new release of kisslicer they have implemented a bunch of wizards that get you zeroed in pretty close right away, and then you can fine tune it from there.
I guess it's just what you're used to!

Thanks again!

Phaedrux

Cura has most setting hidden by default, but you can hide and unhide them as needed.

Some of the settings I find particularly useful:

Detect specified overhang angle and set a fan speed and a speed override.
Detailed control over bridging parameters for walls and skin, fan speed, flow, print speed, jerk, acceleration.
Wider range of solid infill patterns to choose from. For some models concentric makes far more sense than zig zig.
complete control over speed, accel, and jerk settings for every move type.

Things I dislike:

Cura does not let you impose a volumetric speed limit. So you have to keep an eye on your extrusion width, layer height, and print speed to ensure you don't try to push more plastic than the extruder can handle. Slic3r on the other hand allows you to set a volumetric speed limit and all top speeds will be tamed to stay within it.
Cura has abysmal thin wall support. If your wall thickness doesn't perfectly fit an even multiple of perimeters it will try and cram tiny zig zag moves into it which shakes the hell out of the printer and ends up over extruding like crazy and inflates print times by hours.

If you do want to give Cura a try, I highly recommend using this custom build by smartavionics that has many fixes and improvements that haven't made it into mainline Cura yet.

https://www.dropbox.com/sh/s43vqzmi4d2bqe2/AAADdYdSu9iwcKa0Knqgurm4a?dl=0&lst=

Things I like about Prusa Slicer:

it's fast and generally produces good gcode
it has a filament library function that you can use to store the parameters of your filaments like diameter, temps, fan profiles, flow rates, plus a custom gcode section to set things like retraction, pressure advance, or jerk
It has excellent thin wall detection and will replace a number of inner walls with a single wide gap fill extrusion where appropriate

Things I dislike:

It lacks many of the fine control options that Cura has
Using modifier meshes is still painful compared to Cura
It's become very Prusa printer centric so be sure to switch to the RepRap gcode flavor

I'll have to make concerted effort to give kisslicer another try.

timcurtis67

@Duke said in Extruder skipping on prime [SOLVED]:

Just out of curiosity, what slicer is everyone using and why do you like it?

I used both Kisslicer and Simplfy 3D. I used to use Cura which worked fine for me but I do like the some of the path features in Kisslicer over all of them.