Retraction issues

Phaedrux

No, it's not needed to do firmware retraction. Cura has good retraction control. Just wondering what settings you're trying to use. The low jerk value could be preventing you from hitting it.

If you're coming from Marlin you may be used to seeing the jerk values in mm/s rather than the mm/min in RRF.

Stealthy_TT

@phaedrux

I’m coming from Marlin, so this is all different haha. I’ll definitely up my jerk settings and see what happens.

Also I have this issue where I can set a perfect offset from the bed for the first layer, but after a couple layers the nozzle starts touching the print. I’m thinking it’s my z steps but I had set those to what I had in Marlin firmware, So I’m not sure lol.

Phaedrux

@stealthy_tt What are you using for a Z probe? What does your homez.g file look like?

Stealthy_TT

@phaedrux

Have no access to the home file at the moment, but I’m using dc42s mini ir probe

Stealthy_TT

@phaedrux

Heres my homez file

; homez.g
; called to home the Z axis
;
; generated by RepRapFirmware Configuration Tool on Sat Apr 14 2018 16:11:45 GMT-0700 (Pacific Daylight Time)
;G91 ; relative positioning
;G1 Z5 F6000 S2 ; lift Z relative to current position
;G1 S1 Z-405 F1800 ; move Z down until the switch triggers
;G92 Z2.5 ; set Z position to trigger height

; Uncomment the following lines to lift Z after probing
G91 ; relative positioning
G1 Z20 F100 S2 ; lift Z relative to current position
G90 ; absolute positioning /
g1 x180 y180 s2 f2000
g30

I know i probably messed something up here, was a crap shoot for me to get the probe to work haha.

dc42

RepRapFirmware will do whatever the gcode generated by the slicer commands. It isn't normal to retract and travel at the same time, although some slicers have a "wipe while retracting" option.

Stealthy_TT

@dc42

The way im describing it is probably wrong. I know its not retracting correctly though. On my stock anet board the nozzle would never stop to retract, and if it did it wasnt long enough for me to think hey something is wrong. On the Duet the hotend stops dead in its tracks long enough for me to notice something is wrong with my settings or something. Ill have to get a video of it as I know im not describing it correctly lol.

dc42

Perhaps you have the maximum extruder speed or acceleration set much too low in the M203 or M201 command?

Stealthy_TT

@dc42
Probably, im going to try some changes when i get off work. Are we able to upload videos directly or do we have to upload somewhere like youtube?

Using my phone thats why I ask.

Thanks dc42

dc42

Upload to YouTube and post the link here.

Stealthy_TT

@dc42

Thanks will do when I get off work.

Any ideas as to why when I get my nozzle offset corect after a first couple layers print the nozzle starts to scrape over the top of the print?

I calibrated the extruder steps and when I extrude 100mm of filament 100mm is indeed what is taken up. So I dont think it can be that. I was thinking maybe the z axis steps, but thats the same as I had in Marlin. Is there like an offset per layer or something?

Stealthy_TT

May have figured out my issue with the nozzle dragging on the print after the first layer or so. Searching around i found that a M8 rod 1.25 pitch at x16 should have a value of 2560 steps/mm i have mine set to 400 steps/mm ill have to try when i get home

Phaedrux

@stealthy_tt Are you maybe skipping steps on the Z axis?

Stealthy_TT

@phaedrux
Not skipping that i am sure of, see my reply above you, i think i figured it out but wont know till later

Stealthy_TT

Okay, So just messed with my Z steps/mm 400 is infact correct with my printer afaik. I homed z and took a measurement and then moved z up 10mm and it was exactly 10mm. so thats not my dragging issue.

Stealthy_TT

https://youtu.be/IFxbb1yQTXU

Heres the video of what it is doing. The hums you hear are it retracting and re extruding

Phaedrux

Did increasing jerk and acceleration help at all?
What do the retraction settings look like in Cura?

Stealthy_TT

@phaedrux

current settings in Config.g
; Drives
M569 P0 S1 ; Drive 0 goes forwards
M569 P1 S0 ; Drive 1 goes forwards
M569 P2 S0 ; Drive 2 goes backwards
M569 P3 S0 ; Drive 3 goes backwards
M350 X16 Y16 Z16 E16 I1 ; Configure microstepping with interpolation
M92 X100 Y99 Z400 E470 ; Set steps per mm
M566 X500 Y500 Z60 E800 ; Set maximum instantaneous speed changes (mm/min)
M203 X15000 Y15000 Z800 E1800 ; Set maximum speeds (mm/min)
M201 X1000 Y1000 Z800 E8000 ; Set accelerations (mm/s^2)
M906 X800 Y1500 Z800 E800 I30 ; Set motor currents (mA) and motor idle factor in per cent
M84 S0 ; Set idle timeout

Cura settings
retract distance: 6.5mm
retract and prime speed: 80mm/s
retract extra prime amount: 0

dc42

Try reducing the Z acceleration in the M201 command.

Stealthy_TT

@dc42

Thanks dc I’ll try that.

Another thing, sometimes i have to home all twice in order to get all axis homed. It usually happens when I move an axis by hand or with the web gui past roughly the center point.

For example

I home all and it works correctly, my config is set to put the hotend in the center of heat bed after it homes. So after homing the hotend will be at 185 for x and y. So if I move X with the web gui +100 and do another home all command it will usually fail to home X and I’ll have to home all again for it to make it to the limit switch. Is there a fail safe setting for homing distance somewhere?