Rippels and Ghosting on Y-Axis of converted Ender 3



  • Hey everyone!

    My Ender 3 conversion is pretty much done, just needs some final touches. It features a magnetic hotswap tool mount and currently has a E3D V6 with a MaPa nozzle and all-metal heatbreak as well as a 500mW laser. It also has a Y-Splitter for Dual Material printing.

    alt text

    Anyways, I got a chance to make my first test print, and while it looks good, there are some weird ripples on the y-axis. For X and Y I'm running identical JK42HM40-1684 0.9 degree steppers.

    This is my first print, and there are some wide spaced ripples:
    alt text

    I then tightened my y-axis belt so you can string it like a base guitar string, and the rippels got closer together... How can that be? Maybe a bent motor shaft?
    alt text

    I just finished printing my XYZ cube as well, but I'm honestly baffled, and I really don't know how to interpret these results. I have never seen a texture like this before... I mean, it looks cool, but not perfect the way I want it, and I knew my printer could do better.
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    Not really sure what to make of this? I have calibrated e-steps as well as flow rate. It's the same filament I have always been using. I'm doing 4mm retraction, maybe that's too high for my all metal hotend?

    Also, my hotend temperature is everything but stable, maybe this has to do with it.
    0_1554411430623_95e18e33-7f8a-4e54-a7d5-c01e4730763a-image.png
    I'm running a E3D V6 with a 40W cartridge, already PID tuned (with M303 H1 S240) . The thermistor is a ATC Semitec 104GT-2, and the config for it is like this:

    ; Hotend
    M305 P1 T100000 B4725 C7.06e-8 R4700
    M143 H1 S280
    M307 H1 A662.5 C243.2 D8.7 S1.00 V24.0 B0
    

    Maybe the wierd texture has to do with the temperature fluctuations?

    ... And finally, some before and after comparisons. Left is before conversion, right is after.
    alt text
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    Atleast the ringing is gone!



  • @devleon said in Weird ripples and texture on y-axis of converted ender 3:

    Atleast the ringing is gone!

    It definitely doesn't look gone in your pictures.

    What acceleration and jerk values are you using for X and Y? Because the weight of X and Y are different, you may need to use different values for each.

    You may also want to try dynamic acceleration adjustment. https://duet3d.dozuki.com/Wiki/Gcode#Section_M593_Configure_Dynamic_Acceleration_Adjustment



  • @phaedrux My config looks like this currently, it's the same values I had with my ender 3 marlin config. Acceleration and Jerk for X and Y are indeed the same. I also didn't print with the glass bed for a while, because I got some bad ringing. But since I fried my BLTouch by connecting it up wrong and my bed is warped as hell, I need to use the glass plate now to get any usable results. But I figured now that I have 0.9 steppers with higher torque, it would get better.

    M350 X16 Y16 Z16 E16:16 I1                         ; Configure microstepping with interpolation
    M92 X160.00 Y160.00 Z400.00 E830.00:830.00         ; Set steps per mm
    M566 X600.00 Y600.00 Z18.00 E2000.00:2000.00       ; Set maximum instantaneous speed changes (mm/min)
    M203 X30000.00 Y30000.00 Z300.00 E1800.00:1800.00  ; Set maximum speeds (mm/min)
    M201 X500.00 Y500.00 Z100.00 E3000.00:3000.00      ; Set accelerations (mm/s^2)
    M906 X1260.00 Y1260.00 Z725.00 E1000.50:1000.50 I30 ; Set motor currents (mA) and motor idle factor in per cent
    

    Dynamic Acceleration Adjustment is already on my todo list, will try it tomorrow.

    I also just discovered that both the setscrew inside the left bondtech bmg as well as in the gear on the stepper came loose somehow. Maybe that's the reason for the weird pattern. I've tightened them both, now filament is fed correctly again, it had stopped feeding alltogether. It's too late to start another print now, but I'll try another cube tomorrow and try measuring the ringing and setting up M593. Thanks!



  • The loose grub screw would totally explain the weird texture.

    For the ringing, the dynamic acceleration link may help you tune it out.



  • @phaedrux The ringing pretty much disappeared now, and it looks much better, so I didn't do anything for the dynamic acceleration adjustment, as there was nothing to measure.

    However, now I'm getting some weird blobs here and there. Any idea what that might be?

    0_1554459208823_42342b2d-6931-440d-94d1-4e4c4ff77c13-image.png

    I know I'm also getting some thinner extrusion, always in the same heights, maybe my z-axis is binding. I'll lubricate my z-axis later with some WD-40 Specialist PTFE Dry Lubricant Spray, lets see if that helps.

    Also, I setup the following macro to help me unload filament from above the y-splitter.

    ; Unload E0
    T-1 ; make sure everything is unloaded
    M117 Unloading E0
    T0 P0; select T0 without running any tool change macros
    M302 P1 ; Allow cold extrusion
    M82 ; use absolute distances for extrusion
    G92 E0 ; Reset Extruder
    G1 E-430 F3600 ; retract 430 mm
    M302 P0 ; Disable cold extrusion
    T-1 P0 ; Deselect all tools without running any tool change macros
    

    But when i try to run it from DWC, I get the error:
    Tool 0 was not driven because its heater temperatures were not high enough or it has a heater fault

    However, if I enter all the commands one after another in the gcode console, it works just fine. Any idea what I'm doing wrong?


  • administrators

    @devleon said in Weird ripples and texture on y-axis of converted ender 3:

    Also, I setup the following macro to help me unload filament from above the y-splitter.
    ; Unload E0
    T-1 ; make sure everything is unloaded
    M117 Unloading E0
    T0 P0; select T0 without running any tool change macros
    M302 P1 ; Allow cold extrusion
    M82 ; use absolute distances for extrusion
    G92 E0 ; Reset Extruder
    G1 E-430 F3600 ; retract 430 mm
    M302 P0 ; Disable cold extrusion
    T-1 P0 ; Deselect all tools without running any tool change macros

    But when i try to run it from DWC, I get the error:
    Tool 0 was not driven because its heater temperatures were not high enough or it has a heater fault
    However, if I enter all the commands one after another in the gcode console, it works just fine. Any idea what I'm doing wrong?

    You've found a bug! M302 does not currently wait for moves already in the movement pipeline to complete. So the M302 P0 command is being executed before the G1 E command has completed. I'll fix it in the next release. Meanwhile, insert command M400 before the M302 P0 command.



  • @dc42 Thanks, it works now.

    I just tried Dynamic Acceleration Adjustment, because while I was getting no ringing on the hollow 20x20 cube, I'm definitely getting some with the XYZ cube.

    0_1554464450244_9c08c41c-eba3-4252-b097-71fd7e6e3503-image.png

    While printing the upper cube, I looked at the speed in DWC and it showed 30 mm/s for requested and top speed when printing the perimeters. I then measured the distance between the peaks, which is 1mm. So I simply entered M593 F30.0 into the G-Code Console before starting the exact same print again. However, as you can see on the cube below, nothing changed. Did I do something wrong?

    I've also tried 33.3Hz and 37.5Hz, but no difference whatsoever, they all look exactly the same.

    Edit: I'm not the only one with this issue. If ones searches for Ender 3 ringing, they'll find tons of posts about ringing on the Y-Axis - but those enders are all stock. Guess it's something mechanical then? I'm out of ideas.

    Edit 2:
    I have since upped my accel and jerk and the ghosting got a tiny bit better, but it's still very much there. I'm also currently printing without the glass bed.

    M566 X900.00 Y900.00 Z18.00 E2000.00:2000.00       ; Set maximum instantaneous speed changes (mm/min)
    M203 X18000.00 Y18000.00 Z300.00 E1800.00:1800.00  ; Set maximum speeds (mm/min)
    M201 X1000.00 Y1000.00 Z100.00 E3000.00:3000.00    ; Set accelerations (mm/s^2)
    

    Edit 3:
    No difference with the cube printed without the glass bed.



  • Well, after lots of attempts, clogs because of the all-metal hotend, heater faults because the part cooling fan would cool the hotend too much, weird babystep offset issues during tool changes, where after a toolchange the offset would just be ignored and the nozzle would bury itself in the print, I finally got a complete dual color print 🙂

    alt text


  • administrators

    Welcome to the dual extrusion club!

    where after a toolchange the offset would just be ignored and the nozzle would bury itself in the print

    Please can you elaborate: what was the problem, and what did you do to fix it?



  • @dc42 Thanks!

    For my first print, I had my z-height slightly too low, so when the printer started printing, the nozzle was too close to the bed. I used babystepping in DWC to make it higher, and that worked for the first layer until a toolchange happened.
    After the toolchange, the nozzle was too low again (I guess the babystepping was reset, even though it stayed the same in DWC), dug itself in the already printed layer and ultimately caused a clog in my heatbreak. My first guess was that it was caused by a "G1 R1" in my purge_bucket.g macro that was called after purging and cleaning from a toolchange, so I removed it.

    However, even with it removed, I still had the issue that if there was babystepping before a toolchange, it would not get applied correctly after the toolchange. If I had babystepped during the first layer of the first tool, the nozzle would always be too high or too low after a toolchange (causing some clogs in the all metal hotend). I'm also running grid mesh compensation, so maybe the combination of babystepping, grid bed leveling and a toolchange didn't work well together. Or maybe the baystepping get's reset after a toolchange? It stays the same in DWC. The actual offsets (G10) are the same for both tools, as it's the same nozzle anyways.

    I ultimately fixed it by carefully tuning the z-height before the print so I wouldn't need babystepping. This finally produced the cone above.

    Im running the latest beta3 btw.



  • @dc42 Just confirmed that the offset it reset when changing tools. I checked by baby stepping up by 4mm, then running a toolchange. The nozzle goes back down 4mm, but it still says 4mm in DWC. I also have a M451 in my tpre0.g and tpre1.g to make sure the printer is in FFF mode, because I have a M452 in my tpre2.g for my laser. Maybe that's the reason?



  • @devleon said in Rippels and Ghosting on Y-Axis of converted Ender 3:

    I just finished printing my XYZ cube as well, but I'm honestly baffled, and I really don't know how to interpret these results. I have never seen a texture like this before... I mean, it looks cool, but not perfect the way I want it, and I knew my printer could do better.

    The Bondtech has 50 cogs on the plastic gear. (The gear on the motor has 17.) I have patterns very similar to yours as well. Can you relate the frequency on your parts to 50, each time a plastic cog hits a cog on the motor gear?

    Do you use pressure advance?

    Is the amplitude reduced if you increase the temperature 30C ? This would lower the viscosity and reduce the pressure and thereby lowering the force on the cogs.



  • @urban I can only say that the peaks are about 1mm apart in the y-axis, there is no pattern on the x-axis. I'm not using pressure advance. I'll try increasing the temperature next.



  • @devleon Can you:

    1. Confirm that you are using a Bondtech BMG with 1.75mm filament
    2. Measure 5 to10 waves as exactly as you can and calculate the average distance
    3. Tell us what the extruded width and layer height you are using
    4. The number of steps per mm
    5. and how many micro steps per full step (16?)
    6. how many full steps per turn the stepper has (200 or 400)

    This is enough to calculate if it is the cogging that is causing you problem.


 

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