Strange Printing Defect! Please Help,



  • I have built a corexy printer based on the hypercube. All gates idlers, pulleys and belts.
    I cannot get rid of this weird texture!

    I have tried upping and lowering currents, rebuilding and cleaning the hotend (v6) and liner rails, printing faster, printing slower, adjusting jerk, acceleration and max speed, calibrated the esteps a few times, changing filament, PID tuning, praying to the beard of Zues, however no luck.

    alt text



  • have you tried removing the belt and moving the hotend in all direction with least amount of force.
    the resistance should be constant. i.e at no stage should you have to apply more force for the movement than at the other places.



  • Yes, I have. It's all nice and smooth it just seems a bit inconsistent when extruding. Apparently from some digging in several forums you can add 15k diff fluid as a lubricant on the nimble which apparently helps?



  • Can you post your config file?

    What is the extruder? Bowden or direct?

    Does the filament feed off the role easily?

    Have you tried printing a larger object?



  • Have you contacted Lykle or Brian? They will go out of there way to help. You should have got an invite link to the Discord channel when you bought the Nimble and a link to the forum. From the forum:
    "Ripple report

    We have undertaken extensive testing and back to back comparisons, not without some difficulty.

    One difficulty was reproducing these artifacts. It was an effort in itself and was only possible to much subtler effect. Another difficulty was that we tested multiple “tainted” Nimbles sent to us by customers, once installed on our own printers they did not exhibit the same issues shown in the photo’s of prints the customer had sent us.

    After having one of the test printers create “fake” artifacts that were the result of other hardware issues, we threw away those results and started again with multiple other printers.

    We conclude the effect is caused by a combination of factors.

    These factors include:

    Firmware settings
    Worm or gear eccentricityLubricant (incorrect, or lack of)
    Mounting adapter
    Nimble breech
    Nimble housing
    PrinterSlicer

    When there are evident ripples it is usually a combination of at least 2 or 3 of these. Looking at survey data, all but one case occurred in Nimbles with an older shell and an older gear type.

    We think a key causative factor is tolerance stacking. Tolerance stacking in this case also includes firmware and slicer settings. The tolerance of the laser sintered process is usually 0.1 to 0.2 mm, depending on the size of the part. The tolerance in the bearing shaft is 0.05 mm.
    When these tolerances are all maxed out the wrong way, the result is tainted Nimble.

    If you then combine it with slicer settings and firmware settings that add to the effect and put the whole thing into a printer where the hot end is not as rigid as you would want, you get the worst case scenario.

    Note

    It’s important to remember this issue affects around 1% of our customers. This is below the failure rate of condoms (which is 2%), but without the drastically life-altering effect.

    How to fix it
    Fine tune the extrusion and firmware settings
    Work with 1 slicer and tune it
    Check to see how rigid your printer is
    Check the clearance on the breech in the Nimble and the filament path in the breech.
    Check if there is any play between the bearings and the housing.

    If all else fails, just talk to us and we will fix it for you.

    In the meantime, know that we are not resting. We will continue to test, iterate, and improve print quality of Zesty extruders.

    ConclusionAll manufactured objects have failure ratesThe Nimble exhibits an extremely low failure rateWe try to provide the best customer support we can, and will always help any customer get their Nimble working on their printer."



  • @alexander-mundy
    I agree wth alexander.
    I had a similar problem with my old flex3drive.
    I had to change the cabledrive and the bearings.

    alt text



  • @alexander-mundy I have contacted the guys at zesty earlier today and await their reply.

    Config below:

    ; Configuration file for S.H.I.E.L.D. Printer (by James Lawes)
    ;Date Mofidied: 03-2-19

    ; Communication and General
    G90 ; Send absolute coordinates...
    M83 ; ...but relative extruder moves

    M667 S1 ; Switch to CoreXY mode

    M111 S0 ; Debugging off
    G21 ; Work in millimetres
    M555 P2 ; Set firmware compatibility to look like Marlin

    ; WIFI
    M550 PSHIELD ; Set machine name
    M540 P0x60:0x01:0x94:0x0C:0x54:0x28 ; set MAC address
    M552 S1 ; Enable network and acquire dynamic address via DHCP
    M554 P192.168.1.1 ; Set gateway

    ; *** PanelDue Touch Display
    M575 P1 B57600 S1 ; Assign serial channel #1 (P1)
    ; Set baud to 57.6k and only accept commands
    ; valid with checksum (parameter S1)

    ; Drives
    M569 P0 S0 ; X Motor runs forwards
    M569 P1 S0 ; Y Motor runs forwards
    M569 P2 S1 ; Z Motor runs forwards
    M569 P4 S1 ; E Motor runs forwards

    ; Movement
    M906 X800 Y800 Z800 E600 I60 ; Set motor currents (mA) and motor idle factor in per cent (tweaked for motor temps)
    M201 X4000 Y4000 Z12 E240 ; Set accelerations (mm/s^2)
    M203 X8000 Y8000 Z240 E2750 ; Set maximum speeds (mm/min)
    M566 X400 Y400 Z20 E30 ; Set maximum instantaneous speed changes (mm/min)
    M84 S30 ; Set idle timeout

    ; Stepping
    M350 X64 Y64 Z16 E16 I1 ; Configure microstepping with interpolation
    M92 X320 Y320 Z400 E2820 ; Set steps per mm

    ; Pressure Advance
    ;M572 D0 S0.7

    ; Axis Limits
    M208 X-15 Y-10 Z0 S1 ; Set axis minima
    M208 X315 Y290 Z300 S0 ; Set axis maxima

    ; Endstops
    M574 X1 Y2 S1 ; Define active high microswitches

    ; Z-Probe
    M574 Z1 S2 ; Set endstops controlled by probe
    M307 H3 A-1 C-1 D-1 ; Disable heater on PWM channel for BLTouch
    M558 P9 H5 F120 T6000 ; Set Z probe type to bltouch and the dive height + speeds
    G31 P500 X0 Y0 Z1.6 ; Set Z probe trigger value, offset and trigger height
    M557 X40:280 Y40:280 S55 ; Define mesh grid

    ; Heaters
    M307 H0 B0 S1.00 ; Disable bang-bang mode for the bed heater and set PWM limit
    M305 P0 T100000 B4138 R4700 ; Set thermistor + ADC parameters for heater 0
    M143 H0 S110 ; Set temperature limit for heater 0 to 120C
    M305 P1 X501 R4700 ; Configure PT1000 for heater 1
    M307 H1 A505.6 C174.5 D6.6 S1.00 V24.3 B0
    M143 H1 S290 ; Set temperature limit for heater 1 to 280C

    ; Fans
    M106 P0 S1 I0 F500 H1 T40 ; Set fan 0 value, PWM signal inversion and frequency. Thermostatic control is turned on
    M106 P1 S0 I0 F100 H-1 ; Set fan 1 value, PWM signal inversion and frequency. Thermostatic control is turned off

    ; Tools
    M563 P0 D0 H1 F1 ; Define Tool 0
    G10 P0 X0 Y0 Z0 ; Set tool 0 axis offsets
    G10 P0 R0 S0 ; Set initial tool 0 active and standby temperatures to 0C
    M572 D0 S0.03

    M564 H0
    M501

    T0



  • @syko_symatic I had prints (pla) looking the same but it was not all over the complete height. For me it was the first ~10 layers.
    It was caused by a too low temperature+to high fan speed. I had to print this pla at 225° with lower fan speed and the "texture" disappeared completely.



  • I returned my nimble for the same situation. This printer printed perfectly before the nimble and perfectly afterwards, and it was calibrated according to their instructions. There was nothing wrong except that nimble. I will say they were helpful and good to work with, but I will also say this post above shifting blame to the users other components does rub me the wrong way.



  • @syko_symatic said in Strange Printing Defect! Please Help,:

    M566 X400 Y400 Z20 E30 ; Set maximum instantaneous speed changes (mm/min)

    ; Pressure Advance
    ;M572 D0 S0.7

    Very low extruder jerk and very high pressure advance can lead to some odd side effects. I'm not super familiar with the nimble, but I realize they recommend low jerk due to the worm gear drive?

    If you're running firmware 2.03 You could try enabling the new jerk policy setting with M566 P1 and see if it makes a difference. It's a long shot, but worth a try.

    Looking at the pictures though it definitely seems like some sort of extruder eccentricity.



  • @phaedrux extruder eccentricity? Never heard that term before? Could you give me a quick run down on it?



  • @syko_symatic A gear or something in the path that transfers the rotation of the motor to the gear that pushes the filament is out of true. So instead of consistent motion there is pulsing, or vibration, or extra drag/friction. Some mechanical action causing the pattern you see.

    Have you tried printing larger objects yet? Circles? Diagonals?



  • @phaedrux diagonals, yes, circles no.

    With the nimble what could actually cause that eccentricity?



  • I imagine that would be the tolerance stacking they mentioned in that copy and paste above.



  • Doesn't look like an eccentric gear or loose bearings/case/hob shaft due to the tight spacing. I had an undersized hobb shaft and the effect was more spread out. Looks more to me like cable/stepper side problem. What is your minimum cable radius? Can you detect any slapping of the cable against the sheath? Re lube, I use 20K diff lube and it works fine. Others I have heard using 10K to 100K.



  • Oh, another thing to check is that the end of the cable is all the way down inside the worm gear.



  • @phaedrux said in Strange Printing Defect! Please Help,:

    Very low extruder jerk and very high pressure advance can lead to some odd side effects. I'm not super familiar with the nimble, but I realize they recommend low jerk due to the worm gear drive?

    Honestly the low jerk / acceleration was the biggest hurdle for me. I almost gave up but I hunted for low inertia / fast steppers. I found that 3.6 degree parallel disc magnet steppers from Portescap (P430 258 005 01 with the coils wired parallel) allow for some serious extruder acceleration and jerk. As a test I have tried up to 100mm/s retraction without any problem even with the 30 to 1 gearing. Be sitting down if you look that stepper up though. Fortunately I got them used for less than 10% new price.



  • Spoke quickly to Brian from Zesty Tech over email. He suggested a few things which have improved the quality but still not quite there 100%. May be having a call with him tomorrow.

    One thing I have mentioned to him though, the worm gear seems much looser in the bearing on one end, I am not sure if this is intentional but may be an issue?

    If anyone can suggest anything to improve this result further I am all ears....

    Improved



  • I have the same problem. Did you manage to solve it?


    My website: https://letica.pl/

    https://gloryshop.pl/ |



  • @damianm reducing the extruder acceleration to 1000 did wonders to be honest. I will have to check a few other slicer settings and esteps to see if I can improve on the finish I am currently getting.

    It's good but now as good as I got from it on my previous printer.


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