Zesty Tech Nimble and retraction issues/re-engaging issues



  • So I am currently stumped as to what i could try to fix my issue and would love any feed back.

    Recently i have been noticing a lot of zits and blobs left where my extruder starts and stops a print. Upon investigation, I noticed that when I retracted 10 millimeters and waited a few seconds to re-engage the same 10 millimeters, an extra amount of plastic would come oozing out like it extruded more than 10 millimeters. I then created a testing macro to prime the nozzle and then retract filament wait half a second, then re-engage at the same amount retracted. Every time it re-engaged there was plastic the would begin oozing with pressure behind it. I then messed with all the settings in Simplify3D to control oozing with no viable outcome. I then turned off negative restart distance and no coasting, then bumped up my pressure advance settings on the printer all the way to .3 to get really good results. However it did begin messing with other areas of quality.

    here are the specs for my printer.

    Custom Core XY
    E3D Chimera
    Zesty Tech Nimble (with all recommended config settings)
    PLA @ 175C

    Oh and I did also recheck my E-Steps and it was actually extruding less than the target distance. I changed it and still got the same results.



  • Hi,

    You didn't mention what sort of filament you are using.

    On my Nimble/E3Dv6 setup I use 1mm retraction for PLA and to date it has been working fine.

    What material/temp are you using?

    Frederick



  • I am using black Hatchbox PLA printing at 175 degrees C.
    Initially i was printing at 195 degrees C but figured out that was higher than needed.



  • Here is an example of a simple cylinder i did to show the issue

    https://www.reddit.com/user/3DimensionalCAD/comments/a6a3xp/no_pressure_advancement/

    here is the same print but i turn the pressure advance all the way to .28, this caused the printer to slow down dramatically.

    https://www.reddit.com/user/3DimensionalCAD/comments/a6a3nv/pressure_advancement_on/



  • I just tried adjusting the extrusion factor all the way down to 50% to get the same issue.

    https://i.redd.it/j6kmfv6kzb421.jpg



  • Can you post your config file?


  • administrators

    @dakota said in Zesty Tech Nimble and retraction issues/re-engaging issues:

    Here is an example of a simple cylinder i did to show the issue

    https://www.reddit.com/user/3DimensionalCAD/comments/a6a3xp/no_pressure_advancement/

    here is the same print but i turn the pressure advance all the way to .28, this caused the printer to slow down dramatically.

    https://www.reddit.com/user/3DimensionalCAD/comments/a6a3nv/pressure_advancement_on/

    If turning up pressure advance slows down the print, the fix is to increase extruder jerk, if you can do that without losing steps.



  • 0_1544906728674_config.g

    There is my config file, i messed with some of the settings for the extruder but nothing has shown to improve the problem other than adjusting the pressure advance a lot higher than i would have expected for a direct drive set up.

    and thank you @dc42 i will try this soon.



  • @dakota extruder jerk and acceleration are very low. I don't know if that's a requirement for the zesty nimble or not but it may be interfering with pressure advance.



  • The low extruder jerk required for satisfactory retraction with the Nimble and standard hybrid steppers doesn't play well with pressure advance. However you can try increasing jerk. I was using 80 before I experimented with permanent magnet steppers which allowed what are considered "normal" jerk and acceleration settings.



  • I agree @Phaedrux and @Alexander-Mundy , I just came home to inspect a print that I changed the pressure advance down to .16 and changed the jerk value to 80 and that did help with keeping the print at the original speed.

    I guess I'm still trying to understand why there is so much pressure built up in my hot end when the nimble is as close as can be...



  • That is odd, if I use pressure advance it is around .04 to .06.



  • For comparison: I have a Hypercube Evolution with a Zesty Nimble, E3D Volcano currently using 0.6 nozzle. I am in the middle of trying to tune it for PETG. I have written a Python script that prints 3 partial polygons each at different speeds with various For loops. The idea for the partial polygons is to explore what shapes are useful for calibrating new filaments as a routine task and also as nozzle size is changed, particularly as a lot of the general printing parameters do not apply for this hardware. Partial polygons allow for almost any regular shape from a single line (an n-sided polygon with n-1 sides omitted) to arcs and circles placed in any configuration.

    Have tested retraction vs unretraction vs Pressure Advance and with each polygon at different speeds. What I have discovered so far is 70 mm/s is the max speed for my PETG (at 245 deg) and below that speed does not affect printing too much for many combination of settings. Unretraction seems a minor issue. Pressure advance around 0.01 - 0.03 seems best, HOWEVER that was for very high jerk and acceleration compared to Nimble recommendations.

    Also tested various combinations of Accln and Jerk. Zesty recommend Jerk of E40 and acceleration of E120 and I have been using numbers several times larger than that as it appears to work (maybe because of nozzle size). Acceleration up to E340 worked. It is possible that Jerk of E100 and Accln of E300 might be OK. The best setting is uncertain at the moment.

    I am cautious about giving suggestions at the moment as I am new to this and more testing is needed to cover a reasonable set of combinations and to get a feel for what is important. I thought I had a good combination of settings when printing 3 towers each U shaped (ie 3 sides of a square). Then when I re-ran the same settings with full squares (ie a complete polygon) the same settings did not produce good prints. More "Rinse and Repeat".



  • @dakota said in Zesty Tech Nimble and retraction issues/re-engaging issues:

    I guess I'm still trying to understand why there is so much pressure built up in my hot end when the nimble is as close as can be...

    I'm surprised you are using pressure advance at all. My Nimble setup works fine without it.

    Frederick



  • Which is why I am so confused @fcwilt, I haven't found a single post regarding a similar issue like mine...



  • @dakota said in Zesty Tech Nimble and retraction issues/re-engaging issues:

    Which is why I am so confused @fcwilt, I haven't found a single post regarding a similar issue like mine...

    I run PLA at 195-200 but, of course, component variations may mean that my 200 is not the same as your 200.

    I've never tried as low as 175.

    Did you try the 1mm retraction that I use?

    Frederick



  • I run PLA at 215/210. Need a bit better cooling, but it comes out OK if I don't print thin spires or the like. Using a small stepper for the nimble. Had problems with losing steps with a regular sized stepper.

    Here's my settings:
    M92 X160 Y160 Z160 E2600 ; Set steps per mm
    M566 X1200 Y1200 Z1200 E100 ; Set maximum instantaneous speed changes (mm/min)
    M203 X22000 Y22000 Z22000 E6000 ; Set maximum speeds (mm/min)
    M201 X6000 Y6000 Z6000 E1500 ; Set accelerations (mm/s^2)
    M906 X1000 Y1000 Z1000 E750 I30 ; Set motor currents (mA) and motor idle factor in per cent
    M84 S30 ; Set idle timeout
    M207 S2.0 F1500 T900 Z0.5 ; Set FW retraction length and speed
    M572 D0 S0.10 ; Set pressure advance



  • @gone2far did your extruder extrude more plastic at the start of each extrusion when it skipped steps?



  • @fcwilt sorry for the late reply.
    i tried the 1mm retraction and that didn't solve my issue, however it did prove I didn't need to retract 4mm like i was.

    my running theory is that my heat sink is not providing a cool enough zone compared to the heater block, giving the filament a larger elasticity zone when retracting.

    however i never had this issue before when i was using marlin with all the same hardware... this issue is really making me question how much i thought i knew haha



  • @dakota said in Zesty Tech Nimble and retraction issues/re-engaging issues:

    @fcwilt sorry for the late reply.
    i tried the 1mm retraction and that didn't solve my issue, however it did prove I didn't need to retract 4mm like i was.

    Did you disable pressure advance? That should not be needed with the Nimble.

    Frederick



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