Zesty Tech Nimble and retraction issues/re-engaging issues
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@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.
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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.
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@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.
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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.
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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...
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That is odd, if I use pressure advance it is around .04 to .06.
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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".
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@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
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Which is why I am so confused @fcwilt, I haven't found a single post regarding a similar issue like mine...
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@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
Printers: a small Utilmaker style, a small CoreXY and a E3D MS/TC setup. Various hotends. Using Duet 3 hardware running 3.4.6
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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?
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@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
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@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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@fcwilt As of now I still need the pressure advance to maintain a good print. However over the holidays I have been working on redesigning some components and implementing a 40mm noctua fan for my heat sink. once I have it all thrown together I'll try no pressure advance and see where that lands me.
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I'm just jumping back into this 3d printer adventure, printer being down the last 6 months.
I have a zesty nimble, and volcano using 0.8 nozzle and am using PETG.
I have yet to find a good combo of settings to get my prints to where I want.
I have also just started playing with Pressure advance. Using the calibration print that is in another thread with the python script to adjust it, It tells me I need 0.17 pressure advance.This then makes my prints extremely slow, so I have upped the jerk from the recommended 40 to 80 and 100.
I'm no longer sure the correct methodology for calibration with every new variable.
The above mentioned print is great for calibrating Pressure advance, but what is a good methodology/calibration for acceleration, and jerk ? -
Hi,
I use a Nimble with a .4 nozzle on a delta.
I have not used pressure advance as it works fine without.
Frederick
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Dakota, I have the exact same issue as you with my Nimble and using simplify3D. The print in your video is a mirror of my prints. Did you get it sorted, if so please can you share your settings?
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Seems like most of you have a very high pressure advance. I run a Zesty Nimble on a Hypercube Evolution with a 0.6 mm E3D Volcano hotend. Sweet spot seems to be somewhere around 0.01-0.03 depending on how flexible the filament is.
I usually run 2 mm retraction at 40 mm/s, seems to work good for the Volcano.
I created this script to generate test files for pressure advance calibration if you would like to try:
https://github.com/LHelge/RRF_PressureAdvanceCalibration
