Posts made by Kodachrome

@dc42
Thanks, was able to make progress by making that suggested runonce.cfg a macro instead and running from PanelDue. It was not executed automatically, presumably as it only gets "run once" a network is connected (ie the thing thats broken) per the docs. But Im back in operation again! I took the opportunity to move to a newer faster SDCard and now I have a nice little macro to reset Wifi should I need it in future.

PS: I must have had the old Wifi Firmware version and just not have noticed, which caused this to begin with!

@dc42

Just updated from Duet Wifi from 3.5 RC3 to RC4, just used the big Duet2and3Firmware-3.5.0-rc.4.zip file and let it do its thing. Unfortunately on reboot Im greeted with Wifi Module No Known Networks found (and M587 says none saved) and constant Wifi Idle errors.

Ive tried reverting to the older RC3 (via SD Card sys file changes and also have a Paneldue to run its console) to no avail... Im stuck now!

Im now testing an LDO NEMA 17 motor OverTheMoon LDO-42STH25-1004AC which is a High Temp High Speed pancake motor.

And I think I found the real root cause, aside from not-ideal stepper choices, I was using a Jerk speed of 200 mm/min, which is a value I found online as a recommended "extreme" setting. The default value is 40mm/min. When I dropped this down to 100mm/min and combined with the new light and fast stepper I can now achieve a pretty impressive 400ma current on the Stepper driving the Nimble (and still at high speeds).

@droftarts

Alright, an update and progress. I tried two smaller half height Nema17 steppers from my junk box. I also isolated a piece of movement from the actual print Gcode and made it into a macro. This was the most "offending" section, the last two fast extrusions back to back.

Macro:
G0 F2500
G1 X39.245 Y28.111 E12.53808
G1 X38.845 Y30.238 E.65933
G1 X11.598 Y57.486 E11.7389
G1 X39.245 Y28.111 E12.53808

This piece of GCode causes stalls on both the full size, high torque Stepper motors (the Wantai and the StepperOnline), Ie both fail, no matter the current (amps).

Conversely both the smaller Steppers could complete it with the following settings:

Working with 17HS3001-C5X (without gearbox, so its now a low torque direct motor)
M906 X1250 Y1250 Z1250 E1615 I25

Working with unnamed (it literally only has "XY" written on it) half height stepper
M906 X1250 Y1250 Z1250 E1545 I25

So basically the cheap ass, no name small Stepper works the best in this scenario. Im going to look for a better option online, annoyingly not mentioned in the Zesty Manuals but is on their old product page is a specific recommendation: https://www.omc-stepperonline.com/nema-17-bipolar-1-8deg-16ncm-22-6oz-in-1a-3-7v-42x42x20mm-4-wires-17hs08-1004s

@droftarts

Well that certainly does sound like a promising lead!

The Zesty is a remote drive extruder, my V1 is has a 30:1 multiplier on the torque input.
I found the screeching stall happens when exceeding 32mm/s on a sustained (ie more than second) extrusion on the 1.2mm extruder and 0.7mm layer height. I have a 1000w 24v PSU.

Zesty recommend the following ideal stepper specs:

--
Low rotor inertia
This allows it to start and stop rotating fast.
A value lower than 15 g-cm2 is desirable.
This often isn’t shown on the specification sheet, In this case an overall weight of the stepper of 120 to 150 grams is way to get something close to the target.

Low inductance
This means that the currents set up by the pulses are not too strong.
This allows the stepper to spin fast without the pulses interfering with each other.
Aim for a value of 3.5mH to 4.5mH

--

Now, where this interesting is the spec's of the two steppers I tried.

1. My original (supplied as part of the Anycublic tower motor I think) Wantai 42byghw811p2 has a Rotor inertia: 68 g⋅c㎡ and an Inductance of 1.8 mH
2. The replacement StepperOnline motor, which in practice was no better at all, has a Rotor Inertia of 105gcm2 and an Inductance of 3.0 mH.

So basically the StepperOnline motor is much worse for this application, lol. Im pretty sure in my junk box I have a half size Nema17 that was part of a geared setup (it had a little gearbox on the end of it) that most likely better than both of these Steppers.

@engikeneer said in Nimble + 1.2mm Nozzle - extruder stalls unless Amps increased 4x:

@Kodachrome doesn't matter whether it is the motor skipping steps because it doesn't have enough torque or the extruder gear slipping against the filament. Fundamentally the extruder system cannot push the filament through the nozzle at the rate you are asking. Apologies I have kind of used the terms interchangeably

Ok, cool, so it will be interesting the change when swapping out the 4200g-cm (at 2.5amp) torque Wantai 42byghw811p2 for the StepperOnline Nema17 rated 5900g-cm (at 2.0amp) stepper. On paper, thats maybe closing on 50% more torque for a given Amp rating (since Im not running the Wantai at the full 2.5amp its not actually pushing 4200g-am torque).

@engikeneer
I'm really confused on why both of you are mentioning melt rates and temps. The issue isnt an Extruder skipping problem, I said the Stepper motor driving the extruder stalls. The stepper stops spinning (well, it vibrates slightly) and the stepper motor (not extruder) makes high pitched noises. If I just had the basic and known clickly-skippy extruder noise then yeah, whack up the temp (which I tried but as I said, its irrelevant due to the fact the stepper motor isnt feeding the extruder anything when its stalling out!). But I suspect this has nothing to do with the extruder actually. I am running at 24v. And as I said, the problem is "circumvented" with a now confirmed 2150ma (of the 2500ma the motor is rated at). But this makes be uncomfortable due to high heat of stepper motor and the fact its so way over the top of Zesty doc's (which dont mention any nozzle or flow specs).

Did you misread me or did I misread (misunderstand) you both?

EDIT: Just found out that Zesty, who I assume are now out of business based on having no stock for a year now, once made a High Volume version of the Nimble, the Zesty Giddy. Never heard of it before right now!?
https://zesty.tech/products/the-nimble-giddy

To reiteration, the key issue in my case isnt melting of filament, its an electrical issue with the Stepper, the Zesty isnt skipping or hitting resistance with the filament. The Extruder stepper itself visually stalls to a standstill and "screams" on fast moves with extrusion. I dont know if this is a Duet Driver or Stepper motor issue. Further testing is showing that even 2200ma isn't enough.

I will try a 3rd stepper motor soon, ordered a SteppersOnline model, which has about 25% more holding torque.

@T3P3Tony Sensible stuff, though your last paragraph has me thinking, while its not actually acceleration, it actually only craps out on sustained straight lines (ie top speed, sustained for a few seconds). But its a crazy looking thing when going (with the amps high), the filament reel is just spinning constantly, it is actually quite impressive. There is also a crunchy-creaking sound coming from the Zesty, but I think thats the filament which is a quite hard PLA (branded as High Speed PLA+).

As to the drawbacks, heat in the Stepper is one, which may eventually cause its to also shutdown when over heating and also this poorly explained logic (IMO) from Zesty themselves:

Because the Nimble has so much torque available, you can/must run a much lower vref for your stepper than normal. This also helps getting the pulses across properly as you are not fighting decay in the pulses caused by too much current.

Well yeah, but while the flow rate is higher, the effort to push it is lower. Like it's really easy to push it by hand on the 1.2mm vs the 0.6.

I thought these would kinda negate each other. I did try slowing the print significantly though too, to no avail. Also the Zesty instructions make no reference to flow rate or nozzle size at all, only that the torque it generates so huge you need to start at 500ma and drop it from there till you get clicking sounds.

I had also tried ramping the temp way up, which is what I thought would solve it but made no difference.

Ive just (as in today) swapped over my E3D Revo Obxidian 0.6mm nozzle to a Revo High Flow 1.2mm nozzle and tried some prints. All ended up looking way under extruded, like the filament snagged then released over and over.

I was watching it print on the 3rd test and noticed the Extruder Stepper stops moving and makes a buzzing sound. Sometimes, though not always, this was accompanied by a console error:
"Warning: Driver 3 warning: phase B may be disconnected"

I thought the Stepper itself maybe was a bit undersized for the new nozzle or just defective so I fished out a larger unit from my bag of parts (an old Wantai 42byghw811p2, 2.5amp rating, 4200 g-cm holding torque). Came with a new cable, no change to issue.

Exactly the same issue. I then tried slowing down the extruder limits set in Duet, no change.
I then swapped out the Zesty Nimble for a second identical Nimble I used to use. No Change.

Finally I tried increasing the amps from the tiny 500ma that Zesty insist you should limit the Nimble (v1.2) to, first to 650ma, then 750ma then finally at 2000ma. At 2amps... everything just works fine.

But this is 4 times the guideline Zesty advised (and what was working beforehand)??
https://zestytechnology.readthedocs.io/en/latest/nimble/nimblev2/tuning.html

Should I care about this, is there some problem somewhere or is this what is required to drive a larger nozzle (hard to understand, its so big there is little resistance)?

EDIT: Ive tested down to 1200ma now and appears to be working, so the min value is somewhere between 750ma and 1200ma. Still way outside of spec though. Further testing shows the required figure is indeed around 2000ma, maybe 1900ma or something.

As per the wiki
https://duet3d.dozuki.com/Wiki/Pressure_advance

For setting multiple Drive pressure advance, the command suggested above doesnt seem to work, ie:

“ M572 D0:1 S0.3:0.1 “

then if you send a M572 and you get

" M572

Extruder pressure advance: 0.300, 0.300, 0.000, 0.000 "

Instead of D1 having "0.1" it appears to just keep the D0 setting?

Firmware Version: 2.05.1 (2020-02-09b1)

To add:

• stripped the Whambam bed off, back to bare clean aluminium plate.
• added 3 more bolt down washers to snag the aluminium plate into the frame even tighter
  Got the deviation in Auto Cal down to "0.043" but...

Literally none of these changes make any actual difference. The same problem positions (rear left vs front right of bed) occur all the time? What else am I missing?

So to update my own experiments, I made an easily attachable mount (magnets) for the IR probe and mounted it directly below the nozzles. Its dead on centered but the results from Auto Calibration are kinda the same at 6 Factor and useless at 8. Rear right of the bed is about 0.25 too high and front left is -0.15.

Deviation is ~0.110 .

So far:

• changed effector platform from metal to custom PETG one
• changed all Endstops from inaccurate optical ones to tried and trusted mechanical endtop switches (from SeeMeCNC)
• moved IR probe close to center, about 10mm off nozzles
• then moved IR probe directly below nozzle (G31 X0 Y0 Z35)

Literally none of these changes make any actual difference. The same error positions occur all the time? What else am I missing?

Nozzles, not nozzle, so cant use the Smart Effector (as per my other thread, thanks for the response there too, appreciate it).
On the piezo sensor, not sure how to physically integrate on a E3D Chimera .

I did have JohnSL FSR's setup too, to compare. Definately gave different results, but cant say for certain it was more accurate. I think FSRs are not a great solution for this size of bed.
Its maybe not as pressing as before, Im printing my 5th sensor holder now, seeing how close I can get before the PETG takes heat damage. Printing is gone way up in quality. I also changed the crap Optical sensors to the old SeeMeCNC mechanical switch endstops.

@bearer - Well yeah maybe, but that's also the reason for asking, the Smart Effector's central probing angle would make it much less likely to suffer effector tilt. Like.. people with dual nozzles still need to probe their beds one way or another.

This only matters when probing anyhow, "triggering" when printing wont do anything.

Thanks for the detailed replies, seems pretty clear no modifications are possible. Looking at the models in Fusion360, the angle a bowden tube would have to bend though the middle then out (they are 18mm spaced* but the opening is 12mm) is too severe.

*20mm on V2 Chimera

After moving the IR Sensor closer (again) to the middle I did indeed get much much better results.
Makes be wonder.. do the Nozzle(s) have to actually be in the middle?
I could really stretch the design and put the IR Probe in the middle (which is as close to eliminating effector tilt as it gets) and offset the nozzles, by maybe 3mm.

Thoughts?

Frustrated with the lack of a dual nozzle compatible Duet Smart Effector, I've been measuring it up in Fusion360. With some minimal drilling or cutting around the central opening it could easily accommodate the E3D Chimera.

Could anyone comment (maybe check a dead board?) if there are traces running through the PCB around that central hole?

Aside from Resin SLA printers, my entire history with 3D printing is delta's (5years?). I guess Ill go easy mode on the next big build and try out Railcore type design. Ive had no real problems with smaller delta's but the Predators huge build volume (and dubious end stops) have proven problematic from day 1. So much potential though.

On this problem I've made yet another IR Probe mount, super slim and just 1mm gap between the mount itself and the hotends (which are in silicone socks). The IR probe is another 3mm further out.. this is realistically as close as its going to get. I'll test it later when more filament gets delivered!