Any ideas how to have more consistent diameter in this setup

Thanks for the thoughts.

Moving stuff will be a good project for next weekend.

Do you mean raise the sensor? My sensor is currently about 35 inches down from nozzle, which is more than the 25 you stated.

My setup has been tweaked Alot over the past year. I did start at 180 a long time ago. I think my rate was really slow... Pretty sure I have read of others using temps in this range.... But I agree lower temp should help.

Sorry, was going off the posted photo.

It is possible to use higher temperatures, but it's a bit like taking the training wheels off - at higher temperatures, everything has to be just right.

As for non-circular, that likely means either ovality induced from the cooling fan or from the nozzle orifice not being round.

The Filawinder firmware is open source and available:

http://www.soliforum.com/topic/5088/fil … mentation/

One mod on the filawinder firmware I am considering is a minimum auto speed so it never actually fully stops. It really should never have to completely stop if ya think about it. And stopping and starting in my experience is always somewhat jerky. Inertia is always a killer when you stop. ( At least in industrial robotics.)

From that updated photo, I'd try to move the winder and struder a little further apart, and the sensor up. That and I'd reduce the temperature to 185C. This will likely bring your average diameter up, I'd compensate with less cooling though you may need a non-overdrilled nozzle.

What speeds are you seeing currently, and what were you seeing at 180C?

Hi All

So i spent the weekend playing with the filastruder.
I was able to get things better, but still not where i think it should be.
Filawinder is now about 33 inches to the right of the extruder (cannot go any further, out of room)
Loop goes down about 30", temperature is 184.
Diameter average is about right.
Played with the firmware on the filawinder, setting min speed from 25 to 60 (which is a bit above stall speed). Also made the maximum increment of speed change 6 instead of 25. (I think i will reduce this a bit further to 4). In general, the filawinder seems to be running about as smooth as possible, introducing minimal oscillation in the filament loop. I did remove the PTFE tube loop, and now just have a straight section of tube, up to my dial caliper measurement setup, which seems to provide enough tension for the spool.
Also adjusted the guide angle step from 1.5 to 1.9. I had put in a linkage arrangement on the quide to limit overall range from +/-180 to about half that, while reducing the stress on the motor. Adjusting this angle definitely makes the spool, spool up better. Also tweaked the location of the hall transducer, i think it was bent back a bit too far from the magnet and not guite reading reliable.

Filament height sensor is slightly offset to the filawinder side.

Turned the fan off, so their is no wind affecting the filament.
At 184, my diameter is fine without it. (Although maybe i need coolant to minimize the unsteadyness of the diameter, see below)

I did manage to put 3 guides that limit movement of the filament about 6" below the nozzle. Somewhat surprised that appears to be working out just fine.

Here is a video mid way through the weekend.
https://youtu.be/wmB0wgmJpFk

So in the end, I am just barely achieving +/- 0.05 mm Every once  in a blue moon it maybe goes +/- 0.06 mm.
I can live with that, as it is usable.
However, what really surprises me is the overall behavior.
When I hear +/0.05mm, I would think 90% of the time its between +/-0.03, and maybe spends 5% of the time at the full +/-0.05mm.
What i see, is it goes back and forth between the extreme pretty fast. Like if its at +0.05, then it will likely end up at -0.05 within 6-20 seconds, and then it swings back the other way. Sometimes it will hunt around the midpoint for a bit, but I would say its swinging between the extremes at least 50% of the time.

What behaviors do others see? You really have to have a thickness gauge on it to track the diameter over time.

My thickness gauge holder does have the centerline of the pulley 0.5mm off center of the in/out hole, to provide a bit of tension. I was thinking maybe this offset causes changes in diameter to be exagurated in the gauge due to the angle of flex of the filament, but in general, the thickness gauge match my hand reading with a caliper...

Picture of guides.

I had thought about the bearings, and put a mark on them to try and correlate the diameter oscillation to the bearing going round. I didn't observe any correlation, in my scientific eyeball test.

I had run a bit of store bought filament through and seem to remember the measurement being more stable. However, I never ran bought filament through and actually winding it on the filawinder.....

Will try that.

I had put a fair amount of MG94 through it, but that was before I made the loop this large. I don't think the results were any better, but probably not much worse. Hard to tell, didn't have the thickness gauge setup yet.

Tonight i grabbed a spool of Taulman bridge, and another spool of purchased filament i had.
After initially being annoyed both rolls were at 1.7 nominal... instead of 1.75, I ran some through the filawinder thickness gauge setup. Probably 2-3 minutes worth. The general deviation matched what I as hand measuring and didn't do the oscillation. Total variation was probably +/- 0.3 and it kinda slowly meandered around, not large swings like I see when i extrude.

What I am most curious to see, is video of extrusion through other real time diameter monitoring setups (or copies of mine). I know there is a light based thickness sensor.
Really want to know if this oscillation is inherent to the vertical setup in general, or if its specific to my machine in some way.

Maybe their is something odd about the power getting to the motor, or the motor itself causing slight cyclical changes in motor speed.... I can easily monitor voltage... Should probably get the new motor controller board so i can see the current also... Any change in barrel pressure I would think would have a corresponding voltage/current change.

I will mention, now that I think about it.
Back when i was trying to fight PLA (kinda given up that fight for now.) I do remember seeing the barrel kinda walk around a bit, i think it happened when i was using too low a temp. It did stall once, but i was right their and stopped it. The nozzel end probably does still wonder a bit... Probably means my motor to barrel setup is completely straight, although I had thought it was kinda tolerant of misalignment since the coupling isn't rally rigid. Maybe it indicates something is bent... I will rig up a pointer or something so its easy to see how far the actual hole is drifting around while extruding. Wouldn't think it to matter much initially, but maybe whatever is causing the drift also causes a cyclical change in barrel pressure... And if barrel pressure is oscillating, that would explain diameter oscillation. All that said, the motor sounds consistently annoying, but bearably loud.

Im out of town next week for work, so its going to be a couple weeks till i get back to this.

Edit: Totally blanked, I already do have a voltage read out hooked up to the output of the PWM Board version 1. Voltage is stable. Maybe thats expected though, and i have to look at current.

Sorry 0.03

Hi All

So i finally got time to play with this setup again.
I got the new motor driver that displays voltage and amperage.
The amperage is fluctuating about .2 amps at the most.

How much fluctuation do other people see???

The fluctuation kinda sorta matches the fluctuation in diameter, buts its hard to really tell.
The nozzle does trace a small circle, its not much, maybe a few millimeters...

Without completely replacing the nozzle/barrel/mounting hardware, and replacing the wood body with a real metal body, i doubt i can get things aligned better...

Any other thoughts out there?

FYI, i did end up allowing the filawinder to stop, but its reaction is much much slower, which definitly helps it consistently it pull, and not start/stop so much and abruptly.

Here is video of the lastest setup.
https://youtu.be/HMHZV-eDhL4
Running 17V, i got out 700 grams, in maybe 7 hours, of colored PA 746.
Diameter is around +/- 0.5, good enough, that im about to give up on making improvements.

I added a second power supply for the motor a long time ago. Can't say I noticed any particular improvement, but I was changing so many things who knows. In reality, its so easy to add a second supply and most everyone has an old box full of power supplies, it can't hurt.