Posts made by mak

I wonder if you can put an accelerometer onto tool head and input on the duet, to record the feedback,

you perhaps could use that data… and the real time data to create a PID tuning system to dampen out the oscillation real-time.. perfect printing. also you could use that accelerometer to judge if there have been skipped steps or nozzle crashes..
?
...imagine having that setup then somebody mounts their accelerometers off axis and the whole printer goes haywire correcting wrong values lol
alright Thanks for hearing me out Dc42- I hear you’re doing exciting things with duet. Keep up the good work- best wishes.
the struggles to get rid of belt wobble are real.

Alden Hart
4 years ago
Acceleration is performed using a piecewise linear representation of a constant-jerk equation. This is the 3rd derivative of position instead of the 2nd derivative (constant acceleration) that is commonly used. The pulse rate is computed for each of the S-curve segments. Each axis is run as a "minor axis" of the 50 Khz clock rate. This minimizes jitter and aliasing - at the expense of running a fast clock rate all the time. The code is on github under tinyg if you want to take a look.

perhaps look here.

Id donate for you to take a serious look at this but something about your intellect tells me you're good for money dc42

source:

https://www.youtube.com/watch?v=Om0wTqFA-Dw

does duet firmware not handle jerk as-well as marlin?

The notion that the ripples and oscillation in the water would correlate to the ripples and oscillation in the belt is compelling.
I hope Lars uploads his firmware and i will do some test prints and compare.
Lars has claimed it reduces ringing not quite hard evidence i agree- perhaps not enough for you to invest time and effort- i respect that.
thanks for considering it at the very least.
I hope this is revisited. if only for the purpose of learning.

non-poliginal vector STL files? in a perfect world

i mean surely it can be implemented without that
seems lars figured it out. maybe with some sort of approximation technique?

im hoping he publicizes his documentation maybe you can take a look at it?

correct me if im wrong- but the other thread asked for different acceleration values based on speed
not a whole different acceleration profile to make for more efficient movement over-all and less ringing..
is Ian discrediting lars's findings with less ringing artifacts and higher print speeds?

Perhaps im just too stupid to understand? haha.

i think this is a whole new topic?

Ringing is caused (generally) by flex in the belt and oscillation thereafter.- the new acceleration profile not only myself but others theorize will reduce oscillation frequencies that trigger belts to act erratically therefore better surface finish.

is this an incorrect assumption stemming from the video evidence presented?

why would Trinamic invest R&D if its not a useful feature?
why would Lars invest time and effort to implementing this also, Is his findings inaccurate?

please educate me

a quote from Lars's findings

I'm currently up to about 550mm/s travel, 425mm/s infill printing (extruder permitting) and 100-150 mm/s perimeters (depending on quality & planner speed – and if sharp corners are needed -- extruder response limits crisp corners at high speed). Even at lower speeds, the s-curve profile gives better print quality -- for example, less oscillation / waves after hard corners .

we can theories till the cows come home- but it seems from the evidence that Sin- wave acceleration profiling as the future of high quality fdm movement? once again i am open minded to be crushed - if you can give me evidence to prove its not effective please present it here.

Give me this, and you will change somany lives.

https://www.youtube.com/watch?v=D9tGB-FtyJQ
https://www.youtube.com/watch?v=qYJpl7SNoww

Thank you

ps Lars is impressive, I dont think he even uses trinamic drivers that natively support S-curve ramps either.

edit* Thank you for your hard work DC42