Pressure Advance for direct drive
-
@hairy_kiwi - do you have photos of printed parts with and without M572?
-
What kind of model is good for testing pressure advance?
-
What kind of model is good for testing pressure advance?
I'd guess the effect would be more noticable with longer print (extrusion) moves between changes of direction.
-
@hairy_kiwi - do you have photos of printed parts with and without M572?
No, sorry. I'll post some when I get a moment.
-
What kind of model is good for testing pressure advance?
A solid infill 20 - 30 mm square x 3 mm height block ought to be of sufficient size to visually assess all the nuances of changing pressure advance. You may even need less z-height than 3mm to reach a conclusion. I would also suggest using the half-split-successive-guesstimate-technique* to derive your preferred value, rather than changing the value in small increments; you should find it much easier to see any changes that way. Until last week I was using a single 50 x 50 x 1.8 mm block with 0.3mm layer height and solid infill while setting up my machine. I found it a useful size block for checking bed flatness, E-steps/mm, jerk and acceleration and did also use it for setting pressure advance, but its size is probably overkill if you only want to set pressure advance.
*There's bound to be a bona fide mathematical process name for what I'm describing, but I can't find it so I've mashed one together: the half-split-technique (from electrical fault-finding) with successive-approximation (from mathematics, for finding roots of equations). 'Approximation' is further replaced by 'guesstimate', because at the end of the day it's all a somewhat subjective process.
Good luck!Have fun
-
Thanks both, I'll start experimenting.
-
*There's bound to be a bona fide mathematical process name for what I'm describing, but I can't find it so I've mashed one together: the half-split-technique (from electrical fault-finding) with successive-approximation (from mathematics, for finding roots of equations). 'Approximation' is further replaced by 'guesstimate', because at the end of the day it's all a somewhat subjective process.
I think you mean binary search. I remember using this technique when i was a student, to determine the appropriate amount of chilli to use when cooking chilli con carne. It only took me 3 meals to get it right.
-
What kind of model is good for testing pressure advance?
*There's bound to be a bona fide mathematical process name for what I'm describing, but I can't find it so I've mashed one together: the half-split-technique (from electrical fault-finding) with successive-approximation (from mathematics, for finding roots of equations). 'Approximation' is further replaced by 'guesstimate', because at the end of the day it's all a somewhat subjective process.
Good luck!Have funBack when I was a bench tech we called it "divide and conquer".
Good job with the naming convention!
I looked it up in a class training book from the '70's that I still have ( I'm not a pack rat ) and it was called the "half-split rule" there. -
further Q on this, what E Jerk value would be a good starting point, its currently set to 20. I run a 0.9 deg stepper on the titan extruder
-
I think you mean binary search. I remember using this technique when i was a student, to determine the appropriate amount of chilli to use when cooking chilli con carne. It only took me 3 meals to get it right.
That's it dc42! Many thanks for enlightening 
