Acceleration?
I had a previous problem addressed on here about a print with a number of shifts in the X Axis during the print. I was told to upgrade to the latest and greatest firmware so got that from https://github.com/prusa3d/Prusa-Firmware.git
I still had a bit of a problem, even though it was a smaller shift in the X Axis it still ruined a print. So I asked on the reprap IRC channel and somebody mentioned that the most likely cause was too high an acceleration setting. I've since found out that there is an expert mode in Slic3r which allows you to set the max acceleration but it bares little or no resemblance to the settings in Configuration_prusa.h:
Configuration_prusa.h:
#define DEFAULT_MAX_ACCELERATION {9000,9000,30,10000} // X, Y, Z, E maximum start speed for accelerated moves. E default values are good for Skeinforge 40+, for older versions raise them a lot.
#define DEFAULT_ACCELERATION 3000 // X, Y, Z and E max acceleration in mm/s^2 for printing moves
#define DEFAULT_RETRACT_ACCELERATION 3000 // X, Y, Z and E max acceleration in mm/s^2 for retracts
And in Configuration.h:
// The speed change that does not require acceleration (i.e. the software might assume it can be done instantaneously)
#define DEFAULT_XYJERK 20.0 // (mm/sec)
#define DEFAULT_ZJERK 0.4 // (mm/sec)
#define DEFAULT_EJERK 5.0 // (mm/sec)
I was hoping to use these firmware Configuration settings as my starting point in Slic3r and work down from there. However in Slic3r the acceleration settings are:
Perimeters
Infill
Bridge
First Layer
Default
I'm not even sure whether it's my DEFAULT_MAX_ACCELERATION or DEFAULT_ACCELERATION I should be adjusting.
Then I could maybe use GCode http://reprap.org/wiki/G-code#M201:_Set_max_printing_acceleration
But reprap don't support "max travel acceleration" according to that web page. And given that it's printing two perfect disjointed halves I assume it's the travel acceleration that's the problem.
Man this is a mine field. Any assistance would be really appreciated
Re: Acceleration?
Hi John
Acceleration is actually really simple as Marlin only uses one set of figures and it is a firmware setting.
The best way to implement the correct acceleration settings is to add one line of "Start Gcode" within the slicer:
M201 X1000 Y1000 E600
These are the suggestions Josef made on here a while back. However, I have experimented somewhat and found that increasing the values by 50% still works fine and allows a decent increase in the print speed.
Peter
EDIT: I believe that the gcode above is implemented in the default Slic3r settings published by PR; if you are already using these, then acceleration may not be the cause of your shifts.
Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…
Re: Acceleration?
The best way to implement the correct acceleration settings is to add one line of "Start Gcode" within the slicer:
M201 X1000 Y1000 E600
Has anyone tried this acceleration GCODE in Simplify 3D? It should work fine there correct? Asking because I'm getting a big of ghosting in some of my prints and thought this could help with that. If so, would I just need to put this at the beginning of my Start GCODE in Simplify 3D?
Re: Acceleration?
You dont need to use M201 X1000 Y1000 E600 in Slic3r PE, it has its own advanced acceleration control (its better and values are already included in the PR profile).
You can use similar "advanced" acceleration control in Simplify by adding this code to the post-processing field (SXXX is acceleration value).
{REPLACE "; outer perimeter\n" "; outer perimeter\nM204 S800\n"}
{REPLACE "; inner perimeter\n" "; inner perimeter\nM204 S800\n"}
{REPLACE "; solid layer\n" "; solid layer\nM204 S1000\n"}
{REPLACE "; infill\n" "; infill\nM204 S2000\n"}
Re: Acceleration?
Understood... I'm using Simplify 3D though, and not Slic3r, so I was asking about what I need in Simplify 3D for tuning the acceleration control (see original post by me above).
Re: Acceleration?
What are the equivalent M commands for setting accel for perimiters only?
Re: Acceleration?
What are the equivalent M commands for setting accel for perimiters only?
G-code commands are interpreted by the firmware in real-time.
How would the firmware know whether it is printing a perimeter? It doesn't have a clue about the model, it is being told what to do, one command at a time.
Peter
Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…