Rounded Corners config.g acceleration parameters
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Hello,
Trying to reduce my rounded corners. On a 20mm test cube, I get symmetrical bulging in the corners at around 0.1-0.2mm. Not awful, but I'd like suggestions as to changes in my config.g file. I have a Tronxy X5SA-400 Pro modified with an E3D Hemera.
I get about the same corner overshoot with both a 0.4 and 0.6 nozzle, both with a 60mm/sec print speed and a 45mm/sec outer perimeter speed.
Not sure if I should look at max. instantaneous speed change, acceleration, or Pressure Advance. Thanks for any feedback.
Here is the relevant section of my config.g file:
M350 X16 Y16 Z16 E16 I1 ; configure microstepping with interpolation M92 X80.00 Y80.00 Z400.00 E430 ; set steps per mm M566 X600.00 Y600.00 Z200.00 E8000 ; set maximum instantaneous speed changes (mm/min) M203 X18000.00 Y18000.00 Z2000.00 E20000.00 ; set maximum speeds (mm/min) M201 X500.00 Y500.00 Z20.00 E100.00 ; set accelerations (mm/s^2) M204 P1000 T4000 ; Set printing and travel accelerations M906 X950 Y950 Z950 E950 I30 ; set motor currents (mA) and motor idle factor in per cent M84 S30 ; Set idle timeout M572 D0 S0.001 ; Presure Advanced M207 S0.75 R-0.000 F3200 T3200 Z0.0 ; Firmware RetractionI have a Duet 2 Maestro.
Here is the test cube printed at 0.3mm layer height, 0.6mm nozzle:
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Are the bulges only on layer changes where the seam is?
Your Z axis has a very high top speed, but very low jerk and acceleration. Same for the low accel on the extruder.
Your pressure advance is also very low. Like by an order of magnitude below what I'd expect for a minimal amount.
What kind of z axis and extruder do you have?
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@phaedrux The Extruder is a direct drive E3D Hemera
The Z axis is a dual leadscrew, dual stepper in a coreXY machine.
The bulges are symmetrical on all 4 corners. -
Based on that I would suggest the following changes
M566 P1 M203 Z600 M201 Z120 E4000 M572 D0 S0.025 -
@j-pickens Very long 6mm belts often cause rounded corners. I have a saphire plus with the same problem. I am exploring 9 or10mm belts as an upgrade for this very reason.
Additionally, increasing the moving mass exacerbates this problem.
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@phaedrux Thanks so much!
I believe the M566 P1 was the trick.
I put all your suggestions into the config file.
Here are the vernier caliper measurements of the 20mm test box before and after the changes (Same Gcode used for both):Center across X measured along Z axis Before: 19.95mm After: 20.12mm
X axis measured along X side (includes corners) Before: 20.36 After: 20.11Center across Y measured along Z axis Before: 20.09mm After: 20.15mm
Y axis measured along Y side (includes corners) Before: 20.45 After: 20.15So the bulging has gone from approx. 0.4 mm (0.2mm per corner) to ZERO!
Yay!
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@bubblevisor I'm sure you are correct about the 6mm belts. The CoreXY design can minimize the effect to some extent due to the pulling from both directions in the design.
However, what I was hoping to achieve was to correct the cornering problem as much as possible with the config file settings.
With the help of @Phaedrux, I am very happy with the results!
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@phaedrux said in Rounded Corners config.g acceleration parameters:
Based on that I would suggest the following changes
M566 P1 M203 Z600 M201 Z120 E4000 M572 D0 S0.0254000 mm/min2 for the extruder as acceleration? Isn't it too much?
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@thedragonlord 4000mm/s^2 is reasonably high, but should be no problem unless you have a low power extruder motor (like a pancake motor). A hemera should be able to do 4000mm/s^2 easy.
I run my little 25mm pancake extruders at 1600mm/s^2, no sweat and could probably go higher
OP had his set at 20mm/s^2 which would be way too low and start impacting xy motion as the extruder wouldn't be able to keep up
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@engikeneer said in Rounded Corners config.g acceleration parameters:
@thedragonlord 4000mm/s^2 is reasonably high, but should be no problem unless you have a low power extruder motor (like a pancake motor). A hemera should be able to do 4000mm/s^2 easy.
I run my little 25mm pancake extruders at 1600mm/s^2, no sweat and could probably go higher
OP had his set at 20mm/s^2 which would be way too low and start impacting xy motion as the extruder wouldn't be able to keep up
It's not for the stepper but for the extruder...I'm afraid that after few hour at 4000 you'll find the BMG pieces on the bed....
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@thedragonlord OP has a Hemera, not a BMG, so no plastic gears
Given how long I've been running my BMGs at this level (plus I previously had them as bowden with big motors, high accelerations and big PA), I doubt they'd fail at 4000mm/s^2! They're more sturdy than you think
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@thedragonlord There's very little angular momentum on an extruder motor. The distances moved for direct drive extrusion and retraction are very small. You may hear more clicking as it goes back and forth rapidly, but I don't think there's much more wear and tear. I run 6000 on a titan aero without issue. I thought 4000 was a safe compromise.
