Outer perimeter speed not responding

On 1.2.9 on a 3 wall perimeter, when I set the perimeter speed and the outer perimeter speed to 50 mm/s, it does the proper speed on the inner two perimeters but then speeds up on the outer perimeter. Any setting I change does not seem to slow the outer perimeter speed down. Is this normal?

Can you link a gcode file with your assumed issue?

Attached

Seems to me as if Slic3r respects your external perimeter speed and all the other speeds are brought down for some reason.
Your external perimeters are the only ones at 50 mm/s, the rest are at 40 mm/s, even though you've set them at 50. Slowing down due to very fast layers?
A debug setting for output might reveal more.

Where do you set the debug?

Ah right, it was named a bit differently.
This is what I meant:

I think the reason is: You are using Max Volumetric Speed of 5 mm3/sec (on the Speed tab).
This setting is shown at the bottom of your gcode: "; max_volumetric_speed = 5"

Now as you stated, you are using 50 for both inner and outer perimeter speeds, however you are also using perimeter extrusion widths of 0 (auto).

Take a look at the top of the file, it shows what will actually be used for perimeters:
; external perimeters extrusion width = 0.40mm
; perimeters extrusion width = 0.48mm

So what happens is a combination of things.
You have told it to print at a maximum extrusion rate of 5 mm3/sec - so if it is commanded to extrude faster than that it will slow down the feed rate, so (I believe):
-When it is printing inner perimeters at .48mm it hits the 5mm3/sec wall and prints slower to compensate.
-When it does outer perimeters at .4mm it can go faster since the volume per second is less.

If you do post the commented gcode I can confirm this with my debugger. It indicates line by line what the extrusion rate is.

This kind of thing is why I do not use auto settings for anything.

Actually that is probably the problem. Max Vol Extrusion (at 5) worked so well that I have not even considered turning it off, and if it's speeding up on the outer walls then it's working great. After all, a nozzle can only heat up filament so fast, and so that should be the defining limit.

Quote
RRuser
Actually that is probably the problem. Max Vol Extrusion (at 5) worked so well that I have not even considered turning it off, and if it's speeding up on the outer walls then it's working great. After all, a nozzle can only heat up filament so fast, and so that should be the defining limit.

Also the extruder motor only has power to push the plastic through the small nozzle up to a certain speed - eventually the back pressure will cause the motor to skip even if the plastic is plenty hot enough.

Dave