Spiral Vase - Changing print speed accordingly perimeter length

Hi.

I'm wondering if it is possible to automatic change the printing speed accordingly the total layer perimeter length.
My goal is to have the printer print at full speed when total layer perimeter is above certain amount and proportionally reduce the speed to layers on smaller perimeter layers.

The situation I'm trying to improve is common when printing Spiral Vases, where typically we have a considerable different total layer perimeters length among the model (see the Dandelion vase model below for example), what makes the smaller perimeter layers be printer with potential problems due the layers being printed faster speed and not having enough time to cool. On this example, the mid bottom perimeter length is considerable larger than the near top (neck) region. Printing this without any type of cooling is problematic considering that the printer always use the same speed, for smaller or larger regions.

My goal is to have the printer automatic adjust the speed accordingly the length of perimeter for each layer.

I'm wondering if there's some way to accomplish this behavior, or maybe, post this as a development idea.

Thanks in advance.

Yes, that is a standard feature in Slic3r

Look under "Filament Settings">"Cooling"

There is a parameter for "Slow down if layer print time is below:" Enter the minimum number of seconds you need a layer to take. This should result in what you want - the small perimeters will slow down so that it takes the minimum time you have set to print. It certainly works for normal prints, I don't know about spiral vase.

You'll note there is also a minimum speed that will over-ride the layer time so that really small perimeters are not slowed down ridiculously.

Note it does not help when printing very narrow columns because the nozzle remains in close proximity to the entire layer, keeping it all hot, and slowing down in fact makes the situation worse.

Dave

HI Dave.

Thanks for your reply!

I played with the Cooling parameters of slic3r a bit.
I noticed that slic3r takes in consideration each Z axis change to compute the layer time. In the spiral vase mode, the time for each Z change is really really small, making it impossible to use the Slow Down parameters as it only accepts values in seconds (integer).
As I understand, Ideally, slic3r should take the total layer time into account, from the first to the last line in the example code below.
Please, correct me if I'm wrong, but that was my findings when I tried that feature.

G1 Z0.8 F7800.000 ; move to next layer (3)
G1 Z0.800 X117.994 Y117.993 E20.57313 F2520.000 ; perimeter
G1 Z0.832 X100.002 Y125.446 E21.48398 ; perimeter
G1 Z0.863 X82.011 Y117.993 E22.39482 ; perimeter
G1 Z0.894 X74.539 Y100.000 E23.30607 ; perimeter
G1 Z0.926 X82.011 Y82.007 E24.21732 ; perimeter
G1 Z0.957 X100.002 Y74.554 E25.12817 ; perimeter
G1 Z0.974 X109.859 Y78.637 E25.62718 ; perimeter
G1 Z0.988 X117.994 Y82.007 E26.03901 F2520.000 ; perimeter
G1 Z1.019 X125.446 Y100.000 E26.94992 ; perimeter
G1 Z1.050 X118.112 Y117.709 E27.84642 ; perimeter
G1 Z1.05 F7800.000 ; move to next layer (4)

A side note: The Slow Down parameter accepts negative numbers. Any idea of what it does it mean?

Thanks a lot.

Maybe I was just using this on a old Slic3r version. I just tested on the new 1.1.7 and works fine!

Thanks for the help!