Speeding up slow sections to get a uniform outer-layer?

Hey everyone,

I’m a little lost by not finding a way to speed up slow sections to mitigate changing artifacts on outer-walls like on this part:

Lowering the “Max volumetric speed” from 12 to 7 works somewhat to create that uniform outer layer but increases the print-time by almost 40% (slowing down everything to almost match the slower paths, and that’s not in my interest.

I’d like to speed up the slower paths printed - that should solve the problem and even decrease print-time.

I do generally NOT understand why that top part is printed so slow anyways as there is no overhang or anything that would justify printing that slow.

Anyone any idea?!

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Here’s the setting for speeds.

Don’t overlook the speed setting under device.

You can also try experimenting with this setting. Default is inner/outer. Changing to outer/inner often can help with dimensional accuracy and may have impact on certain models when it comes to speed.

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I have changed every speed setting possible without any change to those reddish areas. I’m generally printing with standard-speed as everything faster seems crazy IMO ^^ and yes, I`m already printing with inner/outer.

If you uae high speed filament, it wont change color as the speed changes. all bambu pla is high speed.

The top part is probably slow to allow for cooling. There is a minimum layer time in the filament setting, so it does not print multiple layers too fast and put a new layer onto a layer before it’s cooled. Bambu’s default settings are 4 seconds for Bambu or high speed PLA and 6-8 for Generic PLA. Also, the volumetric flow setting in the filament will limit the speed (higher is faster).

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Ya, it’s min time. If it’s really important and you don’t mind wasting filament, you can always print something next to it, placed far away to make travel eat up the time.

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The printer is already running at the highest speed it can achieve. It’s not really a function of flow rate (though low flow rate can limit top speed). It’s more a function of acceleration. The printer goes faster on longer stretches because it has more room to accelerate and decelerate. So if you want to go faster, you want to crank the acceleration numbers up, but the quality of the print will degrade severely.

If you want uniform outer walls, reduce the wall speed until the slicer is using the same speed for the entire model. It’s the only real solution.

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I for some reason already feared that this would be the case… the confirmation sucks ^^ I hoped for just not having found the alternative setting. Hm…

@partferret
I just added another object to the print-bed and the red middle-zone disappeared.
After adding another one the top reddish area also started to get lighter in color.

So the problem is definitely the reduced layer time forcing the printer to print slower.

@Eponymous
Seems like you’re right…
You’re saying there is a “Layer time” setting… where exactly can I find that? Was already looking for it yesterday, but someone said, the only similar function that exists is “max volumetric speed”

Thx everyone for helping out :slight_smile:

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layer time is in filament properties, cooling tab

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Oh man… YOU ARE AWESOME!!
I finally got what I was looking for! Juhuuuuu!! :smiley:
The function is called: “Slow printing down for better layer cooling” and this is the result:

Thank you soooooooooo MUCH!!

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There’s a reason that setting exists. Before you run the entire thing, i’d suggest cutting the top section and running it without min layer time to see how well your filament holds. You may need to engage the aux fan more.

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If the print is OK and only the finish of the outer wall is bad, then simply change the speed for the outer wall. Take a value, your image will tell you the value you can use: e.g. 60mm/s. Then all speeds will be kept as Bambu Studio calculates them and only the outer walls will always be printed at the same speed.

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I did what you suggested and the upper piece printed just fine. I actually printed half the design upwards and its flawless! So thx for the concern (just in case) but it works just fine and all artifacts are equal now - resulting in a great looking finish :smiley:

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I now also decreased the outer and inner lines by 50% and infill by 30 to avoid posible drawbacks with future prints. Now everything should work to my likes.

Thx a lot to all :pray:

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THANK YOU SO MUCH! I looked everywhere for this info. This is a godsend. :pray:t2:

where is this screen? I know this is an older post but on my new p1s I can’t find these settings. I am trying to slow down the first layer becasue I am having bed adhesion problems with small parts with asa on textured pei.