Quick speed settings and volumetric speed limit

Bambu Lab Software Bambu Studio
1

Pretty new to 3d printing here, just got an X1C as an upgrade from my absolute Relic Dremel 3D20 circa 2015.

I am still learning many of the parameters/terms in the slicer. I was poking around trying things out and tried the “sport” and “ludicrous” quick settings during a small print (filament Y splitter) with PLA on the bambu 0.2 normal profile and it did fine, I did see the change in surface finish from the different speeds, and saw the time to completion change as well, it was a cool test.

I then tried this again while printing some AMS desiccant boxes, but on 0.28 extra draft.

I hit Ludicrous mode on the second layer and it instantly starting super under extruding (also had to look up the term for “terrible poops of plastic all over the bed”).

After doing some thinking and youtubing, I came to the conclusion it was the hot end not keeping up. I saw a youtube test where a stock X1C hot end maxed out at about 23mm3/s, but when I went into the BS preview and looked at the flow, it showed a max of 21ish mm3/s, so I had no idea why it didn’t seem to be keeping up. I then read that the quick speed settings IGNORE the flow limits, so even though my preview showed me 21mm3/s, it could have been flowing much more, and it won’t show you how much, as the preview doesn’t change based on the quick settings for speed.

To confirm this I went into BS and sliced the same file again, but this time with the volumetric speed limit at 50, and the print speeds manually changed to 166%, to replicate ludicrous speed. On this preview, it showed it was actually (trying) to flow closer to 42mm3/s, which explained what happened.

I guess I am left wondering, why do they have the quick speed settings NOT take into account the max flow speed setting, as it’s obviously pretty important. Something like a warning box popping up saying “this setting will exceed the max volumetric speed of your selected filament” before letting you change it would be nice. I was lucky to have changed it on layer 2, I would have been kinda mad if I ruined a print farther in, and that also brings the question, how I am supposed to know what I can and can’t safely turn up the speed on now? Do I need to do the “simulated speed” test and look at the flow every time?

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you should run this test and find out the max possible for the filament. Not all of them are capable of abs high speeds Printables

3

I LOVED the Dremel copy of the Flashforge and how they tried to advertise it in hardware stores :slight_smile:
Back to your observations…
I see where you are coming from and that all those new things and settings can be more confusing than helpful.
You are indeed correct to assume there is no real consideration for vital factors when changing the print speed on the go.

I can only assume here about the intentions but it looks as if Bambu wanted a quick way for users to allow for the higher speeds that are possible at lower layer heights.
But unless this also includes an adjustment for the K-factor and extrusion temp it is just a gimmick.
Even if you try it the other way around the system still fails.
Like by manually finding the best settings to allow for the max speed to then use the slower options without having to worry.
I am unable to observe more than an overall speed change and that alone just won’t work as advertised.

Just because a filament prints great at the default settings won’t mean the printer is able to reproduce this in sports, let alone insane mode.
I actually only try to establish two basic print setting for a given filament.
The first to establish good results at the default 200mm/s sec on models that are not too complex.
The second for a lower speed that allows me to properly print models with tiny details printing in islands.
Imagine the pipe of the Benchy thinner, longer and with a bigger top…
A print profile that makes sure such details will work without sagging, turning into a blob or wobbling around with the nozzle.
Compared to my last printer it is like stepping up from a push bike to a Ducati…

Check the slicing preview and change it to show the speeds on a layer.
This lets you check whether or not your model requires slowing down in certain areas, like where this overhangs and such.
You might even find that this slowing down option, if disabled, produces better results - if the print speeds are a good match.
It also possible to visualize the flow rate…
Both options help to determine what the highest (sane) printing speed would be on top of that you can use the flow visualization AFTER manually changing the speeds to ludicrous to confirm that the machine actually uses this high speed and that the max flow rate won’t be above what you specified.

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4

Yes, your last suggestion is what I was thinking one would have to do to maximize speeds, but that basically makes the quick speed settings irrelevant and a gimmick like you said. The slicer has all the info needed to be able to limit it, so why would they not implement that? I don’t see why they would let the speed settings ignore/override the max volumetric flow as that’s obviously a critical factor. At least issuing a warning before letting you select it would be nice. These printers seem to be marketed more towards “set and forget” owners newer to 3d printing and this seems like a major flaw to let them so easily select a speed not compatible with their application.

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The issue I’m pointing out is that even if you find the max flow for a filament, the speed settings would still override whatever you have in the max flow limits in the filament settings, when you select Sport or Ludicrous, without warning.

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Again you are spot on but you have to consider how they develop their software and that we talk about a Chinese company here :wink:
Same the models sliced for a P1 series will include useless moves and such to address the non existing lidar or build plate code recognition other parts are slapped together the same way.
Often resulting in confusion for the user for no reason.
Still Bambu studio and the whole integration is quite good, just needs some time and TLC to get working properly.

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I find the “speed modes” pretty much useless but on the rare occasions I do use them, the whole idea is to go (a bit) past that flow rate limit. If they wouldn’t do so, they’d be even more useless.

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8

True, but they should make the situation more transparent, either 1. Let you select the Sport/Lud modes in “preview” pane to easily check the volumetric flow to see if it will be possible, without having to manually change the settings (although I guess you could just make 2 presets for sport/lud modes) or 2. Issue a warning first if the software sees that a faster quick mode would grossly increase the flow past the limit, something like that.

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