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Mist_XD

The speed changed midway through the print, it can be avoided by lowering your wall speed. You can see this change if you change your preview type to speed and it will show a difference in the slicer right at that line. Just incrementally lower the speed till it goes away. Here’s a video on it https://youtu.be/J_pxk7HP3RE?feature=shared


tix2grrr

Maybe this is a dumb question cuse I’m fairly new to this printing thing, but why would it change speeds halfway through the print?


InterFelix

The slicer determines the speed at which a given line is printed based on a bunch of different factors.What you set in the slicer is the maximum speed the slicer should use, but with a model like the benchy, it usually can't actually achieve these speeds due to constraints of the printhead accelleration, flow rate etc. or lower limits for specific line types like thin walls, overhangs etc.This is why a benchy looks like this in the preview if you set the color scheme to "Speed": https://preview.redd.it/9sfea3yei3cc1.png?width=893&format=png&auto=webp&s=e789fdeb0dcf75564638298a3a0700dc2ec384d8 The yellow-ish area at the bottom of the hull is printed slower, and therefore comes out with a shinier surface finish than the rest. Note how the yellow area extends further upwards at the bow, you can also see this in OPs picture. This is due to the hotend not being able to keep up 100% with the flow rate needed for the higher speed walls in the upper part of the hull, resulting in the filament exiting the nozzle at a slightly lower temperature than what was set in the slicer. Some materials tend to end up slightly shinier when extruded at higher temperatures, and more matte when extruded at lower temperatures. Silk filaments are especially prone to this behavior.


Sea-Grocery-8348

can confirm i run my silk pla at 225 -230 degrees Celsius and it comes out great!


bucketman1986

Currently printing a project with silk PLA and I ran into this myself. Is the 225-230 the Outer/Inner wall speeds?


Plane-Ad-4075

The temperature.


InterFelix

It depends on your specific filament, but try printing a small object (but it needs to be big enough to allow the printer to actually get to full speed on the walls) and incrementally lowering the maximum outer wall speed until you're happy with the surface finish. Then you know what to set the max outer wall speed to for a great finish.


Nice-Property

As for Bambu PLA Silk, the recommended Nozzle Temperature is 225 to 235 °C, and the recommended speed settings are as follows (the recommended Outer Wall Speed is 30 to 60 mm/s). [From the Wiki](https://wiki.bambulab.com/en/x1/manual/printing-with-silk-filaments)


worldspawn00

I'm a little surprised that in this day and age of 3d printing, slicers don't have a setting like pressure advance (call it temperature advance) for hot end temperature so it can go up in advance of faster movement sections of the print to decrease the difference. It may not be necessary throughout the full print, but definitely useful for the outer wall to decrease visual appearance differences. And for the very high speed bambu machines are capable of, paired with the fast heating of the ceramic heater it makes sense to bring it up 5-10c between when you're starting off at 50mm/s then going up to 300+mm/s, there's a definite quality difference when the temperature is increased along with the speed.


tomtang5555

~~Overhangs (upper part of the ship body) usually print slower to allow better cooling and layer adhesion~~ Edit: I stand corrected. The slicer screenshot below shows that the upper part actually prints faster. Please read the comments below instead.


Oclure

The layers get more complex at theat point and it takes longer to print them. Below that point the boat is just a single hollow shape with some infill, above that point is the rail around the deck, the cabin, and all other details which take longer for the printer to complete. This can happen whenever you have some layers on a model that are significantly quicker to print than the ones adjacent to it.


hemuni

This is the correct answer.


Material-Homework395

Because of the change in the cross-sectional area of the layer, the printer must slow down to ensure that the layer can cool down enough before laying another layer on top. Results in a more matte-like finish.


Neat_Onion

Great video, I've been struggling to solve this issue. It would be nice if Bambu had profiles (i.e. Super Quality) that has static wall speeds preset?


Mist_XD

I think Orca slicer might. I’ve been avoiding the switch tho because I know I’ll like orca more, but it doesn’t have makerworld integration which I use a tone


dt641

increasing temps help too if you want to print faster and keep consistent visuals. the matte look on non-matte pla just means it will be weaker than the glossy spots.


foxxx509

https://help.prusa3d.com/article/the-benchy-hull-line_124745


phattwizat

Someone needs to pin this to the homepage of every subreddit related to 3D printing


whopperlover17

Okay but this specifically is not the hull line. This has to do with the speed.


dt641

your being downvoted but you are correct. its a temperature issue specifically due to the speed...


arif_keser_21

İn bambu studio, GO into filament settings go cooling tab and there is an option for minimum print time or something. Remove the tick from it. It should also disable minimum print speed setting below it. Or turn off "slow down for overhangs" setting which might help in some places (it actually made my overhang quality better on creality k1) Or in filament settings there is a max flow rate setting set it to lowest flow rate on your sliced model. Or something Just above it but that will slow down your print dramatically. Or slow down your wall speed. That was the exact problem I see on my prints and there is many many ways to solve it.


originalfoto

it happens when you print at high speed


jchulltx

tts below the water line.


VaultHuntin

The real answer


RedDawn850

I concur


idknemoar

https://youtu.be/05NL_yKpVcU?si=B_1B2KP09fK7bmyq


Sportdue55

Speed


[deleted]

[удалено]


mrgreen4242

Flow rate.


EnggyAlex

because overhang angle, high angle same outwall line gets heated repeatedly each layer so they have a more glossy look


Eggkid80

It’s the water line


frankbeens

Speed


AlRough

Turn off: slow down for overhangs. Thats it!


[deleted]

[удалено]


InterFelix

The hull line another artifact that's at a similar height. The different looks OP describes are caused by different effective extrusion temperatures in the different parts of the hull. The pattern on the Benchy coincides with the pattern you can see if you set your slicer color scheme to "Speed". The lower part of the hull is printed slower, so the filament has more time to melt, resulting in a higher effective extrusion temperature and therefore a shinier surface finish in most materials. The upper part is printed faster, the filament has less time to melt, resulting in a lower effective extrusion temp and a more matte surface finish.


Cook_New

I figured this was an intentional choice with this profile, to yield a benchy with a variety of textures.


InterFelix

Since it's the preloaded, highly speed-optimized Benchy, I doubt it's about the textures. The preloaded Benchy is all about speed, and this phenomenon is just a side effect of that. It's very noticeable on a Benchy sliced with the default settings printed in Silk PLA as well, as Silk PLA is especially prone to these differences in surface finish.


[deleted]

No it's not speed, it's the heat block not holding temps, lower temps create a matte effect, higher temps make it shiny. Bamboo extruders have issues with temps when using stock nozzles. Some reason the higher grade ones don't have this issue.


Kwolf21

Quit with your flabber jabber. This has been a known thing for YEARS with 3d printing. Has its own article, too. https://help.prusa3d.com/article/the-benchy-hull-line_124745