Is there any way or best way to achieve this so the outer wall is consistent appearance?
(posted in orca as well but seems very quiet and not had any posts answered there)
As you probably know, 3D printing often has more in common with cooking than science. There isnât a single recipe that works best; it usually comes down to a combination of factors to reach a âsweet spotâ for the particular model/filament combo.
Two methods that greatly affect wall smoothness come to mind. Experiment to see which one, or a combination of both, makes a difference.
Increasing the wall loops, and therefore wall thickness, creates a sturdier outer wall and makes the underlying infill pattern less visible. Itâs important to note that on large models with a high density of filament, the interior can sometimes pull on the outer wall, especially if the infill density is higher. The downside of increasing wall thickness is print speed, as youâre significantly increasing the outer wall travel, but the results are usually much better than the default of 2.
The other method is to change the default wall order from the default of inner/outer to outer/inner. This will give the outer wall more time to cool and therefore stiffen up.
Of course, itâs preferred to manually tune your filament to ensure that youâre getting optimal settings. If youâre using a hydroscopic filament like PETG, then drying is really a must.
Thanks for your reply @Olias
Might have missed my point.
There are a couple of youtubes
that cover all this but there is no legitimate parameter to help control it. ie Whilst there is volumetric flow rate as a pseudo global speed control, there is no granular way to address this parameter
The finish is not the issue, its great. It is the inconsistency due to layer speed that glosses/matts the finish due to the melt point/cooling variations etc
I was hoping that there was something I was missingâŚbut alas it seems not
Cheers
OK. Had I seen those photos first, I could have stated what was happening.
This is caused by the change in speed when traveling from one object to another.
The simple fix is to change printer order from the default of print Sequence from Print by Layer to Print by Object.
This will force the slicer to print each model completely before moving onto the next.
It is not an easy tool to use. Since one now has to take into account the fact that another model is present on the plate, the slicer forces a ridiculous amount of space as a safety margin. So letâs say you had four models that were large but fit on the plate when printing by layer. Once you change to print by object, youâll see patterns around the models showing a new âexclusion zoneâ.
If the slicer didnât do that, you could have the tool head smash into the other model. One way is to trick the slicer into printing the models in sequence so that the shorter models are near the back and the taller are in the front.
Sometimes it simply wonât let you do it all on the same plate. Here are three cylendar primitives 25mm, 75mm and 125mm in height. Note the slicer objects to the 125mm.
Using auto arrange works⌠most of the time but not always.
Note you can rearrange these in the objects menu as in this example.
I should have added. You can also slow the print speed or acceleration but that requires a lot of trial and error. Also calibrating the filament max flow rate and then cutting it by 50% may also influence this. Another alternative is to use high speed filament that advertises flow rate. Iâve used those and they work but not like advertised.
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Sorry that image was just to display the surface finish as an example
The issue is having the actual parameter to manage the GCode write
I should have explained, Ive been printing industrially since 2015.
I use the X1 to quickly prototype (scale models) and hence, the models undergo, for this project, gloss finishing. However the underlying suface variance comes through on the final finishing process causing a lot of work to just present proofs of concept.
So yeah, my question is really not best practise so much, but how to force a global constant to a particular parameter which, as its an offline process to get the gcode, needs to be coded into the software which I cant see and doesnt exist at this time, it would seem.
Heâs asking how to get a constant wall speed not how to print by object.
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Honestly, I donât understand the global parameter thing and what exactly is meant with constant print speed.
The printer always has to accelerate and decelerate.
Regarding the issue in the fotos:
In my experience, different filaments need different maximum print speeds. All the PLA I have used so far has the same surface at 270mm/s and at 50 mm/s.
Other types are more sensitive.
The matte surface is a sign for too high speed for that filament. Let me guess: This is PETG? Possibly BambuLab Basic PETG? then the issue is simply print speeds in the default process profile.
I have had a separate profile for that filament where all speeds are reduced to 100mm/s. Then I got consistent shiny surfaces. Actually I have stopped using that filament for this and other reasons. Sunlu prints much faster consistently although I have slightly reduced the speeds for best layer adhesion. filament from dasfilament.de was completely agnostic of print speed but is more expensive than Sunlu. There certainly are other good filaments as well.
That is correct @Murata_Industries
and the issue here is variability in melt which is commensurate with speed.
Its simply about achieving a constant for external finish, be it matte or gloss.
Its just a PLC with code and if I type in a parameter eg outline speed, then that should be respected excepting global overrides eg flow rate
OR
At least some way of managing it
A constant outer speed is physically impossible, because at any corner, the printer would have to instantly change direction.
The reduction in overall speed that you see in the upper layers in the screenshots is a feature to prevent too short layer times which would produce far more ugly surface defects in some circumstances.
And the matte surface really is a faulty extrusion with reduced stability. So you should avoid that completely.
I proposed a simple solution above, that solves the root problem and yields the result you are asking for. At slower speed settings, you get a consistent glossy surface, no matter how speed changes as long as it is slow enough.
Constant speed is not needed and harmful in many respects. That is also the reason why such an option is not available in slicers even if it would be easy to implement.
In the latest Orca Slicer versions is a new filament option, you can try, called âDonât slow down outer wallsâ. This can help to keep the surface appeare consistent.
Thatâs an interesting new option! Didnât notice this yet, thanks!
Still, I think this is only a solution for Aurasphere overhangs come into play which again are slowed down by another feature and Iâm not sure if that is the last one.
If the filament isnât capable to be printed at the default speed, to me the most logical options are to either print slow enough or to use a different filament. Everything else is a workaround with side effects in my opinion.
@Alex_vG
You might be merging my 2 posts?
I never said in the external layers had overhang issuesâŚthey are all internal and on multiple shells
Thanks @print.in.3d, yeah I actually found this vid which solved all my problems in a couple of minsâŚthis guy is absolutely brilliant and full of manufacture compliant advice. The krauts are brilliant!
As he shows in the vid, there are simply 2 parameters required
The external skin of prints are of course, always pegged by the slowest denominator but walls are a couple of skins thick so problems solved for anyone else wondering how to do it as this applies only to the external skinâŚnot wall.
Regards
M
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A great interim solution for anyone that needs it