Allow brim thickness to be different than Initial Layer?

[mkoic 2]

I use 0.8mm nozzles frequently and often use a 0.3mm or 0.4mm layer height.  On some materials, a brim this thick can be difficult to remove cleanly without a lot of effort.  I would be interested in being able to set the brim thickness independently from the initial layer thickness.  Similarly, at times on parts/materials that are warping, it might be helpful to increase the brim thickness.

[Smithy 1,144]

As far as I know there is no way to have different layer heights for the brim and model.

But there is a setting "Brim distance" which could help to remove the brim. I am not sure if "Brim distance" is included in the official Cura or only in @burtoogle 's version.

[hako 2]

There were some feature requests but the dev team turned them down because they prefer people to use a Raft.
It's false reasoning but I guess you'll need to develop it yourself and fork it if you need brim height settings.

[GregValiant 1,288]

"...because they prefer people to use a Raft..."

I don't see that at all.  Why would anyone care what anyone else uses?  Rafts are old tech that the new printers don't require, they use a lot of plastic, are hard to remove and require post-processing of the part to get rid of the scars.  A skirt does nothing for build plate adhesion, it just gets the juices flowing.

If you really want to hold it down to prevent warping or some such then throw some mouse ears around.

[Cuq 202]

+1 for anti warping solution, like mouse ears multi-layer.

 

But concerning Raft I think your wrong. It ' s not an old technology, it's an old one for plastic but not for metal printing. Otherwise Ultimaker wouldn't introduce all these new Raft parameters in Cura 5.0  

Edited June 2, 2022 by Cuq

[GregValiant 1,288]

OK, I'll concede the point on Rafts.  I've never found a need to use one and that probably colors my opinion.  Mouse ears on the other hand...I use those a lot on PETG prints.  My preference is to design them into the part as I can add chamfers where the ear attaches to the part so they break off easier.  For quick fixes the "Tab Anti-Warping" gizmos work fine using "Print as Part" and no walls.

 

[hako 2]

6 hours ago, Cuq said:

+1 for anti warping solution, like mouse ears multi-layer.

 

But concerning Raft I think your wrong. It ' s not an old technology, it's an old one for plastic but not for metal printing. Otherwise Ultimaker wouldn't introduce all these new Raft parameters in Cura 5.0  

Mouse ears tend to work best when printing with wide Nylon prints.
And the best, if you place them carefully you can peel them off without even damaging the original part.

Even better and for all materials would be a 0.06mm brim that interconnects a multi layer adhesion structure
So a combination of a thin brim with thick "mouse-ears", that would allow to peel it off easily after print, but that sort of setup requires a change in Cura which they likely won't make ever.
Hell, I am waiting for months for them to fix multi monitor hard crashes in Cura-5, they didn't even respond to the tens of bug reports since beta release.

 

[Cuq 202]

42 minutes ago, hako said:

Even better and for all materials would be a 0.06mm brim that interconnects a multi layer adhesion structure
So a combination of a thin brim with thick "mouse-ears", that would allow to peel it off easily after print.

 

 

I don't really understand your technic. something like that ?

[hako 2]

 

More like this!
You can see the circular pillars connected by a brim with the model.
To make this work the brim layer needs to be very thin, best below 0.1mm (depends on material)
I currently print it like the top two pillars, the lower ones are moved a bit down for demonstration purposes.

Without those round pillars the above print consistently fails due to massive warping (a nylon co polymer)
The circular shape is very stable in terms of adhesion and is not as much affected by the warping forces of the main model. 
It makes the main model stick down reliably, in the above model I use it as a 1 layer model, I've also used it as multi layer (like in your example)

After printing, the pillars and the brim can be removed without knife if it's printed thinner than 0.1mm
At 0.1mm it requires some force and a knife in some places, above 0.1mm it's difficult to remove without leaving damages to the model.

That's a quite large surface area Nylon print, I've not found any other method (even using huge brims) to print that successfully.

Edited June 2, 2022 by hako

[GregValiant 1,288]

This is the method I came up with.  You can see that the mouse ears are part of the model and have chamfers at the trim lines.  It works and that's always the bottom line.  I print this model in PETG with a skirt (a brim didn't add anything) as the part was narrow enough that all the pull was from the ends.  The print works hard to pull those tabs up.

[hako 2]

Hm interesting, basically the same thing I am using just integrated into the model mesh.
One difference is that the outer shape is circular in my case, that's in general the best shape for adhesion (sharp corners are a weak point)
Another difference is that the pure circularity of the model makes the separation very easy, the slicer prints a round wall so when you "pull" the layers between the "ear" and the "model" separate clean.

Cura should offer these type of "mounts" natively, it's not complicated to implement at all.
 

Edited June 2, 2022 by hako

[GregValiant 1,288]

Circular would have been better.  I went with "Easy".  I did end up printing several of these.  They came out fine.  The parts are in the Florida sun and so PETG was a much better choice.

[Cuq 202]

I make my plugins for my own needs. And as I don't print so tricky material , I don't need such type of tricks; but thanks a lot for this exchange It 's always interesting. You give me anyway an idea. As it is very easy to get the convex hull of the model ( the shadow of the model you already see on the build plate)  I think I will try in a futur release to place automaticaly some tab in the corner of these positions. Thanks a lot for this idea.    

Edited June 3, 2022 by Cuq

[hako 2]

@Cuq
Sounds great, I've not looked into plugins yet. 
I tried to compile Cura-5 to fix their crash on multi-monitors but after 2 hours I gave up trying to make a working environment, not sure if plugins are the same hassle ?

I made a feature request on it here: https://github.com/Ultimaker/Cura/issues/12426

I doubt their devs will look at it but maybe it's useful if you go for a plugin.

[Cuq 202]

One small step for mankind one giant leap for me  😄

 

 

[hako 2]

That does indeed look quite great!
Is it able to print the adhesion between model and pillars with a different (smaller) layer height ? 
Is it public ?

The speed you got that out is remarkable, I really need to look into plugin development 🙂

[Cuq 202]

By using a postprocessing script , yes , you can easily decrease the layer height and reduce the flow according to this reduction by using a M220 instruction, I have a script to increase the layer height, do the opposite should not be difficult.

 

Actual plugin source code : https://github.com/5axes/TabPlus

 

Edited June 4, 2022 by Cuq

[ahoeben 1,955]

1 hour ago, Cuq said:

you can easily decrease the layer height (...) by using a M220 instruction

Er... how? Changing the layer height would change the number of layers needed to print the whole model. There's no way you can do this with a simple gcode command. You can change the amount of material that is deposited (and as a result the line width), but not the distance between layers (the layer height).

[Cuq 202]

Not really because in this case we change just the layer height of the SKIRT Section (Change the Z value AND the flow via M221 : I made an error in my previous post with M220 sorry) . As the Skirt doesn't support any other layer, there is on my point of view no issue to do that ( but of course this idea must be tested to be sure of that ) .

 

Note : parameter "Support Brim Width" in this case must be set to 0 !

 

And If you fix a value in this case you can have some issue but as we are talking about support, I don't think it will be a problem to have a gap of between the Skirp and the second support layer. 

 

 

 

My actual script to to the opposite (MultiBrim) : https://github.com/5axes/TabPlus/blob/main/resources/scripts/MultiBrim.py

 

Edited June 4, 2022 by Cuq
Change the code M221

[Cuq 202]

Must be tested : https://github.com/5axes/TabPlus/blob/V1.0.1/resources/scripts/ReduceZBrim.py 

 

I don't have time to do it these days.

 

The last release with some minor modifications and 3 scripts 

https://github.com/5axes/TabPlus/releases/tag/V1.0.1

 

Edited June 4, 2022 by Cuq

[GregValiant 1,288]

I'll bite.  Anything in particular I should be looking for?

 

I won't be printing this but it was handy.  I have a bit of PETG to get rid of.  Something narrow and long would be a good test.  The settings were 12mm support brim, 3mm regular brim, the big circle is 25mm diameter.  

 

 

Edited June 4, 2022 by GregValiant

[hako 2]

For testing I would recommend any stronger warping material, then just print something at least 1cm in height at moderate to fast speed.
The faster and the higher the more the bottom forces increase.
I will give it a test during the week as well.

[Cuq 202]

Finaly regading your request my new plugin "Spoon Anti-warping" seems closer to the initial request : https://github.com/5axes/SpoonAntiWarping  

 

 

If you define the "Handle" ( attach width ) to 0 you can have a very similar result. 

 

 

 

Edited January 24, 2023 by Cuq