How to correct big gaps in skin in Cura

[Billy771 0]

 

Please help me to correct problem of big gaps in some parts of skin of sliced glider wing (see attached screen shots). Real printed part has the same gaps.

What print setting parameters to modify to correct the problem? Thanks for the answers

Edited August 2, 2021 by Billy771
correct grammar

[GregValiant 1,251]

If that is a single wall print it's going to be tough.  In Cura use "File | Save Project" and post the 3mf file here.  It will contain the model, printer, and settings you are using.  If the model is proprietary then load a similar one if you can.

[Billy771 0]

Yes it is single wall print. I put left and right part of wing into project because there is the same problem. Thank you for your support🙂

 

Joker wing-part-1-left, right - Billy ed.01.3mf

[Billy771 0]

On 8/2/2021 at 5:11 PM, GregValiant said:

If that is a single wall print it's going to be tough.  In Cura use "File | Save Project" and post the 3mf file here.  It will contain the model, printer, and settings you are using.  If the model is proprietary then load a similar one if you can.

 

Yes it is single wall print. I put left and right part of wing into project because there is the same problem. Thank you for your support639804002_Jokerwing-part-1-leftright-Billyed.01.3mf

Joker wing-part-1-left, right - Billy ed.01.3mf

[GregValiant 1,251]

When the slope of a surface is near horizontal, the layer edges get farther apart.  With a single wall the extrusions don't touch and you see that in the gaps between the stripes of plastic (the ones that didn't fall through).  If you lower the layer height it will get better but any surface that is nearly horizontal will have this problem.

If you add a support blocker to the area of the wing root where the radius is, you can set the "Overlap" setting to a top/bottom thickness of 1.0 and see how it looks.

You can see how far apart the individual red stripes are and there is just air between them.  That area is almost flat.  The extrusions can't actually make a curve in air either and so they either fall through or make a straight line.

 

This support blocker is configured so overlaps have 4 top layers.  That provides plastic to fill the gaps between the lonesome stripes we see in the previous image.  I know it's adding weight, but it isn't a lot and it's either that or going without wing roots.

 

 

 

That's my take on it.  Did you check with whoever provided the design?  Maybe they have a particular setup that works better.  @geert_2 and @Torgeir have been around the block a couple of times and maybe they will have an idea as well.

Edited August 18, 2021 by GregValiant

[Torgeir 242]

Hi there, @Billy771

I've made the same correction as @GregValiant, using top layer in order to print the fairing for the stub wing.
However, I've removed the infill used and did not use any support.

 

Key issues for this part of the wing.

It transfer the lift forces to the air frame and is the most stressed part on the glider.
Need to have good adhesion to make it strong -and the fairing is integrated into the stubwing -supporting the wing.
Due to the above fact, the layer height is reduced to 0.1mm.

Sure, I've tried using 0.15mm layer height -but did not work well.
You may try to change the layer height and see the problem in preview mode.

 

For sure, there is a number of ways to do this.

 

Here is the way I did it.

 

Using Cura 4.1.0 for THIS print.

 

So, to the important change to setting  for this slicing is:

Used your profile and changed:

 

Quality.
Layer height:  0.1 mm

 

Shell.
Outer Before Inner wall: Selected on.
Compensate Outer Wall Overlaps: Selected on.
Top layers: 8
 

 

Infill.
Infill density: 0

 

Build plate Adhesion.
Build plate Adhesion type: Skirt (you may use brim, but it's some work to remove).

 

Experimental.
Minimum polygon Circumference: 0.5 mm
Use adaptive layers: Selected on.

 

That's all.

 

Here is a picture of how an adaptive layer is supported during build up.

 

And two..

 

This is how it looks in the critical area, -much better line adhesion this way.

 

I'll think this part is lighter (56 gram), but it take a long time to print!

 

Before starting printing such a model, make sure your printer can handle this task. Everything has to be well tuned!

 

Here is your modified project file.

CE3_639804002_Jokerwing-part-1-leftright-Billyed.01_Cura_4_1_0_.3mf

 

And here is the gcode file.

CE3_639804002_Jokerwing-part-1-leftright-Billyed.01_Cura_4_1_0_.gcode

 

For practical reason I've removed the other side of the stub wing, but settings will be the same.

I'll think it's better to print one by time.

 

There might be some area to fine tune, as wall width and flow etc.

 

Good luck

Thanks

Torgeir.

 

 

Edited August 20, 2021 by Torgeir
Text.

[Billy771 0]

On 18. 8. 2021 at 20:32, GregValiant said:

Keď je sklon povrchu blízko horizontály, okraje vrstvy sa od seba vzdialia. Pri jednej stene sa výlisky nedotýkajú a vidíte to v medzerách medzi pruhmi plastu (tie, ktoré neprepadli). Ak znížite výšku vrstvy, bude to lepšie, ale tento problém bude mať akýkoľvek povrch, ktorý je takmer horizontálny.

Ak do oblasti koreňa krídla, kde je polomer, pridáte podporný blokátor, môžete nastaviť „Prekrývanie“ na hornú/dolnú hrúbku 1,0 a zistiť, ako vyzerá.

Vidíte, ako ďaleko sú od seba jednotlivé červené pruhy a je medzi nimi len vzduch. Táto oblasť je takmer rovná. Vytlačenia v skutočnosti nedokážu vytvoriť ani krivku vo vzduchu, a tak buď prepadnú, alebo urobia priamku.

 

Tento blokovač podpory je nakonfigurovaný tak, aby prekrytia mali 4 horné vrstvy. To poskytuje plast na vyplnenie medzier medzi osamelými pruhmi, ktoré vidíme na predchádzajúcom obrázku. Viem, že to pridáva na váhe, ale nie je to veľa a buď to alebo nie, bez koreňov krídel.

 

 

 

To je môj pohľad na vec. Skontaktovali ste sa s tým, kto poskytol dizajn? Možno majú konkrétne nastavenie, ktoré funguje lepšie.  @geert_2 a @Torgeir boli párkrát okolo bloku a možno budú mať aj nápad.

 

[Billy771 0]

On 8/18/2021 at 8:32 PM, GregValiant said:

When the slope of a surface is near horizontal, the layer edges get farther apart.  With a single wall the extrusions don't touch and you see that in the gaps between the stripes of plastic (the ones that didn't fall through).  If you lower the layer height it will get better but any surface that is nearly horizontal will have this problem.

If you add a support blocker to the area of the wing root where the radius is, you can set the "Overlap" setting to a top/bottom thickness of 1.0 and see how it looks.

You can see how far apart the individual red stripes are and there is just air between them.  That area is almost flat.  The extrusions can't actually make a curve in air either and so they either fall through or make a straight line.

 

This support blocker is configured so overlaps have 4 top layers.  That provides plastic to fill the gaps between the lonesome stripes we see in the previous image.  I know it's adding weight, but it isn't a lot and it's either that or going without wing roots.

 

 

 

That's my take on it.  Did you check with whoever provided the design?  Maybe they have a particular setup that works better.  @geert_2 and @Torgeir have been around the block a couple of times and maybe they will have an idea as well.

Hi Greg,

thank you very much for your support. Yes it is good solution. I thought about it but I am not enough experienced with settings. I was thinking also about of covering gap wing area with glasstextil strip with epoxy. I have bought the project of this glider with gcode files but for Prusa printer but I have Ender 3V2. I will try some test prints accordance to your advice and also Torgeir and then I will choose final solution.

[Billy771 0]

On 8/20/2021 at 11:39 PM, Torgeir said:

Hi there, @Billy771

I've made the same correction as @GregValiant, using top layer in order to print the fairing for the stub wing.
However, I've removed the infill used and did not use any support.

 

Key issues for this part of the wing.

It transfer the lift forces to the air frame and is the most stressed part on the glider.
Need to have good adhesion to make it strong -and the fairing is integrated into the stubwing -supporting the wing.
Due to the above fact, the layer height is reduced to 0.1mm.

Sure, I've tried using 0.15mm layer height -but did not work well.
You may try to change the layer height and see the problem in preview mode.

 

For sure, there is a number of ways to do this.

 

Here is the way I did it.

 

Using Cura 4.1.0 for THIS print.

 

So, to the important change to setting  for this slicing is:

Used your profile and changed:

 

Quality.
Layer height:  0.1 mm

 

Shell.
Outer Before Inner wall: Selected on.
Compensate Outer Wall Overlaps: Selected on.
Top layers: 8
 

 

Infill.
Infill density: 0

 

Build plate Adhesion.
Build plate Adhesion type: Skirt (you may use brim, but it's some work to remove).

 

Experimental.
Minimum polygon Circumference: 0.5 mm
Use adaptive layers: Selected on.

 

That's all.

 

Here is a picture of how an adaptive layer is supported during build up.

 

And two..

 

This is how it looks in the critical area, -much better line adhesion this way.

 

I'll think this part is lighter (56 gram), but it take a long time to print!

 

Before starting printing such a model, make sure your printer can handle this task. Everything has to be well tuned!

 

Here is your modified project file.

CE3_639804002_Jokerwing-part-1-leftright-Billyed.01_Cura_4_1_0_.3mf 1.08 MB · 0 downloads

 

And here is the gcode file.

CE3_639804002_Jokerwing-part-1-leftright-Billyed.01_Cura_4_1_0_.gcode 29.26 MB · 0 downloads

 

For practical reason I've removed the other side of the stub wing, but settings will be the same.

I'll think it's better to print one by time.

 

There might be some area to fine tune, as wall width and flow etc.

 

Good luck

Thanks

Torgeir.

 

 

Hi Torgeir,

Thank you very much for your effort, project files and changes in print settings. I will try some test prints accordance to your advice and also Greg and then I will choose final solution. Then I will inform you and Greg about the final result.

Regards, 

Billy

[geert_2 557]

I am not familiar with single wall stuff, so I can't comment on this issue.

 

However, what I have been wondering about is why do people print wings *vertically*? Then the problem is that the wing has the least strength in the direction of the biggest load in flight, due to the layer lines. Any high G turn could rip off or fold-up the wings. Just like in an overloaded real plane (I recently saw a crash-analysis video of such an event).

 

Why not print the wings horizontally? Why not cut the wing horizontally across the cord line to get a flat plate, and then print the top half and bottom half separately (with a bit of support), and then glue top and bottom half together? It would be a bit heavier, but much stronger I think? Wash-out of most wings (=designed-in twisting of the surface) is not that big that this method would be impossible.

 

Anyway, when printing in PLA, never leave the plane in your car on a sunny day, even not a mild spring or autumn sun: it will definitely warp. Also, don't let it sit in the sun on a hot concrete runway.

 

Maybe the warping tendency could be reduced, and strength and impact-resistance increased, by injecting very lightweight but very sturdy PU-foam into the wings? Or maybe make the whole wing out of PU-foam? Print a mould in PLA, sand and polish that, and cast the foam wings in it (with plenty of release spray)? Just an idea, I don't know if it would work...?

 

[GregValiant 1,251]

There was balsa wood covered with tissue paper and finished with "airplane dope".

Then it was balsa covered with monokote shrink plastic.

Then there was foam covered with balsa or monokote

Now it's " Just print the damn thing all at once."

 

A printed wing with a well designed interior using angled ribs and integral spars should be fine for small electric planes.  I wouldn't count on a printed wing on a plane powered by an Enya 90.

[Torgeir 242]

Hi there.

 

Don't we forget an important "detail" here, -that we're also using carbon fiber rods along the entire wing, and that this is also used in the tail section and the rest of the hull (air frame) -when necessary.

This reinforces the entire "aircraft" and maintains the needed flexibility.

Also, a horizontal printed wing will be stronger, -but suffer for the aerodynamic shape..

 

Just some thoughts.

 

Torgeir

 

 

Edited September 9, 2021 by Torgeir
Correction of text.

[Billy771 0]

Hi guys,

thank you for your ideas. For your better information here is asembly video