Supports not being generated underneath overhang on print bed
 
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jeremy.s25
(@jeremy-s25)
Eminent Member
Supports not being generated underneath overhang on print bed

Hello, Thank you for taking a moment to look at my topic and help.

I am trying to print a katana model - however, the back of the blade is not 100% flat, thus it does not cleanly stay on the print bed.

However, when I try to generate support material or brim, it does not generate on the blue area, which makes this file impossible to print. It will make a spaghetti monster without fail. Prusa slicer detects the blue area as overhang, but support material does not generate. I want to lay the print on the bed like so, so it requires the least amount of sanding and looks as clean as possible.

I have tried:

Adding a support enforcer underneath

Adding Brim (the brim does not go on the overhang material because it is overhang)

Overhang threshold at 0, 45, 90. ( supports will still not generate under the blue overhang at 90)

I have attached the file here. I need to do this for all the parts of the sword, as all of the back of the blade is not quite evenly flat.

Any ideas how to get this to print with stability?

Posted : 06/07/2024 10:59 pm
Diem
 Diem
(@diem)
Illustrious Member

No file attached, you may have to zip it.  The best file to attach is the project 3mf.

Files > Save Project as

Zip the .3mf and post it here. It will contain both your part and your settings for us to diagnose.

Cheerio,

Posted : 06/07/2024 11:05 pm
jeremy.s25
(@jeremy-s25)
Eminent Member
Topic starter answered:
RE:

Added the 3mf file here.

This post was modified 6 days ago 2 times by jeremy.s25
Posted : 07/07/2024 2:16 am
Diem
 Diem
(@diem)
Illustrious Member

The surface in contact with the build plate is not flat.  It has a subtle curve which, despite your use of 0.07mm ULTRADETAIL layers (with the first layer at 0.2mm), does not rise high enough to fit any support material underneath.  There is nothing here to justify 0.07mm layers, you may as well use 0.2mm layers.

The easiest way to print this would be to flatten the underside but if you really want to print this with the curve then if you have access to a MMU you could raise it a few mm off the bed and support it with a soluble interface which would then have room to conform.

Cheerio,

Posted : 07/07/2024 4:17 am
jeremy.s25
(@jeremy-s25)
Eminent Member
Topic starter answered:
RE: Supports not being generated underneath overhang on print bed

So there is no way to print this file without an MMU? Why is the prusa software not properly generating supports for the overhang?

Posted : 07/07/2024 8:37 pm
jeremy.s25
(@jeremy-s25)
Eminent Member
Topic starter answered:
RE: Supports not being generated underneath overhang on print bed

Alternatively, I could try flattening the katana pieces, but I do not have one big model - I have several small ones. How would I go about flattening them all on the same part? I have meshmixer too, but I Don't think this is possible in prusa slicer because prusa slicer seems to not be able to correctly place this item onto a 90 degree plane?

Posted : 07/07/2024 8:44 pm
mvikman
(@mvikman)
Trusted Member
RE: Supports not being generated underneath overhang on print bed

How about adding some cones (or similar with minimal footprint on the object) to the underside of the object to raise it up from the print surface enough to generate sufficient support material below?

Posted : 08/07/2024 10:48 am
Neophyl
(@neophyl)
Illustrious Member
RE: Supports not being generated underneath overhang on print bed

If you are going to raise it then just add a raft.  Why bother with 'cones' .  Personal;ly I dont like rafts as that means the entire surface would be supported which is just messy and wont give a good surface.

As Diem pointed out supports can only be generated under a surface is there is sufficient room for at least 1 layer of supports PLUS the support contact gap.  This model doesn't allow that so no support.

An alternative to modifying the model to be flat you could always just sink it by one layer (0.2mm).  That produce a flat back surface on the bed with zero model work.  More surface area and zero support needed for that area.

Posted : 08/07/2024 2:04 pm
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