Support not printed for first layer..?

[shoe 1]

I post 4 screenshots here. Standard Profile with Tree Support 45° or 60° Overhand Support. 60° is plenty enough for this part.

 

First two screenshots Layer 1 and Layer 2 with 45°

 

 

 

Next two screenshots Layer 1 and Layer 2 with 60°

 

All screenshots show, that the ZigZag support starts with Layer2. With 45° there are at least a few dots of support, the Layer2 ZigZag can bind to. With 60° Overhang Angle, there is ZERO support for the first layer to which the ZigZag cound bind to.

 

Switching off Skirt to 0 Lines or turning it off completely doesn't help: https://www.reddit.com/r/ender3v2/comments/125yq7p/support_not_printing_on_first_layer_cura_530/

 

[Slashee_the_Cow 272]

First off: it always makes it a lot easier for us to figure it out if you post a Cura project file (.3mf, get it ready to print then go to File > Save Project).

 

But the answer as best as I can tell: You're using trees. You're not getting zigzags as support, you're getting grid (or zigzag, hard to tell because they look pretty much the same) support interface (which is why it's dark blue instead of light blue), which prints on top of the support, the idea being it's easier to remove cleanly after it's printed. (that idea often doesn't bear out in real life).

 

As for the difference with overhang angle: it's hard to tell based on the screenshots (which is why having the project file is so helpful) but it looks like the back part of your model -  rises up at about a 45° angle, so a 45° support angle won't generate support for it because it assumes the printer can handle a 45° overhang. I usually have my support overhang angle set at about 55° for PLA.

 

The tree trunks I've highlighted from the first screenshot aren't there to support the main part (with the support interface), they're there to support that raised lip at the back:

So why no tree trunks under the support interface? My guess would be Support > Minimum Height to Model (if you can't see it, make sure support structure is set to trees then search for it): it won't generate trees for areas under a certain height to prevent tiny blobs of tree.

[shoe 1]

Does this help?

 

You are right...I wasn't able to remove that grid-like stuff starting at layer2 😞

CE3MAX_V2_6_ALL.3mf

[Slashee_the_Cow 272]

Thanks... that's exactly the file I needed.

 

Fixing it is trickier than I thought it might be. The idea with support interface is that by default there's an air gap of one layer below a floor or above a roof (so that it comes off more easily), but it doesn't seem to be taking into account being on the baseplate (which should give it regular support below, except that your height is exactly what it would use for interface.

 

Unsatisfactory solution #1: Disable Support > Enable Support Interface > Enable Support Roof

Gets us the base support we'll use, but it also means we have no interface so supports are going to be harder to remove (especially little ones like this).

 

Unsatisfactory solution #2: Set Support > Support Structure to Normal

That's exactly how the support should look in that situation. It also gives us the problem that there's a bunch of tiny holes that will get filled with support which is going to be a pain to remove which wouldn't be there if we were using trees.

 

Somewhat satisfactory solution #1: Set Support > Support Interface Thickness > Support Roof Thickness to 0.4mm

This makes the support roof short enough that it'll print regular support beneath it to hold it up. Is it going to make a huge difference having two roof layers instead of the default four? In a model like this, probably not. 

 

Effective but really, really fiddly solution #1: Add supports manually

I've only done it for one section in this screenshot, but you can create a support blocker, move and scale it so that it's the right position and size, and use the Per Model Settings tool to set the Mesh type to "Print as support". But you'd need to use several here due to the shapes the support area goes in.

 

And, umm... that's all I can think of for now. I would definitely advise going with the "lower support roof thickness" option.

[shoe 1]

Thanks! I will try it out and give feedback!