Printing off of the bed

[fingerpuk 0]

Hello,

I'm wondering if the best way to print flat surfaces off if the bed as the brim material is effecting the quality of the parts.

If I have a wheel for example that has rim detail where it touches the bed, that detail gets lost. If I raise the part up and use supports I have a nightmare if a cleaning job. So I wonder the best way to print these parts.

Cheers.

[IRobertI 520]

Depending on the model and the PLA you use you could very well get away with printing without a brim and still have only minimal warping (some brands/colours/batches warp less than others) .

If it still warps more than you'd like, adding glue if you haven't already will help keep the part from warping. You might also consider having the bed at a slightly higher temperature than what is generally recommended. Maybe 70C or so. But note that it can affect the quality of the lower layers if there are overhangs.

It's also important that the first layer is nicely smushed into the bed to avoid having any air leaking in underneath.

Not having a lot of infill will reduce the amount of plastic trying to pull the part in on itself as well.

 

[somewhereinla 2]

It would be helpful to see what you are talking about...

But in general you are better off not using the brim and support within Cura, and instead build it yourself in your 3d/CAD modeler.

 

[IRobertI 520]

I disagree with somewhereinla on the brim. If you add the brim yourself in your model it will be printed as one chunk together with the bottom of your model. This will make it harder to remove without doing damage to the model (which you wanted to avoid in the first place). The way the brim is printed by cura makes it really easy to remove in most cases as you can just "peel" it off so to speak.

 

[gr5 2,167]

Please post a picture of what you talk about. I think this "rim" can only be printed if it is facing upwards.

Is this like a coin? Maybe cut it in half and print it on edge?

 

[fingerpuk 0]

OK, so take this model:

I'd print that laying on it's side, however because the treads are about 3mm off of the bed and the curve of the lower part is subtle the brim that gets printed to stop it warping ends up being quite invasive - it ruins whichever side is lowest. I have bottom and top (can we split these settings) at 1.2mm which I may cut in half, not sure if that's the cause.

So I decided to split the model, because the geometry is complex this involves creating a hollow part:

However when I load this in Cura it adds quite a large chunk to the bottom of the entire tyre section, so the tyre isn't hollow. This isn't brim but some kind of support structure? I'm guessing it's the lower/upper thickness. Of course I want upper thickness but no lower thickness, you can see what it's doing below, the tyre is hollow with no connection at all at the point of splitting, the yellow is all Cura. The red and green I'd be happy with, I don't need that yellow, and I think maybe that is the cause of the problem?

 

[fingerpuk 0]

Solid Infill Bottom - unchecked it. Let's see what happens. Can't believe I only just found that

 

[skint 61]

Yes that`s the solid infill, you may need a bit of infill to support the top surfaces depending on the size of the wheel

 

[jonnybischof 60]

And of course 0% infill, or you'll get the square infills...

Just remember to put "solid infill bottom" back on after having sliced the tyres! I thought my Cura was broken for some time until I realised that I deactivated the "solid infill.." settings

 

[gr5 2,167]

Wow - you answered all of your own questions perfectly!

I noticed Cura put a brim on the inside *and* the outside. I think that's fixed in the latest Cura.

 

[jonnybischof 60]

The newer versions still add a Brim inside, but only for relatively larger openings, and only a few lines, not the full amount of Brim until the whole opening would be covered.