Cura is not allowing me all the accessible print space

[Lerxst2112 0]

Hello, I just joined here and I am just getting into 3D printing.
Right off the bat I'm having an issue with the Cura 4.6.1 slicer not slicing for me. I am using the Ender 5 Plus which has a 350mm x 350mm print space. It just so happens my model is that exact external dimension... 350mm x 350mm. I have used a different slicing program and printed the model successfully in the past, but with the Cura slicer, unless I reduce the model to around 300mm x 300mm, it gives me error messages when I press the slice button. So something is way off.

First I get a Model error when I size up my model to 350mm x 350mm;
"Your model is not manifold. The highlighted areas indicate either missing or extraneous surfaces." 

Then when I hit "slice" I get this message;
"Unable to slice.
Please review your settings and check if your models:
-Fit within the build volume
-Are assigned to an enabled extruder
-Are not all set as modifier meshes"

Can someone possibly explain what I might need to do to extend the print space in Cura enough to be able to slice the print? Or if I'm doing something very wrong in the process...

Thank you in advance!

[GregValiant 1,410]

Being line-to-line with the build surface size may be an issue (where 349.99 x 349.99 may not be an issue) .  If you have set up for a brim/skirt/raft then that detracts from the surface size as they take up room outside the model.

Non-manifold means Cura is having issues with the model file itself.  If you post the model file here someone will take a look and suggest fixes for it.  A non-manifold model cannot be sliced by Cura because there are gaps in the model (it isn't water tight).

[Lerxst2112 0]

On 7/1/2020 at 10:03 AM, GregValiant said:

Being line-to-line with the build surface size may be an issue (where 349.99 x 349.99 may not be an issue) .  If you have set up for a brim/skirt/raft then that detracts from the surface size as they take up room outside the model.

Non-manifold means Cura is having issues with the model file itself.  If you post the model file here someone will take a look and suggest fixes for it.  A non-manifold model cannot be sliced by Cura because there are gaps in the model (it isn't water tight).

GregValiant, thank you for your input and explanation. I tried sizes even much lower than that with no success.
As for the gaps, what I am trying to print is an array of devices, but due to size constraints, they have to fit VERY close together.
Not being able to print such an array is an issue for me, and I have no problem slicing and printing the full model array with the Ender slicer. But I wanted to use the Cura because it was highly recommended. Is there any sort of override setting to enlarge the active print space to the full 350mm x 350mm size?

[GregValiant 1,410]

I think that you have two problems to solve.  One is the build surface size and the other is a problem with the model.

The actual printable area is determined by a couple of things.  Within Cura, go to "Monitor / {your printer} / Manage Printers / Machine Settings" and check that the build plate size is correct for your machine.  It should be a rectangle 350 x 350 and "Origin at Center" should NOT be checked.

On the printer LCD check the Home Offsets.  I don't know for sure but they should be something like X=-10 Y=-10 Z=0.

The printer can have two zero positions.  One is the absolute machine zero that Auto-Home uses, and the other is a relative zero that is the position of the head when it is at the Home Offset position.  When a Gcode file is read, it uses the home offset position as zero.  It calculates MaxX and MaxY by adding the numbers  (350 and 350 in your case) to the home offset.  That means that when you send the print head to X175 Y175 the nozzle should be dead nuts in the middle of the build surface.  If it isn't you'll need to adjust the Home Offsets.

Regarding the model, the gaps between the members of the array don't matter.  Cura understands that they are gaps.  Your individual model (that you have arrayed) is the problem.  You can try to slice one model (single member of the array) just as a test.  I believe even one model won't slice because of internal issues.  If Cura 4.6 puts polka dots on the model or highlights particular faces of the model then Cura will refuse to slice because of problems in the STL file.  I think there is a Mesh Fixer plugin for Cura in the Marketplace but I have never used it.  Hopefully somebody else here can point you in a direction to check that model.