My little details keep falling into the infill abyss!

[spauliszyn 0]

Let me explain as best as I can and forgive me if the answer is already found in the forums (it's a big site and hard to put the concept into a few keywords)

 

So I am printing some lego style blocks as counting blocks for teaching grade 3 math.  They are usually called "Base 10 Blocks" and built with square blocks. 

This is a 10x10x1cm 100's unit.  The bottom 3mm has a recess for the 2mm tall studs when stacking blocks on blocks.  So the majority of the 3D model is solid so I can use the CURA generated infill (20% cubic in this case).  Printing on a Creality CR-6 SE.

 

 

The following slice preview shows the construction of the transition from the solid rectangular chunk to the solid studs. 

 

For this specific layer, the infill was printed first then the circles for the inside wall of the infill, then the first layer of the general ceiling.  Hopefully you can see the problem that some of the circles fall between the infill walls.  In the real print, even though this layer looked very ugly, by the time it reached the outer layer of the shell, I was still achieving decent surfaces and studs.

 

Here are some options that I can think of.  The first one would be my preference:

 

1. I would like to instruct the slicer to print a 100% infill at a specific layer or list of layers.  So the yellow layer you see in the picture would be full yellow, and would act as an internal raft for any small, weirdly placed details.  This would not take too much extra filament as it would simply ignore the circles on this layer and produce an efficient straight-line pattern.  I would have to remember to preview the sliced model to determine the correct layer to use this option.  Maybe this option exists but i can't recognize the keywords from the myriad of other settings in Cura.
2. Alternatively, I could insert a shaped void in the 3D model between the stud and block, forcing the slicer to add extra full layers at those locations.  It is finikey to get the void modeled efficiently and would use more filament and time.  It would be slicer independent though.
3. Lastly I could just use a grid infill with enough density so that I get a wall every 2.5mm or 3.33mm.  But it's just more filament and time.

 

The output quality of this project is not intended to be very high but I can imagine that i will coming across this for a more accurate model in the future.

 

Any thoughts or suggestions? Your help is appreciated :)

 

 

[Framar 38]

In such case I would use a thin block as a  support blocker and assign it a 100% infill. Or I would split the 3D model at the location Where the 100% infill is needed and stack them on each other so you get top layer of the fisrt block and then bottom layer of the second one.

[geert_2 557]

Or leave a gap of 0.01mm between the plate, and the studs, in the same CAD-model. So the plate would print as one block including top layers. And then there would be a 0.01mm vertical gap, after which the studs are printed. Such a tiny gap will obviously be filled, and the studs will fuse to the baseplate as if there was no gap.

 

I don't think this is the optimal way of doing it; too much CAD-work. Beter would be to find the exact right slicer-setting to handle this (if present). But it might be a way around if nothing else works...

 

[spauliszyn 0]

Thanks @geert_2.  That is like my option 2, which is what I am using now.  All I did is put a 0.2mm thick disk-shaped void right at the base of each stud.  The print looks very clean and I get neat ceiling layers at the top of the whole block, right before the studs print.  But then there are redundant floor layers at the base of the studs.

 

If I could just specify a "100% infill at layer #", I could specify the ceiling layers of the big block, and the studs could continue printing as if they were the only things on the bed (as in no additional floor layers for them). 

 

Or is there a way to turn of the generation of certain ceilings and floors at s specified layer?

 

...Just got a brain wave while writing this!  I should intentionally make my studs hollow.  That will get rid of redundant floor layers of the studs.  And a 7mmø cylinder doesn't need any infill anyway.  I will still have additional ceiling layers right under the studs that would would be a bit of a waste of  materials.  But the trade-off is that the speed of the ceiling of the block will be maxed.