Printing small Yoda bust

[Nicolinux 288]

Hi,

I am trying to print a scaled down version of the famous Yoda bust:

http://www.thingiverse.com/thing:10650

However I noticed that the ears do feature some big holes.

How to get rid of these? I am pretty sure that I have seen scaled down Yodas without broken ears. I tried different layer height and shells - but it doesn't help. I didn't print it yet though. Just looking at the gcode preview tells me that it will fail

Thanks.

 

[illuminarti 18]

It;s probably just an artefact of how the latest Cura slices it.... I have a larger print here on my desk, and looking at it, those parts of the ear are really thin; scaled down, you're probably getting to less than 1.5 times the nozzle width, causing Cura to ignore it.

You could try a different slicer, or try claiming a smaller nozzle size, and see if you can persuade it to slice. Or use a tool like Sculptris to thicken up that part of the ears a bit.

 

[Nicolinux 288]

Thanks Simon. I think I'll wait for the next Cura version (that I think is just about to be released). It would be a nice test case.

By the way, I used Sculptris before and found it a bit complicated (the ZBrush legacy is clearly there). Meshmixer 2.0 from Autodesk is also free and fun to use.

http://www.meshmixer.com

 

[alex-marakesch 0]

Cura ignore it because it is less than 0.4 mm thick. If you increase it by yourself in model, it will be printable.

 

[gr5 2,026]

Waiting for the next Cura isn't going to help. Those ears are just too thin. As Alex tried to explain. And Illuminarti. And now me.

Personally I would just not shrink the yoda by quite so much. Cura will not print thinner than .8mm unless you tell it you have a nozzle smaller than .4mm. If you tell cura the nozzle is .3mm it will work relatively just fine. If you tell it your nozzle is .1mm it won't work so well - as it will underextrude by much too much.

 

[LePaul 312]

Try, you must

(I'm sorry, I couldn't resist)

 

[Nicolinux 288]

Waiting for the next Cura isn't going to help. Those ears are just too thin. As Alex tried to explain. And Illuminarti. And now me.

Personally I would just not shrink the yoda by quite so much. Cura will not print thinner than .8mm unless you tell it you have a nozzle smaller than .4mm. If you tell cura the nozzle is .3mm it will work relatively just fine. If you tell it your nozzle is .1mm it won't work so well - as it will underextrude by much too much.

 

Now I feel stupid, thanks.

But indeed, I still don't understand why "lying" about the nozzle size would work just fine. I get it that Cure would slice it then. But wouldn't the print feature heavy underextrusion because less plastic is extruded through a "bigger" nozzle? Should it then be compensated by increasing the flow rate?

There are two reasons I would like to scale it down. For one, I like small objects and find it fascinating to see how small/detailed the Ultimaker can go. The other reason is that I want to prepare for a full scale Yoda print and want to see if there is anything else that can fail. It is no fun to have a multi hour print fail due to stupid slicing settings.

 

[gr5 2,026]

If you tell it the nozzle width is .3mm and you make say 3 passes on the skin (1.2mm) then it will extrude the correct amount to get a .3mm width bead. But the nozzle is .4mm so it will be a little underextruded but not too much but on the second pass, there will already be a wall in the way and so it will extrude perfectly. Same with the 3rd pass. So mostly only the first pass will be underextruded and the final outer wall should be pretty decent.

Solid infill works even better. It will always put out just enough to fill in a .3mm line and the previous line will be covering part of the nozzle so it should work pretty well.

It basically mostly just works.

But if you tell cura the nozzle is .2mm it will also work but not as well. You just have to experiment.