Hollow Cylinder printing solid


#1

I have created a cylinder on Sketchup by placing a circle on the surface, using the push/pull tool to extrude it, placing another circle on top of that, and using push/pull to extrude down to the surface, and it creates a void and thus a hollow cylinder. The issue I am having is that my printer, an Ultimaker 2, is printing it as a solid. Not hollow. The Cura app seems to see it hollow when you load the model, but if you view the layers, it is printing as a complete solid and not hollow. Any ideas why?


#2

Without seeing it my guess would be that you have some faces reversed so the printer doesn’t know what is not there.
By default the outside faces should all be white, and the inside the blue/grey colour.


#3

cylinder.skp (1.1 MB)

Here it is. I dont see faces reversed, but please take a look and tell me.


#4

I don’t see what could be causing it, seems right.
I made one the same size a slightly different way, see if that works.
By the way, Purge your models to get rid of things you have deleted.
1.1mb down to 51kb
Rings.skp (51.2 KB)


#5

Thank you for the top about purging. Still learning so it is greatly appreciated. Let me look at your model and I will get back.


#6

Yours looks to print properly. What way did you create it please?


#7

Ok, and Im sorry to be such a pain, but how do you go about “Purging” your models? I just did a help search purging and it came up with nothing. Like I said, still learnging.


#8

Quick gif for you.
Draw a circle, draw another circle, delete the middle and pull up to height.

Purge, Window menu/ model info/ statistics, purge unused.

You can purge directly from the components window and the materials window also or even install a purge plugin that will clear everything out. But stick with the basics for now.


#9

Thanks. Giving it a try now. Interesting that the same result one way, is not achieved the other way. I wonder why. Thats for another day. And I will keep purging! :smile:
Greatly appreciate the help.


#10

Yup, that did the trick. I even added the teeth to it (didnt mention that earlier) and it prints like a dream.


#11

Very good, post some pics of your printings when you have something nice to show.


#12

Absolutely. The end product of what I was making is this.

As soon as the printing gets done, I will send pics of the result.
This is an arm that is to connect directly to a servo. Obviously, the part I was referring to in this post is the part that connects to the servo.


#13

I’ve exported your cylinder to STL and imported it in Cura, the preview seem to be OK…


#14

Iteresting. This is what I was getting out of Cura with my cylinder.


#15

Since our discussions here I have tried different variations, and every variation where I start with and solid extruded cylinder, and then create a void in that cylinder makes the printed product solid. Using your method is the only way to get it hollow when printing. Even though the result looks the same in SketchUp, when you examine the layers in Curo, it is different.


#16

What is your process for exporting to STL? I’ve been using the SketchUp STL extension.


#17

Me too, and Cura 15.02.1, SU 2015. I’ve tried different ways of creating such a hollow cylinder too and all look OK in Cura.


#18

What did you use to create the video screenshots earlier? I can use the same thing to show exactly what I did if you are interested.


#19

The screencast was created by @Box.


#20

Well, I dont know what to say, but now I cannot reproduce what I was seeing. Now if I do exactly what I was saying at the start of this thread, it is not producing the screenshot I just sent, yet I did the exact same thing. At thing point in time, I am at a loss for words. Maybe it actually had to do with purging you mentioned earlier?