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jweaver

Struggling to print a spinning top.

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I am trying to print this:

http://www.thingiverse.com/thing:23686/#files

Clearly it needs supports.. And when I add them, it looks fine.. But after a few layers, the centre of the spinning top comes away from the bed as its only making contact by a tiny point.

If I enable a 'brim', it builds the brim around the supports, rather than the model, so it doesn't help.

If I remove supports and use a brim, the brim forms circles around the centre point of the top and would help it stick.. But not when Supports are switched on.

How exactly would/could you print something like this?

Is it right that a brim takes the support into account, rather than simply adding a brim to the model?

Jon

 

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You could always split the part into two halves along the z axis and print it that way. Would still work as a top, and you wouldn't have to worry about supports and brim. (provided you're getting good first layer bonding to begin with). I think someone said Netfab lets you slice a part.

Or you could model in your own supports and/or brim. I think Meshmixer can help here.

Or you can use "cut off bottom" in Cura to give the base of the top (that's confusing) a larger foot print. You could then file/sand the flat bottom into the desirable shape (presumably a point). If you're worried about losing height, you can scale in the Z direction in Cura, just unlock the scale proportions so that it is only scaling in the Z axis.

that;s all I can think of off the top of my head, good luck :)

 

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I wasn't aware of the "Cut Of The Bottom" feature and will look at that... But I still think there is something wrong with the way that CURA handles Brim and Supports at the same time.

If I try to print it with a Brim, I get a nice 'bulls eye' effect on the point, giving me a round platform as a brim.

But if I do the same with support added, then the CURA tries to put a brim around the supports (Which I would say arn't needed) and the one on the tip of the spinning top is a mess...

So even if I cut of the bottom, to reveal a slightly larger footprint, the "brim" still wouldn't be right..

Jon

 

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Hi jweaver,

I've generated the tool path of the model in Cura 14.09 and see that it does generate a brim around the model, as well as a brim around the support.

The issue you are experiencing is therefore not a software issue, unless it does occur in other versions of Cura.

Take a look at the tool path view and scroll down to the first layer; I suspect you will find a brim around the spinning point of the InceptionTop.

 

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Hi jweaver,

I've generated the tool path of the model in Cura 14.09 and see that it does generate a brim around the model, as well as a brim around the support.

The issue you are experiencing is therefore not a software issue, unless it does occur in other versions of Cura.

Take a look at the tool path view and scroll down to the first layer; I suspect you will find a brim around the spinning point of the InceptionTop.

 

I have done exactly the same thinig (14.09) and the brim is different...

When you enable a brim without support, you get a nice round brim attached to the point at all sides.. But when you enable support, the brim changes to take the support into account and its not completely attached to the point of the top.

When you print it, it just breaks away!

I still can't get my head around why CURA puts a brim on the support? Surely the brim should be the same with or without the support?

Jon

 

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Here are some photos.. I have to put them on an external site as I can't for the life of me work out how to upload to the "Gallery".

This is the standard brim with no supports:

2ns066x.jpg

Now here is the same thing with supports (Not that there is only 1 ring of brim).

112fpxg.jpg

If you zoom out a bit, you can see that the 'brim' is now arround the support:

206e7hh.jpg

So to me this looks like a 'bug' in the way that CURA handles a brim.

Jon

 

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Sorry.. I didn't think the brim looked right in these pics.. I just checked my settings and had been playing with the Support/Brim values.

This is what happens with the default settings

dr2ydv.jpg

Clearly more brim on the top.. But its not right.. There is a lot of 'air' between it and I can't get it to stick.. But its nothing like the brim you get when Support = OFF.

 

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Just model in your own supports and brim

Here, I've loaded the .stl file into a rendering program, viewed it from an orthographic font view, took a screen shot, carried the screen shot over to my CAD program and traced the outline to recreate the top. Then I added supports that would support the rings better than a grid. Added a .2mm brim and done.

top2

top3

top4

 

about 10 minutes total time, and I'm pretty sure it will print.

Learning to model in your own brim and supports is a valuable skill to have. I would recommend learning to do so to anyone who wants to really get the most out of their printer.

 

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I hear you.. I obviously plan to learn "CAD" but right now, I am only able to build a simple 'washer' in SketchUp.

But in time, I am going to embrace CAD and learn how to do it.. For now, I am just learning and was trying to understand whether there were any tips to changing how CURA handles such a situation.

Clearly I can either split the model or build my own support/brim.. But to be honest, I have so many things to print in my backlog, I will come back to this one when I have some free time.

That said, since you have added supports/brim, any chance you could share the STL file? Just so that I can have a look at what you added?

Jon

 

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