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sydneydesigner

Thinnest vase wall?

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G'day from Sydney again.

Suppose you are printing something like a vase (vertically - i.e. the right way up).....and I know some of you already have!

If you want both the outside and inside of the vase to be good smooth finishes, how thin can the vase wall get to, with the Ultimaker 0.4mm nozzle?

For example, could the vase wall be 5mm thick at the base tapering to 0.5mm thick at the top lip, and still give smooth outside and inside walls? If not, then what is the thinnest that the top lip can be?

Would it be best to print the vase solid throughout, or with some sort of fill (up to a certain minimum wall thickness of course)?

Thanking you in anticipation....

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I'm not sure about the angles on the vase, but if they are small enough you might be able to print it with just 1 line of 0.4mm thick. A smoother finish requires thiner layers really, not much else.

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Thanks for your help. I don't think I phrased my questions well enough so I'll have another go.

With a UM with a 0.4mm nozzle, suppose you are printing a vertical tapered wall 10cm high where you want a good smooth finish on both sides of the wall. Could the wall be 5mm thick at the base tapering to 0.5mm thick at the top, and still give a good smooth finish on both sides of the wall, all the way up to the top?

The basic issue that I see, is that the 0.4mm wide extrusions for each side of the wall will start to bump into each other when the wall gets to around 0.8mm thick. Any thinner and I can't see how both sides of the wall would have a good smooth surface finish. But maybe I am missing something.

What wall thickness do people think would start to loose surface finish quality on one or both sides of the wall?

Would it be best to print the wall solid throughout, or with some sort of fill?

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So I made a wedge with a 10 mm base to a razor edge, 70 mm tall and sliced it with Netfabb. I haven't printed it but I looked and the simulation and looks like the wall slowly comes together until it stops infilling and for a few layers does a hollow section with just an outline. Then it looks like the outside and inside contours but against each other and then overlap until it only traces a single line, interestingly it does that for only a few layers then stops short of the intended height of the object for several layers, I assume the wall thickness is less than .4 at that point (or whatever the width of a smashed flat .4 extrusion is) and so it just doesn't place any plastic. I doubt there would be much noticable difference in the wall surface, but the height might not be what you intended, nor as razor sharp.

-b

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So I made a wedge with a 10 mm base to a razor edge, 70 mm tall and sliced it with Netfabb. I haven't printed it but I looked and the simulation and looks like the wall slowly comes together until it stops infilling and for a few layers does a hollow section with just an outline. Then it looks like the outside and inside contours but against each other and then overlap until it only traces a single line, interestingly it does that for only a few layers then stops short of the intended height of the object for several layers, I assume the wall thickness is less than .4 at that point (or whatever the width of a smashed flat .4 extrusion is) and so it just doesn't place any plastic. I doubt there would be much noticable difference in the wall surface, but the height might not be what you intended, nor as razor sharp.

-b

Many thanks for this. I'm particularly interested to learn about the quality of both walls when the outside and inside contours butt against each other and then overlap as you say.

Has anybody actually printed anything like this and got a good result on both surfaces?

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I haven't but in general, I don't see why you couldn't get good surfaces on both sides..

The only real issue is the z blob - the tiny bit of extra plastic you sometimes get when things move to the next layer. Usually people with skeinforge hide the z blob but having the slicing software do layer changes on the interior of the object and if there is no interior, it's gotta be on the exterior.. You could probably minimize this using reversal or something - I haven't really done many vase-like things so can't comment on how hard it would be.

You know this part of the object would be pretty fragile, yes?

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Thanks ddurant. Not having a machine yet, I'm sure how fragile a 0.5mm wall will be? In PLA would it be very easy to snap with your fingers? Would ABS be a lot stronger?

The bit I have difficulty getting my head around is when the wall is (say) 0.8mm thick. Then presumably the 0.4mm nozzle does the left side of the wall for one layer and then does the right side of the wall for the next layer .... etc. It seems to me that the central 0.4mm will end up with twice as much PLA as the two 0.2mm wall sides.....so the two 0.2mm wall sides will end up being light on material. Is that right, or does the PLA/ABS just squish out so it all evens up?

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Thanks ddurant. Not having a machine yet, I'm sure how fragile a 0.5mm wall will be? In PLA would it be very easy to snap with your fingers? Would ABS be a lot stronger?

ABS wouldn't be any stronger. The problem is that a layer of a wall only 1-2 threads thick doesn't have a lot of adhesion to the layer beneath it.. If you're talking about tapering quickly from walls that are thick to ones that are thin, that's not too bad. If you're talking about doing it over lots and lots of layers, you're going to have big areas with not much stuff sticking them to one another.

There's probably tweaks you can do to make this better.. Higher temperatures might help since it'll make the plastic more liquidy and get you better adhesion, though there are downsides to running hotter. Wider threads (ie: bigger contact patch) would probably help but that's not the direction you seem to want to go and there are limits to this anyway.

 

The bit I have difficulty getting my head around is when the wall is (say) 0.8mm thick. Then presumably the 0.4mm nozzle does the left side of the wall for one layer and then does the right side of the wall for the next layer .... etc. It seems to me that the central 0.4mm will end up with twice as much PLA as the two 0.2mm wall sides.....so the two 0.2mm wall sides will end up being light on material. Is that right, or does the PLA/ABS just squish out so it all evens up?

In general, I think all slicers treat each layer as a single entity. There are sorta-exceptions to this like 1/2-height perimeters but overall, they're not going to split things up like I think you're saying.

A better example might be a wall width of 1.0mm.. If you do 0.4mm wide threads around the perimeter that's a total of 0.8mm, leaving 0.2mm in the middle. What's a slicer to do with that 0.2mm of empty space? It leaves it empty - not much else it can do..

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The bit I have difficulty getting my head around is when the wall is (say) 0.8mm thick. Then presumably the 0.4mm nozzle does the left side of the wall for one layer and then does the right side of the wall for the next layer .... etc. It seems to me that the central 0.4mm will end up with twice as much PLA as the two 0.2mm wall sides.....so the two 0.2mm wall sides will end up being light on material. Is that right, or does the PLA/ABS just squish out so it all evens up?

I've been printing Paul's Netfabb calibration tubes for a while, and you end up with various 0.4, 0.5 and 0.6mm single walled cylinders. .4 is thin and quite flexible, like a stiff paper rolled into a tube... 0.6mm is already quite strong, and I can see a vase working with 0.6mm walls. 0.8mm would definitely beginning to look good&solid, especially as a single wall (printed from a 0.4 or 0.5mm nozzle), with 0.1mm layer height, giving enough surface to hold on to the previous layer. Joris prints his 1€/min projects at 1.6mm single wall with a 0.8mm nozzle (not sure about his layer height)

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