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dree

Leakage

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Hi,

I try to print this but it’s leaking.

The walls of this amphora are 2 mm thick.

The print is good and looks strong and beautiful, I printed a few that were not leaking and a few that are, what is the trick?

Ever though I print PLA at 230 C it still looks like the plastic is not fusing together good enough.

(see earlier post)

Should I go even hotter?

Should I lower the fan speed?

What can I do?

Print Options

Shell thickness/bottom-Top 1 mm

Layer height 0.12 mm

Fill Density 100%

Temperature 230 C

Filament 3.00 mm

Print speed 50

Brim only, no support.

2013-10-28153053_zps28577844.jpg

Groet Dree

 

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I don't know much about this subject. But I do know that Joris, who is the expert on making cups that don't leak, uses a thicker nozzle. The Ultimaker has a .4mm nozzle diameter hole. He uses larger - I think .8mm or 1mm maybe. I found it is easy to change the nozzle (make sure you heat to 180C first and be careful not to destroy the brass - be gentle) and they are very inexpensive online.

Hopefully someone else has more information than me. Or try google.

 

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Oh - instead of 100% infill, try setting shell thickness to a high value - for example 200mm. This might give you a better pattern of infill.

Or instead consider modeling this in CAD with a top and slicing with shell thickness an integral number of .4mm diameter passes e.g. 2mm and unchecking "solid infill top". Or is that what you did?

 

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Hi,

To me there are three main reasons for leaking:

- leaking through bottom: infill is not dense enough / bottom thickness to low

- leaking shell: underextrusion / bad layer adhesion

- leaks between bottom and shell, which I find is the most difficult issue

First and second are relatively easy to fix. Actually, if settings are fine even shells with a single outline are watertight.

But I am frequently fighting the third issue. My suspicion is that even the lightest ripple in the top-most layer of the bottom impedes a watertight fusion with the perimeter lines on top of it. Recently I played two days with slicer settings and even two nozzles (0.4mm and 0.7 mm) to get double-walled espresso cups watertight with Coforfabb XT filament - and failed. If the bottom/shell detail is under your control, adding a fillet and using more perimeter lines might help.

But there should be some expert advice available here ...

Markus

 

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Hi,

Thanks for the quick responses, I try to show two things in one screenshot, the thickness of the bottom is the whole foot and that I designed the amphora as it is, already hollow.

I will try Gr5's infill trick, if I set the shell thickness to e.g. 200mm, should I leave the infill to 100%?

EDIT: I will also try to reduce layer height to 0.08.

But I am afraid it's leaking right between the bottom and the shell, Markus' option 3....

Amphora3_zpsdebff74c.jpg

Dree

 

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... perhaps also temporarily increase the flow rate when the bottom is almost finished and the shell starts.

Or even increase layer height: the lower the layer height, the lower the "reserves" to even out any ripples beneath (just a theory so far).

Generally speaking, it looks like the problem has to do with the viscosity of the filament and its gap-filling properties. For instance, yellow and green PLA/PHA works fine while XT drives me nuts (despite producing a very good looking surface).

 

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Well, I had the same thing with a few of my vases. The most important thing (ofcourse) is that the extruded lines are touching each other. If that is not the case, then it doesn't matter how much your bottom height is, it will always be leaking. But if the lines touch, 1 mm bottom height is more then enough. I think it's just a case of increasing the flow a little bit so the bottom lines are nicely squeezed next to eachother. You can try to do it manually, so when printing 110% flow for the bottom and then set it back to 100%.

 

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EDIT: I will also try to reduce layer height to 0.08.

 

I really doubt thinner layers is better. Thinner layers are more sensitive to errors in your Z-height so you can get layers that are a little too thick or too thin. If anything I would go to .2mm layers.

The idea of increasing flow makes much more sense to me. When I was doing another experiment I increased flow dramatically (200% at one point) and it helped that project but that project had nothing to do with water tight.

Again, I've never done something waterproof so I would listen to BaasB and foehnsturm.

 

 

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Ok, I will try the Fr percentage on the Ulticontroller to 110% for the bottom and the dangerous part until its up to the walls.

Tomorrow results for that.

Dree

Edit, I will stick to my 0.12 layers gr5, keep on this topic and it makes you a specialist on water tight things.. :)

 

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Hi,

To me there are three main reasons for leaking:

snip

even shells with a single outline are watertight.

snip

a using more perimeter lines might help.

 

Hi Markus, please excuse my inexperience.

What does a "single outline" mean?

What are "perimeter lines"?

Cheers, Pete

 

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Fr percentage on the Ulticontroller to 110% for the bottom

 

No! Not feedrate. Flow. Once the printer starts printing there is a new menu called "Tune". Go to that menu, scroll down to "flow". And increase that. I would go to 125% as a minimum. 110% isn't going to make much difference.

 

What are "perimeter lines"?

 

Single outline and perimeter lines are how many passes you get for your wall. It's actually called "shell" in Cura. A shell of .4mm means it makes one pass with the .4mm nozzle. 2mm would be 5 passes.

 

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No! Not feedrate

Ow :oops: I thought I tell what I do.... afin, I probably can trow away the amphora that is almost ready now...

I found the Tune menu with the Flow thing, is that the same flow I see in the Cura menu?

What does FeedRate do?

Dree

 

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Well, the Fr didn't help indeed… :shock:

Now I made a small amphora for testing but I made a mistake, I thought I made the walls and bottom 1mm thick but they are only 0.5 mm. Printing the whole thing with a 125% Flow, while it’s printing I see a lot of blobs already from over extrusion I think.

That was not a success, only the bottom and top cm are looking good but the bottom is not leaking, there is hope… Strange thing is that with the bad middle section the printer didn’t go round and round but acted more Parkinson- like, probably due to the thin wall. Maybe it’s better to take the 0.4 nozzle in account by designing a wall, E.g. 0.8 - 1.2 - 1.6 - 2.0 thick?

2013-10-29125039_zpsa3617b28.jpg

Then I made one with 1 mm thickness, printed the whole thing at 110% flow.

Print was better, some blobs on the inside from over extrusion.

Still leaking from two small holes, strange.

2013-10-29144823_zps25188480.jpg

Then 1.5 mm thick wall and bottom.

Only 110 flow for the bottom this time to prevent over extrusion on the wall.

No more blobs, no more leakage on that one :-P

2013-10-29162015_zps72764ae3.jpg

Dree

 

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fr/feedrate... It's the X,Y speed.

First understand that before there were 3d printers there were milling machines. Feed rate was basically how fast you "fed" the material to be cut through the cutter (router/milling bit).

In the Ultimaker, Feed rate is the speed of x,y,z or e axis (e is extruder axis). In practice movements use tiny E and Z movements but large X,Y movements. So the speed of X,Y is the limiting factor for feedrate. So typically people print at 50mm/sec or 100mm/sec. That is the feedrate.

The feedrate on the ulticontroller (or in Cura print window) increases or decreases that speed (the XY speed).

If your feedrate is 100mm/sec, the print head can actually move up to 141mm/sec in a diagonal as the feedrate is the maximum speed for the 4 axes taken individually.

 

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So basically the FeedRate speeds up or slows down everything, thanks for the explanation, I wont touch it again, I print at Cura default speeds and have no desire to go quicker or slower.

The confusion was made by some lazy brain cells of mine that translated Fr into FlowRate :-P

I'm now starting up the initial project with my new learned skills, tomorrow news about that,

To leak or not to leak will be the question...

Dree

 

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Two things...

1) there's absolutely nothing magical about Cura's 'Default' speeds. They just had to put something in there to start with. I'm not even sure what the default is... but you should know, be aware of it, and be willing to consider changing it if it helps you get better results, or the same results faster :smile:

2) Actually, I think George isn't quite right on the maximum feed rate... the requested speed IS the speed that the head moves in a straight line in space, not per axis - it calculates the total distance (allowing for any diagonal component) and then uses the requested speed to calculate the time the move should take. So if you have a 100mm move at 45º, i.e. 70.7 mm each in X and Y, if the requested speed is 100mm/s, it will take 1 second to make the move (ignoring acceleration).

(Maximum speed, acceleration and jerk settings ARE applied on a per-axis basis, but the actual basic speed calculation uses speed over the straight line distance).

 

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Print of last night is still leaking were the bottom meets the shell :mad:

Further tests will be with more than 110% flow in that area and with another color filament.

But for now I’m going to do some other prints.

Dree

Edit:

For the next try I changed the design a bit, I lowered the inside bottom, the botom is now no more the whole foot thick but maches the wall thats 2 mm.

Amphora4_zpsc4e5f31d.jpg

 

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Hi,

Last night I had success :-P

I started with 125% flow and I forgot to put it back to 100% so the whole project printed at 125%.

Now the question is; was it the changing of color filament that made the trick or the changing of flow?

Foehnsturm mentioned that color can make the difference?

Is that so?

I mentioned in the opening post that sometimes the print is leaking, sometimes not, I buy my PLA with Plastic2Print, I had success with the dark blue both are "ultimate" same 0.75 kg spool.

The leaking orange (no more available) ones are on 1 kg spools it looks like another brand.

Is it just the color or the brand that causes difference in layer adhesion??

Dree

KanBlauw_zps15917a1d.jpg

 

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Congratulations!

As far as I know, coloring is done by putting some additives into the plastics blend. Besides their color, those additives differ in various other properties as well. An unwanted side effect, which manufacturers try to minimize.

 

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Thanks,

After this success I also sent the manufacturer of the filament my last post and a link to this discussion, they replied very quick, seems that some filament I bought from them was not 3.00 mm but actually 2.85 so by giving extra flow we accidentally solved that mistake.

It looks like a beginners error of mine but in the extensive specifications of that filament it's also 3.00 so I think it's a mistake of them.

Next test will be with the right thickness settings and no extra flow.

groet Dree

 

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In Cura there is a spot where you can enter the filament diameter. What did you have there? That affects the flow also in the same way.

So if you enter 1.414mm you will get twice as much flow as if you enter 1.00mm because flow is proportional to the *area* of the filament (pi * diameter).

Anyway I believe that should default to 2.89. The difference between 2.89 and 2.85 is minimal.

If you don't have them, buy some calipers that are accurate to .01mm and measure the filament often.

 

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In Cura there is a spot where you can enter the filament diameter.

i'm aware of that and I understand it's effect on the flow, I just had thinner filament than I thought so I had a wrong number there.

Dree

 

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Manufacturers pretty much never tell you the actual diameter of the filament that you have. Anything that is labelled '3mm' is usually just shorthand for this general category of sizes. The target size they were trying to produce is usually less - usually 2.8 - 2.9mm - and then the natural variation in the production process can affect that still further. So even if it's labelled with something more specific, that may not be applicable to the section of plastic that you actually use to print. So for something where extrusion amount is critical, it's best to always measure the filament with calipers. Remember also that the filament is rarely truly round. So at each measurement point, take two measurements at right angles across the diameter; do this at several places, and then average the values.

Also bear in mind that when you're actually forcing plastic through the nozzle to print it, that raises the pressure in the print head. This pushes back on the filament, making the extruder work harder, and can easily result in the extruder not pushing the filament effectively as it should. This by itself can reduce extrusion between 5% and 25% of the requested amount, depending on the volume of plastic being printed every second, relative to the head's maximum capacity. So, setting a deliberate 10% over-extrusion probably won't cause anything bad to happen to your print, but certainly might help with sealing the layers.

 

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I just had thinner filament than I thought so I had a wrong number there.

Well the difference between 2.85 and 3 is 11% so like you said, adding 10% to your flow was about the same difference as putting in the correct filament diameter. Interesting.

 

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Manufacturers pretty much never tell you the actual diameter of the filament that you have.

Mine just did by email and pretty quick too and he's going to change the values on the website, now all their 3 mm filament tell 3.00, they are going to change that into 2.85 and 2.95, they sell two different 3 mm filament.

If that are the right dimensions than the rest is theory for me, and if I have trouble again in the future with the right filament thickness settings I know what to do :)

@Gr5 Interesting indeed, funny actually how we came to the right conclusion...

Dree

 

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