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jenschr

100% infill?

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Hi,

Cura is fantastic, but I have a question/bug for you. 100% infill is quite far away from 100%. Have a look at this picture:

Cura_underextrusion_at_100_percent.png

This is a print of my Raaco storage compartments that has been set to a Shell thickness of 4.8mm and 100% infill. It's printed with ColorFabb's XT material that looks almost transparent when fully filled in.

Looking at the picture, you can see that 4.8mm in along the edges, it's quite transparent. When it comes to the part that is filled in (along the bottom) it is VERY clear that 100% is really more like 60% or something?

If I crank up the flow rate to 170% it starts to look somewhere near correctly filled, but that ruins the dimensions as it's depositing way too much plastic along the outlines.

So my question is - isn't this a bug? If it's like this by design, I would very much appreciate the removal of the 100% infill limit so I can crank it up to 170% ;-)

 

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My guess is that you have your settings such that infill speed is faster than perimeter speed? That would cause such a problem if you were approaching the volume per second limit at your given nozzle temp.

 

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I believe:

It's generally not a good idea to increase the flow of material enormous, because it can lead to unsightly irregularities. I think it is a much Better off to take the average filament diameter, and then the machine to give a slightly smaller diameter material value, maybe 0:10-0.25mm less.

Also, it may help a little, much slower to print, and with a slightly higher temperature.

Markus

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It doesn't matter whether you increase the material flow amount or change the filament diameter a corresponding amount (adjusting the reported cross-sectional area of the filament by the same percentage). Inside the firmware, the net result is the same thing - it just extrudes an additional percentage amount of plastic above what the gcode asks for. In every other respect, it's identical.

 

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I believed it to have experienced a different way, but I would like to specify not there. By simply trying it can be determined to find out.

Markus

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I don't think anything is wrong with Cura - I think you are just underextruding because you are printing too fast or cold. Try slowing down the print speed by 50%. I don't know what kind of printer you have but I think it can't handle the speed you chose. Also try increasing the temperature a bit (warmer PLA flows more like honey. Cold PLA flows like toothpaste).

Or possibly there is an error with your steps/mm for your E axis or you have the filament diameter set wrong in Cura (defaults I think to 2.85mm).

 

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Hi guys,

I'm am not under-extruding. My infill speed is set to 0 and should thus be the same as other infill. There is no visible difference (on the bottom infill of the model) if I'm using 25mm/sec, 35mm/sec or 50 mm/sec. I actually did http://flashgamer.com/arduino/comments/colorfabb-xt-tests. My temperature/speed/flow rates are all fine and I know my Ultimaker original can handle this just fine. After all - it has done more than 3500 hours of printing. As for flow adjustments - I thought it was obvious that I did this just to see how much material was missing. I guess not? ;-)

I am 100% sure that Cura is under-calculating the infill, but you'll only notice this when printing with a transparent material.

If I use Kisslicer or Slic3r the infill looks MUCH better, so this definitely has something to do with how Cura calculates the infill. 100% infill on both of these programs will produce fully filled in bottom with no visible gaps of air like Cura generates.

 

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I am 100% sure that Cura is under-calculating the infill, but you'll only notice this when printing with a transparent material.

And I'm 110% sure it does not.

Did you know the layer-view calculates the amount of material back from the E values, and displays the width of the lines depending on that. Making it a great debug tool for issues like this?

 

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Well, I'm sure you know Daid :-)

It is nice to view the problem in Layer-view, but I still have the same problem, so how can I increase the amount of material on the infill? (As in going beyond what is said to be 100%)

I can post an image of a Kisslicer-sliced print if you'd like to see the difference for yourself? It looks a lot better when it comes to the infill, but not so much in other regards. Cura is much better than KS, but for transparent parts, this is a major drawback.

 

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I took a 2nd good look at your photo:

SdRzjL9.png

This is the side-wall of the highlight you did. The sides are also not connecting up properly, which is an indication that you have a general extrusion issue, not a infill issue.

Might be related to some setting, material or machine. But you do not have me convinced that this is a Cura issue.

Just to compare, this is, on an UM1, printed yesterday, with the latest Cura default settings, with ColorFabb Orange:

http://daid.eu/~daid/IMG_20140429_133454.small.jpg

(Material got tangled up at the last 2 layers, so that's where the tiny blobs come from)

 

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Hi Daid,

That picture looks nice, but it isn't showing any infill at all? From what I can see, this picture shows a normal print with a normally filled in top? The top and bottom fills just fine - also in my picture. In fact - since the top/bottom fills just fine, you cannot really see it in my picture - it's 99% transparent :-)

It's only the infill (i.e. not the top/bottom x layers) that is lacking plastic. Not the outlines or top/bottom. Do you have some Colorfabb XT or any other translucent plastic in the office? You will need to use transparent plastic to actually be able to view the issue. Using transparent plastic, you'll very easily see where there is not enough infill.

 

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If you set the sparse-infill to 100% it internally sets the bottom-top thickness to 10000 layers, causing the whole print being a top/bottom. So, it does not really matter that I looked at the top of a print for this case.

 

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Hmmm.... That is very odd then. How could I possibly get the results I'm getting? I mean - that should use the same amount of material for both outlines and infill. How come there is such a visually noticeable difference AND only on the infill?

J

 

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jenschr you post quite the puzzle! So the sides look good if you look carefully but in your picture they look bad because we are seeing the infill *through* the sides?

Before I read that I thought maybe something was wrong with your Z axis and your Z axis was moving more than you thought and that was causing underextrusion but it sounds like the sides/top/bottom are fine but the middle isn't.

I guess you need to post a few things for us. Please "save profile" and then post that entire text file here. Also please put your gcode file somewhere on the internet so we can download it and look at it with tools that measure the amount of extrusion on the inner layers and line seperation.

 

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Sure. Here are my Cura settings http://flashgamer.com/a/infill/colorfabb_xt2.ini and here's a couple more images.

IMG_0843_infill2.jpg

As you can see from this one - the walls are quite transparent. If something like this label is pressed against it, you can read it quite easily.

IMG_0843_infill1.jpg

At the bottom, it's much harder to read since there is not enough infill - creating reflections.

IMG_0843_infill3.jpg

When held up against the light, it's more easy to see the difference. The infill refracts more, due to the air gaps.

I'll switch to a yellow translucent PLA now and see how that works.

 

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Ok. I feel like I'm not being believed here, so I've made a very simple test. It's a 25x25mm square with rounded corners printed with three different settings for the "Shell thickness" (0.8 - 6.0 - 13.0), infill set to 100% and 35mm/s print speed.

It should be quite obvious from these images what my problem is:

IMG_0847_infill1.jpg

Just in case someone thinks that rotation matters (other than for the reflection that would be equal):

IMG_0847_infill2.jpg

Can we agree that the first does not look like it has 100% infill? Please?

 

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Can we agree that the first does not look like it has 100% infill? Please?

 

They all don't really look like 100% infill to me...

 

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Right...

So - how do I get "100% infill"? What is wrong with the settings I posted - or is it something else?

http://flashgamer.com/a/infill/colorfabb_xt2.ini

Test file posted here: https://www.youmagine.com/designs/rounded-square

Here's an image of this box next to another box I made back in August 2013, probably using Kisslicer but it might have been Cura also. Notice how you can see the internal divider walls of the Kissliced one? I happened to jot down the settings I used as well on the box itself, so 50mm/s at 100% infill.

infill_kisslicer_old.jpg

 

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I wont get into the 100% infill thing but that the transparency differs doesn't seem that strange to me. In one case you have perfectly stacked lines next to each other which makes them easy to see through. In the other case you have lines "randomly" crossing each other causing massive amount of refraction so you can't see through it.

 

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So if I ignore the pictures of sets of 3...

There is an earlier image of the part you are printing - it looks kind of like shelves. Each shelf I assume is unsupported except on the edges. What happens is when you start printing the bottom of the shelf the filament droops a little so that the next layer up is higher above the previous layer. I've had this happen before. It typically takes maybe 10 layers to finally catch up except your shelf ends before it has a chance.

If you print this so that the shelves point vertically I think it will come out much clearer. That way you don't have any unsupported printing.

Now to the pictures of sets of 3 - I'm not sure what's going on here - this is totally different - but I tend to agree a little bit with Robert that it's just the pattern and not underextrusion but... then it should look quite a bit different from your shelves. Does it look not as bad as the shelves?

Anyway try printing your shelves with the open end down (or up) so that the shelves are vertical.

 

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I agree that the infill does look somewhat under-extruded... but equally, I agree that the opacity could just be due to refraction from having lines running at 45º to one another, rather than stacking up neatly on top of each other.

I looked at the gcode: I took a snippet of code from the bottom layer, a middle layer, and the top layer, in a section like this where the lines are running at 45º to the walls, and ending on lines that are parallel to the axes:

100% infill gcode

I used my gcode spreadsheet to check the lengths of the lines, their separation, and the the amount of plastic requested for each line:

Gcode for 100% infill

 

On all three layers that I looked at, the infill lines are exactly 0.4mm apart, and the amount of plastic asked for in the gcode is exactly correct for the length of line, and the layer height (which is 0.3mm for the first layer, and 0.2mm for the rest).

 

Whatever, may be causing the effects, the gcode is exactly correct.

 

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@gr5 There's no unsupported layers. These are the models I am printing http://www.youmagine.com/designs/thin-components-for-raaco-storage The infill is on the print-bed, so nothing hangs.

@illuminarti Yeah. I'm sure that @Daid is right about the calculations being correct, but it still does not look correct.

All I want is to have parts that are as transparent as possible and I want to be able to do this with Cura since it's my favorite slicer ;)

 

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If the "wrong" infill is the side laying on the bed isn't this more of a bed levelling issue? Just asking?

This plus the fact that the resolution of Z is better than X and Y could be the reason now?

If i say something stupid don't hesitate to throw me rocks ^^

 

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