Problem with top layer

Hi guys, I own a prusa mendel i2.
have to say it is printing quite nicely but have tried to make bridging work and was unsucessful.
I also tied to print a wing for the 350mm glider and had problems with top layer.

Print parameters:
Nozle dia = 0.35mm
Fillament = 3mm
Hotend temp = 170
Bed temp = 50
Layer height = 0.1mm
Botom solid layers = 2
Top solid layers = 3
Perimeters min = 2
Fill density = 0.25
Fill pattern = rectlinear
Top/bottom pattern = concentric

Speeds:
Perimeters = 15mm/s
Small/Ext perimeters = 10mm/s
Infill = 20mm/s
Solid infill = 20mm/s
Top solid infill = 15mm/s

What happens is that the top layer does not cover the infill, so I end up with small holes in the top layer.
I use a 60mm fan with a custom fan mount blowing onto the print and hot end.
Here is a picture of the wing and I colored the spot around the holes.
I also use the latest wersion of slic3r with the detect bridging function so the fan is at 100% when covering the top.



Any ideas what to change or what im doing wrong?

Which of the "latest versions" of Slic3r are you using. They have 0.9.10b out as released code and 1.0.0rc1 as more or less beta. At least on my printer, 0.9.10b had top layer issues that were fixed in 1.0.0rc1

Hi Dear, try this, change "Top solid layers = 3" to "0.3"

Because your "Nozle dia = 0.35mm", you have to change "Botom solid layers = 2 Top solid layers = 3", you should add a point in front of digit, should be 0.2 and 0.3.

Just try it, good luck

Last time I checked, in Slic3r, the top / bottom / perimeter specs are in number of layers or extruder widths. They enter them with little scroll box windows to try to keep them as integers.

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JNZ
Because your "Nozle dia = 0.35mm", you have to change "Botom solid layers = 2 Top solid layers = 3", you should add a point in front of digit, should be 0.2 and 0.3.

Just try it, good luck

Hi, are you shure this will work?
As far I know the top/botom layer nuber is the nuber of layers.
So in my case i do bottom 2 layers each 0.1mm high, and on top I do 3 layers each 0.1mm

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uncle_bob
Which of the "latest versions" of Slic3r are you using. They have 0.9.10b out as released code and 1.0.0rc1 as more or less beta. At least on my printer, 0.9.10b had top layer issues that were fixed in 1.0.0rc1

Hi bob,
yes I'm using 1.0.0rc1 build, and the difference as far I could see is that the new version detects bridging and enables the fan at 100% for the first top solid layer.
Wich kinda brings me to conclusion that I have innsuficient cooling.

In my case (on certain objects) the 0.9.10b version simply was not putting a top layer into the gcode at all. You could look at it on a viewer and it was notable by it's absence. The 1.0.0rc1 puts the top layers in on the same objects.

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tadejv

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JNZ
Because your "Nozle dia = 0.35mm", you have to change "Botom solid layers = 2 Top solid layers = 3", you should add a point in front of digit, should be 0.2 and 0.3.

Just try it, good luck

Hi, are you shure this will work?
As far I know the top/botom layer nuber is the nuber of layers.
So in my case i do bottom 2 layers each 0.1mm high, and on top I do 3 layers each 0.1mm

I am not sure, just in my experience, i think you can adjust the top layer to 0.3 or 0.5mm. Just my personal experience

When I set a 4 or a in Slic3r for top and bottom layers with a 0.3mm layer height, it prints 4 layers of 0.3 mm. It does not print twelve layers. It may do something completely different when it sees a 0.x number in that field.

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uncle_bob
When I set a 4 or a in Slic3r for top and bottom layers with a 0.3mm layer height, it prints 4 layers of 0.3 mm. It does not print twelve layers. It may do something completely different when it sees a 0.x number in that field.

Tried it, you cannot enter anything else than a whole nuber.

Hmm ok, somewhat fixed the problem with retraction.
I used to retract 4mm@200mm/s
The prints are better when retracting 1mm@40mm/s.
Any idea why?

may be you wanna look in your firmware settings to check your feedrate for the extruder.
but you can also print two sigle walled circels with are spaced to have the printer retract between them (turn off any random settings for this. for example jitter) then you will be able to see where the extruding fails. i bet he restart to week having not the grip he needs on the filament at 200mm/s.

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tadejv
So in my case i do bottom 2 layers each 0.1mm high, and on top I do 3 layers each 0.1mm

I think this is your issue. With just 3 layers at 100 microns, I don't think you're going to get the coverage you want. What happens if you go with 7 or ten layers at this layer height?

Your extruder can only spin just so fast. Anything over about 40 or 50 mm/s is unlikely to work. Your firmware should be set to a reasonable feed limt. If the firmware (not Slic3r) is at 200, I'd drop it down to 50.

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Unless you have a nozzle diameter below 0.2 mm, a 0.1 mm layer height simply isn't going to work for extrusion. It would only work with that nozzle if your bed is level to about 0.01 mm (and thus flat to better than 0.01 mm). Even with auto bed leveling and a fancy bed those numbers will be very hard to hit.

o.0

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uncel_bob
Unless you have a nozzle diameter below 0.2 mm, a 0.1 mm layer height simply isn't going to work for extrusion. It would only work with that nozzle if your bed is level to about 0.01 mm (and thus flat to better than 0.01 mm). Even with auto bed leveling and a fancy bed those numbers will be very hard to hit.

taking paper or wood as print ground 0.05mm layerheigth is working with a 0.5mm diameter nozzel on my mendel.

Edited 1 time(s). Last edit at 12/05/2013 02:29PM by mekmekmek.

Anything under about a 2:1 nozzle diameter to thickness ratio does not work on a glass surface with my printer. With a flexible surface you may have some odd things going on. There simply is not enough force to push the plastic between two hard surfaces that close together. Calibrating your bed so you are *sure* the first layer is 0.05 mm is quite difficult.

Edited 2 time(s). Last edit at 12/05/2013 07:14PM by uncle_bob.