First layer / callibration issue (Prusa i3 - Slic3r)

Hello,

I am in the process of tuning my newly built Prusa i3 and I have some issue finding the right parameters to tweak in order to fix some issues with the infill of my first layers.

I am using Repetier firmware/host and Slic3r 0.9.10b.

The basic calibration seams quite ok and I am getting very usable parts but my first layers often look quite ugly. Here is a picture of the first layer of a test object:



It looks like too much plastic is extruded and with each pass the head scraps a bit of plastic and creates some ugly blobs. The second layer is better but does not really cover the mess:



Later in the print everything seems ok:



And the top layer usually turns out not bad:



At some point I have been playing with the nozle diameter in Slic3r to fix the issue and I got slightly better result by setting the nozzle diameter to 0.32mm instead of 0.4mm but it was not perfect and I suspect that this is not the right way of doing it.

I have been playing with:
1/ Leveling the print bed.
2/ Setting a slightly bigger height for the first layer.
3/ Changing the print temperature.
4/ Changing the extrusion width and playing with the advanced "extrusion width" parameters.

None of those experiments did give me very good results and I am not sure how to proceed and what to try in which order :-)

I am now running with nozzle diameter 0.4mm (which corresponds to my nozzle), my filament settings are set to default with a 1 extrusion multiplier and I have put back my extrusion width to default.

Let me know if you have ideas or links on how to troubleshoot the problem and tune the parameters!

Cheers!

Franck

I have the exact same issues on my prints, first layer seems way too much material, I have adjusted the print height, flow rate, and tons of other stuff. I have yet to figure it out.

---

Ryan
Quality Engineer & Hobbyist
thingsandtrains.blogspot.com

Yep I had that problem, trouble is I can't remember exactley what I did to sort it (have had to mess about with so many other things over the last week or so, memory gets hazy)

I played with extrusion widths (Solid infill, Top solid infill).

I also calibrated using the 5mm thin wall, and setting the extrusion multiplier for the layer height your printing at. See Slicer Calibration (note I didn't use the calibration object in that link, I just used the 5mm thin wall, I don't think it matters which version you use)

When I bought my Prusa I3 I was told to get version 0.9.9 of Slic3r. Apparently the newer versions cause this problem with my makerfarm kit. I'm a newbie to printing though so its just my 2 cents.

I have a prusa i3 with a JHead.

I use CURA (free and fast slicer) and I am very happy for the moment.
[software.ultimaker.com]


For a beginner like me, there is a profile for the i3 and there are less parameter to tweak. So it is easier to not make too many mistakes in the parameters and it give really decent prints

Cheers,
Régis.

I had the same issue and fixed it by changing those "advanced" extrusion widths you mentioned. The default width for the first layer was 200% (of normal extrusion width). In my opinion this should be set to 100%, or slightly more if it's really necessary.

I have the same problem, and I'm still looking for a solution.

Lower your speed and either reduce your extrusion multiplier to at least 0.9 or set your first layer to close to same as printing layer.

But with just printing first layer half the speed of printing speed most of the lines will be gone.

I also have seen this on my prints, when I lower the bed a tiny bit more it stops doing it, not a final solution but it works mostly. I always see people reference a piece of paper for nozzle spacing from the bed when leveling it, I found that to be to close, I have been using a 10 thau shim from my spark plug gap measurement tool and it is pretty dang close to where I want to be, I usually tweak the height a tiny bit higher once I see the print look like yours to make it go away.

ya, i have basicaly the same problem. Just cant get Z to go down below zero at home posistion
i can change the z offset to -1 or sobut does not move. No i am not using bedleving function, just manual endstop
am i missing something in my code?
thanks

Quote

Just cant get Z to go down below zero at home posistion
i can change the z offset to -1 or sobut does not move.

If you have a physical switch endstop and you went below it you run the risk of breaking the switch, misaligning Z motors and such. So yea, negative Z setting is probably prevented by firmware to keep from destroying stuff.

Franck. Looks like first layer extrusion is too high. Look under Print settings/advanced and see if first layer extrusion is set to something other than 0, Sometimes people set this high to help with adhesion but too high can cause overlapping first layer that just gets messy. Also make sure your first layer is set around 50% slower than the rest under Print settings/ speed.

Quote
tmorris9
Franck...

Franck posted his question 2 years ago. He probably either figured it out by now, or gave up.

l have this kind of problem, cannot get a nice finish bottom layer. Top layer however gets nice !

[www.dropbox.com]
[www.dropbox.com]

How to get bottom layer with same quality has top one ?
With no visible lines...

Hi, I had the exact same problem, and believe my issue was bed levelling. I thought I should share with you why:

Here are the things that I tried, that did not work:

• Setting extrusion widths
• Lowering Infill/perimeters overlap
• Changing layer heights
• Vary temperatures

Although adjusting these settings sometimes change the appearance of the print, none of them reduce the amount of plastic deposited. Unless you decide to reduce the overall extrusion rate, Slic3r simply does not seems vary the amount of plastic extruded, just the manner in which that same amount is deposited.

The real problem actually turned out to be improper bed leveling: after auto leveling, the printer would always lay down the first layer closer to the bed than expected. So when I used a first layer height of 0.4 mm, it would place the nozzle at a 0.3 mm distance from the print bed, making the first layer - and a number of successive layers - appear over extruded.

The best way of solving this is probably to recalibrate the firmware settings for bed levelling; however, a quick fix for this (and a good way to experiment with this) is to adjust the Z-offset in Slic3r. In my case, I found that setting a Z-offset of 0.10 mm would move the nozzle just enough upwards from the bed to no longer generate scars on the first layer.

Hope that helps someone!

Edited 1 time(s). Last edit at 01/09/2016 11:08AM by tormodhau.

Yes bed leveling is most important. A steel frame, with rigid triangular braces, and a glass plate with a silicone thermal pad on each corner, works great.

Quote

The default width for the first layer was 200% (of normal extrusion width). In my opinion this should be set to 100%, or slightly more if it's really necessary.

I set mine to 250%, and I have two glass plates of different thicknesses; I can swap the plates and the thick first layer will absorb most of the difference in height.

Had the same issue, tried a few things and dropping the bed did the trick for me.