Bottom layer(s) flaring out

Hi all,

This is something I have been battling for a while with the mini. When I was first using the mini with cura, it seems about the bottom 5 layers or so would flair out. I’ve since moved to a different program and have been tweaking settings. Its been a slow process and I am close to getting the bottom layers to go straight up with the rest of the model.

I still have slight flair though on layers 1 and maybe layer 2. I think ive about tried what I can and id like to hear what others have done to correct this and even some insight as to why I am seeing this.

I have tried setting adjustments such as Z-axis offset, first layer height, first layer width and print speeds for all aspects of the first layer. Outline speeds, infill speeds, solid infill styles.

On old prints I could see the first outline of the first layer as a wide line, the following lines would be “normal” width. Ive still got an outline that is slightly wider than the rest of the first layer lines but I am close. Adjusting the first layer height/width to far causes the print to work over its self it seems, like the previously placed line gets partially covered by the new line going down and it starts to peal the print off the bed etc.

Anyways, look forward to hearing what I can try next

Post a couple of photos if you can

Also, what slicer software are you using, and what type of material too. In Cura, two settings you want to look at are Initial layer thickness and initial layer line width. Z stop can affect it, but it sounds like you are on top of that, and also under Expert Settings, Infill overlap. You still are going to need infill overlap to insure good bonding of the outer layers to the shell. That flair is difficult to eliminate, or can be considered normal. Another approach to combat the problem that I’ve seen suggested (but not personally tried) is to add a small bevel or fillet to the design of your print to compensate.

Scott

Typically, the bottoms flaring out would be too much “squash” or the nozzle is too close to the bed for the first layer. But since you’re on the Mini, with the auto-level, the z-stop isn’t adjustable.

This could be the first signs that your wipe pads need to be replaced… in other words, the pad isn’t cleaning the tip enough for good contact. Which may require more pressure from the nozzle to establish a good contact with the leveling discs. Take a look at the nozzle, and manually clean (probably need the nozzle at extruding temp before wiping).

If all that looks good, then a few options:

  • Adjust the Z Gcode offset by .1-.2mm, this will raise the nozzle height slightly at the start of the print… after the auto-level process.
  • If the bottoms are flared only one side, then the X-axis may be out of alignment… check with a ruler that the rods are the same height left and right.

I am now running Simplify3D and I was printing in a solid color PLA. I’ve had the flair nearly eliminated but it would now only show on layer 1. Its really wierd in that if I print a part with 2 outlines, it will print outline 1, the farthest really slow, then pickup speed for outline 2, the inner outline. I cant find in the software where to adjust that, its like its hard coded or something, as its all the first layer it should all be at the same speed. Anyways, ill have to keep trying I guess. Its also weird in S3D in that it starts printing 10 degree’s early each time too.

I monitor every auto level and manual clean the nozzle at around 160 degree before it starts the auto level process. If it ever pushes on the first washer I restart. Something else, I did a test print for someone and they commented, are you sure you are on .2mm layer height, its really detailed. This is the print attached,


I dont know if its just the great detail from the mini or if something else is up and im actually printing in higher detail, more nozzle squish and thus the flaired edges? This was infact .2mm in S3D I know that for sure so…

Not in front of the computer at the moment, but check the speed settings on the last tab. You’re looking for the outline underspeed setting. Default speed is the infill print speed.

For S3D its actually not the last tab, either way, I have adjusted this speed with some results but not a perfect fix. I have been slowing down the outline underspeed but maybe I should speed it up. Bed adhesion is always good so…hmm

0kay its the second to last tab… “Other”.

II find that for detail keep the outline underspeed percentage to equal 2200.

I regularly print at 5400mm/min as a default speed, 40% outline underspeed, solid infill 80% and suppprts at 110%… X/Y at 6000. For a default speed of 4800 bump the outline underspeed to 43%.

I find it weird that S3D starts 10degrees early, but it actually works out. By the time the toolhead mooves to the start of the brim or skirt, the initial temp is only a degree or two off. Also found that I typically need a brim or skirt of about 30mm to ensure the hotend is primed and extruding filament.

For the flaring, add .1 to the Z-Offset GCode in the " G-Code" tab. Sounds like some residue on the nozzle or touch points bringing the nozzle too close to the bed.

Thanks for the tips! I will try some of them out for sure. I also prime with usually 2-3 outlines just to ensure proper flow. As for the Z offset, I have some in there currently. I always watch my nozzle clean and perform my own cleaning once the nozzle cools to 160degrees and just before it does the auto level process. If it ever pushes down to hard I restart

In Simplify3D, under the FFF settings, the options are spread out.
Under the layers tab you can set the general speed for the first layer. Also, you can select weather to print outline direction. I always print from inside out. This will help with printing overhangs.
Under the Other tab, you set the Outline Underspeed, Solid Infill Underspeed, and Support Underspeed. The Outline Underspeed is the speed of the outer most shell as a percentage of the print speed. These underspeeds have an accumulative effect with the First Layer Speed.
If you want the entire first layer printed at the same speed, set these to 100%. If you want to vary these speeds for different parts of the model, you will need to have multiple FFF settings with start and end settings set. That is done on the Advance tab under Layer Modification.

I use layer modification to have the lower part of a part printed at a lower resolution, then switch to a higher resolution to print the top most section of the part (the top of the part is the ‘show’ side).


Scott

Scott