smoothing out loops


here is a photo of a first layer for an object:

As you can see, first couple of loops are good, (the outer ones), but when it starts going towards inside, they seem to shrivel or something like that.
Is it a temperature problem? My bed temperature changes during the first layer, from 110c to 90c.
It happens on a lot of my prints, during the first layer. Then it inherits the mistake for some time, and gradually fixes it.

Generally, the first layer adheres great, but those extra loops I add to skirt and brim seem to become less transparent as the primary ones. Is it possible that previous loops cool too fast, and they are not connecting well?


It’s not something you should worry about. Some Slic3r versions have different characteristics, and may handle inside circle surfaces a little bit differently. You may also want to use a slightly higher first layer homing height. Rotate the Z axis enstop trigger by a quarter turn or two.

Thank you for the reply,

Even though you say I should not worry, I would like to understand why does that happen.
It would be good to understand how things work, so if someone can point out some facts that would be great.

Do I expect too much of the machine, and I should let it correct it’s own mess?

Apologies for my bluntness, but I want to establish full control and understanding, one day, at least…


Your first layer height may be too low. The extrusion may be too wide, because the gap between the nozzle and the bed is lower than it should be (potentially), so the excess material has to go somewhere, in that model the excess material would collect on the inside diameter. Try the suggestion above to see how things are improved.

Well, it seems that you were right. The trick was to adjust the relationship between the Z endstop and the extrusion width.
What I don’t understand is the Config we got from lulzbot, which have extrusion widths for some elements (infill, etc.) as thick as 0.6mm. How is that possible, because the nozzle is 0.35mm diameter. It shouldn’t be able to extrude more.

Anyhow, I will play with these settings now to see the differences. Thank you for the help

While the nozzle diameter is 0.35mm, the filament can have a larger extrusion width, when the filament is extruded into a smaller gap (nozzle > bed or nozzle to previous layer). The extruded filament has to go somewhere, so it’s squeezed out the sides, much like spreading jelly on a piece of bread.