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I have a LultzBot TAZ 6 3D printer and the software I use for my prints is "Cura LulzBot Edition - 3.6.3". All of my printing settings/parameters are at their defaults (i.e. no personal customization is employed).

Below, two pictures are included that highlight an issue I have observed in many of my prints; these prints are carried out using the "default settings" provided by Cura for PLA. The two pictures are different orientations of the same printed out object; the volume of interest is outlined in red. Additionally, this volume represents the first several layers that are laid down by the extruder.

I am not familiar enough with 3D printing jargon to know if this has a particular name, but as you can see, there is clearly a lack of homogeneity in the laying down of several consecutive layers. Depending on the object being printed, this is not necessarily an issue. However, some of my objects have features that occur near the first several layers and are therefore affected by this issue.

Additionally, some of the these objects are inserted into other pieces, which are designed to be very tight-fitting. If you look carefully, you will see that this lack of homogeneity in the layer deposition leads to bulging of the PLA, which can increase the thickness of the part by ~0.5 - 1.00 mm for several layers. This increased thickness prevents these insertion pieces from fitting into their appropriate locations.

Any suggestions for fixing this issue? Is it an issue of over-extrusion for the first layer that then propagates for a few additional layers? Remember, all settings are at their software defaults for PLA.

First Angle

enter image description here

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  • $\begingroup$ Difficult to see but my best guess is that the first layers curl up hence the next few layers have too less space to deposit the filament and it over-extrudes outside the print part. Maybe you can spare some words on the bed and what you do to adhere the filament to the bed. Note that you also have a ringing problem, your print speed might be too high. $\endgroup$
    – 0scar ♦
    Commented Mar 15, 2020 at 7:52
  • $\begingroup$ @0scar♦ To provide you with the requested information, it's just a standard heating bed that comes with a Taz6 (@ 60 degrees Celsius) and I use a raft. Also, what is "ringing"? $\endgroup$
    – S.C.
    Commented Mar 16, 2020 at 1:34
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    $\begingroup$ Try printing without a raft, rafts aren't necessary for PLA. Ringing is the echoing of edges, see the hole and the waves to the right. Usually printing slower and increasing belt tension fixes this. $\endgroup$
    – 0scar ♦
    Commented Mar 16, 2020 at 6:07

1 Answer 1

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There are several solution you should check in this order :

1"

The part is printed too close to bed: measure the first layer with a digital caliper to mach your first layer thikness, usualy 0.35 mm like so:

enter image description here

2"

Verify that there is no bevel on the first layer if the part looks like this : U make it look like this ■ and see if it changes something.

enter image description here

3"

Maybe it is a cooling / temperature problem. the bed should be at max 70 °C for PLA and check the cooling of the noozle.

enter image description here

4"

Check for an over extrusion problem! When you ask for 100 mm of filament, does it push 500 mm through? If so change this soon.

enter image description here

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  • $\begingroup$ I am looking into "Shell : Initial layer horizontal expansion" right now to get you a perfect first layer. $\endgroup$
    – Thundercoal
    Commented Mar 29, 2020 at 11:45

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