Feb 6, 2015

Slicing Software matters in 3D Printing - Cura vs Slic3r

NOTE: Post Updated (5 weeks later): I've found parameters to make CURA slicing very consistently successful - mostly thanks to the folks at LulzBot who sell great filament and provide great filament profile/config files for CURA - but also after a bunch of experimentation. I've been using CURA exclusively now and while I tweak speed and top/bottom layers on different models for different needs, I have not had a fail like the one pictured in this post since writing the original post... but leaving the post here for historical purposes.
Original post follows:

I discovered that Lulzbot seems to suggest CURA as their prefered Slicing app for generating gcode files for 3DPrinting (gcode is the language that many #3dPrinters understand). I was initially using Slic3r because that's what the Lulzbot TAZ4 manual pointed me towards. Since I'm just starting to understand the basic controls I have in Slic3r, getting a taste of CURA was a great experience - to see how it exposed and set different parameter versus the way Slic3r did.

CURA model on the left, SLIC3R on the right.
At first, I thought I had discovered gold - since one of my models generated GCode much (much!) faster than Slic3r and then the generated gcode printed extremely fast. My second try also showed improvement - printing the CURA gcode in almost half the time on a small model - and the quality was quite good.

Then I tried a new and very different model. Still very simple - some geometric shapes extruding up off a rounded courder rectangle. Sure - it happened to be the Google Classroom logo - but it's a simple one. This is where CURA not only fails me so far, but perplexes me. The top layer is practically not completed - and there is actually a shape missing. Check out the image here comparing the CURA print to the Slic3r print. See the missing shape? (it's a chalkboard eraser, by the way). The SLIC3R model is by no means perfect - I have some work to do figuring out why the top layer has gaps - but it's still much better than what CURA produced.

I still have lots (LOTS) of experimenting to do - but for now, I can see that I might have to start digging into the gcode to see what's going wrong.


  1. Do you have a link to the STL file? I've been using Cura on my Bukito without any issues.

  2. Is this PLA? Did you have the cooling fan enabled? Your slic3r one looks to be underextruding. I'd increase your flow by 5-10% and keep increasing until the gaps on the top just start to file in.

    The cura one looks like the filament was way too hot (either no cooling fan, or the wrong temp).

    I found a png of the google classroom logo, converted it to svg online and did some extruding in FreeCAD. My print, sliced in Cura, looks like this: https://www.dropbox.com/s/5bcz9ksa59ivg1r/IMG_20150210_193301.jpg?dl=0

    I need to bump my flow a bit (I had it set up for a different color filament), and each brand/color may need slightly different flow rates to get really good prints.

    You may want to take a look at http://reprap.org/wiki/Triffid_Hunter%27s_Calibration_Guide

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