I am attempting to print an axial fan blade, and due to the size requirements, I have to angle it on its side (despite only being 7.44 inches in diameter...). I am using an Ultimaker 3, which I thought was able to print 215mm (or 8.46 inches). This leads me to two questions:

Question 1: If my diameter is only 7.44 inches, why am I unable to lay the fan blade flat (see below - notice the dimensions are within the bounds)? Fan blade cannot be laid flat

Question 2: What is so wrong with the surfaces in red that Cura cannot print, even with supports? I am using PVA as a support material, yet there is something wrong with my model in Cura. I checked the X-ray view and nothing seemed amiss. enter image description here

  • $\begingroup$ Change your Support Z Distance to match your layer thickness and see if that helps. This is a guess on my part, but thinking there needs to be something set there (mine has a set distance of 0.1mm on a 0.1mm layer thickness). $\endgroup$ Nov 12, 2018 at 21:05
  • 1
    $\begingroup$ SE websites are driven by questions and answers, your question contains multiple questions which makes it more difficult to answer as there are multiple answers. Please split up your question by adding the other questions in a separate question! $\endgroup$
    – 0scar
    Nov 12, 2018 at 21:57
  • $\begingroup$ @0scar moved this to meta 3dprinting.meta.stackexchange.com/questions/368/… $\endgroup$
    – StarWind0
    Nov 13, 2018 at 20:40
  • $\begingroup$ What is the status? Your second question is unclear, it would be best to copy it into a new question where people can ask you what you mean with "cannot print", e.g. have you tried printing it flat or upright? You can use extruder 1 as support extruder, the bed will be larger then. $\endgroup$
    – 0scar
    Nov 15, 2018 at 7:22

1 Answer 1


Ultimaker Cura print bed size sizes (shrinks) when you enable skirt, brim or raft build adhesion options. Try to print without build plate adhesion option if you want to push printing to the limits of the build plate. Furthermore, you mention the use of PVA, using 2 cores, the priming print tower also needs space to be printed, this can be also limiting your build plate space. Note that you can define where to print the tower, you could try locating it in a corner where the fan does not reach.

From your screenshot with the fan flat it appears that you have selected dual extrusion. Note that the bed size depends on the amount of cores you use, from Ultimaker:

Left or right nozzle:
215 x 215 x 300 mm
(8.5 x 8.5 x 11.8 inches)

Dual extrusion:
197 x 215 x 300 mm
(7.8 x 8.5 x 11.8 inches)

As an example I have made a 7.44" cylinder of 2" height and put it onto the UM3E build plate to show the differences when you use dual extrusion.

This image shows the cylinder when printed with a single core: Single core build platform size

This image shows the same cylinder, but now with enabled "Extruder 2" as the "Support Extruder" option: Dual core build platform size

Having an Ultimaker 3E myself, printing PVA might not be very good choice as you need to print a lot of support material when printing upright. PVA cooks easily even in the B core, it also needs to be very dry, PVA takes up moisture very fast and becomes useless after that. At work we have much better experience with break-away support material.

Another consideration why you should not print this upright is the orientation of the layers. It is generally known that the layer to layer bonding is less strong that the material itself, it at least provides a lot of notches from which cracks can initiate and grow. This means that if you want to print this, you should lay it flat, this way the centrifugal force is in line with the layer deposition direction.

With the correct layer height (read thin layers), you should be able to print this flat without support. I have printed similar structures like turbo turbine wheels with similar overhangs without support.


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