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I find when printing with supports there will almost always be cracking/warping where the object intersects the support material (i.e. the areas that needed supports). Is there a way to avoid this?

Here is an example of one of my first ever PLA prints that exhibited this behavior. As can be seen, the top part printed fine; the bottom part that had supports attached--not so much.

enter image description here

enter image description here

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  • $\begingroup$ Whta material/temperature/settings are you using? How does the part looks like? Add a picture, if you can! :) $\endgroup$ – mac Feb 11 '18 at 17:14
  • $\begingroup$ @mac Sorry for the delay, am a little under the weather. I've thrown out all examples, but is PLA 190/60/ 50 mm/s, support pattern generated by Cura- type: lines, density 15%. $\endgroup$ – David Reed Feb 12 '18 at 15:11
  • $\begingroup$ are you sure that is really a warping and cracking what is happening? PLA is not really the material that behaves so. Could it be a failed/collapsed support structure instead? $\endgroup$ – mac Feb 12 '18 at 16:00
  • $\begingroup$ @mac Found an oldie. See edited post. $\endgroup$ – David Reed Feb 12 '18 at 17:27
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If I am iterpreting your picture correctly, what you are referring to as "cracking and warping" is simply the irregularities of the plastic where it rested on (and partially bonded with) the support material.

Unluckily, apart from upgrading to a dual extruder printer (and use water-soluble filament for the support) or switching printing technology entirely (e.g.: using a sintering printer) you can only mitigate the problem, but the defects will remain, and will require post-processing to be rectified.

So, in no particular order, here's a list of the most common way to tackle this:

  • Use a slicer that allows you to place support only where strictly needed. I have never used it myself as I am a FLOSS enthusiast, but - at the time of writing - among the mainstream ones only Simplify 3D offers this feature.
  • If your slicers does not support that, tweak your support material settings. In Cura (and for my printer/filament) - for example - it helps using "support interfaces" and leaving quite a XY gap between model and support.
  • Instead of printing your model in one go, print it in multiple parts that you can then glue or assemble together. For example: the spaceship you took pictures of could be printed without any support at all if you were to cut it in half (back and front of the ship, the cylinder connecting cockpit and wings also cut in two).
  • Use a material that can be chemically smoothed. Traditionally that would be ABS + acetone vapour, both of them cheap and toxic, but more recently it polysmooth has hit the market with a safer (and way more expensive) system. This approach will also improve the look and finish of the rest of the print (as also the layer marks will be smoothed out).

Again though... support material marks are sort of part of the game, when using FDM technology, so you should expect some sanding in most prints that required support.

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