Monday, May 13, 2013

Part orientation and part scaling

Here is an example how the positioning of your model on the print bed can somewhat affect the print quality of your part.
Each print layer has to start somewhere, and it is usually at the front, and sometimes the print layer starting point can be visible.

The Owl that was printed in "Thick" fill was oriented facing towards the front (toward touchscreen) on the print bed.
In this case how the owl was positioned, one side of the overhang of the owl's beginning of the head, was right at the layer print start and it caused a "droop" of the filament.
See picture below.
I printed the Owl again but had it rotated 180 degrees on the print platform (z-position), so the owl faced the other way. Now with the layer print start at the back of the owl the over hang at the head of the owl did not droop.
See second picture below.

It's good to study your part a little and where critical features like overhangs or cosmetic features are and position it accordingly on the platform to get the best print. Often the "knit" line is not even visible, but I am making it a habit to be aware at least when setting up the model for the print build.

Holes in Parts
Holes in a part tend to be a little smaller when printed than the size in the model. The printed hole being a little smaller is kind of good because if the hole is critcal, you can just drill it out to the exact dimension. (Look for a post coming up soon with measurements of model vs print sizes).
Drilling and tapping in PLA should be done at very low speed so you don't melt the plastic.
If you have an option, position the part so the holes print vertically. If holes are printed horizontally, they can tend to print a little oval, especially bigger holes.

Part scaling.
Here are some examples what can happen if parts are scaled down too much. So features or gaps get too small and the part or portions of it might not come out so well.
I printed the Eiffel Tower in smaller scale than need to be for 3D printing and the details at the top of the tower became too small to print successfully. Overall the tower still came out quite nice, but I will print it larger the next time.
So it is always good to review your part when you build it in the CubeX software and look at the feature sizes also look thru the slicing after the build process if there are gaps or overly thin areas.
Many 3D models online are not specifically designed for 3D printing and might need support features or modifications, so it's always good to check if somebody else has successfully printed the part.

The Cuban Chain, is another example where I scaled the model down too much. I saw it already when looking thru the slicing in the CubeX software that the small scaled down version would have issues, but I printed it anyway for example purpose.

And here are just some more other fun prints:
The translucent Natural PLA is pretty cool. You can print multicolor with internal features or parts that will show thru.


  1. Awesome, Awesome stuff Rick!!
    Love it!
    Is that Natural PLA translucent??

  2. Yes, the Natural PLA is translucent. It's pretty cool.
    You can print stuff with internal different colors and they will show thru.
    I wish I had the dino egg solid model file (not just .stl). Would like to modify the model to print in three colors, Eggshell in white, Dino in natural (translucent) and internal organs in red. Well, I'll have to design my own model.
    I just got the natural PLA cartridge from Source Graphics. Still waiting on the ABS but should be here soon.


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