Can You Print Anything? A Lesson On "Printability"

3D printing is an impressive technology. Now, can you use it to print ANYTHING!? Maybe.. but there are some limitations and things to consider.

Organic shapes are all around us. Humans, animals, trees, etc. Organic shapes can be tricky to print.

• Trees have a thin base and then many small branches that hang over the ground.. these are "overhangs"
• Humans have hands hanging at their sides
• Animals stand on 4 legs but may have tails, trunks, tusks, and bellies that are 90 degrees to the ground (build plate)

We'll use an elephant in this example to illustrate how a seemingly simple object can still be difficult to 3D print.

The Elephant

Trunk

The elephant's trunk is the first feature that makes this a difficult print. It has no surface area touching the ground (build plate) so the initial layers are in mid air.

Belly

The elephant's belly is the next feature. It is at such a steep overhang. The belly begins depositing plastic in mid air as well, and then begins to lay a lot of plastic on top of it. These layers are likely to droop, curl, or create a failure! If the two hind legs are not secured to the build plate, the added mass of the belly could cause the legs to fall over.

Tusks

The elephant's tusks require fine detail and also print in thin air. The tusks would fail to print, since there is nothing to attach to.

What are our options?

Print with Supports

Support material (shown below in gray below) is sacrificial plastic, printed underneath the object, to support it. When your print is complete, you peel or pick away the support material.

Plastic creates a very strong bond with itself. That is what makes your part stick together! The same applies for support material. Slicing programs combat this by making it so that there is a small gap between the support material and the part itself.

• Larger gap = poor quality overhangs, but easy to remove
• Smaller gap = good quality overhangs, but difficult to remove

If your support material is difficult to remove, try using some needlenose pliers or adjusting the settings.

In the photo below, you'll notice that using support material adds..

• 1 hour 35 minutes
• 19.02 grams
• $0.48 of plastic

The best way to use support material.. is to use none at all! Try to design or orient your object in a way that it requires no support material.

Cut the Object In Half

Another option is to cut your object in half and glue it together afterwards. For this, you'll need another program. For windows, we recommend using the 3D builder software included with Windows. Here's a video that shows you how to cut your object in two.

If you're on Mac, we recommend PrusaSlicer (download here). Instructions here.

Cutting the object in half, and flipping the lower portion over, means that there are almost no "overhangs" or areas that are being printed without any material underneath them. The tusks here might pose a problem, but it is far better than the alternative.