Mice/hamster chew proof plastic material
Smooth surfaces without ridges or angles for teeth to grab onto are as important to a successful design as your material choice.  Think of your enclosure design from the point of view of its occupant.  Any joint between two surfaces which are narrow enough to fit between its teeth will become a focus for gnawing.


Air vents are also common weak points because simply drilling a hole in an otherwise flat wall leaves a right angle which hamster teeth can work with.  Metal vent covers can fortify these necessary weak spots.

Manufacturing can also play a part in making an escape proof cage.  3D Printer surfaces, no matter how hard the plastic, will have ridges in them that hamster teeth can find and exploit.  There are chemicals which can smooth out these ridges, but they may not be food safe.  

As for plastic types, there are food safe versions of most of the hard plastics.  PET or PVC would probably serve your purposes, but for absolute certainty, I would make the surfaces that need to be transparent out of glass and the rest out of sheet steel.  Plastics are great for a lot of projects, but hamsters are world class escape artists and they deserve a cage that can truly test their capabilities.

Good Luck!