Right off the machine? With this particular technology, throw them on the ground and they would shatter.

You can infiltrate them with various epoxies, glues, etc to make them FAR harder. That was the key that I was missing a year and a half ago when I first got started toying (heh) around with this idea for a potential business.

In that time, they have come out with ways to make the material so stiff, you could ride it like a skateboard if you printed out a skateboard.

http://www.youtube.com/watch?v=iXza4usjgrc

It requires some vacuum and heat post processing, but nothing TOO complex or costly.