Important disclaimers below
I did have some trouble fighting the printer on this one... I couldn't use the printers at my school because the freshmen class was using it, and the only other printer I have access to is a Lulzbot Mini at my local library. The Lulzbot has a, well, interesting method of determining whether or not to use supports, and due to time and platform size limitations, I could only print a very small section of the costume. These smaller sections can, however, be easily printed on even Mini 3D printers, and can then be linked together to form a full (plastic) armored suit or helmet.
Also, as usual, I am going to complain about the lack of the option "Onshape" in the design tools used section. Whoever reads this, if you have the power to add Onshape to the design tools used section, please do. For the rest of us broke designers who don't have the money to buy SolidWorks or Autodesk Inventor, I find the user interface of Onshape to be nicer than either of the above programs, and the only feature the FREE version of Onshape lacks is rendering. (Yup! Onshape is free)
Any printer were supports actually work.
I mentioned I didn't like the Lulzbot above, but the one thing it showed me was that you don't necessarily need supports on this design. If you don't add supports, the design will be messy, but who will really notice in the dark at Halloween?
I will also note that of the 3 printer brands I have played with (Ultimaker, Makerbot, and Lulzbot), Makerbot has by far the most consistent prints and the fewest errors.
I actually only designed 3 of the links, then used a multi-directional pattern to complete the full suit.
My part studio only had a few activities:
Linear Pattern 1
Linear Pattern 2
THIS THING WILL NOT PROTECT YOU FROM CLOWN ATTACKS
Or any other attacks, for that matter.
Anyway, watch out for creepy clowns (Such as Donald Trump) on the 31st, and watch out again on November 8th.
Ok, seriously though.
Here is the link to my file. If you want more (or less) pieces of chain link, create an onshape account and go to this link. Edit "Linear Pattern 2" under the "Features" bar on the left side of the screen. The number of occurrences in each direction is the number of inches of chain link you will have if you print it at 100% scale.
To print from onshape, right click on the label that says "Part Studio 1," and select export. Change the file type from Parasolid to STL, and change the units from Inches to Millimeters.
Here the file is: https://cad.onshape.com/documents/49fd3a8bf4b8d81b02f97bcc/w/8dc80877c2ca9a122c91ed8a/e/6fd5e4bbcc9138b47edfa0c3