3-D Printing a key chain is not difficult, easy to do, and doesn't take much time. To make a key chain you will need the following:
3-D modeling Program
Maker-Bot 3-D Printer
Step 1: Step 1: Design
When designing your 3D printed key chain on Auto desk Inventor or any other 3D modeling program, it is important to know what size you are going to make your key chain. Have a set idea of what you want and how big you want it. A good size is anywhere from 2-4 inches wide, and long. Make sure in the sketch phase you leave an opened loop in a corner so you can attach it to your key loop. Make this loop at least .2" in diameter. Depending on what you are making and personal preference extrude 2D sketch to desired length. I did .2" and it was comfortable.
Step 2: Step 2: Preparing for 3-D Printing
When finished with designing key chain make sure you save a copy as an " .stl " type. This ensures that you can open the file in the Maker-bot program where you can configure the settings to desired standard.Put the file on a flash drive so you can move the file to a computer that is set up with the Maker-Bot program. Here you can change the position, angle, and size of your key chain. Next go into the "Print Settings" and change settings to what is desired. Considering you are making a key chain (which will go through more stress than any figure or whatever it may be you make on a 3D printer), you will want to make it stronger and last longer. To do this you will need to change the number of shells to 3 or more. This will make the outside stronger and harder to break. I suggest leaving the infill at 10%, it is still as strong.
Step 3: Step 3: 3-D Printing
Now that you have the files on an SD card, you can move them to the Maker bot machine and are ready to print. You want to find your files once inserting the card by manually going through the machine until you find the desired file. If the plastic in the machine is not the correct color, you can change this by simply taking out the plastic filling, and replacing it with the desired color. Once that step is complete and the 3-D printer is zeroed, you are ready to print. It will begin to make the base plate, which is put down first so your key chain does not stick to the plate. The key chain will take anywhere from about 10-40 minutes to completely print, depending on the size and complexity. Once the key chain is completely printed, you will need to remove it from the base by sliding it off using a spatula. The plate that was originally printed will still be attached. You will need to remove this by hand, and try to get it all off in one try. If it comes off in smaller pieces, that is also okay. Now you have your finished 3-D printed key chain!