Thank you for considering my submission.
This was a fun project and I really hope this helps children and young adults get excited about science and technology.
I got an email telling me about this challenge around noon, and within a few hours I was holding the 1st print in my hand. Of course I had to try to make it better, so I printed a second one changing some of the printer's parameters.
This is the great appeal of 3D printing technology, within a few hours I can go from my 5 year old daughter helping me design the ornament to holding the finished plastic part right next to the monitor and seeing a great big smile on her face.
I only wish all parents could amaze their children everyday the way I have the opportunity to.
I live in San Pedro, CA and I'm a US Citizen.
Step 1: Creating Your 3D Model
Choose your favorite CAD software.
I choose Google's SketchUp Make.
I chose a round pendant style ornament to reflect the presidential seal.
The 13 Stars around the perimeter obviously represent our original 13 colonies.
I chose the White House because that's where (hopefully) this ornament will be hanging. Google image search and the back of a $20 bill and a set of digital calipers gave me the approximate dimensions to make the White House pop off this ornament.
The 3D printer I use is mainly for making larger fixtures for metal/wood working, but the .5mm diameter nozzle still gives me some fine details. They do make a .35mm nozzle for my printer, but I just had to make some of the details a little bigger, and omit some of the finer details to make it come our looking right.
Once I was happy with the design I added the "Happy Holidays" text using the 3D Text tool. SketchUp makes the text "Components" so I had to explode those components then merge them with the rest of the ornament.
Once everything was done I made everything 1 Component, checked to make sure it was solid using the "Solid Inspector" plugin.
Once I fixed all of the errors I exported the solid Component to a .stl file format.
Step 2: Preparing Your 3D Model for Printing
I use Repetier-Host to prepare my 3D models for printing.
I load the .stl file into the program that has been set up with the dimensions that my 3D printer is capable of printing.
I position the .stl file in the build volume and make sure that the part is manifold (solid, or water tight with no holes.)
Once in position I "Slice" the .stl file with a program called Slic3r, but there are many other free slicing programs available.
Step 3: Generating the "G-Code"
G-Code is the language most 3D printers speak. The slicing program you use will generate a G-Code specifically tailored to your printer.
The slicing program has numerous variable that can drastically change the quality, and speed of your printed object.
The following are the variables I used are below.
Layer height: 0.2mm
Fill density: 100%
External perimeters, top and bottom layers: 70% speed
Bridging speed: 40mm/s
No support material
Extruder temp: 1st layer 250c, rest 240c
Bed temp: 115c
Time to Print: 1h:13m:34s
3mm Filament used: 5577mm (35.6cm3)
Step 4: The Finished Product
This ornament didn't come out of the printer looking this good. I had to do some cleanup with an exact-o knife to get all of the little "tails" off of the print.
These tails happen because I disable the retraction option on my printer. This option pulls the filament back into the nozzle when it's moving in-between different areas of the part. This pulling back prevents any plastic from oozing out during these moves(creating a tail.) The reason I disabled the option was because the gear that feeds the filament will sometimes strip and lose traction when it is retracting a lot due to small and numerous details. I would rather come back after four hours of printing and have to do a little bit of cleanup then come back to a 1/2 printed build.
Hopefully you enjoyed this and are as excited about 3D printing as I am.
Merry Christmas and Happy Holidays!