Intro: 3D Periodic Table
The first periodic table was developed in 1862 by a French geologist called Alexandre-Émile Béguyer de Chancourtois. He plotted the elements on a cylinder with a circumference of 16 units, and noted the resulting helix placed elements with similar properties in line with each other. But his idea - which he called the "Telluric Spiral", because the element tellurium was near the middle - never caught on, perhaps because it was published in a geology journal unread by chemists, and because de Chancourtois failed to include the diagram and described the helix as a square circle triangle. Mendeleev got all the glory, and it is his 1869 version (dramatically updated, but still recognizable) that nearly everyone uses today. This instructable documents my efforts to reimagine a 3D periodic table of the elements, using modern making methods. It's based on the structure of a chiral nanotube, and is made from a 3D printed lattice, laser cut acrylic, a lazy susan bearing, 118 sample vials and a cylindrical lamp.
Step 1: Design
The design process went through many iterations and down various dead ends that didn't work for structural or aesthetic reasons. Eventually, I decided to just 3D print the framework. Making the file for printing was pretty easy: I generated an output file using TubeASP, hid all the atoms I didn't need in Mercury, and exported it for 3D printing. I cleaned up the file using Fusion360. All steps are laid out in much more detail in my instructable "How to make accurate 3D molecular models".
However... when I printed it, glued it up and assembled it, I realized that the gaps between frame and acrylic panels were aesthetically, well, revolting. Most people didn't notice it, but it bugged me a LOT. The final design was basically the same, but with hexagonal punches taken out of the back of each cell to hold the acrylic panels. There are some slight irregularities with the wall thicknesses, but I liked it much better than the previous design and it was much stronger and easier to assemble. Thanks to the talented Scott Daigle (current innovator-in-residence @Pier9) for helping me out on the CAD when I got stuck. The STL file for the updated model is attached.
Step 2: Print
I did this print in 2 parts, as it didn't otherwise fit in the build volume. I did a test print at small scale first and checked that I'd got the layout correct by inserting a paper cylinder and writing all the elements in.
At the scale I printed it - each hexagon is about 2" across - the two prints took 31 and 49 hours on the Fortus Stratasys printer. I'm incredibly fortunate to have access to the Pier 9 3D printing lab, because I imagine doing this print commercially would have been outrageously expensive. It uses about 50 cubic inches of model material and 60 of support, which is close to 4 lb (2 kg) of filament.
Step 3: Assemble
I glued the layers together using E6000 and clothes pegs and rubber bands for fixturing. I added the glue to both parts and left to dry overnight.
Step 4: Laser Cut Hexagons
I cut 1/8" transparent acrylic of different colors into etched hexagons with holes cut in them. The etching indicated the atomic number, element symbol, and name. I was initially going to include atomic weight and electronic configuration, but it made it distractingly busy. The hole was for a sample vial: the diameter was chosen so that the lid would trap the vial (i.e. the diameter is slightly less than the actual vial, but greater than the thread. Illustrator files for the nine different colors I used are attached. The colors are not critical, I just picked a layout I liked the look of, and that used all 9 colors of transparent acrylic that I could buy. Use whatever colors you like. Even 4 would work fine: one for each of the s, p, d and f blocks. Here's how I broke mine down.
Clear: Hydrogen (1)
Red: Noble gases, Group 18 (7)
Orange: Alkali metals, rest of Group 1 (6)
Yellow: Alkaline earth metals, Group 2 (6)
Bronze: Lanthanides and lutetium (Lu is a Group 3 element, but is considered a lanthanide) (15)
Grey: Actinides and lawrencium (Lw is a Group 3 element, but is considered an actinide) (15)
Green: Transition metals (not including Group 12) (34)
Pale blue: Poor metals (Group 12, and the metals and metalloids of the p block) (18)
Blue: Non-metals, not including the noble gases (15)
Step 5: Install Hexagons
Press-fit all of the hexagons. Triple-check you have them in the right position and oriented correctly. Glue using a little E6000 around edges of all hexagons. I considered using acrylic cement, but even the gel-like ones were too runny for my liking.
Step 6: Make Rotating Stand
I made a stand using 1/4" clear acrylic, 6 thin washers and a 12" lazy susan bearing. Because the base of the periodic table varies in height due to its helical nature, you need to make uprights to ensure it is vertical. I also used clear acrylic for the uprights. The cut file I used is attached. I aligned everything exactly before gluing, and made marks where each upright needed to be placed. I used E6000 to glue the acrylic ring to the lazy susan bearing, by filling each of the holes that accommodated the feet. I popped washers around the feet to prevent the acrylic from rubbing on the stationary ring.
Step 7: Add Sample Vials
Put a little of each element in a vial, put through the hole in the acrylic hexagon, and screw on the lid from behind. Apply glue to the threads first if you don't want anyone to be able to access the sample. Including yourself!
At this stage I just have 20 samples; I will fill up more when I return home.
I used glow-in-the-dark PLA to print small radioactive symbols for the radioactive elements (STL file attached). I used a Dremel Idea Builder (great little machine). I used 5-8 symbols per vial.
Step 8: Illuminate
I added a cylindrical lamp to the inside of the lazy susan bearing. I was going to make one but in the end I found one just like I wanted to make at the Home Depot. I used a long skinny LED bulb to diffuse the light as much as possible.