Lets Make a Simple Extruded Aluminum Display Cube.

We occasionally display works or projects in public. Sometimes a project needs to be protected from the public, and sometimes, the public needs to be protected from the project. Occasionally, a project must be isolated from the audience to effectively demonstrate a principle or effect. One of the easiest ways to do this is to construct a display cube.

Other uses included a reactive light, stage props, supports for electronic and motion projects, etc. We have built projects that use a cube to display feedback from the weather information, the stock market, the time of day, and the chance of a snow day. Some stage props we constructed included a "Voice-activated computer" prop and a framework to support the pepper's ghost effect.

In these examples, the sides of the cube are based on a panel size of 11 inches square. Why eleven inches, you may ask? It's one less than a foot and the most significant diagonal space on the bed of our 3d printer.

Aluminum extrusions

8020 or equivalent

beams

connectors

2020

beams

connectors

Panel material

wood

polycarbonate

glass

metal

3D printed parts

Baserail

For 8020 Printables Thingiverse

For 2020 Printables Thingiverse

We worked with two variants of extruded aluminum, 8020 Series ten and 2020. 8020 series ten is 25.4 mm on a side, and 2020 is 20 mm on a side. They cut in the same manner. (Please take a look at our instructions on cutting aluminum profiles.)

There are several different options available for connecting the beams. For this instructable, we will use Single Tab End Fastener Clips for 8020 and 3 Way Corner Bracket Connectors for 2020.

Panels are discussed in the next section.

Panels are used to fill the interior faces of the cube. They can be made from a large number of materials, including polycarbonate, plywood, MDF, or aluminum.

When thinking about how big to make a cube, we usually start with how big the panels should be. It is helpful because the material used for the panels may come in a precut size.

In the examples shown in this instructable, all panels are eleven inches.

The cube is constructed of two different sizes of beams, long and short. The basic configuration uses four long beams (shown in red) and eight short beams ( shown in green.) All of the sides (two red, two green) are equal, as are the top and bottom (four green).

In the examples shown in this instructable, the bottom is left open.

For a diagram of an 2020 extruded aluminum beam.

For a diagram of an 8020 extruded aluminum beam.

The connectors used in these examples are 10 series single tab end fastener clips.

The connectors we use for the 2020 beams are 3-way end corner bracket connectors.

The 8020 series 10 beams will have to be drilled and tapped. The long beam will have to drill on both sides at both ends. The short beams will have to be taped. ( We use 1/4-20 ) Please look at steps 8 and 9 in this instructable for a better explanation. The tab on the connector must be orientated away from the panel, toward the outside of the cube.

The connectors for the 2020 beams have to be screwed into place. The two-prong sides of the connector are always attached to the Long beam in these examples.

Let's look at the calculations to produce the cut list for the beams.

The calculations for the length of the beams are slightly different because of the type of connectors used. Let's examine the 8020-style beam first.

First the panels

panelHeight = 11in or 279.4 mm

panelWidth = 11in or 279.4 mm

The top panel is cut to the exact dimensions as the side panels but requires a square notch cut in each corner. The 8020 beam is a little larger than the 2020 beam, so those are the dimensions we use for the cut. Please take a look at the next section for more information.

toppanelcornercutdepth = 1in- 0.087in-0.23in- 0.356in or 8.3 mm

For the 8020 series 10 style extrusion

profileWidth = 1in or 25.4mm

profileChannelDepth =1in- 0.323in- 0.356in or 8.15mm

profileChannelWidth = 0.256in or 6.5mm

For 2020 style extrusion

profileWidth = 20. mm

profileChannelDepth =6.1mm

profileChannelWidth = 6.2mm

We also need to consider the connector for the 2020-style beam.

conectorTwoProng = 5mm

conectorSingleprong = 0mm

An example with 8020 series 10

the long beam

Series10_longbeam = panelWidth +( 2 *(profileWidth - profileChannelDepth))

= 313.9 mm

the short beam

Series10_shortbeam = panelWidth - (2 * profileChannelDepth)

= 263.1 mm

An example with 2020

the long beam

2020_longbeam = panelWidth + ( 2 *(profileWidth - profileChannelDepth)) - 2 (conectorTwoProng)

= 297.2 mm

the short beam

2020_shortbeam = panelWidth - (2* profileChannelDepth)

= 267.2 mm

An additional cut is necessary on the top panel to provide clearance for the long beams in the corner. This should only be done on the top panel. The variable toppanelcornercutdepth will give you the measured value we used. ( 8.3mm round up to 8.5mm )

Again, this only needs to be done to the top and bottom panel (if there is one.)

Please take a look at our instructable on cutting aluminum extrusions.

The panels can be cut in any method suitable for the material. We cut the polycarbonate and wood panels with a table saw. The glass panes were ordered pre-cut to size, or we used a metal ruler and a glass cutter to score glass and then broke the glass at the score. The aluminum panels were cut on a metal shear.

As we have already mentioned, panels can be constructed from a large group of materials. The easiest one is plastics, where you have to remove the proactive material, and the panel is ready for installation.

Glass with a 1/4 inch or 6mm thickness can be cut into panels. This thickness ensures the panel will not be lose in the channels on the extruded aluminum. It is worth paying a little extra to have the edges of panels sanded or beveled.

Wood can be used naturally or painted. The pictured example has the panels' interior painted with a flat black. The exterior was painted a glossy black. The paint had an integrated primer and was applied as two coats, 45 minutes apart. All cutting and sanding were done before the paint was applied.

This is also a good time to check that the panel used for the top of the cube has notches cut into the corner.

If you are not using transparent panels for a display case, think about how you might want to light the cube's interior. If the panels block light, there is nothing to do, but if the panels are translucent, you should light the interior surfaces.

The above images show a variety of lighting options we have employed.

Translucent panels are lit with high-power LEDs, neopixels, and an RGB-led panel. An Arduino drove the Neopixels. An Adafruit matrix portal drove the RGB-led panel.

A top-mounted LED is used as a spotlight. We used a metal diaphragm to reduce the size of the spot, only to cover the center of the stage.

UV LEDs (400nm) are used to illuminate fluorescent parts. The panels were made out of glass which does pass black light at 400nm.

A UVC lamp (222nm) is used to illuminate fluorescent minerals. The panels were made of transparent polycarbonate, which does not pass UVC.

If you would like more information on UV lights to illuminate a display, you can see our upcoming instructable on UV photography.

The assemble sequence is the same for both systems, 8020 and 2020. First, build the base, then the sides, and lastly, the top. But because of the difference in the connectors, The order of assembly is a little different.

The base.

For this example, we used an open base, but if you have a panel for the bottom, insert it during assembly.

The sequence of assembling.

1. Take all the short beams and attach the connectors to the end.
2. Take a long beam and attach two short beams to one end. Stand the assembly upright so that the long beam is vertical. The long beam will have an end touching the work surface. (see the picture.)
3. Attach long beans to the open ends of the short beams.
4. Place two more short and long beams to complete the square base.
5. Insert the side panels
6. Place three short beams at the tops of three panels, but wait to tighten them.
7. Place the top panel (Make sure you have the panel with the cut corners.)
8. insert the last top short beam. It may require a little wiggling.
9. Tighten all the screws.

The assemble sequence for 2020 is the same as for 8020, build the base, then the sides, and lastly, the top. The 2020 connectors make the process a little simpler.

The sequence of assembling.

1. Take four connectors and attach short beams to the single finger on each connector.
2. Lay the resulting square on a work surface so that the solid part of the connector touches the surface and the two fingers on each connector are pointed upward.
3. Attach long beans to the two fingers on each open connector.
4. Insert the side panels
5. Take four connectors and attach short beams to the single finger on each connector. Insert the top panel before tightening the screws. (Make sure you have the panel with the cut corners.)
6. Attach the top panel to the open long beans and tighten the screws.

This project pairs nicely with our rotating base instructable. This allows for viewing a project or an art piece from all sides.

Add guide rails to mount the aluminum extrusions to make a more permanent installation. The rails make it more difficult to lift the cube off that base. They also keep the cube centered when using the turntable.

We usually print the rail in color to match the base. The red rails are only for visibility.

Samples of the guide rails we used for the 11 panels can be found here.

For 8020 Printables Thingiverse

For 2020 Printables Thingiverse