Introduction: Generic Electronic Enclosure, Acrylic
The goal of this instructable is to help you create your own simple acrylic enclosure that works for any electronics project. Once you've designed your first enclosure, you should be able to easily modify it to accommodate a large range of dimensions and future projects.
I've attached a design I'm using for a crystal radio I'm presently building, and you are welcome to use it as a starting point. All photos in this instructable are of this design.
Tools required include:
- Laser cutter
- Hex wrenches, metric
- 2D vector software. I recommend: Vectorworks (free), autocad (free for all students), and solidworks (very expensive but my favorite). Inkscape is another free vector program, but it's difficult to build a well dimensioned schematic in it.
Step 1: Design Electronics
The first step is to design or acquire whatever electronic project you want to put into the enclosure. This part, to be honest, is probably the hardest bit, and being that I don't know what you're working on, I can't help you with this.
Specifically, what you need from this section is:
- A parts list
- Dimensions of all parts. If you have already bought the parts, you can use calipers. Alternatively and probably a better solution is to use the data sheet if available.
Step 2: Enclosure Layout
After designing your electronic project, you need to figure out where every component goes. Questions to consider include:
- How many feedthroughs does it need?
- What hole diameters is required for each feedthrough?
- How many PCBs need to be mounted?
- How many switches are there?
- Where do all of these go?
- What components should be adjacent to other components?
- What interface arrangement would make the most sense?
- How tightly packed should everything be? Etc.
As you can see, there are a lot of questions and details that must first be ascertained before designing the enclosure. I recommend starting with pencil and paper to get the rough layout and using a 2D cad software for your final layout. Place each component on 1 of the 6 sides of the enclosure. I recommend using the bottom surface for mounting PCBs and other internal components, and using the top and 4 sides for feedthroughs, switches, dials, etc. If you have designing a densely packed enclosure, make sure parts from adjacent sides aren't overlapping.
For my latest project, I decided to mount everything (including the PCB) from the top piece so that I wouldn't have to deal with excessively long wires connecting one side of the enclosure to another.
Step 3: Order Parts
Next, order your parts. It's always better to design your projects before ordering parts (as the design should be the primary driver in your project), but sometimes your parts need to be ordered first (especially when spec sheets aren't provided).
Hopefully, your design and layout in the previous two steps will provide you with the quantity of each of the following parts.
You'll need the following for your enclosure:
- Acrylic sheets, 1/8" thick (0.118" actual). I recommend Ebay, Amazon, Inventables, and McMaster-Carr as suppliers. Clear looks the best to me, but you may have other preferences or design constraints.
- M3 nuts. The square nuts work better in the t-slots, but hex nuts have their benefits as well. See picture for difference.
- M3 bolts/screws. I primarily used m3x12mm for the enclosure. No shorter than 8mm. I recommend button head.
- M3 nylon standoffs. Good for mounting PCBs and other components to the enclosure.
If you don't wish to work with metric, consider using 4-40 nuts, bolts/screws, and standoffs as they are nearly the same size and likely work just as well.
Step 4: CAD
The next step is to design or CAD your enclosure using a 2D vector software such as vectorworks, autocad, or solidworks. I've provided my design in both dxf and solidworks formats to provide a foundation to your design.
The enclosure is composed of 6 interconnecting sides. The bottom plane of the enclosure is intended for mounting PCBs and other internal components and has a small gap between it and the floor/table/surface below for mounted to be out of the way. The top and sides of the enclosure are intended for feedthroughs, switches, dials, and similar components.
To interconnect the sides, I recommend a combination of T-slots and interconnecting teeth (see pictures), and the final product will be quite sturdy. The number or frequency of the T-slots and teeth depend on the length of the edge in question. Additionally, an acrylic solvent could be used to permanently bond portions of your enclosure although I always recommend allowing at least of side of your enclosure to be removable for maintenance. I personally wouldn't recommend acrylic solvent unless your enclosure needed to withstand sizable loads/forces.T
T-slots are a neat concept that I only recently came across. It allows two perpendicular planes to be clamped together using a nut and screw (see pictures). If the T-slot is designed correctly, the nut (ideally a square nut) catches in its slot when the screw is tightened, and no external tool is required to hold the nut stationary. I've provided dimensions for a T-slot designed around an M3x12mm screw and M3 square nut.
The teeth (I know there must be a proper term for these) are just staggered steps (I used 0.5" and 1.0" teeth) that also allow perpendicular planes to interconnect. These teeth make assembly much easier and provide much of the rigidity for the enclosure. If you wanted to use acrylic solvent, bonding these teeth together after assembly would be a good starting place.
Of particular importance is the mounting hole layout of your various components. Check out the data sheets on your parts as they can provide exact dimensions that may be difficult to ascertain with calipers. Additionally, always make your holes a little larger than you strictly need in case your measurements of the hole locations weren't perfect.
Remember that the laser cutter has a finite cutting width and that your final cut pieces will be ever-so-slightly smaller or larger than the schematic.
Lastly, round any corners that people may come in contact with. It also makes the design look better.
Step 5: Laser Cut
If you don't have immediate access to a laser cutter, I recommend that you look into joining your local makerspace as they may have one.
The specifics of operating a laser cutter are unique to each machine so I won't go into any detail here.
I do, however, recommend that you practice cutting a test piece (maybe a 0.5" x 0.25" rectangle) until you get your settings right with the cutter. If not, you may mess up quite a bit of acrylic before you realize your settings were wrong.
Step 6: Assemble
Finally, assemble the enclosure and install your electronics to it. That's it!
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