Nearly all electronics projects nowadays end up in an enclosure. This specially designed box has proven a boon for the electronics world, what with the threat of electromagnetic interference growing on a regular basis. Now, most electronics manufacturers have a certain idea about the preferred look of their enclosure, but engineering the circuit into the final form presents several challenges. After all, it’s one thing to ensure the functionality of the product; it’s a totally different ball game incorporating this component while preserving the feel-good factor for users. No wonder custom enclosure designs are gaining traction in the electromagnetic shielding industry. Varying wildly in shape and size, these contraptions have multiple working parts. Manufacturers must determine how they will remain in position while facilitating end-user access to power and sensors. If all this sounds like a complicated procedure, that’s because it is. However, you’ve nothing to worry about as the following guide can help make sense of what goes into the creation of a reliable electronics enclosure:
Preparation and Layout
Begin laying out the different components in real space. This will give you a sense of the enclosure size required, the best placement of the inside parts, and the setup that works best for the external connectors. If you’re yet to gather all the necessary parts in one place, use datasheets for drawing or printing out their footprints. Make sure they are scaled to the correct size beforehand.
Printouts also prove useful when positioning the holes in the system. Mark the centers of the component holes in the printout and temporarily attach them to the enclosure with sticky tape. Punch the setup whenever you need to mark the center, and lightly tap with a hammer to form a divot in the surface of the enclosure. This way, there will be less resistance while drilling later.
Types of Electronics Enclosures
Enclosures are not a one-size-fits-all solution. Numerous forms exist, from simple, off-the-shelf projects to custom 3D printed boxes with snap fasteners. The final format depends primarily on the environment the enclosure will be subjected to. For example, if you require a combination of security and speed, it’s best to opt for a sandwich enclosure, which is nothing more than two boards that are divided by standoffs. The components are present between them.
One of the advanced shielding manufacturing methods involves laser cutting the base on which the parts will be laid out, and 3D printing a lid that will connect to the base using screws or snaps. One of the advantages of developing your own custom enclosure is you can add smart design elements like secure connections, and easy fasteners. However, these upgrades cost both time and effort. What you need to do is experiment with various arrangements and determine the best configuration for your electronics enclosure. Sure, attempting to rectify problems with the enclosure at the design stage is a long-drawn process. But it’s still better than taking apart a completed product and trying to pinpoint the problem later.
Use of Plastic Materials
More often than not, electronics enclosures are composed of plastic. Why? Because compared to other materials, plastic is cost-efficient, durable, lightweight, and sourceable. There’s just one drawback – it’s difficult to drill plastics. Thankfully, low-cost specialty drills are available for work with plastic materials. The biggest advantage is that this tool prevents the plastic from climbing the drill flutes as it nears the end of the hole. The location of the hole has to be marked in advance. Holes are preferably forged into a central position.
Such a positioning leaves a divot in tough plastics like Delrin and nylon, and create a suitable starting point for smaller-sized drills. However, when working with hard plastics, avoid applying a center punch as the material might shatter. Instead, use a 1/8 inch twist drill to create a starting divot into the surface. A couple of turns should be enough to form chips.
Assembling Enclosure Components
You’ll find lots of different connectors and fasteners that simplify the process of binding the custom electronics enclosure.
- Heat-Set Threaded Inserts: This tool is perfect for attaching tight threaded holes to certain 3D printed enclosures. Use a soldering iron to melt these into a hole.
- Captive Nut: Having the same profile as a hex nut but a quarter millimeter wider, a captive nut helps to insert a fastener quickly into the print. Screws coming in from a through hole on the other side of the cavity will be captured by the hex nut.
- Helicoils: This is a technique used to add metal threads to holes of any shape and size. Apply the helicoil insert after running the correctly-sized tap into the hole. This feature is great for plastic enclosure components that experience a lot of services and have their screws installed and uninstalled numerous times. What’s more, the helicoils can easily be replaced once worn out without requiring re-drilling of the hole.
Suitable Tools for the Job
Certain tools help make the job of building an electronics enclosure easier.
- Heat Gun: Shrink heat tubing is an easy enough task with a lighter. However, why not add more convenience with a heat gun? Available for ten bucks or less, this handy tool is suitable for creating strain relief wraps needed for hundreds of wire bundles.
- Washers: A staple of the fabrication process, washers help salvage the situation when you accidentally purchase screws that are too long or drill a hole that is larger than required for the fastener’s head.
- Standoffs: Standoffs help connect circuit boards to anything.
- Hand Counter Sink: Perfect for cleaning tiny holes, a hand countersink is available in variants with built-in deburring tools that help clean up the edges of freshly cut plastic or metal edges.
When customers search for electronic enclosures, they want products that meet their EMI shielding requirements to a T. However, that level of perfection is achieved only through the creation of a custom enclosure. And manufacturers must have the necessary materials and tools on hand along with a working knowledge of the creative processes if they want to produce a robust enclosure design.