How to Choose the Best Enclosure Material for Wireless Controls

Why Choosing an Enclosure Material Is an Important Design Decision

Designing a wireless device requires taking hundreds — if not thousands — of factors into consideration. However, the two basic needs you’ll have to reckon with are transmission and protection. Each is critical to a wireless device’s performance, and each must be kept in balance to various degrees depending on your application:

• Transmission. All wireless devices share one common element: they transmit a signal. Therefore, optimizing your device’s performance will require choosing a material that hinders transmission as little as possible, while still protecting the sensitive equipment.
• Protection. Many remote devices must perform their duties in environments where it’s impractical or dangerous to station a human operator. That means they’re often subject to all kinds of hazards that can compromise the equipment’s integrity. Thus, durability is a key consideration when choosing an enclosure. But an enclosure that’s made from the wrong material may not permit a strong enough signal.

Balancing these needs is one of the key tasks in wireless device design. Keeping them in harmony (or failing to) can have effects that resonate across entire organizations. Those considerations are also applicable across a huge range of devices:

• Alarms and other security systems

• Medical devices

• Remote sensors that monitor environmental conditions

• Control systems for machinery
  • Smart warehouse technology

• Wireless A/V systems

• Routers and other devices that provide WiFi signal

Polycase offers high-performance electronics enclosures in dozens of different styles and materials. But which one is right for your application? How do you find the right balance of power and protection? We’ll explore those topics below.

How Can I Figure Out Whether I Need a Non-Metallic or Metallic Enclosure?

We offer an industry-leading range of electronics enclosures in a wide variety of materials suitable for many different applications. However, for devices that transmit wireless signals, your first major decision will be whether to choose a non-metallic or metallic enclosure.

For the majority of wireless applications, a non-metallic enclosure is the better choice. Non-metallic enclosures are lighter, still durable and easier to work with. Most importantly of all, they usually provide excellent signal transmission.

However, in certain cases, a metallic enclosure will be necessary. Polycase offers high-performance industrial enclosure solutions for both scenarios, so let’s take a quick look at what each type of enclosure offers:

Non-Metallic Enclosures

• The preferred enclosure type for most signal-transmitting wireless devices
• Generally much better at allowing unimpeded signal transmission
• Wide variety of materials available, such as polycarbonate and ABS plastic
• Can be extremely durable and resistant to water, dirt and hazardous chemicals
• Some material types offer excellent temperature resistance
• Non-conductive material
• Resistant to most types of corrosion
• Easy to machine with cutouts and custom features

Metallic Enclosures

• Necessary for some specialized applications
• Often require use of an external antenna to overcome transmission difficulties
• Can offer exceptional corrosion resistance depending on material
• More resistant to extremely high temperatures
• Come in larger sizes than non-metallic enclosures
• Frequently more expensive than comparable non-metallic enclosures
• More difficult and expensive to perform custom machining on

Next, let’s take a deeper dive into the capabilities each Polycase enclosure offers. With our incredibly wide range, we offer an enclosure solution for virtually every application.

Just How Much Wireless Device Protection Do I Need?

One thing you’ll want to consider as you’re investigating material choices is what kind of protective rating your enclosure may require. If you’re not familiar with enclosure rating systems, here’s a quick cheat sheet:

• NEMA Ratings: In the U.S., the National Electrical Manufacturers Association establishes these ratings to define how well an enclosure protects against water, dirt, corrosion and other environmental hazards.

• IP Ratings: Similar to NEMA ratings, but used around the world, including the EU. Either a NEMA- or IP-rated device will provide excellent protection for its rated applications but check your local laws and corporate standards to see if one or the other is required.

• UL Ratings: A UL rating provides a standard for how well an enclosure resists smoke, fire and extreme heat — in addition to certifying NEMA type ratings.

Take a minute to do some research and determine what level of protection you’ll need. Often, your corporate headquarters or industry trade association will have pre-set standards for your electronics enclosures. Next, take a look at our extensive selection of high-performance enclosures.

What Kinds of Non-Metallic Enclosure Materials Does Polycase Offer for Wireless Electronics?

At Polycase, we’ve spent years developing an industry-leading selection of enclosures for electronics. So, we’re confident that we can offer you the perfect balance between performance and protection that you’re looking for. We’ll start off with some of our highly popular non-metallic enclosure models.

While other non-metallic enclosure options such as acrylic and fiberglass enclosures are sometimes used for wireless electronics, Polycase focuses on the two options that offer the best balance of price, versatility and performance: ABS and polycarbonate.

ABS Plastic Enclosures

Acrylonitrile butadiene styrene, or ABS plastic, is one of the most common types of plastic used in electronics worldwide. You’ll find key fobs, computer accessories, electrical plugs and many other electronic devices made from this durable and attractive material.

Advantages of ABS plastic enclosures include:

• Cost — ABS is one of the most cost-effective enclosure types for electronics.

• Transmission friendly — Computer accessories are often made from ABS because it creates minimal interference with WiFi and other signals.

• Aesthetics — This plastic is often used in consumer goods applications for its sleek look, particularly in our classic black.

• UL ratings — Many of Polycase’s ABS enclosures are UL flame-rated. We offer everything from the UL94V-0 rated BX series potting boxes and BT series enclosures all the way up to the UL945V-A rated heavy-duty DC series.

• Lightweight — While it’s not as light as polycarbonate, ABS is still considered a lightweight plastic. That makes it excellent for handheld applications such as our FB-45 series fob enclosures.

However, if you need extreme durability, an ABS plastic enclosure may not be what you’re looking for. While it’s a sturdy material that’s great for many different applications, ABS is not in the same league of heat, corrosion and impact resistance as polycarbonate. And although it can be suitable for light outdoor applications when UV stabilizers are included in the molding process, it’s not recommended for prolonged exposure to the elements. For the ultimate non-metallic durability, you may want to take a step up to our polycarbonate enclosures.

Polycarbonate Enclosures

Polycarbonate enclosures are the apex of Polycase’s high-performance electronic enclosure offerings. These thermoplastic polymers offer a superb balance between rugged protection and signal-friendliness, and they’re available in a wide variety of models and specs designed to suit the needs of your wireless device.

Our line of polycarbonate enclosures offers many attractive features, including:

• Durability — Polycarbonate is the gold standard of toughness for non-metallic electrical enclosures. We offer many models with NEMA, IP and UL ratings, such as our highly popular ML series.

• Transmission friendly — Just like ABS, polycarbonate produces minimal interference with airwave signals.

• Weatherproofing — Our polycarbonate models feature gasketed designs for performance in tough outdoor conditions, including rain, sleet and snow. Some, such as our hinged ZH Series, are even IP68 rated to survive temporary submersion.

• Ultra-light — Polycarbonate is the perfect combination of lightweight and durability, making it great for handheld applications such as our USB series.

If you’re looking for enclosures that are lightweight, versatile and tough enough for even the roughest conditions, polycarbonate may well be just what you need. However, there are still some circumstances when a non-metallic enclosure just won’t do. We’ll look at those next.

What About Metallic Enclosures?

Despite most professionals’ preference for non-metallic enclosures, sometimes metallic is the only way to go. Not to worry — Polycase has that covered, too. There are a few main types of applications where you’ll want to go with a metallic enclosure:

• Devices with a high risk of contact with strong acids or other corrosive chemicals

• Applications requiring a large enclosure

• Devices regularly exposed to extremely high temperatures or that are mission-critical in a fire-related emergency

The biggest caveat to know about metallic enclosures is that you’ll likely need an external antenna. With only an internal antenna, your device’s performance will likely be poor due to the high signal interference of metal housing. (We recommend a watertight cable gland in many of these cases.) Unfortunately, external antennas have risks of their own — corrosion, extra wear and tear, impacts and more — so it’s essential that you also protect your antenna if you’re using one.

If you need a metal housing for a wireless device, you’ll want either stainless steel, carbon steel or aluminum. All three have their benefits:

• Stainless steel enclosures, such as Polycase’s SA Series, are some of the biggest and toughest you’ll find. These enclosures come in larger sizes than many other models and are tested to the ultra-rigorous UL-508A standard. They’re heavyweight champions that are designed to survive the roughest conditions, and they can even stand up to strong organic solvents, which both polycarbonate and aluminum are unsuitable for. The SA Series is also your best choice if you need an enclosure with a NEMA 4X rating for corrosive chemical resistance.

• Carbon steel enclosures, such as the SB Series, offer many of the same benefits as stainless steel enclosures at a lower price point. Our SB Series models are constructed from 16 gauge steel with a powder coat finish that improves corrosion resistance.
• Aluminum enclosures, such as our EX series, are much more lightweight and portable than stainless steel. However, they are not suitable for most corrosive environments, have lower heat resistance, dent more easily than stainless steel and almost always require the use of an external antenna due to their EMI shielding properties.

Due to their poor transmission properties, metallic enclosures see less use today in the field of wireless electronics. However, when you need their specific properties, it’s important to have them at your disposal. They still see frequent use in livestock processing, marine applications and other specialized fields.

I Need Custom Cutouts on My Enclosures — Can Polycase Help?

If you’ve chosen to go with a non-metallic enclosure, the answer is a resounding yes! We offer competitively priced custom CNC machining on almost all of our non-metallic enclosure models. (Unfortunately, we do not offer custom machining for our stainless steel line of enclosures at this time.) Polycase is fully equipped to offer the custom machining solution your enclosure needs:

• One-Stop Shopping: Don’t waste valuable time calling machine shops for bids that end up being too high. We offer an all-in-one solution at the right price.

• High-Quality Work: Polycase works with the latest in CAM technology to make sure your cuts are just right, with a tolerance of only +/-0.005 inches.

• Fast Turnarounds: We offer a standard three-week lead time, and we can usually expedite our process all the way down to one week if you’re in a hurry.

• No Scrap Costs: With over 25 years of experience in custom machining, we’ve refined our process and equipment to virtually eliminate scrap — meaning no scrap costs for our customers.

• Help When You Need It: Our experts will be with you every step of the way to ensure your customized enclosures come out perfectly to spec. All you need to get started is a CAD file or engineering drawing of the cuts you want.

Need warning labels, instructions, branding or other graphics applied to your enclosure? We also offer custom digital printing on our enclosures, with brilliant full-color graphics applied directly onto the material. At Polycase, our commitment to customer satisfaction includes value-added services to help you create exactly the customized enclosure you want, with the specs you want and the performance you demand!

Naturally, the information in this guide is only the beginning. Depending on your field, you may well need to consider other factors when choosing your enclosure material. But as you work through your design process, keep your fundamental goals in mind — and don’t be afraid to reach out to our team for guidance! Whatever your electronics enclosure needs, Polycase is dedicated to helping you succeed.