As product and process technologies change and improve, enclosure technology must change along with them. For instance, today's enclosures range from simple storage devices to complex climate-controlled units. So more than ever, enclosure designs must provide flexible solutions for wide-ranging environments-and still meet a variety of tough standards.
Take a look at the way engineers are designing with electric drives and you'll see a shift toward more intelligent control systems. Gradually, the control function is becoming more decentralized. Flexible, computer-controlled systems are replacing systems with centralized control. As a result, PCs have become commonplace on the plant floor.
All-in-one PC enclosures. For enclosure makers, this trend creates a new set of packaging concerns. Rittal Corp., Springfield, OH, took this into account in the design of its latest PC enclosure.
The Rittal unit protects a standard office PC, housing both the CPU and monitor. A pull-out drawer for the keyboard features a built-in mouse pad. An internal lock on the front panel secures the drawer. The enclosure also includes a one-piece monitor window made of safety glass to help protect sensitive inside components, but doesn't dilute screen visibility. For added versatility, the enclosure can be used as a desk-top unit or mounted on a mobile pedestal.
And with the move to intelligent control systems and the surge in integrated electronics technology, a new breed of enclosures has evolved. "They are no longer just metal boxes,"says Peter Werwick, industrial products manager at Rittal Corp., "but system integrated solutions."
New technologies are being combined to create systems with completely new packaging considerations. To meet these needs, industrial enclosure designs must focus on three things, says Werwick: Customization, maintainability, and the integration of various technologies while maintaining NEMA integrity.
Use of operator interface computers has increased in process industries, again requiring more specialized enclosure designs. Case in point: The APX(R) stainless-steel, operator interface (OI) enclosure from Hoffman Engineering, Anoka, MN.
The enclosure mounts on a pedestal, making it possible to move the stand-alone OI device almost anywhere. That's why Mark Smith, electrical engineering manager at Shick Tube-veyor, Kansas City, MO, chose the versatile enclosures. About 75% of Shick's business revolves around supplying pneumatic systems and equipment to companies in the food processing and baking industries. "Our customers can place the unit at nearly any location in their plant and not have to worry about a support structure," says Smith.
Another plus for Shick's customers: environmental resistance. The enclosures are rated UL/CSA Type 4X (IP66) and can withstand salt spray, cleaning solvents, and corrosive process byproducts.
An array of options enables the unit to house the latest operator interface work stations. Three different sloped tops fit the enclosure to most OI brands; while a variety of front accessories can accommodate keyboards, mice, and pushbuttons, or provide a convenient writing surface.
Keeping things cool. Electronics, especially in industrial and data communications applications, are being packed more densely into small spaces. This, in turn, has created the need for smaller enclosures. More importantly, reliable enclosure climate control has become a necessity.
Excessive heat-loads can drastically reduce the life span of electronics and increase the risk of a complete shut-down. Enclosure makers have responded with readily available climate-control solutions. Devices range from specially treated air conditioners for corrosive environments to air-to-water heat exchangers and filter fans.
Another trend in electronic applications: Single enclosures used to house complete system solutions. One example: The HAWCS II hardware/software control system from Hobart Lasers & Advanced Systems, Troy, OH. The system provides motion, process parameter, and manufacturing cell control from a single point controller. The enclosure plays host to a Motorola VME-based computer system with motion control capabilities, I/O distribution and isolation, VGA monitor, keyboard, and wire feed control system.
Accommodating all of the system's equipment was no easy task. "We needed something that we could customize to fit our exact specifications," says Kent Walker, manager of engineering at Hobart. The solution: use of a modular, off-the-shelf, PC Industrial cabinet from Rittal.
The cabinet line features a range of interchangeable side walls, back panels, and doors that can be screwed together to form a complete enclosure. Pull-out and fold-down options are available for the keyboard drawer. Selecting each piece individually allowed Hobart to create the exact enclosure needed for its application.
In spite of all the changes in enclosure requirements, one thing remains essential: Good looks! Enclosures that are aesthetically pleasing enhance the value of their final product. But a pretty package need not reduce a unit's functionality.
The "Executive" Series of instrumentation and computer peripheral housings from Frederick, MD-based Bopla Enclosures provides a good example. A beveled lid and base and a two-tone, light gray color scheme ensure aesthetic acceptance in nearly any environment. The impact-resistant, polystyrene housings conceal assembly hardware that is secured from the rear. Internal mounting bosses accept self-tapping screws, while a base keyhole knockout provides for wall mounting.
Bopla's sister company, Rose Enclosures, Frederick, MD, offers its own high visibility products. The company's "Aluform" enclosures feature a shallow depth profile, beveled lid, and external cross-head screws. Customers can choose between a painted white/gray powder coat or unpainted versions. The NEMA 4X-rated units consist of die-cast aluminum. Threaded internal mounting bosses in the base and lid ease component installation.
What does the future hold in store for the enclosure industry? Pre-assembled components, reliable service, and maintainability will continue to be emphasized, say manufacturers. They also predict that makers of packaging solutions will take an expanded role in product development. The reason: some OEMs have stopped making their own packaging and are looking to enclosure makers for design services, engineering support, just-in-time stocks, and purchasing assistance. "OEM companies have discovered that enclosure manufacturers can have quite an impact on influencing quality, cost, and speed to market," says Werwick. As a result, enclosures will increasingly become an integral part of product design.
How to choose the right enclosure
Todays packaging requirements are complex. With the range of products available, how do you select the right enclosure for your special product? Here are a few tips from Rittal Corp., Springfield, OH, that can help you match your system's needs with the best enclosure value.
What is going into the cabinet?
What is important -- security, corrosion protection, aesthetics?
Where will the enclosure be located? For example: plant floor, laboratory, processing plant.
What standards must be met?
Are "noise" and interference a concern?
How much room will the equipment take up?
How much space is required for maintenance?
Is the equipment easily accessible in the enclosure?
What are the application's climate control requirements?
Does the air conditioner utilize a CFC-free refrigerant?
Is a microcontroller or sensor available for air conditioners-especially for remote locations?
Is engineering support available?
Is the supplier equipped with on-line systems to facilitate communication and design modifications?
Is the enclosure easily assembled and expandable in the future?
Are spare parts readily available?
Does the supplier meet international certifications?
Is the service available long after the initial sale?