Considering enclosure needs up-front saves time and cost

Bud Industries’ President Blair Haas answers ECN’s questions regarding what designers should consider when specifying and choosing an enclosure and how to build-in cost-effectiveness.



What are the most important factors an engineer must consider when specifying an enclosure?

Those factors are as follows:

Size of the equipment to be enclosed;

Environment in which the equipment will be used (office, lab, factory, outdoors, etc.);

Weight of the equipment to be enclosed;

Enclosure materials (plastic, aluminum, steel, fiberglass, etc.);

Visual requirements (the difference between installing the enclosure in a wiring closet and using it in a finished product);

How the enclosure may need to be modified for its eventual use.



As a manufacturer, what information do you need from an engineer or product designer? Is there any particular thing that is frequently overlooked?

Typically, we need answers to the questions above. A good understanding of the intended use of the product is very helpful in supporting the design function. The biggest challenge that we have in supporting our customers is that they design the components with limited sense of how they want to enclose them. Instead, if the enclosure is an integral part of the initial design, then designers can save significant cost. While engineers often focus on the electronics, the enclosures can have a selling price that is higher than the boards involved.



What is the most common misconception about enclosure requirements?

Engineers often think of the enclosure as a necessary evil to be added to the product as an afterthought. The fact is that the enclosure can assist in the proper design and function of their designs, providing added features and benefits. Further, if the encoder supplier can assist the engineer in creating a design that is closer to its standard product, then the customer can save significant tooling expenses.



In your recent ECN Webcast (www.ecndesignnetwork.com), you spoke about the three pitfalls when specifying a NEMA rated enclosure -- choosing the incorrect rating, material and size. How can an engineer or designer get a better understanding of NEMA ratings in order to make the correct choice? Are there Web sites that offer help in understanding NEMA ratings?

There are many Web sites that can assist in the specification of NEMA enclosures including the official NEMA website (www.nema.org). Engineers can also request an enclosure design tips handbook at www.budind.com that provides guidance in proper enclosure selection.



What is the basis for choosing the right material or construction?

Often it is a combination of features that are important. For example, weight load capacity and the ability to diffuse heat might lead the designer to select a ventilated metal cabinet. Also, the aesthetics can be crucial both in terms of visuals and use. A portable scanner would need to both look attractive and be ergonomic. Typically, the application drives proper material selection, and it can also be a matter of personal preference.



What can engineers do to ensure a good experience when requesting prototypes and production quantities from an enclosure manufacturer?

The most important thing is for the design engineer to include complete information about the project, including what is being enclosed and the environment in which the enclosure will be used. The more details provided, the more likely it is to get the ideal enclosure. It is also important to provide this information as soon as possible because some enclosures, particularly custom enclosures, may have an extended lead time.



Talk a little bit about cost effectiveness with regard to prototypes, materials of construction and re-tooling.

In today’s global economy, cost often drives the enclosure selection. Unlike some electronic components that fall in price because of advancing technology, enclosures are subject to raw material costs that keep prices constant or even rising. Therefore, cost minimization is very important. Engineers must consider several steps:

If the prototype is developed around a manufacturer’s standard product, costs will be significantly lower.

Allowing proper lead times for prototypes also assists in holding down costs by avoiding labor and material surcharges.

Be sure to align the materials to the application. One would not attempt to use plastic in a heavy load bearing situation. One would not use steel if portability were an important consideration, because steel is heavy.

In terms of design and materials, there is a difference between what is truly needed and what has been used in the past. Rely on the enclosure manufacturer to know its products and to advise appropriately.

Try to avoid retooling as much as possible. A new tool for a plastic enclosure can run into the tens of thousands of dollars. Even adjustments to hole locations can cause the cost of enclosure tooling to double.



Is there a trend toward more customization?

There is a major trend towards customization in the industry today. The reality is that enclosures typically cannot be used as they are purchased, but rather they must be modified to allow for cable access, readouts, power, etc. It is typically more cost effective for the enclosure manufacturer to do this work as it can create these modifications in the production stages, minimizing costs.



Is there any other advice you would like to share?

Search for an enclosure vendor as you would for any component provider. Value length of tenure and breadth of products so that all of the enclosure needs can be met by one provide.