Digitran/EMRISE, A switch in time

Manufacturing in Action, Source : The Manufacturer US

Vertically integrated operations, long-term contracts with the military and aerospace industries, and developing new products for new markets are ensuring a solid future for Digitran/EMRISE, company president Bill Miller explains to Gary Toushek

Bill Miller gets excited when he describes Digitran’s new Very Low Profile (VLP) rotary switches, which are attracting a lot of attention from consumer products and automotive companies, among others.

Designed for the company’s military and aerospace customers, this series of rotary switches has been issued one patent and has two others pending. The switches feature fewer parts, higher reliability, and reduce the weight and size of typical rotary switches by up to 85 percent. The key feature of the Digitran VLP rotary switches is their considerably reduced “post-panel depth.” This means when installed the switch takes up less room behind the operator panel (of a cockpit, for example), allowing more electronics to be added, if desired.

“There’s an emphasis today on smaller, lighter components for aircraft. For example, the very light jet (VLJ) market is growing, especially as an air limo service, as one alternative to long security checks on commercial flights. So our technology is also VLP for the VLJ, I guess you could say,” Miller chuckles. “But other products like car radios and GPS systems have multi-function rotary switches that not only select positions, they also offer mechanical isolation—you can pull and turn the switch, or use a concentric shaft that allows you to push a button while rotating the shaft. There are a seemingly endless number of applications that use rotary switches, so we’re looking to license our patented VLP technology to other markets and manufacturers as well.”

Miller is president of Rancho Cucamonga, CA–based Digitran, which has a second facility in nearby Monrovia that manufactures printed circuit boards for the switches. Both plants are ISO 9001:2000 certified, and they have 55 employees between them. Digitran is a division of EMRISE Electronics Corporation (EEC), which also provides custom power conversion and RF component and subsystem products. EEC is a wholly owned subsidiary of EMRISE Corporation, a public company also based in Rancho Cucamonga. With more than 300 employees globally, EMRISE Corporation’s US facilities serve North and South America; its Japan facility serves Asia, India, and Australia; and its UK and French facilities serve Europe, the Mediterranean, and Africa. EMRISE Corporation’s revenues for 2005 were $41 million, and EMRISE’s other companies provide network access and timing, synchronization, and transmission products, as well as communications test equipment to the telecom industry.

Digitran’s history began in 1959 with its first coded-output thumbwheel switch product line for aircraft. With the advent of IBM and similar types of computers, Digitran also made keyboards, but when mass production in the marketplace eventually drove the manufacturing offshore, it exited that business. But the fundamental design of Digitran’s switches formed the basis for a specification written by the US military, MIL-PRF-22710, to endorse their use in combat platforms, communications systems, and defensive equipment—and Digitran became a Tier Three component supplier to the worldwide military and aerospace industry.

Throughout the 1970s and ’80s, Digitran switches were in virtually every cockpit of military aircraft, as well as many commercial jetliners, since they feature sunlight readability and specialty lighting for night vision imaging, as well as other special cockpit low-light applications. Over time Digitran’s standard and custom switches evolved into expanded switch products, like lever and push-button switches, integrated switch assemblies, and then subsystems, expanding the company’s product offerings to its customers. Lately, says Miller, the Tier Ones supplying the Boeing and Airbus types of aircraft manufacturers are beginning to demand more from their Tier Two subcontractors, and those in turn are demanding more from the Tier Threes.

That’s not a big challenge for Digitran, he says, since it already has a reputation for excellent quality and tight controls. “We’ve chosen to maintain a vertical integration of our processes and operations, which is probably bucking the trend of most electronic or electro-mechanical component manufacturers these days, with their movement toward outsourcing more elements,” says Miller. “But when you outsource, you lose control of how the part is made—usually through a communication or language problem—and the response time is much too long. And quick response is a high priority with Digitran; I can’t emphasize enough how important we consider it to adapt to our customers and give them exactly what they need, when they need it. So years ago we made the decision not to outsource; we had the opportunity but discovered that for our products and markets, it was a competitive edge not to outsource.”

As far as its military and aircraft customers are concerned, he adds, the simpler the design of a switch—using high-quality exotic and unique materials with longer life characteristics and controlled by customer specifications—the more reliable it is. For example, Digitran can mold plastics that are as strong as steel but with lighter weight. It maintains a qualified vendors list, mostly for raw materials but also for some for specialty work or production overload of simple parts.

“We make it easy for customers to ‘design us in’ via our Website, using a unique model configurator for rotary switches; we call it the EZ Rotary Configurator.” Miller says. By going online to www.digitran-switches.com and answering basic questions about requirements and desired capabilities for a proposed switch, current and potential customers can then download a two- or three-dimensional drawing that can be inserted directly into their 3D or 2D design system and checked for form, fit, and function at no cost. If the design is a good fit, the customer can request a quote. “We can also create quick prototypes of design—we call them ‘proof of design units’—and depending on how radical the design is and how busy our current workload is, we can produce them in as little as two weeks.”

Using CAD (computer-aided design) and CAM (computer-aided manufacturing) programs, Digitran engineers design parts, verify designs, and transfer the design electronically to CNC machines; then the part is made within 24 hours. Digitran recently invested substantially in new CNC equipment (automatic machining centers, vertical mills and horizontal lathes) for both engineering and production. Proof of design prototypes are created more quickly, and the production department can increase the number of units manufactured and assembled. The production department is organized into smaller departments—injection molding, CNC, paint, and assembly. Component parts are machined or molded, kitted, and made into subassemblies using technologies such as heat staking and sonic welding. “Since we buy beryllium copper brushes and form them to our proprietary and field proven contact designs, we heat-treat internally; we also passivate [treat or coat metal to reduce the chemical reactivity of its surface] and form our own stainless steel products.

Subassemblies are then brought together for the final assembly of the product. We’ve recently added a Class 10,000 cleanroom for final assembly and QA testing and will complete the implementation of lean manufacturing methodologies in 2007. We must continually improve our designs, materials, and processes to keep our production and overhead costs low. Although we manufacture excellent products, only profitability guarantees longevity, so continuous improvement and cost containment are a way of life at Digitran,” Miller says.

Digitran switches are easily and quickly assembled by loading three or four parts or subassemblies onto a stainless steel shaft and inserting that into the body of the switch, then clamping it all using in house designed and built equipment. Assembly is performed on a line or in a cell, usually in lots of 100 to 1,000; higher volume depends on the design of a unit. The new rotary switches are compliant with MIL-DTL-3786, a detail military specification written for rotary switches.

The next generation of rotary switches is already on the horizon; it’s called an optical encoder and also uses the VLP configuration. Whereas a rotary switch is an electro-mechanical encoder, an optical switch uses internal light from a continuously emitting diode to provide an electric signal. A major advantage is the noiseless aspect: when an electric current is broken (in a rotary switch), “electrical noise” is generated, but when a light stream is broken (in an optical switch), it’s noiseless. As well, over time electric current can erode contacts, but light does not. The light is broken by a window tied to a shaft whose rotation breaks the stream. “If electrical outputs are provided 90 degrees from each other on a circular switch, the system can determine the direction the shaft is turning, and from its position the system can determine internal data relative to the resulting electrical code,” Miller says.

Quality assurance is a priority, and on its own initiative the company continually provides re-qualification aspects for customers. An environmental lab at the Rancho Cucamonga facility is qualified by the military’s Defense Electronic Supply Center of Dayton, OH. “They have examined our environmental test capabilities and allow us to conduct our own tests and certify the results,” says Miller. Digitran has about 2,000 part numbers on the US military’s Qualified Parts List that require recertification biannually (about 80 percent of testing is done in-house, and some of the more exotic tests are sent out).

Most employees are cross-trained on various equipment and process specifications and have long tenure with the company, an average of 20 to 25 years, “because they like our working environment and the stability we offer them. What’s interesting is that those few who did depart seeking greener pastures during the peak of the dot-com era six or seven years ago have mostly returned to us, and we’ve accommodated many of them.”

He summarizes challenges for the company going forward as the need to diversify by designing new products and looking for new markets. “That’s how we’ll grow. With our standard products, our customers tend to buy what they’re familiar with. If a product works well, they’re reluctant to try something new. Most programs we have with the military have a long gestation period. But we know there’s a continual need in other markets for smaller, lighter-weight, more capable, longer-lasting switch components. So we’re striving to be innovative with new products to take advantage of the Digitran brand and reputation for reliability and quality—and we’re anxious to license our patented technologies to other industries that may require higher volumes than our capacities. I’m very confident that, because we have the financial backing of our parent company, EMRISE Corporation, Digitran has a solid future as a major high-quality component supplier to customers who demand the best for their systems and products.”

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