Machining Company Serves Specialized Niche in Military Aviation Lighting

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Military Aviation Lighting

Precision components for applications like cockpit lighting and night vision imaging systems are the specialty of an Indiana company that also offers research, design, and testing

Very few contract manufacturing companies in America are able to produce the exacting and specialized, miniature glass parts and components that Pynco, Inc., produces for military aviation lighting applications. In fact, there are probably only a handful of companies in the entire country that can make that claim. Located in Bedford, Indiana, Pynco helped pioneer an innovative glass machining production process in the 1980s, and is still operating on the leading edge of this remarkable technology (www.pynco.com).

Pynco specializes in the design, engineering, testing, and manufacture of custom and stock night vision imaging systems (NVIS), which include flat and ring filters, filtered lamp assemblies (flat and hemispherical domes), sunlight readable annunciators (words embedded in lights) and display panels, and indicator lights -- both incandescent and LED. In addition, the unique company offers testing and recertification, as well as spectro-radiometric measurement services.

Besides producing new parts and components, Pynco offers value-added services, often converting existing hardware to an NVIS. The company also manufactures and installs sunlight readable annunciator filters into customer hardware, OEM hardware, or hardware manufactured by Pynco to customer specifications.

About 90 percent of Pynco's work relates to night vision types of products, mainly for military helicopters and fighter jets, but also for some commercial aviation applications. "We're now starting to make more products for ground hardware that are being retrofitted for night vision, mostly for the Army," says Jim Collins, Pynco's physicist and co-founder. There are also a few commercial police applications, such as for the Border Patrol and police surveillance work. "Within the night vision community, there are probably only about three or four manufacturing companies in the whole country that we would consider competitors," he added. "There are similar companies doing similar types of work, but they're not connected with the aerospace or aviation industries."

With a full range of manual and CNC machining equipment, Pynco's production staff is able to manufacture close tolerance, precision machined parts from raw glass stock. Although the company can produce lighting products up to 18 inches x 18 inches in size, most of the parts and components that it produces are miniature--the diameter of a wooden pencil and from 1/4 inch to 1 inch in length. Some of the products that are used with night vision goggles are designed to remove the longer wavelengths of light, ensuring that the goggles don't become so bright that the pilot or crew member loses their visual acuity.

Family-owned Company Pioneered Glass Machining in the 1980s

Pynco is a family-owned company that was founded by an engineer with a high regard for innovation. "With the help of senior physicist Jim Collins, Pynco quickly became an industry respected organization for the development of leading edge technologies," according to company literature. "Throughout the 1980s, the demand for the development of night vision compatibility for aircraft instrumentation and cockpit lighting became an important requisite for a variety of military and aerospace applications. With industry leading research and development, Pynco became the first organization in the 1980s to manufacture reliable night vision lighting solutions and NVIS compatible glass filters for a variety of mission critical industries."

Engineer Jim Seib started the company back in 1986. "Jim and I were good friends, so I came to work with him and helped start the company," Collins recalls. "At that point in time, in the '80s, there wasn't much out there in this area that would satisfy the night vision mil specs at all," Collins insists. "What we were doing at the time seemed to work, and some of these original customers are still with us."

Two of Pynco's products -- glass filters and annunciators -- have applications in a variety of NVIS lighting situations, namely for crew stations, aircraft interiors, and ground vehicles. The company's physicist says that the glass filter is a device that reduces the infrared signature and provides proper color to the unaided eye. The infrared signature is what affects a night vision goggle, and the color affects the human eye. In terms of the annunciator, most cockpits and workstations have instrument displays that alert the pilot or crew that something needs attention, like a low fuel tank or engine overheating. Any cockpit instrument panel will have a variety of these annunciators in operation.

"They all have to be sunlight readable because sometimes a cockpit will be exposed to direct sunlight," Collins explains. "The lighting devices have to be easily read when the sun is shining on them. And they also have to be night vision compatible because the panel is also used for flying at night. So these two different environments have to be addressed."

Pynco's precision CNC machining is a very specialized process, one subsequent to the precision grinding and polishing of specialized glasses. Ordinary, colored container glass could never be used for this highly-specialized work. The glass used for these NVIS tasks is specially engineered for these applications. "There are special glasses that have been designed for the particular colors that we need, and the infrared absorption that we have to have," says Collins. "Glasses have been available for many years that do a moderate amount of absorption in the near infrared spectrum. But the glasses we use now have much deeper absorption than has commonly been available over the years."

Collins says that the machining of glass is very analogous to the machining of metals and plastics, but with machine feeds and speeds that are unique to this type of machining. He says that his company has mastered many "tricks of the trade" to be able to process and handle these tiny, fragile pieces of glass. "There's a significant learning curve with these materials to become good at processing them," Collins points out. "One reason that working with glass is so hard is because it's so brittle. Some are very brittle and don't tolerate temperature differentials very well at all, and crumble when you try to machine them. Heating the substrate also has to be learned very systematically."

Another unique production capability that Pynco provides customers is the ability to core-drill glass ring filters to 0.020-inch in wall thickness, or flat filters as thin as 0.018-inch. Pynco touts itself as "the only company known worldwide that can mill glass products to such a high degree of precision."

Design, Research, and Testing

Pynco performs all of the design, testing, and engineering necessary to create its unique products. The glass making plants have their own product lines already made up with specific colors. The glass plant stocks hundreds of different types and colors of glass that Pynco can use for this exotic work. Most of the glasses used in night vision goggle (NVG) applications nowadays are phosphate-based, but borosilicates are used in non-NVG applications. The borosilicates are more durable, in the sense that they don't break as easily, but they don't have the color and infrared absorption needed for NVIS applications.

"We buy the raw glass in a blank," says Collins, "which is a 6-inch square piece of glass and about 1/4-inch or 1/2-inch thick, and then we grind it and polish it to the thickness that we need, and then do whatever machining has to be done to it. We can run small quantities and still be cost-effective. Our average lot size, although it varies, would be anywhere from a few hundred parts to a few thousand."

While chemistry comes into play during the glass making process, physics -- particularly optics -- is the science that is most in demand in Pynco's plant. "Our work has to do with optics in the sense that the characteristics that need to be measured for the raw material and the finished product are performed with optical test equipment," Collins states.

"We use a spectro-radiometer for almost all of the measurements that we do," he continues. "There are other ancillary pieces of equipment, but most of it's done with the radiometer. This instrument measures the light intensity at discrete wave lengths, and then goes through a series of calculations to present you with the color coordinates, and the NVIS radiance (NR) value, which is a figure of merit for brightness from the NVG point of view. NR is very similar to the concept of luminance with the human eye, except that you're taking into account the sensitivity curve of the goggles."

With such a specialized niche in the manufacturing world, the company's night vision applications list is growing all the time. The company, reportedly, hasn't seen a downturn in business for the past two years. One new application is in the commercial passenger aircraft industry, a market that now wants night vision goggle-compatible instrument displays. Law enforcement agencies are also seeing the benefits of night vision equipment, which is also being used increasingly by soldiers in the field.

The applications for flat filters seem to be increasing at a rapid rate, especially for military aviation uses. "I see something new in this field every week," Collins concedes. "The military's need for indicators, and other types of lights, dictates a need for a specific shape of filter. There are so many different types of lights in a cockpit, like indicators and annunciators and flood lights, that there is almost no limit to the types of filters that are needed."

Pynco also makes plastic and aluminum parts and metal fixturing for its in-house machining processes. Plastic and aluminum parts are also mainly used in aerospace and aviation applications. They're mostly small filter bezels, or frames that hold the annunciator lights in aircraft instrument panels. The company also constructs its own tooling for jigs and fixtures. All of the filter products are machined with six CNC mills, and, in another building, conventional machining equipment is available for the jigs and fixtures.

The grinding and polishing processes, and other finishing processes, are also accomplished in-house. Not surprisingly, the company's polishing equipment was made in its own shop. During polishing, the parts are held in a fixture for batch polishing, with maybe 50 or more parts all processed at once.

In addition, Pynco handles its own assembly work in-house, including a kitting operation for packaging large orders. Some of its final assemblies consist of three or four different components, all of which are assembled into one unit. Indeed, many of the lamp assemblies are very small, as small as 0.135-inch maximum OD x 0.185-inch nominal OAL (overall length) -- which makes this work even more challenging and difficult. "The assembly we do is mostly for filtered lamp assemblies, which is mostly hand assembly work," says Collins. "Some of the assembly work is done under a microscope because the parts are so small."

On occasion, a contract will require that several custom-made parts be packaged together in what is called a ship set, or kit. An aircraft company, for example, might want to buy all of the parts for an entire cockpit conversion. Therefore, everything needed for the cockpit conversion will be packaged in one kit.

LED Technology Creates New Challenges

One recent innovation in the field of night vision imaging systems is the switch from incandescent lamps to light emitting diodes (LEDs). The LEDs have created a good many new design and manufacturing challenges for Pynco and other manufacturers. Several of the company's products, such as annunciators and indicators, are turning to LEDs for a light source. "The glass material itself is different for the lamps and the LEDs," Collins observes. "The reason you need different types of glass is that the spectral emissions of the incandescent lamp are a lot different than what's typical of an LED. So the glass has to have different absorption characteristics to compensate for that."

Many military specs for this exacting work have gone by the wayside during the past few years, says Collins, as procurement officers in the military have followed a dictum to buy commercial, off-the-shelf hardware. "This move has kind of put military specs in the background, although they're still referred to all the time," Collins maintains. "There are portions of the specs that we still have to pay attention to for testing. At one time, there were qualification programs for almost everything, and we had to prove ourselves worthy of making something to get on their QPL (Qualified Producers List). This is all gone now, since there are no more QPLs."

Machining Company Assists Engineers with Intricacies of Glass Cutting

Pynco has routinely offered design, optics research, and testing for its custom-oriented clients for many years. A customer's engineers often query the company about a lamp assembly, indicator light, or filter that has critical specs or other important requirements. "A lot of engineers don't understand our processes, and they don't have the equipment to do the measurements to see if they're getting what they want," Collins explains. "And they might not have the expertise to specify exactly what they need. Sometimes the best they can do is give us a requirement that's been given to them."

There are two engineers and a scientist on staff that can help a client with initial research and design for their parts. One is a mechanical engineer and the other an electrical engineer, and Collins is a physicist with an expertise in optics. "When we're in the design stages of a new filter stack, we'll do a certain amount of testing to see what the prospects are for success," says Collins.

Prototyping at Pynco, Collins points out, refers to the routine research and development work it accomplishes in making a multiple-layer filter. He says this is because a one-layer part will usually accomplish everything that you want to do, but if it doesn't, then other components and colors will have to be added. Sometimes additional testing will be necessary after production starts, since it's impossible to answer certain questions until parts or components are made into their final shape and form.

Although Pynco specializes in night vision imaging systems, the company has designed and manufactured another aircraft-related product for many years. Electronic relay systems were one of the first products that Pynco produced when the company first got started. Jim Seib, Pynco's founder, designed the system based on military specs that were available at the time.

"The particular device that we're talking about is called a Battery Relay Control Unit; it's mostly used in military aircraft," says Collins. "What it does is turn the electrical bus off in a fighter jet. A bus is a device that provides electrical power to the entire aircraft, so it's a very important component."

What precipitated the need for this device, according to Collins, is that when the aircraft is on the ground or in the hangar, sometimes the mechanics will walk away and forget to turn the power off. Then, if pilots have to scramble the jets, they'll have dead batteries. So what the relay does is respond to several different logic operations that have time relationships to them. If something doesn't happen within a certain length of time, then the relay shuts the bus off.

One notation on the company's digital literature says that glass is superior to plastic for these types of applications. Collins was asked why this is the case.

"Well, once again, plastic and glass both have areas where their usage is preferred," says Collins. "But plastic has some problems with temperature stability, and plastic filters that are made in a mold may not have the tight tolerances that we can get with machined glass. This is not to say that plastic doesn't have its place."

Company information also states that the CNC machining of glass parts is more cost-effective and quality-oriented than performing the processes with molding. Therefore, all of its glass products are machined in-house with precision vertical CNC milling centers. Both processes are said to have a place in making miniature glass parts; however, the comparison stops there.

The problem that glass molders have is that they've got to make parts in fairly large quantities in order to make production cost-effective. "The cost of making the molds is what drives whether or not it's profitable for molders," says Collins. "With the machining operation, we can make a lot of parts or just a few and still be cost-effective. The fixturing cost is not that great for these parts."

The company reports that its machining process provides faster lead times, improved dimensional consistency, superior spectral transmittance, and allows it to more readily accept customized, low-volume orders. In addition, the company says that machined glass filters are also superior in their performance and durability versus plastic filters.

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