4/15/1992 – Alcatel Network Systems in Richardson, Texas, is a division of Alcatel, N.V., the world’s largest manufacturers of telecommunications equipment and systems. Their high tech products are used by local telephone companies, long distance carriers, cellular companies and private and government networks. These include asynchronous and synchronous lightwave transmission and network management systems, digital microwave radios, digital cross-connect and digital loop carriers. The Texas based firm has also led the communications field in introducing metropolitan area networking applied to advanced applications such as computer aided design and manufacturing as well as video.
In the manufacturing area, problems surfaced with adhesive applied nylon grommets used to protect cable and wires installed in equipment cabinets, enclosure, cardcage end plates and shelves. Recurring abrasion of these connecting elements passing through sidewall slots or making contact with metal edges lead to cuts in the wire insulation causing electrical shorts.
Additionally, experience showed that nylon was subject to coldÐflow in low and high heat environments. It was also flammable and did not meet the Bellcore, UL or IEC flammability requirements.
The former grometting system, exclusive with the company for some 25 years, required adhesive bonding, a procedure that slowed installation time and eliminated any chance of grommet reuse. Because nylon becomes brittle in high humidity environments, there were shelf life limitations as well.
In one instance, the adhesive-applied nylon grommets mounted in equipment shipped to Korea were affected by the extreme changes in temperature and humidity. The result was that the nylon grommet edging loosened and separated from the metal.
With the practicality of their existing grommets in question, Alcatel began a continuing study to find alternatives to grommet composition and adhesive installation. The firmÕs Mechanical and Product Engineering Departments conducted tests simulating varying abrasion, vibration, temperature, humidity and salt spray conditions on three competitive grommet configurations and also investigated the possibility of machine radii on the bare aluminum metal edges of their cabinets. Mechanical Engineering Manager Charles Havens and Senior Product Engineer Kenneth Chandler ultimately recommended the use of SPRING-FAST® polymer coated stainless steel grommets manufactured by Device Technologies, Inc. of Marlborough, MA. Their decision came after in-depth analysis, engineering usage and manufacturing evaluations convinced them that Device Technologies’ composite grommet edging most effectively addressed job requirements for productivity, reliability, quality and workmanship at a reduced installed cost.
Both the study and one and one-half years of production experience since have demonstrated a wide berth of benefits:
Easy to mount. The tight gripping composite grommet edging engineered with staggered gripping fingers has shown to hold on aluminum and plated steel panel thickness from .033 inched (.84 mm) to 0.128 inches (4.6 mm) without need for adhesives. Installation is accomplished by simply pushing them into place saving time and labor.
Manufactured with a spring stainless steel substrate and clad with 5-mils of thermosetting epoxy polymer coating, the composite grommet edging withstands abrasion and provides positive insulation. Construction is UL and TUV recognized and passes the two-minute needle flame test of IEC 695-2-2.
No component deterioration occurs with changes in humidity and therefore no restrictions exist with shelf life.
Installation costs are reduced. Alcatel’s evaluation study showed mounting time for polymer coated grommets at .48 minutes per grommet foot. Previous mounting time was 3.48 minutes per grommet foot.
The move to the alternative grommet edging has reduced the cost per foot from a previous high of $4.19 to $2.72 per foot Ð an overall savings of 35.1%
Although the conversion process is still continuing, Alcatel to date has switched 75% of its products to stainless steel grommets. The transfer has been conducted on a product-by-product basis, rather than aiming for an across the board sweep according to Chandler. “We are moving toward the exclusive use of polymer coated/stainless grommets after doing things one way for so many years.”
The new grommet edging has found applications with 0.100″ flat packs to discrete cable measuring 1.5″ in diameter. Wires protected by the composite edging run from 8 awg. to 32 awg. Slot sizes range from 1″ to 16″ diameters. In most cabinet installations, an average of 2 cables are inserted through or against sidewall slots during equipment assembly.
In order to enjoy the most economical ordering program, Alcatel purchases the grommets on reels measuring 100 feet. The firms has the option of cutting the grommets to size by using Device Technologies’ adjustable pneumatic cutoff press or special cutoff shears for manual preparation of cut unit lengths.
In summing up the Engineering Department’s study and conversion decision, Chandler comments that SPRING-FAST® Composite Grommet Edging is “well designed, flexible, durable and provides protection against wire insulation cuts and shorts.” He points to the added benefit that production personnel are also better protected against cuts from sharp metal edges, exposure to fumes and contact with the often toxic adhesives. The new edging has been enthusiastically received by manufacturing operators and engineers.
