An Interconnect System Tooling Primer

Every technician knows that having the right tool for the job is a basic requirement for the safe assembly and repair of complex systems. Glenair has the expertise to design a Custom Tool Kit for every electrical interconnect application.

In the control room, the first-line maintenance supervisor had just completed the lengthy process of testing and calibrating the Process Radiation Monitoring System when he noticed one of the pin contacts on the panel mounted interconnect was damaged. "No worries" he thought "we stock replacement pins for all the 5015 type connectors used in the control room. But what about the insertion and removal tool! I wonder if we have the right one on hand?" Unfortunately for the Brown's Ferry plant, the answer to that question was no. And the operation had to wait an excruciating (and expensive) two days before the right tool could be located and hand- delivered to the plant.

Good mechanics never blame their tools when things go wrong in an assembly or repair operation—or so the saying goes. But good mechanics also know that having the right tool for the job is a must if you want to do the job right—first time and every time. Assembly and maintenance of electrical interconnect systems calls for a dizzying array of specialized tools: from wire cutters and strippers to contact termination tools, contact insertion and removal tools, connector holding tools, shield termination tools, circuit testers and more. For large application environments, such as a nuclear power plant, literally hundreds of tools are required to assemble, test, service and repair the electrical interconnect systems which service the control room and the monitoring equipment located throughout the plant.

Glenair manufactures many of the specialty tools used in interconnect harness assembly. And we are distributors for a wide range of additional tooling from the industry's other leading manufacturers. Throughout the globe, but especially in Great Britain, Germany, the Nordic region, France and Italy, Glenair has built a reputation for providing turnkey interconnect tool kits and tooling service programs. Military and commercial customers alike choose Glenair as their interconnect tooling supplier because of our unique ability to create custom kits which combine the tools and services from multiple manufacturers. Additionally, Glenair is able to provide system-level tooling needs assessment and consulting services to ensure tool kit configurations match the exact need of the application. And as is always the case at Glenair, our goal is to maintain extremely short lead times, up to and including same-day stocking, of individual tools and customer-specified kits.

Glenair's Custom Tool Kit Sales and Service Program offers interconnect customers a wealth of program features and advantages, including:

• System-level tooling needs assessment and consulting
• Custom tool kits and workstations for a broad range of interconnect applications, working environments and connector families
• Custom tool kit labeling and packaging
• Translated, local language tooling instruction sets
• Calibration, test and refurbishing services
• Same day availability on individual tooling part numbers and kits

Depending on geography, Glenair can put together tooling solutions from Daniels Manufacturing, AMP, Astro, Ideal, Dubuis, Tie-Dex, and dozens of other specialty tooling manufacturers. And as we mentioned before, we also make our own line of backshell and connector assembly tools. But whether we make the tools ourselves, or pick and choose from the rest of the industry's offerings, we have over 40 years of experience specifying and using the complete range of interconnect tooling in a large-scale production environment.

As the Brown's Ferry nuclear plant example aptly illustrates, not having the right tool on hand is simply not an option for the many Glenair customers who are committed to uninterrupted operation and the fast return of critical equipment to service. For this reason Glenair's Interconnect Tool Kit Sales and Service Program is geared to anticipate customer tooling requirements and to the provision of turnkey tooling solutions for every aspect of factory and field operations.

Wire Preparatory School

Glenair is uniquely positioned to solve one of the major problems faced by owners of interconnect cabling: access and availability to the diverse range of tooling required to put the systems together and fix them when they break.

When selecting wire and cable cutters for high-reliability applications, the most important requirement is for tooling which produces clean cuts without distortion of cable geometry. Larger gauge data communication cables, for example, become extremely difficult to work with if conductor ends are crushed or flattened by poorly engineered cutters. Cutters which fully encircle the wire are therefore preferred for the preparation of large gauge wire. Small gauge wires generally call for cutter tooling which can be used in confined spaces, and can safely cut individual conductors without damaging neighboring wires or terminations. For this reason, standard diagonal cutters, or Dycem pliers, with precision ground blades are preferred.

Cutters for unique applications, such as specialized Kevlar electrician's scissors for cutting Kevlar strength members in fiber optic cable must be carefully selected to insure cuts are clean, and free of ragged endings which will get in the way of subsequent work. The same issue applies to fiber optic stripping tools for removing buffering and jacketing from fiber optic cable: the exposure of the buffered fiber must be accomplished without creating a gordian mass of tattered material or crushing the fiber optic core.

Wire strippers—tools used to remove insulation from a conductor—are selected for ergonomics (the comfort and control of the user) and also for the quality of the blades. As with fiber, the tool must accurately strip away insulation without damaging the conductor. Production-line assemblers generally prefer contoured, cushioned grips to reduce repetitive stress and technician fatigue. Easy to read wire gauge markings are also a must when the same tooling is used on a range of cable gauges.

For hand-held wire preparation tooling which will be housed in a kit, models with integrated locking pawls should be selected for efficient storage of the tooling when not in use. For high-volume applications, fully automatic wire processing systems are available. Automatic tooling is called for when high speed cutting and stripping is required to meet volume production goals, usually in the thousands of wires per hour range.

Contact Termination 101

The termination of crimp contacts for use in military applications is controlled by MIL-DTL-22520G which defines crimp depth, size and the other key parameters necessary to insure good mechanical and electrical performance.

The first standard indent crimp tool developed for the new removable contacts, utilized a four indent crimp pattern and a positive stop locator to control the travel of the indenters (crimp depth). Unlike today's modern crimp tools, the crimp depth for any given contact was not adjustable for different conductor diameters. Improved tool designs featuring independently adjustable crimp depths allowed for optimal crimping of conductors ranging from AWG 12 to 26 regardless of the size of the contact wire barrel. Other innovations included double tipped indenters to produce a more reliable eight indent crimp pattern for superior tensile strength. These innovative crimp tools were the first to employ adjustable turret head locators—devices that contain more than one locator which can be indexed by rotating a circular barrel to position different sizes of contacts.

Today, the termination of removable multi-pin contacts for use in high-reliability applications is controlled by MIL-DTL-22520G which defines crimp depth, size and the other key parameters necessary to insure good mechanical and electrical performance. MIL-C-22520 established a single specification which set forth performance requirements for all indent style crimp tools to be used on military standard electrical connectors. These specifications also defined a miniature crimp tool for conductors as small as AWG 32. The establishment of MIL-C-22520 was a milestone on the road to crimp tool standardization. Its development has eliminated confusion from the many different "standard" crimp tools specified on different military drawings.

Crimp tools for the termination of stamped terminals to conductors are also widely used to assemble and service military and commercial high density connectors. Crimp tools for use with stamped contacts are designed to simultaneously bend both an insulation crimp and conductor crimp in place, creating a reliable, gas tight grip on the exposed wire end.

Glenair contact termination tooling is available to address everything from the contact crimping and assembly requirements for an entire interconnect system—such as a wide-body commercial jet—to the field repair and maintenance of battlefield equipment. Selection of crimp tooling and accessories depends on the specified connector and contact as well as volume production requirements and the required quality of the completed terminations.

At Glenair, "one-stop-shopping" for interconnect tooling means more than just a fat catalog of part numbers. Because we operate our own harness assembly plants, we are intimately familiar with all the tooling required for successful fabrication and test of top-quality interconnect systems.

Glenair is able to provide both discrete tooling as well as standard and custom crimp tooling kits and service programs. Depending on volume, hand tools or fully automatic crimping machines may be specified. Manual hand tools should be specified when production volumes are in the range of 200 terminations per hour. Such manual tools are also ideal for prototype applications and field repairs. Well designed manual crimp tools feature full cycle operation, and close tolerance die closure controls to eliminate contact distortion and ensure crimp joints meet performance requirements.

Automatic and semiautomatic crimp presses can produce up to 2000 or more terminations per hour. Many automatic crimp presses also combine wire cut and strip functions for added convenience. Many automatic crimp tools are also designed to use the same turret heads or positioners, gauges and accessories as their corresponding hand tools. As explained above, crimp tooling is controlled by military specifications to guarantee reliable and repeatable terminations.

Advanced Insertion and Removal

Various contact retention methods are employed including MIL-C-38999 style rear release retention, MIL-DTL-5015 style front release, MIL-C-81511 gang retention, Cannon style interference lock retention and many others. But regardless of the exact contact retention style, all the systems employ simple, hand-held tools to depress the contact retaining clips, tangs or lock rings to allow the contact and conductor to be removed from the connector. The tools are available in both plastic and metal versions and are color coded for contact size and type.

Both front and rear release connectors are easily serviced with these military standard insertion and removal tools. Replaceable tips are available as are other accessories such as installation pliers, tweezers, and contact retention test tools.