Automated Potting of Multiple Connector Assemblies

 

Potting operation is smooth and predictable, allowing a single operator to produce four 80-pin power train connectors every 20 seconds

The perfect computer environment entails a controlled temperature, an even humidity, and protection from contact and airborne contaminants. Now, put those same sensitive computer parts under the bonnet of an automobile. Subject those very delicate parts to wide swings in temperature, salt, humidity, engine fluids and vibrations, and the duplication of the perfection of a clean-room environment would seem like an automotive engineer's worst nightmare.

But it's all in a days work for Augat Automotive, a leading supplier of precision terminals, fasteners, connectors and assemblies for automotive applications. In this case, a module consolidates all the connections between the vehicle's controls and its computer. The module plugs into the computer, tying all the peripherals to it. Some 80 wires come together in the plug-in device that becomes the main connection in the computer network.

4 off SeeFlo 690 mounted in common frame showing 4 off dispense valves prior to installation on-line

Encapsulation of the connectors by something impervious to assault, obviously, is required. Designing a manufacturing system to achieve the demanding production rates of 720 connectors per hour and maintaining the quality was a challenge.

Sealant Equipment & Engineering Inc. (S.E.E. Inc.) has supplied the meter / mix / dispense equipment for this application to a number of major automotive OEM's, enabling them to enhance their ability to meet the increasingly strict quality standards of the Big Three US automakers. The Augat Automotive application is an example of how encapsulating material suppliers, automated conveyor system designers, and manufacturers of dispense equipment can cooperate closely to satisfy the demanding requirements of customers.

How Important is the Meter / Mix / Dispense Equipment ?

At the very heart of Augat Automotive's highly efficient production line lies four SeeFlo 690® Meter / Mix / Dispense units made by S.E.E. Inc. Specialising in fully integrated production systems since 1967, S.E.E.'s potting operation is smooth and predictable, allowing a single operator to produce four 80-pin power train connectors every 20 seconds.

A two-component polyurethane material formulated by Biwax Corporation, is dispensed exactly to the volumetric mix ratio (2:1) by positive-displacement metering pumps. As the rods are forced into the displacement metering cylinders, outlet valves open to permit the proportioned volumes of resin and hardener to flow through to the Snuf-Bak mix-at-the-nozzle dispense valve. There is no dripping or wasted material. A special SeeFlo No-Flush™ disposable, static mixer nozzle eliminates the need for solvent flushing…..friendly to the environment and to the worker. Should production need to be halted for any reason, the nozzle will automatically purge itself with mixed material after its pot life of 5 minutes and refresh itself with fresh material, thereby preventing the mixer from clogging up with hardened material.

The fast-setting material (5 mins / 100 grams) when cured remains pliable at temperatures as low as -40°C and yet maintains stability at temperatures of up to +125°C. The viscosity of the material was formulated to prevent seepage through the connector's pin holes. The A and B components are fed to the four SeeFlo 690 systems via transfer pumps that are gravity fed from four 45-gallon drums utilising special "breathers" and hoses to prevent atmospheric moisture from contacting the polyurethane material.

Prior to potting, aluminium pallets, containing four 80-pin power train connector assemblies each consisting of two 40-pin chambers, are loaded onto the conveyor designed by Thermal Innovations. Preheated in an oven (consisting of medium-wave quartz emitters and aluminised walls for maximum conductivity), they arrive at S.E.E.'s potting station at approximately 85°C. This preheated stage allows for elimination of any ambient moisture, improves the flow of the potting material and enhances the polyurethane-to-part bond.

At the potting station, dispensing may be controlled manually or automatically. In this application, PLC-based controllers integrate the meter / mix / dispense equipment with the manufacturing automation. S.E.E.'s engineered AirDraulic™ power-drive feature ensures a controlled, constant dispense flow rate.

After potting four connectors simultaneously, the state-of-the-art conveyor system carries the connectors to the infrared oven containing short-wave emitters and, again, aluminised walls for greater efficiency. This oven heats the parts to the precise given temperature necessary to obtain the proper cure. The pallets then enter a chilled cooling section where parts reach a temperature of 50°C, low enough for a gloved worker to remove them from the line and pack them for shipment.

A Win / Win / Win Solution !!

Increased production efficiency, a minimum of manpower and high-quality production standards were the objectives of this project. A space-age potting material, the ingenuity of the oven / conveyor system designers and customer input have produced a successful manufacturing process. The heart of the operation will continue to be the contributions of the meter / mix / dispense operation. Every facet of the process is working together for a common goal: to manufacture high-quality products for the end user.