New technology monitors, ensures accuracy of adhesive mixing

A new technology developed by Real Time Ware Inc . is designed to monitor the mixing of adhesives, powders, paints, cement, asphalt, rubber, and any two or more components. The method is applied at Ford Motor Co . to maintain adhesive accuracy on closure panels, such as doors, hoods, and trunks on vehicles.

Automotive engineers chose two adhesive materials because of their bonding strength and long shelf life. However, technology to measure mix ratios accurately has been virtually non-existent. Using the antiquated “Dixie cup test” (a manual method) as a calibration means left many potential problems undetected. As a result, Ford Motor Co. and Real Time Ware worked together to create a new way, called Ferromagnetic Tagging, FMT3000, to monitor the complete dispensing cycle from start to finish.

Ferromagnetic tagging provides real-time, in-line monitoring of the mix-ratio of two-component adhesives and foams (left). FMT3000 can measure actual mix ratio as material is dispensed onto a part and sound an alert if the product is out of spec.

As shown in the illustrations above, sensor B monitors the tagged material: component B. Sensor A monitors the mixture of components A and B. The ratio of sensor A to sensor B is the mix ratio. When the ratio is out of specification, adhesive cannot adhere or cement doesn’t harden.

The mixing element randomly positions ferrous particles throughout the mixer. The particles are exposed to the flux created by an alternating current. Magnetic flux lines react to the permeability of the particles and to small, localized eddy currents created by the alternating flux. When a change occurs in the mixing, new particles continue to be distributed evenly throughout the adhesive.

Disrupted mixing conditions, such as a leaking hose or a missing static mixing element, create an incorrect ratio and cause the FMT3000 to trigger an off-ratio signal indicating particles no longer are being mixed. Shipment of below-spec finished product is thus avoided.

Real Time Ware is exclusively licensed in this technology by Ford Motor Co. The process is patented; several patents are pending. For more on the process, including a look at various applications and an explanation of the Dixie cup test—or to download a pdf about the technology— visit the Real Time Ware Web site .

—Jeanine Katzel, senior editor, Control Engineering, jkatzel@reedbusiness.com

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