Tier I integrator's strategy has sweet smell of success

Tooling & Production, Dec 2006

As anyone in the aviation industry will tell you, details are everything. From the Wrights' first airplane to today's highly engineered spaceships, every component is mission-critical to the performance of the aircraft. So it came as no surprise to the facility supervisors at Vought Aircraft Industries Inc. that a seemingly minor consumable product such as the coolant it uses in its manufacturing processes could considerably affect production output and costs.

Vought, headquartered in Dallas, TX, is a major independent producer of aerostructures. The company employs more than 6,000 people at eight locations and generates more than $1 billion in annual sales. A Tier I integrator to the aerospace industry, Vought manufactures large, complex, turnkey assemblies such as tail and wing sections, nacelles, thrust reversers, and fuselage sub-assemblies for both commercial and government organizations. Boeing, Airbus, Gulfstream, Lockheed Martin, Sikorsky, Cessna, and the U.S. military all rely on Vought for its precision design and manufacturing.

The company's two main machine shops in Dallas have hundreds of cutting, milling, grinding, routing, and drilling machines, as well as lathes, drills, and routers for machining aluminum, titanium, and Inconel. In Building 6, more than 200 machines are in operation, while Building 1 houses approximately 35.

Despite the highest quality product output and an impressive 95 percent machine uptime, Vought determined there was still room for improvement. It was time to address a nagging problem that had surprisingly widespread effects - foul coolant.

Vought was hardly alone in dealing with souring coolants - it's a headache that bedevils the metalworking industry worldwide, especially at facilities that utilize large, centralized coolant systems.

At Vought, the problem was magnified because of the size of their machining operation. Souring coolants represented a significant portion of production costs. The facility's 235 stand-alone coolant sumps and three central coolant systems collectively hold more than 60,000 sump gallons of coolant, and Vought plans to increase capacity by 80,000 gallons in the foreseeable future.

For more than 20 years, Vought maintenance personnel consistently conducted trials on new coolant technology, but never found a solution. "We avoided downtime at all cost and lived with the smell until the weekend, when we would try various fixes to rebuild the coolant in the system," says Bob Murphy, production manager of Building 1.

Building 6 fared no better. "Coolantrelated issues were the leading cause of unplanned downtime," says Lanny Shirk, production manager of Building 6. "To make up for the delays, we ran machines through the weekends. We also worked four to five employees on Saturday and Sunday."

Abruptly, the need for better coolant technology escalated in April 2004. An unstable coolant condition in one of the central systems caused Vought to shut down the entire Building 1 facility for half a day. The company was forced to dump and recharge the entire 13,000-gallon system. This costly incident moved Vought to launch a renewed effort to find a new coolant technology.

"Coolant had been an ongoing issue for years," says Robert Nixon, the process control engineer at Vought who led the charge to find a coolant solution. "The frequent and unsuccessful attempts to find just the right fix were tiring and frustrating. We had already been putting up with the stench and the mess, but now the expenses were getting too great to ignore. Finding a solution became a top priority."

Vought knew firsthand just how expensive coolant-related problems could be. "Most people in the industry think of coolant cost as the cost per gallon of coolant concentrate. They usually don't think of all the items needed to keep coolant clean and performing properly. And they almost never consider the costs of dealing with poor coolants - constant maintenance to clean residue off of tools, parts, and machinery - and expensive dumps, disposal costs, and coolant recharges. Those numbers are significant," says Nixon.

To minimize costs, facility supervisors employed every means possible to extend the life of the coolant, particularly in the central systems. Vought used drag chains to pull out metal chips and filings to help keep the coolant as clean as possible. Vought also purchased a large centrifuge to remove tramp oil and rotated it among the different systems, diverting some of the coolant to the centrifuge where it was cleaned and returned to the flow - a process that takes three to four days.

In addition, Vought personnel conducted regular coolant checks for concentration level, pH level, and traces of bacteria. Vought lab technician Laura Marbut was pulling coolant samples from 16 systems each Thursday, analyzing them for concentration, pH, and biometric readings, and running Grotan tests for biological activity. These activities, plus the resulting discussion of possible fixes with plant staff, consumed more than 10 hours of Marbut s time each week.