3 types of inspection and measurement

Munitions manufacturer gets controls and automation overhaul without interrupting production.

By Mike Bacidore, editor in chief

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At the only NATO-approved munitions manufacturing location in the United States, production is hitting its stride. But a potential slump was avoided, thanks to some updated automation and an organized installation plan.

“When the global war on terrorism began, munitions supply was a huge issue of concern,” says Rod Emery, P.E., VP of operations at RedViking, designer, builder and integrator of manufacturing solutions and dynamic test systems in Plymouth, Michigan. “They were worried they wouldn’t get the munitions supply they needed. The current systems were unable to keep up with new levels of production.”

The facility’s original five lines of production equipment were built in the late 1960s and early 1970s. “The instrumentation, controls and measurement were antiquated, and the parts and technology were no longer available,” says Emery. “The machinery was constantly failing, or the measurement was calling parts bad that weren’t bad. They had too much downtime and too much scrap. The mechanics and the configuration of the machines were solid though. They just needed to be maintained. The bearings, shafts and gears were still available.”

The five production lines are responsible for producing 1.4 billion rounds of ammunition per year. When RedViking was asked to create a solution, it decided the best course was to build one new system from scratch with all new technologies and instrumentation and then prove the system before replacing the existing five lines.

Who’s on first?

The new machine created a need for high-speed, non-contact inspection technology for test and measurement. “Every 50 ms, you’re measuring a part,” says Emery. “We’re using high-speed cameras for non-contact measurement of the dimensions of the case. There was another location where we were using eddy current to look for tears or holes in the casing. We were using laser scanners to look for abrasions on the product (Figure 1).”

The first system was completed in 2010, and RedViking proved it out at its own facility. It utilized modern technology that includes Rockwell Automation ControlLogix PLCs, RSView SCADA and PowerFlex drives with SERCOS communication, along with off-line measurement instruments developed using the National Instruments LabVIEW platform. “We also included a Rockwell Automation servo system for the sample insert wheel,” says Emery. “The sample wheel is used to validate the equipment, and it’s done twice per shift. They put known samples into the sample wheel to make sure they matched. The wheel goes from zero speed to matching up to 1,200/min.”

To prove out the first system, RedViking ran tens of thousands of rounds, and defects were included to prove the system would eject defective parts. “The customer was responsible for creating the defect, so they hired a contractor,” explains Emery. “We went through the runoff. They put 20 bad parts among the tens of thousands of good parts, and we ran it and we got to the end of the line and we had one less defect than we were supposed to. They’d put permanent dye on the defects to identify all 20, and somehow we missed one of them.”

The engineers sifted through the tens of thousands of cases by hand to find the undetected one with the red dye. “It was hours,” says Emery, “but we finally found the needle in the haystack.”

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However, the case had no defect. “That particular one was supposed to have a very small hole,” explains Emery. “But the people who were supposed to put the defect in it didn’t. They missed it.”

Advance the runner

When the first newly designed machine went in, it was important to keep the lines up at all time. “We installed and did the factory-acceptance test at their location,” says Emery. “Then we began tearing down the equipment that it replaced. The inspections on the old machines were done by probes, and they weren’t able to do all of the inspections we were doing. They had eddy current, but it wasn’t covering the entire case. They were using X-ray. As each turret passed, it performed the inspection.”

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