Portable metrology in mining vehicles

A single piece of mining equipment can cost millions, and if it breaks down, the entire mining operations halts, costing operators a small fortune. For component suppliers to mining vehicle companies, those expenses create massive pressure to get things right the first time.

“You don’t want to be the reason a mine shuts down. It’s that old phrase, ‘You’ll never work in this town again.’ People remember you when you cost them that kind of money,” says Dwight Smith, sales manager of Kapp Technologies in Boulder, Colorado, distributors of R&P Metrology gear inspection equipment.

A mining equipment company recently validated R&P’s PM 750 portable gear inspection system. The 2-week trial included correlation with a calibrated master and various shop floor assignments. Spur and helical gears, pinion shafts, and double helical gears were checked on the cutting machines, using the rotary table for positioning, and on the shop floor without rotary motion. The parts ranged in size from a 203mm (8") master to a 4.4m (175") gear. An artifact part was also checked and compared to the measurement on the lab’s CNC gear inspection machine.

Many of the gears inspected were too large to fit onto CNC machines, making traditional metrology techniques a challenge, Smith says.

“There’s a very different set of expectations going on with these large gear producers. In the past, the assumption was that if there were the right number of teeth, we’ll make everything work,” Smith explains. “Now, precision is crucial. The old ‘good enough’ is nowhere near good enough. The ground gears that companies require now have to be incredibly precise.”

Metrology systems designed for small parts can’t deal with 5m diameter gears, Smith adds. Portable systems can move to workpieces, confirming specifications from the floor or on production machines.

During the PM 750 test period, engineers mentioned an internal gear that was not part of the test. They needed to know if the cutter geometry was producing the predicted profile. The part was too large to check using the existing lab machine. The PM 750 was quickly set up and the resulting measurement was used to adjust and confirm the tool design software.

The portable PM 750 was moved from place to place inside the shop using a crane, and was transported to different buildings via a lift truck. From the end of measuring on a production machine, the system was ready to be moved in 6 minutes. Setup on the next machine or location was accomplished in 15 minutes.

“Most gears that will fit on a dedicated machine are going to be small enough to inspect with a typical metrology system. But those really big pieces need something special,” Smith says.

Kapp Technologies
www.kapp-usa.com