A slippery slope: A story of strategic upgrades
A customer perspective
At our automotive stamping plant, our 75-ton critical crane lifts dies at full capacity in order to meet production needs. One morning, our crane operators were hard at work when I witnessed something unsettling: when the crane attempted to make a lift, the load suddenly and unexpectedly drifted back down to the ground. The load had only drifted down about six inches, but we were all shaken by the event. Load drift is extremely serious and potentially very dangerous. We needed to fix this issue immediately.
We tried to realign the brakes, thinking we could eliminate the problem, but the load drift occurred on and off for six months. We called in several companies to look at the brakes, including the original manufacturer, but no one was able to prevent the loads from slipping. During this time, the cranes experienced emergency breakdowns at least once or twice per week. When a crane broke down, we had to call for an emergency repair, wait for the correct parts and then perform the actual repair. The entire process could last anywhere from four to eight hours.
We needed to fix this problem immediately, so we called Konecranes. Their technicians determined the factors causing the load drift: the stamping crane used self-adjusting brakes, which were over-adjusting and pushing themselves out of alignment. Though our cranes used variable frequency drives, they were an early model. So when the brakes slipped, they did not have the technology to override the motor to prevent the load drift.
Konecranes installed new variable frequency drives, which came with advanced safety features. I like the “brake slip detection” feature best: if the brake slips, the inverter drive detects it, keeps the load steady and sounds an alarm. Konecranes also installed new, more reliable brake adjusters. We felt much safer knowing this new equipment minimized the potential for load drift.
Now, we trust Konecranes to care for all of our cranes. They provide monthly inspections and make sure all our cranes are running properly. Thanks to them, breakdowns at our plant have been decreased by 95% compared to last year.