Training and technology for crane operation success in heavy fabrication

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Imagine a hectic morning. The overhead crane operator arrives late. He knows he’s behind when he starts his shift, so he quickly rigs a plate that he needs to move to the next workstation. The rigging isn’t quite centered, and the load swings as the lift starts. The flustered operator slows the lift to compensate for the swinging. Then, snap. The wire rope breaks, and a bad morning turns into a disastrous one.

Cranes remain the backbone of heavy fabrication. Operating them improperly can hinder productivity; running them unsafely can have devastating consequences. To find out how to avoid those consequences and uncover best practices, The FABRICATOR spoke with three crane-service experts at Valley City, Ohio-based Engineered Material Handling (EMH) Inc. Their advice boiled down to several key elements: good training, topnotch inspection and maintenance, and the right technology. An efficient and safe crane operation requires all three.

Choose the Right Crane Technology

Industry standards from the Crane Manufacturing Association of America (CMAA Specification 78), American Society of Mechanical Engineers (ASME B30.2), and OSHA (1910.179) spell out inspection requirements and their frequency, identifying cranes by how often they are used. A crane under normal service performs about five lifts an hour, and no more than half of those loads can be more than 50% of the crane’s rated capacity. A crane under heavy service performs five to 10 lifts an hour, with up to 65% of those loads at the rated capacity. Severe service involves picking near capacity on most loads and performing more than 20 lifts an hour.

The industry also has crane classifications that help identify the spectrum of use. Class A is for infrequent or standby use, B is for light service, C is moderate service, D is heavy service, E is severe, and F is for continuous severe service.

“We often see cranes that are not classified for the kind of duty cycle they’re being used for,” said Joe Piscitello, EMH’s service manager. “If you have a steel warehouse and you’re running a crane at full speed near full capacity, you don’t want to install a Class C crane.”

This doesn’t mean an entire crane needs to be replaced. “We’d likely recommend modifications,” said David Comiono, vice president at EMH. “Perhaps the hoist is too fast or too slow. Or they might need more capacity. The more sensitive the product is, the more speed control you’ll need.”

How does a fabricator define a “sensitive” product? As Comiono explained, the definition varies depending on the application, but as with so much in material handling, the decision involves a healthy dose of common sense.

“A crane to handle mirrors for the new [James Webb] Space Telescope required a crane system with special attachments that allowed very fine, smooth control. At the other end of the spectrum would be moving a piece of plate in which you don’t care so much about damage, as long as you didn’t damage or prematurely wear the crane.”

EMH sources added that the nature of the workpiece itself is just a piece of the puzzle. Selecting a crane requires a holistic view that includes identifying the crane’s role within a shop’s overall material handling strategy. An overhead crane might move inexpensive, easily replaceable workpieces, but what are the ripple effects if a lift goes awry? Will downstream operations starve, or do they have a buffer stock staged nearby to keep running?

Also, what’s the nature of the lifts? Is the crane part of a constantly churning production line ruled by a consistent cycle time? Or does the crane handle a variety of workpiece sizes at different times and frequencies? Does it hold workpieces within fixtures or assist in critical tool changes?

An EMH service tech inspects a bridge crane electrical panel.

Sightlines are another factor. “Sometimes operators who use a traditional pendant can’t see the lift because of an obstruction,” said Jeff Larouche, EMH’s operations manager. “So, they might need to walk with the pendant somewhere that puts them in a dangerous position. In this case, we’d recommend working with a radio control rather than a pendant.”

Environmental factors fit into the equation as well. For instance, some operations have audible alarms to alert everyone that an operator is running the crane. But in a noisy atmosphere, such alarms can be pretty much useless. In these cases, light signals can be a better solution.

The environment’s temperature, humidity, and air quality (that is, amount of particulate and dust) must be factored in as well. If, say, a large waterjet job shop invests in a crane, ideally the crane’s electrical enclosures (and preventive maintenance regimen) should factor in that excess moisture.

EMH sources added that industry-standard crane classifications serve only as a baseline. The trick is to think holistically and consider the ripple effects of poor material handling within the entire value stream. A crane might be used infrequently—say, to change out a critical die in a press—but if the positioning of that die is critical, the crane itself would benefit from being able to move at precise speeds.

“In the old days, cranes just had a single speed, so experienced operators would tap the buttons a lot,” said Piscitello, referring to the “feathering” action operators perform to accelerate and decelerate smoothly and minimize sway throughout a lift. “Today, however, with the advent of two-speed control and variable-frequency drives [VFDs], you can invest in a system that provides exactly the control you need for the product you’re moving.”

The Importance of Training

Larouche compared the features of some modern VFDs to autobraking in some modern cars. The engineering behind both is different, of course, but the general idea is the same: to change speed in the safest, most efficient way possible. This way, a new crane operator need not learn the intricacies of feathering and other idiosyncrasies of working with legacy two-button pendants.

“The equipment has become smart enough to help prevent less experienced people from making a mistake,” he said.

Those mistakes can cause major inefficiencies and prematurely wear crane components. For example, sway can add seconds or even minutes to a lift cycle time. The sway of excess movement can cause hoist motors to overheat.

“If you start a lift and have a lot of sway, you’ll need to accelerate again,” Piscitello said. “You’ll stop, then go, then stop, then go again to control that sway. All that generates a lot of heat. Ultimately, that can burn up a motor.”

Modern VFDs correct for this, helping to prevent such sway from occurring. EMH sources added, however, that technology cannot circumvent the laws of physics or prevent every mishap, and it doesn’t make proper training any less important.

Operators still must know about proper rigging and finding a workpiece’s center of gravity. After all, no matter the crane technology, a lift involving a severely off-center load is bound to swing. They also need to know how detrimental shock loading can be. Especially in a fab shop setting, operators might use a crane to hold a workpiece during an operation, or they might be asked to flip a plate or beam.

“If an operator doesn’t take the time to tension the sling before going to a high speed, you can create premature wear on your rope, on your brake, on your entire structure,” Larouche said. “You can create cracks on the beam itself.”

A technician inspects the components of a bridge crane trolley.

Other times, operators run trolleys into a bridge crane’s end stops, “and the wheels keep spinning,” Piscitello said. “Do this enough, and the wheels can dig divots into the rail. And continually slamming into the end stops can break [the trolley’s] axle bearings.”

“OSHA requires that every operator be trained before running a crane,” Larouche said, adding that industry standards like ASME B30.2, Overhead and Gantry Cranes, get into specifics about who is and isn’t qualified to run a crane.

The standard requires that managers train and provide a certificate or other formal record that says they have been trained and are authorized to run the crane. This involves foundational information applicable to any crane operation, as well as application-specific training involving the duties the crane operator will need to perform. A beginning operator with just a few hours of training likely won’t be ready to flip a large, asymmetrical plate or beam on his or her first day.

Make Time for Inspection

CMAA publishes a list of points operators must inspect at the beginning of every shift (and, of course, be given time in the production plan to do so). The daily inspection list itself should be posted and immediately accessible to the operator, such as on a tag mounted directly onto the pendant or radio transmitter.

As Larouche explained, “Operators need to run the hoist all the way up and all the way down. They need to make sure the limit switches work. They must run the bridge forward and in reverse, make sure the brakes are functional, and perform a visual inspection of the wire rope to make sure there are no kinks or damage.”

“These checklists [that CMAA and other publications provide] are very specific,” Piscitello added, explaining that the details describe how many wires each strand has and how many broken strands an operation is allowed per specific segment of wire rope in specific lifting situations. These publications also describe other wire-rope discontinuities, such as bird-caging, which occurs when the outer strands separate from the core—a common occurrence when the rope is put under serious load. Operators also should look for a narrowing wire diameter, which could be a sign that the inner core has lost support.

If operators see a kink, they’re required to take the crane out of service and call their supervisor. “That wire rope is one of the most critical components,” Piscitello said. “If the wire rope breaks, you have a serious problem. And when you see kinks, you likely have damage that you don’t see. You really can’t see how much the inner core is damaged.” He added this is why it’s often best practice to simply replace the wire rope.

Another checkpoint is the hook itself. A cracked, bent, warped, or distorted hook can turn what otherwise is a perfectly rigged load into a serious hazard. If a hook isn’t fit for service, the operator should note it and replace it.

“Other points include listening for unusual noises from the motor or gearbox,” Comiono said, adding that other noises to listen for (including grinding or thumping noises) might point to a crane that’s skewed or out of alignment, especially if it’s dragging in certain positions. This in turn can lead to premature wear of the crane trolley wheels. If the wheels are wearing more often than they should, the crane might have tracking problems.

“Also, sometimes the door panels on electrical panels are broken or not fastened properly,” he said. “That lets dust from the environment in there. And in a dusty metals manufacturing environment, having an open panel can wreak havoc on your electronics. The same thing goes for moisture.”

EMH sources reiterated that these inspection points, while commonly missed, should be just one portion of an operator’s preshift inspection. Other inspection points include the rigging apparatus, walkways and handrails, blocks, reeving, booms, checks for leak around the machinery housing—the list goes on.

Besides preshift inspections, CMAA publications specify items that must undergo frequent inspection and periodic inspection. Frequent inspection intervals can occur daily, weekly, monthly, or at various other intervals depending on the application and circumstance. Periodic inspections usually occur quarterly, twice-yearly, or annually, depending on the crane’s use and service class.

Still, the industry standards are just starting points. As part of EMH’s service program, Piscitello and his team visit various manufacturing facilities to perform periodic inspection, which involves an in-depth inspection and analysis of a shop’s entire crane system.

How often do they visit? It depends. “We usually sit down with the customer and discuss their crane applications, their use level, and how critical they are to the operation,” Piscitello said. The more critical the crane is, the more frequently thorough inspections are made.

Operator Knowledge

An operator clocks in, grabs the pendant, and makes the crane hoist go up: that, sources said, creates a risky scenario. The crane operator’s safety and effectiveness, or lack thereof, sends ripples throughout the entire fab shop floor. Operating a crane that hasn’t been inspected and cared for properly puts the entire shop at risk.

As EMH sources reiterated, it all starts with giving the operator the right tools to succeed: the right technology for the job, the right training, and an inspection and maintenance routine that’s baked into the shop culture. An untrained, unsupported crane operator is a dangerous operator. The more operators know, the safer and more effective they can be.

For more information on crane maintenance and inspection, see the Crane Operator’s Manual as well as CMAA Specification No. 78-4, Professional Services, Crane Inspection and Maintenance, published by the Crane Manufacturers Association of America; and ASME B30.2, Overhead and Gantry Cranes, published by the American Association of Mechanical Engineers.