Application and Upgrade of Various Overhead Cranes in the Metal Processing Industry

In the metals handling sector the three key words that crop up again and again are safety, monitoring and automation. Simon Hastelow reports.

For lifting in the metals handling and distribution sector, the industry appears to be split into two distinct camps: above-thehook and below-the-hook. While it is obvious that tools attached below the hook to grip and lift metal coils, sheet and bars are very specific to the task it would be a mistake to assume that the equipment ‘above the hook’ is generic to any form of lifting. Often the design and structure is just as specialised.

“We specialise in the cranes, including the hoist,” says Juan Aguirre, sales director, special solutions for GH Cranes. “The equipment below the hook is provided by other companies. It is a completely different industry catering to wide industry requirements. There are magnets, coil grips, C-hooks and there are hooks which allow rotation, others with integrated scales to weigh the stock. The variables are infinite with different brands and qualities.

“Normally a customer will come to us after deciding the below-hook equipment supplier. Or sometimes we will supply a replacement overhead crane where the below-hook equipment already exists. But if it is a new installation and the customer asks for advice we would often choose a supplier with a service facility located near to the plant.”

For lifting rolled metal coils there are several distinct types: C-Hooks, a very simple and effective solution usually cut from single alloy steel plate and designed for heavy continuous use as they require little maintenance, used when stacking coils end-to-end and access to the coil centre is restricted to one side; telescoping coil grabs, the preferred solution when handling coils where the axis is horizontal, open both sides and the customer needs to handle a wide range of coil diameters; parallelogram coil lifters, commonly used where the coil axis is horizontal but where the aisles are narrow in the coil storage areas; and vertical axis coil tongs, for coils positioned with the axis vertical and the underside of the coil is not accessible, can handle a wide range of coil sizes either single-rim grip or double-rim grip.

Aguirre adds: “The coil grips vary depending on design and storage requirements. You can handle coils with an electromagnet to maximise space, but the cost is increased compared to standard coil grips or hooks. This is an equation that the end user needs to solve, with our help, marrying the variables between increased overhead crane cost and more optimised storage space.”

Oliver Kempkes, managing director of Kuli Hebezeuge says: “We mainly sell either just components or complete overhead cranes. In the export market we have a lot of installations in the Middle East for metals handling and aluminium production. These customers mostly use our hoists, travel drives and controls then build their own cranes using local contractors. Whereas in Alemania we mostly sell complete cranes which are completely designed and built by us.”

The exact requirements for handling and storage of the base metal stock varies according to end-use sector as well as the on-site logistics of the company concerned. Discussing the specifics with various suppliers it would be fair to say that metal bars require less item-specific handling and storage when compared to sheet metals, which in turn are easier to handle than coils. However there are also variations in coil handling within the different industries which consume those as its raw product. Aguirre, from GH Cranes says: “The specifics of coil handling depends on the industry using the material. For the automotive industry, careful handling is a priority and the scale of the process is large. So optimisation of the available space to ensure shorter production cycles is also of the utmost importance. Everything is stringently controlled and the aim is for the coils to remain unmarked throughout the process. “If we are dealing with hot coils for general metal fabrication or box girders, for instance, normally the careful handling requirements are not the same as automotive but obviously safety is more of a high priority. It is less important if coils are slightly damaged in the handling process and the production cycles are not as stringent as in the automotive production industry.”

At the hotter end of the process where the coils and sheet metal is formed, the safety aspect has an additional emphasis but the productivity focus shifts to speed of handling.

Antonio Naranjo, sales and marketing for Jaso Industrial Cranes says: “70% of our core business and our turnover comes from the iron and steel industry. We provide overhead cranes for handling scrap charging, liquid steel and furnace charging, semi-finished long and flat products, finished product in the form of coils, barrel packs, corrugated packs, profiles, etc. Plus we have customers dealing with hot coils up to 650°C.

“The environmental conditions for these are quite aggressive, so very fast overhead cranes—130m/min—in bridge travelling motion and also in lifting and trolley travel are important. Security and redundancy in positioning systems and coil code reading systems are standard. LIFTING SAFETY

The paramount concern for safety in metals handling, as in most other lifting environments, shares equal prominence with productivity. Different crane suppliers and the companies who use metal handling equipment can both draw on experience in this respect and handlers in particular often want to avoid repeating previous incidents.

Aguirre says: “Looking at the safety aspects of coil and sheet handling, in the last ten years there have been requirements added such as anti-sway, slack rope detection and multi-level crane detection. We have also added cameras and emergency brakes on the drum. The fitment and use of these facilities usually depends on the customer’s experience and to avoid incidents that have occurred in the past.

“We sometimes fit tethers to anything that can fall to the floor. This is alongside the use of sirens or other alarms and is coupled with the use of floor markings that specify where operators must stand or wait while processes are taking place.”

Chris Jacobs, engineering manager at Ingersoll Rand says: “Ingersoll Rand offers a patented Interlock safety system on all our lifting devices. This monitors the pressure in the balancing system and whenever the system’s internal pressure increases due to the part being lifted the operators’ ability to release the part while suspended is shut off. “Some larger organisations have adopted this methodology and have made it a part of their own specifications. Smaller businesses tend to lean on us for recommendations on how to increase the safety of their process. We also offer many other safety related features that can be developed and customised to fit the customer’s specific needs.

“I think the changes come in the emphasis on operator’s safety while at the same time being conscious of productivity. Keeping operators safe with the everchanging landscape leads to opportunities.”

SYSTEM MONITORING AND AUTOMATION

Remote monitoring of cranes and handling systems has become commonplace and, as the technology to execute this has become more readily available, each crane company has its own take on how this is implemented. Aguirre at GH Cranes puts it succinctly: “New developments in this industry are centred around ‘The internet of things’ and concerns data capture and transmission to a monitoring system.” He continues: “Lately we have found that gearbox oil monitoring has been very popular in this sector along with gearbox vibration monitoring along with regenerative invertors. Our systems can capture all of this data, then it is up to the customers how they handle, analyse and react to the data input.”

Jaso offers a system called SmartLink which is designed to record and relay relevant operational data and allows realtime remote diagnosis of a crane, including the safe working period (SWP), number of cycles, overloads, status of different elements of the cranes coupled with constant communication with the plant management system and data validation to continue operating.

Naranjo says: “As well as the monitoring of the status of the various components of the crane to preserve safety and productivity, the trend of the lifting and crane industry is to automate as many of the processes of the crane as possible.”

The next step on from monitoring is the automation of the metals handling process. This offers companies real productivity benefits. Crane manufacturers do offer levels of automation but this can sometimes be influenced by the customer’s existing warehouse management system. As with the monitoring facilities discussed above, the data and instructions can only be useful if it can be fully utilised.

Aguirre says: “We manufactured our first crane with automated handling for coils in 2003, since that time the revolution in the handling automation has been fantastic. Nowadays we tend to focus on the supply of a crane that can be operated automatically but whereby the criteria and instructions are input and handled by the customer’s own warehouse management system.

“This WMS is not supplied by us, but our cranes can be operated by it. In most cases this is a simple instruction such as ‘Go to Aisle 1, Column 3, pick coil’, the crane we install does not make decisions, only follow instructions.

“We have seen an increase in automation within automotive plants that usually take delivery of the metal coils by rail. The unloading and handling is then automated, placing the coils in storage according to specification of the metal before being picked ready for the panel stamping process.”

Naranjo concludes: “Our customer NAS (North American Stainless) has a plant in development where we will be manufacturing the supply of six fullyautomatic coil cranes for the first fully automated warehouse in Ternium, México located in Pesqueria, Monterrey. The startup will come in 2021 depending on the Covid situation.”

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