Handling metal scrap safely with automation

Scrap metal and spent fluids must be removed from the point of production as quickly as possible to reduce occupational hazards in stamping operations.

Human costs aside, workplace injuries are a significant detriment to profitability and overall sustainability. A stamping plant's environment inherently lends itself to fostering various occupational hazards. Four of the five hazards listed in the "Top 5 Causes and Direct Costs of the Most Disabling U.S. Injuries" in the 2018 Liberty Mutual index can occur during scrap and fluid handling.

Overexertion involving outside sources (lifting, pushing, pulling, and other actions involving objects) caused 23.4 percent of these injuries and cost employers $13.7 billion annually. Back strains, joint sprains, cuts, bruises, and other musculoskeletal conditions can result from employees manually handling, pushing, or lifting heavy loads of scrap metal.

Falls on the same level caused 19.2 percent of these injuries and cost employers $11.2 billion. When lubricants used on dies and parts to reduce heat and friction and water used to clean parts and machinery saturate floors, the likelihood of slips, trips, and falls is higher.

Impact from being struck by an object or equipment caused 9.1 percent of these injuries and cost employers $5.3 billion. Although a forklift truck spares workers the task of lifting heavy loads, it brings its own set of hazards to an operation, as personnel can be struck or killed while operating or working in proximity of a forklift truck.

Bodily reactions caused 7.2 percent of these injuries and cost employers $4.2 billion. Asthma, hypersensitivity pneumonitis (an allergic type of pneumonia), and other lung diseases involving the immune system can result from occupational exposure to hazardous fluids. Additional ailments are dermatitis and cancers of the pancreas, larynx, skin, and bladder.

The potential for any or all of those incidents to occur exists in many workplaces, but it can increase significantly in a stamping operation involving metal scrap and spent fluids. For example, shoveling, sweeping, and handling slugs, skeletal trim, and other scrap metal manually can lead to lacerations and overexertion injuries.

Large plants typically generate pounds of skeletons, slugs, and other pieces of scrap metal during stamping. Factor in the number of parts a high-volume stamping operation produces per day, with metal scrap and water ending up on the shop floor, and it's easy to see how cluttered wet, walking surfaces can present a problem.

Low-volume stamping operations deal with these hazards as well on a smaller scale. But it doesn't take much of either material to cause an accident, injury, or illness.

It's typical for stampers to use large amounts of water for washing and sometimes cooling and to use lubricants to reduce friction and heat on dies and parts in the stamping process. Washwater may drip onto the plant floor and contain various oils, hydrocarbons, heavy metals, and silicones that make it unsuitable for discharge to a sewer. Overexposure to hazardous fluids that are commonly found in stamping plants can put employees at risk of contracting serious illnesses or diseases.

All of these possible outcomes make it clear that stamping plants that process scrap metal and spent fluids need to minimize the dangers associated with handling those materials. They can do so by removing them from the point of production as quickly as possible.

Workplace injuries and the costs associated with them are a significant detriment to profitability and overall sustainability.

Automated systems are designed to quickly and efficiently remove considerable loads of scrap metal and spent fluids from core operations and transfer them to where they can be safely processed and discarded or recycled.

It is critical to understand and assess the advantages of each available system as they apply to a specific operation.

Modern conveyors can reduce or eliminate the need to handle metal scrap manually or with forklift trucks. The best choice for an application depends on a number of operational factors. For example, high-rate applications require a multifaceted conveying system capable of handling large volumes of scrap and fluid in an efficient, automated approach.

Here is an overview of how some of the options can help a metal forming facility maintain a safe working environment by keeping the shop floor free of metal scrap and spent fluid and decreasing forklift traffic and operators’ contact with scrap.

•Steel Belt Conveyors. The simplest and most versatile option for most metalworking operations, this equipment can handle most types of wet or dry metal scrap, from slugs to twisted skeletons, in a variety of conveyor paths. These conveyors can also move a high volume of material consistently, even in piles and surges.

•Stamping Scrap Conveyors. The liquid-tight, leakproof construction of these positive-discharge conveyors allows them to prevent 100 percent of slippery cutting fluids from reaching the shop floor as they transfer all forms of scrap to its destination.

•Magnetic Conveyors. These conveyors effectively transfer wet or dry stamping slugs, parts, and die scrap without carryover via permanent magnets located under a stainless steel slider bed. An oil reservoir in the base of the conveyor self-lubricates the chain for quiet performance and low maintenance.

•Pivot Belt Conveyors. This equipment features a belt surface that prevents scrap from sticking to it while pivoting hinges flip scrap into a hopper. A seamless one-piece pan collects oily fluids and keeps them off the plant floor to reduce housekeeping headaches while improving employee safety and productivity.

•Oscillating Scrap Conveyors. Vibrating scrap handling systems are the top choice for transferring hot, dry, or wet abrasive metal scrap and moving finished parts across horizontal distances. This equipment offers another safe alternative to forklift trucks while helping employees avoid injury from handling dangerous material.

•Load-out Systems. Automating the final load-out of stamping scrap into large trailers or railcars maximizes container fill and minimizes potentially dangerous manual handling. The open-frame construction of shuttle systems provides personnel with quick and safe access to scrap carryover. Their infeed conveyor and continuous back-and-forth operation provide even distribution into larger scrap containers where swivel chute systems would be inadequate.

Steel belt conveyors can move a high volume of material consistently, even in piles and surges, to decrease forklift traffic and operators’ contact with scrap.

Liquid lubricants, rust inhibitors, and cleaning chemicals are necessary in stamping operations, but they present some challenges for employees who must work in proximity to them. Fluid filtration and wastewater treatment systems can help prevent unpleasant consequences and mitigate the safety and regulatory risks involved with some fluids used in stamping and die builds. These equipment options include:

•Vacuum Evaporators. This equipment offers an effective safe-to-sewer method for concentrating and removing heavy metals and hazardous components from fluid waste; reducing wastewater volumes; and producing high-quality, reusable distillate for zero liquid discharge (ZLD). These industrial evaporation systems are fully automated, and modular units are low in energy consumption with a low CO2 footprint and no air emissions.

•Tramp Oil Separators. This equipment extends the life of soluble oils, coolants, and washwater by removing free-floating and mechanically dispersed tramp oil from individual machine sumps, central systems, and wash tanks. Tramp oil contributes to bacterial growth, which lowers the pH of the fluid and turns it into hazardous waste at the time of disposal. Removing it can minimize the possibility of respiratory and dermatitis issues occurring in plant employees.

It may be beneficial for stamping manufacturers to seek the assistance of a trusted, experienced supplier that can help them select the best approach for their specific needs, achieve the greatest return on their investments, and maintain the safest possible workplace.

Mike Hook is the sales and marketing director for PRAB Inc., 5801 E. North Ave., Kalamazoo, MI 49048, 269-382-8241, [email protected], www.prab.com.

In a report issued during the 2018 National Safety Council Congress & Expo, the Campbell Institute—a respected global thought leader on placing environment, health, and safety at the core of business vitality—recommended that strategies designed to minimize serious injuries and fatalities in the workplace should include identifying the precursors to such events. By doing so, companies could focus on eliminating the potential for dangerous incidents to occur pre-emptively, rather than reacting to them after the fact.

Preventive measures such as these are among the reasons that the U.S. workplace is getting safer, according to the report. The gains in safety are illustrated by the total recordable incident rate, which dropped to 3.0 incidents per 200,000 working hours in 2016 from 8.5 incidents per 200,000 hours in 1993.

However, another report indicates that the cost of the most significant workplace injuries is actually increasing. The Liberty Mutual Workplace Safety Index is an annual ranking that helps employers improve workplace safety by highlighting the financial impact and encouraging them to devote resources to eliminating the leading causes of work-related injuries and illnesses. While the number of the most serious workplace injuries and illnesses fell by 1.5 percent between the 2017 and 2018 reports, their cost—the total of medical and lost-wage payments—increased by 2.9 percent to more than $1 billion a week.

The first statistic in those findings is encouraging. The second one, however, indicates that employers in general (and metal forming operations in particular) can do more to reduce the financial costs of an unsafe workplace.