July/August 1997
It’s a fact. Scrap processing and handling equipment is becoming more computerized, bringing production, efficiency, and cost-saving benefits to recyclers. Here’s a look at how computer controls are being used and how they could be used in the future.
By Lynn R. Novelli
Lynn R. Novelli is a writer based in Russell, Ohio.
It’s a computerized world out there. Everywhere you turn, someone is either working on a computer, or computer technology is behind the controls of some machine, whether it be an ATM, cash register, car, microwave, you name it.
That’s certainly the case in the scrap recycling industry today.
Not only are computers continuing to take over the office/administrative functions of scrap companies, but computerized programmable controllers are standard on most new scrap processing and handling equipment.
It would be difficult, in fact, to buy a new baler, shear, car flattener, forklift, skid-steer loader, or excavator that didn’t include computerized controls in some form, such as programmable logic controllers (PLCs). It’s even possible to buy radio remote-controlled excavators that let the operator maneuver the machine from a mile away.
The main benefits of computerized controls, say manufacturers, are that they help increase production and efficiency and, hence, decrease operating costs. “Computerization has a dramatic effect on maintaining throughput and production by creating an automatic continuous processing cycle,” says a baler and shear manufacturer. “Often, this is accomplished with fewer personnel, resulting in cost-savings.”
Additionally, the computerized diagnostics that are a standard part of PLCs can reduce downtime for maintenance and enhance operator safety by shutting down the equipment when a problem—such as a material misfeed—develops.
Computerized controllers can also record information such as operating time, processing output, and downtime that can be downloaded directly to a company’s office computer and used to generate a variety of reports.
With advantages like that, it’s no wonder computer controls have been steadily gaining ground in the past decade.
Here’s a look at how these controls are being used in various types of scrap processing and handling equipment, with an eye toward where the computerization trend is heading in the future.
Crushing Cars by Computer
Car flatteners were among the first scrap processing machines to incorporate automated and remote-control technology, featuring it back in the 1960s. These controls, however, were unsophisticated by today’s standards, being limited to automatic on-off operation.
Today’s crushers, in contrast, are equipped with sophisticated computerized controls that stage, position, load, and crush a vehicle in one continuous operation, directed by a single operator.
The operator can specify crushing time, platen pressure, and the direction and configuration of how the lid comes down, as well as change any of the parameters based on the type of material. Top-of-the-line crushers, in fact, have multiple programs stored on the same chip, allowing the operator to select from two or more cycles.
Balers and Shears Go Upscale
For a perfect example of computerized programmable controls in scrap processing equipment, look no further than balers and shears, which have their processing cycles directed by computer.
In a nutshell, their systems work like this: A program to control specific functions and variables is written onto microchips, called EPROMs—short for erasable programmable read-only memory—which plug into circuit boards inside the controller.
At the very least, these controls regulate the baler’s or shear’s start and stop times, cycle time, and speed to maximize production and minimize downtime. The operator is also able to input variables such as bale density or finished size, or make adjustments for variations in feedstock, usually by simply pushing a few buttons on the controller. Once the machine begins its cycle, the program detects variances from the established parameters and either adjusts performance or sends an error signal to the operator.
The controller is usually enclosed in a box attached to the equipment, easily accessible for servicing on location. But when the program needs to be altered to include different functions or variables, the recycler must call the equipment manufacturer, who creates the desired program, encodes a new chip, and sends it to the recycler to be installed in place of the old one.
The most sophisticated balers and shears don’t require an operator to be onboard, but rather can be operated remotely by buttons located in an attached or freestanding crane. The benefit of this setup is that material can be loaded, baled or sheared, and ejected under computer guidance while the operator sorts material and loads the equipment’s pre-stage area. “In the scrap business, profitability lies in the separation of material, and that’s a process that can’t be computerized,” asserts a baler and shear manufacturer. “When the baler can go through its cycle automatically, it gives the operator more time to sort material.”
The computer controls used to run balers and shears also include a number of safety features, such as overload and jam detection devices. When the program detects a problem, the machine shuts down and an error message appears on the controller’s screen. While such messages are helpful in preventing equipment damage, an employee must still resolve the problem. As one equipment maker warns, “Be wary of manufacturers who say their machine can run without an operator. When problems occur in the material infeed, it still takes a human to fix the jam.”
When it comes to maintenance and troubleshooting, computerized programmable controllers may sound more complex than the previous mechanical-relay controls, but in truth they are simpler to service, say computerized equipment experts. “An old hard-wired system could have up to 45 or 50 switches and relays that could handle a couple of functions and were a nightmare to service,” says an equipment maker. “Today’s controllers can cover 16 functions with an 8-by-11-inch circuit board. It’s all much simpler.”
Typically, error messages print out on the controller’s screen to make troubleshooting and problem correction easier. Yet, while computerized troubleshooting is more reliable and specific than old-fashioned warning lights, the control chips seldom catch an intermittent problem, one equipment executive points out. Printed error messages also have limited usefulness with non-English-speaking or illiterate employees, he adds.
Shredders Stick to Basics
Compared with other types of scrap processing equipment, automobile shredders incorporate few computer controls. In fact, they’re still sold more often without such controls than with—and for good reason, shredder makers agree. “You can put a PLC on a shredder to control as many functions as you want, but you need to ask yourself if that makes sense,” says a shredder producer, asserting, “Shredders are basic equipment and adding elaborate, computerized controls complicates them unnecessarily.”
Not that shredders eschew computer controls entirely. They’re simply used to control limited functions that directly benefit production—functions such as the infeed conveyor and infeed roller system. “Computerized monitoring of the infeed conveyor speed and feed roller speed can maximize production, provided the controller is tied to the main drive amperage or rpms,” a shredder expert explains. “This allows the system to feed more material based on the main drive amperage.” The only caveat, he notes, is that computer controls can only be used for these functions if the shredder has variable-speed drives on the infeed conveyor and the infeed rollers.
Beyond this simple application, however, “computerization adds unnecessary cost, complexity, and maintenance expense to a shredder operation,” he continues. Echoing this point, another shredder maker notes, “I’ve seen whole recycling operations held hostage to the computerized controls on a shredder, particularly when they have all kinds of equipment linked together. One wire comes loose, and it shuts down the whole operation.” For this reason, shredder producers recommend that only processors with capable engineering departments even consider using more complex computer controls on a shredder.
Excavators Pick Up on Controllers
Hydraulic excavators are one genre of scrap handling equipment that has fully embraced the computerization trend, with most current models featuring onboard microprocessors that monitor engine rpms and hydraulic pressure and flow.
This is quite a change from a decade ago, when most hydraulic excavators “were inefficient and consumed a lot of fuel, making them expensive to operate,” says one excavator producer. Today, he notes, “microprocessors, by increasing operating efficiency, have allowed manufacturers to downsize engines and hydraulic systems, which reduces operating costs.”
Among other benefits, onboard computers can maintain optimum horsepower in the hydraulic system to achieve full pressure and flow for as long as possible. To the operator, this translates into faster cycle times and better production.
Computerized controls have also made the operator’s job less physically demanding. According to one excavator expert, the old, manual technology required about 10 pounds of force to move the speed and directional control levers in the cab, whereas microprocessor technology has cut the force required to 1 to 2 pounds, thus minimizing operator fatigue.
On the issue of maintenance, computerized controls do improve an excavator’s reliability, but they also make repairs more costly when something goes wrong, says one excavator representative.
Going Remote
In addition to using computerized controls, excavator manufacturers have explored the use of radio remote-control technology for specialized applications. In short, this technology allows the operator to control the excavator from a distance, even up to a mile away. Digital radio signals are transmitted to a receiver on the excavator, and the operator can observe the action via images sent by video cameras mounted on the machine. Different combinations of signals control the excavator’s various functions, direction, and speed.
Excavators incorporating this technology have been used to process unexploded ordnance and munitions at U.S. military sites, as well as to handle material underneath a ladle pouring molten copper in a Peruvian copper smelter. Another potential application is remediating federal hazardous waste sites.
Several companies specialize in customizing excavators for such unusual applications, using standard machines and adding on radio remote controls or other specialty features. The president of one such company maintains that radio remote-control technology could be applied in the scrap recycling industry to allow a single employee to operate two pieces of equipment. “In a typical recycling operation, the crane or the baler/shear operator sits idle 50 percent of the time waiting for the other equipment to finish its cycle,” he asserts. “With radio remote control, one operator could handle both, thus reducing personnel costs. In this situation, the initial investment in the radio control would be recouped quickly.”
Despite that executive’s convictions, large-scale commercial demand for radio remote-controlled excavators hasn’t materialized, prompting the big excavator manufacturers to lose interest in further research and development. As one excavator spokesperson explains: “It’s been something of great academic interest, and several universities have experimented with the concept, but we aren’t pursuing radio remote control at this time.”
Regulating Forklift Functions
Computerization has also certainly caught on in the forklift niche, with many manufacturers incorporating onboard controllers into gas-, diesel-, and electric-powered forklifts that enhance performance and efficiency, reportedly without adding to the cost. In fact, at least one producer of computer-controlled, battery-powered forklifts claims its new models cost $500 less than its old ones.
At the lower end of the sophistication scale are the gas- or diesel-powered forklifts with computer-controlled engines. The operating program is encoded on a microchip, and sensors positioned throughout the engine take readings and transmit signals to the chip. The chip checks operation against the program and sends signals to adjust performance as needed to bring the motor in line with the established parameters. Such chips can regulate a variety of aspects, including emissions, engine performance, fuel mixture, and fuel consumption to improve operating efficiency.
Battery-powered forklifts, in contrast, generally require a higher level of sophistication in computerization. “The goal is to maximize power management to allow for a longer work cycle with a single battery,” explains a manufacturer of gas-powered and electric forklifts.
In electric models, onboard computers generally regulate the amperage drawn off the battery to give it longer life between charges. But the newest innovation is a transistorized control system with programmable performance monitors that control the hydraulic, steering, and drive motors. In this case, the computer regulates the operation of all three motors to minimize amperage drain on the battery. For example, the hydraulic pump for power steering turns on and off as needed, and the amount of current sent to the drive motor is matched to vehicle speed.
Thanks to these innovations, a single battery charge can reportedly last an eight-hour work shift. “Not having to change batteries in the middle of a shift means lower operating costs,” notes another forklift producer. “The operation doesn’t need as many batteries to maintain work flow, and production continues through the entire shift without interruption.”
Going Shopping
When you go out shopping for your next piece of processing or handling equipment, you should venture out armed with a few facts about computer controls.
For starters, most manufacturers purchase PLCs for their equipment from a limited number of sources, such as Allen-Bradley Co. or Hewlett-Packard Co. This means that there can be minimal differences in controls among various brands of recycling equipment and that competing manufacturers may even use the same controls.
Despite this seeming homogeneity, however, there are significant differences among equipment vendors. Beyond the old standbys of delivery time, service, quality, and reputation—which are still solid criteria on which to base your purchasing decision—there are several factors unique to computerized equipment that can differentiate various equipment suppliers.
You’ll want to compare, for example, the standard computerized programmable control packages offered by different vendors, looking for differences in the number of functions that can be controlled and the level of fine control that can be attained. One shredder system manufacturer, for example, includes $50,000 worth of programmable controls in the standard package on a $2-million shredder. If you want more, you can have it—for an additional cost—or you can seek a system from another manufacturer that includes more in the standard package.
You should also consider the manufacturer’s ability to customize the computer controls in its equipment. Some equipment makers, for instance, program their own chips, which generally means they can offer greater customization and faster turnaround than companies that send theirs to a contractor for programming.
Price also indicates the sophistication of the computer controls in the equipment. The larger excavator manufacturers generally use the latest generation of computer technology in their onboard systems. It’s not unusual, however, for smaller manufacturers to use older, less sophisticated computer technology and, not surprisingly, such equipment usually carries a lower price tag. In this case, it’s up to you to decide what trade-off you’re willing to make when it comes to technology vs. price.
Future Thinking
While computer technology is now an integral part of the scrap recycling industry—both in the office and out in the plant—its use is still relatively new. In less than 10 years, computerized recycling equipment has gone through several generations of development, with each one successively decreasing the size of controllers and expanding the number of functions that can be controlled by a microchip.
One of the most interesting developments, expected to be available within a few years, will be proportional demand controllers for electric motors. With this technology, electric motors will no longer have to operate in either on/off mode, but will instead be able to run in increments, such as quarter or half speed.
Front-end loaders and lifting magnets are likely to be the next large equipment to get the computer treatment, with the latter already having a prototype model featuring programmable controls. This next-generation magnet will reportedly offer the advantages of solid-state controls and thermal sensors that detect when the generator is running too hot, says the prototype designer.
What these and other similar projects mean is that not only is it a computerized scrap recycling industry today, but it’s sure to be an even more computerized one in the future. •
It’s a fact. Scrap processing and handling equipment is becoming more computerized, bringing production, efficiency, and cost-saving benefits to recyclers. Here’s a look at how computer controls are being used and how they could be used in the future.