Conveyors Conform to Your Progress
by Leslie Langnau, senior technical editor
One way to noticeably improve productivity is to adapt product flow to your changing environment. Recent conveyor developments will help you synchronize material handling with your business needs.
If you ask the average material handler what are the key features he wants in a conveyor system today, he’ll tell you that they are configuration flexibility and easier maintenance. Fortunately, the latest developments in conveyors meet these wants.
Heavy-duty, fixed conveyor systems have been the reliable workhorses in material handling applications. But in today’s material handling world, processes are reconfigured frequently, sometimes as often as yearly. This change draws attention to one disadvantage of fixed solutions — they are fixed.
The alternative, of course, is modular systems, and that’s what several vendors are introducing. According to Bob Steele, president of Steele Plastic Equipment, modular conveyor systems are an aggregate of interlocking units, including belts, sides, legs, motors and accessories, that make up modules, which can be configured like “building blocks” to meet changing production flow needs. They enable manufacturers to adapt to a variety of situations, such as running the conveyor around obstacles, transporting parts underwater and even continuing production flow from fixed metal systems.
Installation usually involves bolting modules together, plugging in power and communications cables, and hooking the system to a power supply. Because many of these systems are powered with 24V DC, no special tools are required for connection. The benefit is that modular systems let you create whatever material flow you need by simply repositioning the components.
Modular systems are typically made of strong plastic or light metal material. A few offer steel frames, which increase the load they can transport. For the most part, though, there are load limits for modular systems. Thus, they are usually selected for light- to medium-duty applications. On average, the plastic versions can handle approximately 100 pounds of total product weight per conveyor. With proper placement of components, it’s possible to handle total product of more than 100 pounds. The steel-frame versions can handle more, but it’s best to check with the manufacturer to determine the exact load capability.
Modular systems are in wide use throughout industries that manufacture relatively lightweight injection-molded products, such as auto parts, toys and medical equipment. They are also found in applications with frequent changes in production runs. And these systems are useful in warehouses and distribution centers that are moving away from cartons and palletloads to shipments of single items.
Keep ’em running
Maintenance is a task few look forward to, but it is crucial to maximize conveyor “uptime.” Belting for light-duty applications has improved greatly in the past few decades, evolving into many specialized variations. Light-duty belting, for example, is often infused with synthetic alternatives. These synthetics improve efficiencies because they let manufacturers make thinner, lighter belts, which lower drag, which in turn lowers horsepower consumption.
Light-duty belt thickness ranges from an almost paper-thin 0.030 inch to about 0.25 inch with working strengths from 20 to 200 pounds per inch of belt width.
A key factor in maintaining belt conveyors is the splice. Belt ends are either melded together through vulcanization or mechanical fasteners. In vulcanization, heat or a chemical-reaction blends the ends together making an endless, continuous length.
These belts offer many benefits, including quiet operation. The splice won’t mark conveyed packages, and it is strong and long lasting, reducing maintenance requirements. However, vulcanized belts can be time-consuming to repair because repairs often require separating the splice.
Mechanical fasteners, on the other hand, physically mesh belt ends. Maintenance is easy to schedule because wear is readily apparent. The splices are easy to separate, making for quick repairs.
Thus, depending on your overall conveying needs, if you’re using an endless belt and need quick maintenance and repair, consider switching to mechanical fasteners to improve uptime. If you’re already using mechanical fasteners, consider the possibility and benefits of switching to a different type.
Other developments can be seen as manufacturers add timesaving features to conveyor systems. For example, weigh scales bolted onto conveyors can add in-line weighing capabilities to ordinary sections.
As material handling systems convert from high-current AC power to lower-current 24V DC power, you are likely to see an increasing array of modular, snap-on or bolt-on components. The final result is that these systems will help you design and reconfigure your material handling systems as you need, when you need. MHM
Creative Conveyor Arranging
In the injection-molded plastics business, manufacturers must often retool quickly for new product runs. However, production changes can be restricted by the set layout of fixed conveyors. This was a costly problem for Nyloncraft, Mishawaka, Indiana, a Tier-1 custom manufacturer of injection-molded, under-the-hood parts and exterior trim for automotive manufacturers.
At the company, production runs may occupy multiple adjacent molding setups with a single unit in between.
“The fixed conveyors we were using, coupled with the need to reset our production runs quickly, limited the way we could deliver material to and from the presses,” said Michael Van Zant, manufacturing manager. “Fixed conveyors are fine for many manufacturers with dedicated production runs, but we are a custom house with few dedicated jobs. We need to change our molds and floor layout frequently.
“Our presses are a way apart to allow clearance for resetting the molds, which can occur every day or two,” said Van Zant. “As a result, there was an operator at every press, even though most of our jobs run in 60- to 70-second cycles, which left the operators with nothing to do but wait much of the time. Due to the distance between the presses, there was no way to allow an operator to work two presses, even though they could have done so otherwise.”
At a show in Chicago, Van Zant noticed a new type of conveyor system, the DynaCon modular conveyor system, made by Dynamic Conveyor Corp., Muskegon, Michigan. He decided to give it a try.
Installation of the new system went quickly, since the modules and accessories set up easily. Composed of lightweight, high-impact plastic units, this system offers standard units measuring 18 inches wide as well as a variety of special sectional accessories, all of which offer users maximum flexibility of configuration.
“This system allowed us to be creative,” said Van Zant. “Now I can run jobs by sending one conveyor over to a second press. That means an operator can run multiple jobs without having to walk from press to press.”
The system also let Nyloncraft decrease its labor force from about 20 people per shift to 16. The “extra” operators were quickly absorbed into other parts of the plant.
“If you figure $25K per operator, we’re now saving about $250,000 to $350,000 per year,” said Van Zant. “So the payback on the conveyor system was fairly quick, about six months.
“Our new system has a lot of sections running up and down, under and over equipment,” continued Van Zant. “For instance, we have one area that has four presses that run the same product. We have these conveyors coming up the back side of the presses, underneath the platen feeding in one long conveyor in the back, and then takes all of these parts to a feed-bowl where a vision system inspects every part.”
Three Nyloncraft plants now use the modular conveyors, along with more traditional conveyors that run under the presses, which drop parts too heavy for the DynaCon system to handle. “I believe that these conveyors can only handle parts up to about 10 or 15 pounds with a relatively low impact,” explains Van Zant. “But who knows, maybe someday their conveyors will allow us to replace those conveyors, too.”
Tips on Selecting the Right Mechanical Fasteners
According to product managers Beth Miller and Jim Wingfield of Flexco, you have five basic choices for mechanical splicing, three metallic and two non-metallic. Each type of light-duty belt splice suits specific applications, but large areas of overlap exist between the offerings.
• Wire hook fasteners offer an economical, low-profile, long-lasting splice. They are available in a variety of sizes, metals and configuration for belt thicknesses to 25/64 inch and pulley diameters as small as 15/16 inch. Wire hook segments come in strips with hooks held in proper spacing and alignment by either carded or welded assembly. Carded assembly holds individual wire hooks together with a stiff paper channel that is removed after the hooks are locked into place. In welded assembly, hooks are welded in position along a common crosswire. Both types can be installed by machine, which ranges from powered shop units to small portable tooling.
• Hinged-plate fasteners are a strong, abrasive-resistant choice. Strength comes from compression between upper and lower fastener plates, which sandwich the belt ends, and the dual staples penetrating through both plates and cross-clinching on the bottom side. Installation requires a hammer and a portable tool. Hinged-plate fasteners handle belt thickness from 1/16 to 1/4 inch and pulley diameters as small as 2 inches.
• Stamped metal tooth fasteners are for users who want a low-profile, hinged mechanical splice, with no investment in installation tooling. The design consists of a continuous strip of hinge loops with pointed teeth that are hammer-driven through the belt end. Installation machines are also available. Tooth-type fasteners accommodate belt thickness to 1/2 inch and minimum pulley diameter of one inch.
• Non-metallic fasteners are non-marking, non-abrasive, and compatible with metal detectors. They are made of FDA-approved material. They are an alternative to vulcanizing in applications involving X-ray or scanning, food handling, and finished products that are sensitive to being marked. There are two basic types of non-metallic splicing — plastic rivet and plastic spiral fasteners.
The plastic rivet fastener can be installed on-site with a portable installation tool. Holes are punched into the belt. Then, the fasteners are put through the holes using an application tool to spin-set the molded-in “rivets.” This fastener suits low-tension applications that forbid metal fasteners, on belt thickness to 1/8 inch, operating at less than 65 PIW (11kN/m) and over minimum pulley diameters of 1-1/2 inch.
The low-profile plastic spiral fastener can operate over pulley diameters as small as 1/2 inch. The spirals are assembled onto a webbing material, which is fabricated into the belt ends through various vulcanization processes. This is one fastener system that is not installed on site. It accommodates belt thickness to 1/4 inch with mechanical fastener ratings to 50 PIW (8.7 kN/m) and is able to withstand heat to 392 F.