Assembly Solutions: Cutting the Cord
Once upon a time, battery-powered screwdrivers and torque wrenches were confined to workbenches and toolboxes. Today, cordless tools offer a serious alternative to traditional electric and pneumatic production equipment on the shop floor.
Cordless, battery-powered tools offer a distinct advantage in that they can fit in tight spaces where an air hose or electrical cord may restrict easy access and maneuverability. They also eliminate the trip hazards created by hoses and cords running across the shop floor as well as the downtime that results whenever an operator has to untangle a snagged a cord or hose.
Because they must be carefully placed and led, air and electrical umbilicals often make for complicated and costly plant floor changes when production lines are reconfigured to meet changing market conditions. Battery-powered tools also eliminate product defects caused when cords and hoses snag on corners or sharp edges, breaking off key parts or components, or scratching or marring surface finishes of a product being assembled. On the down side, cordless tool manufacturers face the challenges of battery life, and the accuracy and repeatability of their products. But recent technological advances are beginning to close the performance gap.
In terms of accuracy, cordless tools have made great strides, to the point where they are even providing service in the demanding aerospace sector. Steve Tayler, vice president of business development assembly & aerospace as Makita USA Inc. (La Mirada, CA), says his company is supplying tools to Boeing Co.'s (Chicago) assembly plants in the Seattle area. Tools like Makita's BFT 040FZ pistol grip clutch driver are doing service driving fasteners in automobile interior assembly.
In terms of battery life, both chargers and batteries are rapidly improving, increasing both individual charge capacities and overall battery length. Makita, for example, now uses Nickel Metal Hydride batteries, because they offer better performance and incorporate less toxic waste in their construction. Makita's newest batteries are also equipped with their own chips, which help monitor current flow and temperature to maximize individual charges and overall battery life.
Although numbers vary from application to application, with small easy-to-drive components, Tayler says as many as 700 fasteners can be driven with a charge. Because they are necessarily very efficient, cordless tools can be much cheaper to operate than tools run on compressed air. Studies have shown that cordless tools can operate at a cost, in terms of electricity, of less than a dollar a month. Compare that to the cost of providing compressed air to a tool, which can total hundreds of dollar over the same length of time.
"[Manufacturers] are beginning to see that cordless tools can perform better than many air tools and DC hand tools in the market," says William Staiger, major accounts manager at Bosch Production Tools (Mount Prospect, IL). "Cordless tools produce great results, give more features than air and eliminate the need for cables or hoses, which contributes to making the assembly process more efficient, reducing injury, and changing how people design an assembly line. We are seeing applications where the use of cordless vs. air has decreased the process cycle time of a particular job by as much as 40 percent."