The power of cordless

Advances, advantages make it an attractive option to air tools for your assembly operations

by Steve Tayler

For years, industry has devised innovations to lower production costs throughout the manufacturing and assembly process. One of the largest, consistent expenditures realized by most mass assembly plants is the cost to produce, condition and maintain the compressed air supply utilized, in large part, by pneumatic fastening tools. 

Finally, advancing technologies in power tool development have zeroed in on this opportunity and are bringing into focus alternatives to past (and present) practices. 

Assembly facilities are now capable of providing their line associates cordless fastening tools that can perform tasks as well as or, in many cases, better than their air counterparts and significantly reduce many costs associated with the use of air tools.

Cost advantages
In search of cost reductions, manufacturers identified several areas where cordless assembly tools offer a distinct advantage over the use of air fastening tools.

• The overall energy savings realized through the implementation of cordless tools in assembly vs. the use of air in the same environment is the single-largest tangible benefit. 

In-house studies from two major vehicle manufacturers put the reduction in energy usage beyond the 98 percent mark when comparing electricity consumption needed for air compression and the need by cordless tools. The data provided indicates the energy consumption required to power one cordless tool over a one-month period (20.33 manufacturing days) translates to less than $1 vs. more than $300 for one pneumatic screwdriver. 

Though strict maintenance of air line/air tool leakage may keep pneumatic consumption in check, the energy savings is still extreme.

• Quality control costs have seen significant reductions in certain processes due to the absence of pneumatic hoses. Interior vehicle fastenings, for instance, are one of many targeted opportunities within manufacturing facilities as pre-existing paint finishes can become scratched or marred when working with air tools in and around the workpiece. 

• Cordless tools offer safety-related cost reductions within the work environment through the elimination of cumbersome air hoses that can present problems laying across floors or even hanging from above.

• The versatility of cordless tools, as with all historic trade applications, provides the manufacturer with an easily repositioned fastening system when assembly lines need to be rerouted, expanded or eliminated. Operators are no longer tethered to their fixed position as experienced with anchored fastening processes. This allows the line associate greater maneuverability in completing the intended process.

• Cordless tools allow quicker recoveries from power interruptions due to their independent nature.

Technological advancements
Historically, cordless tools have presented a challenge in their ability to provide consistent fastening torque and in having the durability for long-term use. In addressing these concerns, tool manufacturers spent several years honing their wares through the advice and direction of many of the industry’s top companies and engineering teams. 

In the pursuit of creating the “perfect tool,” new technologies were developed to produce products that:
• have high repeatability levels;
• withstand repetitive long-term operations;
• are ergonomically correct in design; and,
• are fast enough not to slow down the overall production process or line speed. 

Though manufacturers continue to improve designs, these definitely aren’t your typical cordless drills found perpetually charging on the basement workbench:

• Lightweight/durable materials are sourced to produce models as light as 2.4 pounds (with battery) for greatly improved ergonomics and operator comfort.

• Two-piece DC motor designs provide operators and tool cribs an easily maintained and long-life power plant. External access caps provide quick brush replacement and armatures are replaced independently from the field. This saves the company both maintenance time and parts cost.

• Long-life clutches provide high durability and accuracy with little or no maintenance through the life of the tool.

• Advanced nickel metal-hydride battery (NiMH), charging and refreshing technologies extended cycle life of batteries up to double what is experienced by the construction trades. Extended battery life is realized through a combination of smart-charging and deep-cycling technology where advanced battery chargers continually monitor and alter the current flow during the charging process. “Refreshing” adapters automatically sense diminished battery capacity and reinvigorate the cells through a quick deep-cycle process.

• For potentially hazardous conditions, one manufacturer now offers a brushless DC motor design approved for Class 1, Division 2 environments found within military and commercial aircraft sites, mining operations and chemical facilities, to name a few.

Product development
Many of the cordless tools used today in assembly include both impacting tools and clutched screwdrivers/nut runners. Impact tools include quarter-inch hex drive impact drivers (pistol-grip and angled) and impact wrenches equipped with either three-eighths-inch or half-inch square drives. 

Due to an impact tool’s wide torque scatter, it’s difficult to produce consistent clamping force from process to process, though electronically configured models are available that adjust impact time, thereby affecting applied force.

Though their torque repeatability is more difficult to control than screwdrivers and nut runners, impact drivers and wrenches provide a quick and ergonomically friendly fastening tool that performs best in hard-joint processes. These tools generally provide realistic torque ranges of up to 1,327 inch-pounds.

Available cordless screwdrivers and nut runners provide assembly operations with tools achieving very high levels of torque repeatability and subsequently high machine capability (Cm) ratings. 

Though typically slower in speed than their impacting brethren, cordless clutched tools have advanced beyond many of the screwdrivers and pulse tools used in assembly today in both hard- and soft-joint applications. 

Typical products utilize several mechanisms to ensure proper fastening. These include automatic tool shutoffs when the preset torque is achieved, voltage-sensing monitors to ensure enough power is on hand for the next fastening, and low-battery warning and proper tool cycle run indicators that provide the operator visual indication of a proper fastening to the set torque level. 

Torque ranges of pistol-gripped screwdrivers are available from 4.4 to 106 inch-pounds, whereas 3/8-inch right-angle nut runner torque ranges are available up to 177 inch-pounds. 

As streamlining production costs remain a top priority in manufacturing, alternatives to costly pneumatic operations are available and being implemented today in industry.

Steve Tayler is a regional sales manager for Makita U.S.A., a manufacturer of power tools. To learn more, call 800-867-8265 and e-mail stayler@makitausa.com.

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