issue: September 2003 APPLIANCE Magazine
Engineering Power Tools
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engineers at DeWalt in Towson, MD, U.S. began the design process
for its line of routers, the goal was to go beyond just improving
an existing product.
developing its new, modular DW616 and DW618 routers,
DeWalt says it spent a lot of time focusing on making
the router's detachable feature very robust both in
terms of terminal and socket selection and its ability
to survive drop/impact.
from a clean sheet of paper, the company developed a new,
feature-rich router platform with enhancements to satisfy
the professional woodworker. From the reviews that have been
written, it looks like the new design hit the mark and is
well on its way to becoming a major success.
As the new DeWalt DW616 and DW618 routers hit stores, both
amateur and professional woodworking buffs concur that the
new routers clearly stand out from previous models. The major
change involved shifting DeWalt's design to a modular system
that allows easy interchanging of the router base, motor,
and accessories to fit the task at hand. Designers added more
user-friendliness to the router by integrating a detachable
cord set, soft-start motor, and ergonomically placed controls.
These features and more are rolled into a single product that
the manufacturer says will please seasoned wood workers with
a superior, more flexible product while at the same time enticing
the next generation of handy men with a new, easier to use
One of the important innovations resulting from the redesign
was the power cord. In the past, power cords could be cumbersome
when using a router, particularly when switching between router
bases, or when the power cord was accidentally damaged. The
new DeWalt router incorporates a detachable power cord set
that was a collaboration of DeWalt engineers, cable subcontractor
Power Cord Products (Indianapolis, IN, U.S.), and connector
Electronics of Harrisburg, PA, U.S.
The DeWalt team wanted the power cord design to accommodate
its modular concept and interchange between all the new models.
Additionally, since routers generally require more cord replacements
over their useful life than other power tools, DeWalt needed
a robust, but manageable connection to the router. For convenience
and ergonomics, designers wanted to offer several cord lengths
so the router could be easily switched between standard, plunge,
and D-handle bases.
"Normally, if one buys a competitive D-handle router, it
comes with a short - approximately 12-in - cord set that works
well only with that D-handle base," explains Jeff Grant, design
manager, DeWalt Power Tools. "If one buys a fixed base router,
it comes with a 10-ft cord set. Using the same powerhead in
the D-handle base can result in having to wrap 10 ft of power
cord around the base before it is plugged into the D-base
to allow the user to use the trigger switch." With the new
interconnect system, craftsmen no longer need to bundle up
excess cord when using a D-handle base since an appropriately
sized pigtail interconnect is integral to the D-handle. Above
all, this robust, versatile cord would need to be very simple,
easily attached, and reliable.
The joint design effort required close coordination between
DeWalt, Volex, and Tyco Electronics so that the design objectives
were met, while at the same time, making sure that the design
was efficiently manufacturable. During the conceptual phase,
the use of ProEngineer, Stereolithography models, and CAD
model exchange proved invaluable in refining the design requirements.
Once the conceptual design phase was over, the three companies
were able to move quickly into the prototyping phase, and
within 12 weeks of approving the design, Volex and Tyco Electronics
were able to produce the hard-tooled components of the new
cord and connector.
Early in the design definition phase, Tyco Electronics'
development engineers began the process by looking at potential
connector contacts. The initial evaluation of the application
requirements received from DeWalt engineering indicated that
the contacts had to be robust and suitable for use over the
life of the power tool. With literally thousands of existing
contact designs at their disposal, as well as the option to
design one from scratch, the Tyco Electronics engineering
team finally selected the .140 MATE-N-LOK® contact. The contacts
provide a cost-effective interconnect solution that meets
the current carrying and performance requirements for DeWalt's
new router application. Manufacturability was also addressed
with the MATE-N-LOK contacts, as they are available in reel
form, which allows the contacts to be applied using a wide
range of high-speed, semi-automatic, and automatic termination
equipment. Furthermore, since Volex engineers were already
tooled up to produce harnesses with MATE-N-LOK contacts using
its existing AMP-O-LECTRIC® Model G Presses, they would not
have to learn a new production method or invest heavily in
Now that there was a contact to work around, Tyco could
design a housing to package the contacts. To keep the connection
simple, Tyco proposed a connector design that is based upon
a quarter-turn locking mechanism that is being used in another
connector family. To connect the cord, users simply plug it
into the router and twist a locking ring 90 degrees to securely
lock it into place. The cord-side locking ring was designed
to snap around the contact housing and also provide a firm
gripping surface that was easy to handle and lock into the
router. An overmolded strain relief that keys into the contact
housing bolsters the already beefy connector housing and provides
additional cord protection and support.
With the contact and housing now developed, Volex, Tyco
Electronics, and DeWalt electronically exchanged design models
to check that the connector fit into DeWalt's router model
and aid in the design of the overmold tooling required for
the cord set. According to Mr. Grant, the biggest challenge
was keeping the design as small and unobtrusive as possible
while maintaining durability. As it turns out, the first try
was close, but some minor design changes were required to
provide additional component clearance within the router.
After a few iterations and file exchanges, the design was
firm enough that SLA models could be generated. Tyco Electronics
created SLA models of the connector housings and shipped them
off to DeWalt. These parts enabled DeWalt to integrate the
connector SLAs with its router model to review the aesthetics
and fit of the router prototypes.
It was quickly discovered during the assembly of the model
that the contact housing inserted into the router housing
would need additional keying to avert problems on the assembly
line. In this manner, the models proved their value by identifying
assembly issues early in the design cycle where they could
be easily (and inexpensively) addressed.
Shortly thereafter, the design was finalized and the decision
was made to begin building the production molds for the components.
Twelve weeks later, the initial parts were in-hand and after
some minor conditioning, the molds were ready to begin producing
The new router looks to be a hit in the industry. The development
process that it required, which involved the close collaboration
of three companies, was a good example of how the use of CAD
and rapid prototyping can quickly refine a design and help
bring it to market more quickly. By utilizing these tools
and the constant communications between these three companies,
the resulting product was destined to be a technical success.