We've
all been there-on hands and knees under or behind a piece of furniture,
wrestling with a tangle of cords looking for the one that needs to be plugged,
unplugged or otherwise manipulated. In calmer moments, many of us have wished
that someone would come up with a way of sorting out the mess. Micah Maraia,
being an experienced industrial designer, actually invented one.
The
patented Dotz CordIdentifier is a small, colored plastic bubble that snaps onto
the end of a power or connecting cord. It displays, through a clear window, an
icon showing the appliance or electronic device that's on the other end of the
cord and can make your stay behind the couch or under the desk briefer and a
lot less frustrating. The cord identifier is easy to use; just snap it open,
pop the appropriate paper icon out of a perforated sheet and into place behind
the plastic window, and snap the cord identifier closed on the end of the
electrical cord.
"As
a designer, I'm always looking for ideas," says Maraia. "My job is to find
solutions where others see problems, but the idea is just the beginning." While
the concept of the cord identifier may seem simple, the process of developing
it was not.
From
concept to market, Maraia spent three years on the project. One of his biggest
challenges was creating a fully functional part that could be economically
produced in an injection mold.
Beginning
with sketches, Maraia used SolidWorks software to produce 3D CAD models. "I had
developed detailed visual representations, but still needed functional
prototypes for testing and initial marketing. I looked at SLA
and other prototyping methods, but certain features of the Dotz CordIdentifier,
like the living hinge, can only be produced by injection molding. Proto Labs'
rapid injection molding service, Protomold, provided the real molded parts,
affordably with a quick turnaround."
Maraia
also noted that Proto Labs ProtoQuote online
quoting and design analysis helped point out potential problems in the design
to ensure that the 3D CAD model can indeed be molded.
"I
had two prototype versions of the cord identifier made at Protomold," says
Maraia. "The first was molded in non-clarified polypropylene supplied by
Protomold. The second version, produced after I made some design modifications,
was molded in clarified polypropylene, which I chose for its quality and
appearance and purchased and supplied to Protomold."
A
Simple Product with Tricky Design Aspects
The latch on the left side of the
Dotz CordIdentifier looks like it
would require a typical side action mold, but it is actually formed by a
pass-through core from the A-side mold half. As the mold closes, that A-side
core forms a shutoff against the surface of the B-side mold half. The
three-degree draft of that feature prevents entrapment of the mold feature as
the mold opens, forming the side-facing opening without the use of a side
action. The draft also keeps the mold surfaces from abrading one another as the
mold opens.
The living hinge in Maraia's
design is also
very nicely done. Some living hinges don't precisely align their
bends, leaving the meeting of the hinged parts uncertain. On this part, a
wedge-shaped ridge along one side of the hinge fits perfectly into a
corresponding groove on the other side of the hinge. This ensures precise
alignment of the two halves of the part and helps align the clip on the right
half of the part with the mating catch on the left.
One of the trickiest aspects of
this design is the articulated parting line, along which the two mold halves
meet. In particular, it's the "teeth" along the edges of the part that are
trickiest from mold design aspect. These teeth are designed to clamp onto cables
of varying sizes to keep the cord identifier in position once it has been put
in place. They were designed to flex slightly, to hold the cable firmly without
damaging it.
The parting line of the mold goes
up and down following the contours of the teeth, requiring some very smart
design on Maraia's part to allow for such a complex structure without
interfering with molding or ejection. The teeth are spaced and drafted properly
to allow the milling tools to cut the relatively narrow mold features that will
form them and allow the finished part to be cleanly ejected from the B-side
mold half. The A-side mold surface is flat and smooth where it forms the outer
surface of the teeth. The spaces between the teeth are formed by protrusions of
the B-side mold half, which shut off against the surface of the A-side mold
half. These shutoffs are drafted to prevent flash, allow clean mold opening, and
prevent damage to the mold.
Maraia's choice of polypropylene
resin provides the clear window for the paper icon, but it also flows well,
which is important in a complex design like this one. It also happens to make
an excellent living hinge.
Proto Labs gated the part at the
clip and had the resin flow all the way through the hinge to the far end of the
part. Some resins would not have flowed well through the thin area of the hinge
into the thicker area beyond, but polypropylene does. Resins that don't flow as
well might have required two gates to fill the thick areas, in which case the
two mold flows could have met at the hinge, which is exactly where you don't
want a knit line. In this case, the direction of resin flow across the hinge
aligns the polymer chains to increase the hinge's strength and longevity. It's
just one more way that this piece shows the complexity that be achieved in a
lower cost mold.
Cord
Idea Expands
The sophistication of the cord
identifier's design evolved over the long course of development. "Much of the
design came from CAD modeling and existed before the first prototype," says
Maraia, "but I also made some significant changes based on the first
prototype." The second prototype was easier to open and more refined both
visually and functionally."
Maraia considers himself
fortunate in being able to develop the product, the packaging, the Website, and
related materials himself. Outsourced, they would have cost tens of thousands
of dollars. The product is being sold both direct, through the company's
Web
site,
www.cordotz.com, and through retailers including Office Depot and
Crate&Barrel. "Because it's color- and icon-based, it's ideal for
international sales," says Maraia, and it is already being sold in the UK, Germany,
Japan, South Korea, Australia,
Turkey, India and Canada.
"We are continuing to develop
related products and now offer patented and patent-pending CordStraps and
CordWraps," says Maraia.
Dave
Nyseth is a customer service engineer at Proto Labs, www.protolabs.com.
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