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Overmolding
Avalanche
By Tony Deligio, immnet.com / Canon Communications LLC
Pre-Hardened
Tool Steel Saves Time and Money
Using NAK 55 standard
mold bases allows moldmakers to focus on crucial core and
cavity work. Click here for the PDF
version (773k PDF)
By forging business
relationships with nearby companies and proactively
introducing overmolding as an aesthetic and structural
benefit, an Idaho molder has carved out a successful
niche.
With sporting goods OEMs like Smith in its
backyard, Tooling Express Inc. (Bellevue, ID)
developed designs like the molded-in strap for
these goggles to help it win steady business. |
Success
for many molders lies not in pursuing fanciful visions
of what your business could be, but in realistically
appreciating what your business inherently is. Lonnie
Tustison, tooling manager of Tooling Express Inc. (TEI),
has adopted the latter view, and in doing so, accepted
his shop’s weaknesses and exploited its strengths to
the betterment of TEI’s bottom line.
“It’d be nice to get
some gravy, high-volume,
never-have-to-do-anything-with-them jobs,?Tustison
admits, “but that just hasn’t panned out for us, so
we’ve gone more towards the things that other people
haven’t been able to do or haven’t been willing to
expend the money to try.?lt;/font>
This outlook has
increasingly led TEI to multicomponent or overmolding
jobs, leaning heavily on the experience of Tustison and
his two fellow toolmakers. Geographically isolated in
Bellevue, ID, Tustison says TEI, under the leadership of
president Owen Downard and his son Evan, has forged
relationships with local customers, proactively
introducing overmolding‘s aesthetic and functional
benefits to win business.
Snow Jobs
A short cross-country ski trip from many of its
customers, TEI has capitalized on proximity to Sun
Valley’s ski country and worked hard to win the
confidence of local sporting goods OEMs like Smith and
Scott. TEI actually started as a tool shop supplying
molds to a local molder that worked for Scott. Ten years
ago when that molding shop went under, Scott said the
parts business was TEI’s if it would buy a molding
machine, so the company obliged and promptly became a
custom molder.
Molding the goggle straps into a clip rather
than manually threading them enabled TEI to
reduce material scrap and assembly time for
clients like Smith and Scott. TEI devised a
manual process for strap loading that cut 6
seconds from the quoted cycle time for an
automated setup. |
The first major project TEI
took on for Scott was a two-component ski pole grip.
Given only an epoxy model of what Scott was looking for,
TEI was forced to reverse engineer the part. Running one
press, TEI designed a mold for the PP inner component
and a separate tool that held that PP insert to overmold
thermoplastic rubber (TPR). Tustison says TEI spent a
year “dialing [the mold] in?and performing
secondary machining before it produced the parts
suitable for Scott.
Its diligent efforts were
rewarded, however, and although Scott eventually pulled
most of its operations into Europe, that initial program
served as a launching point for TEI’s success. The
grip remains a source of pride for Tustison and TEI,
especially after its production was attempted in Europe
with mixed results.
“[Scott] tried to
replicate what we did here on the European market,?
Tustison says, “and to this day if you line up our
grip with the European grip side by side you can tell
the difference. It was one of those things where we
still step back and say, ‘Yeah, we did it—a couple
of toolmakers in the-middle-of-nowhere Idaho were able
to pull something off that the big-money guys
couldn’t.’”
Soon after, TEI was
contacted by a Norwegian company for ski pole grips, and
another local OEM, Smith, followed fast behind with
various sporting goods components. Tustison says that
things (appropriately) “snowballed?from there, and
soon the company had seven presses (55 to 375 tons), a
CNC EDM, a three-axis machining center, and a CNC lathe.
The investments in technology were important, but it was
the knowledge gleaned from that first pole grip tool
that has proven invaluable for TEI.
A Different
Perspective
Of the many lessons Tustison says TEI learned, the most
important was to view the cycle in reverse. The key was
positioning the PP insert into the second mold and
supporting it in a linear and lateral fashion. Tustison
says the process TEI adopted defies some common shop
knowledge, but that it was critical to the part’s
success.
Located in the heart of Idaho’s ski country,
TEI used an innovative, overmolded ski pole grip
created for a local company to branch into other
sporting goods parts. By using multimaterial
designs, it was able to enhance product
appearance and functionality. |
“I’ve seen many times
that people will blow a mold open, so they increase the
tonnage,?Tustison says. “But then the part won’t
fill because they don’t know they’re pinching out
the gate or the vent, so they give it more injection
pressure to help fill it. They’re actually working the
wrong direction even though logic would tell you to do
this, do this, and do this. Back up, regroup, and
lighten it up. Instead of making the shutoffs harder,
make them lighter.?lt;/font>
Tustison says TEI
doesn’t have the luxury of doing flow simulations on
all of its jobs, but that doesn’t mean it shoots the
first parts into a mold with its fingers crossed. For
most parts, prototype tools are initially cut from
aluminum with only one cavity so there’s room to try
different gating scenarios or runner configurations.
Including Tustison, TEI has just three full-time
toolmakers, but it still managed to crank out 20 molds
last year, and that tally is closer to 30 if you count
the prototype tools. The company also performs
short-shot series and other tests, but through all
processes, the quest for knowledge remains paramount.
“We try to do as much
homework as we can and ask the right people as
intelligent questions as we can,?Tustison says.
“Even a flow analysis is nothing more, in a lot of
ways, than an educated guess.?lt;/font>
Strap It On
TEI continues to market its knowledge of overmolding,
and an aggressive strategy recently won it some new
business. Smith is one of the largest goggle
manufacturers in the world, and just one of its lines
constitutes 6 million pairs annually. TEI had long
coveted, and won, some of the smaller components for the
goggles, but it realized a new design could provide an
excellent opportunity for deeper penetration and
actually save Smith money in the end.
In Smith’s initial
goggle design, the elastic strap was sewn onto a clip
attached to the goggle frame. Working literally from a
bar napkin sketch, Tustison and TEI’s president came
up with a new design that called for the strap to be
molded into the goggle frame. This eliminated the clip
as well as the labor to sew it on.
They designed and cut a
mold in the evening, shot some crude-looking but fairly
representative parts the next morning, and brought the
new concept to Smith—just down the road—the same
day. Smith was immediately enamored with the aesthetic
appeal and durability of the new design.
‘Profit
is not going to come around the corner. It’s
going to require patience and a lot of late
nights.?lt;/font> |
“The strength of adhesion
between the nylon and the strap material was far greater
than the looping and stitching method,?Tustison says.
“You can put one of these new clips in a vice, put
your feet up on it, grab it with a pair of pliers and
rip and tear and tug, and it’s not coming out.?lt;/font>
TEI considered automating
the process, and had even purchased a turnkey
manufacturing cell centered on a Sumitomo injection
molding machine at a trade show, but when the automation
package fell through, TEI developed a streamlined,
manual-loading process that shoots two goggle straps out
of the tool with molded ends in a cycle that’s 6
seconds faster than was quoted with automation.
Understanding
Overmolding
TEI still doesn’t have a preponderance of “gravy?
jobs that Tustison desires, but things remain busy,
including work on goggles with molded-in straps for
coalition troops in Iraq and a recently patented
integrated slider-clip design for strap adjustments.
For shops tantalized by
TEI’s success, Tustison offers advice for adding
overmolding to the repertoire. “You’ve got to
realize that profit is not going to come around the
corner. It’ll take a while. It’s going to require
patience and a whole bunch of time on your own: lots of
off-the-clock hours, lots of late nights.?lt;/font>
Throughout this learning
curve, Tustison says honesty with customers about what
jobs you can and can’t handle is the best policy.
“It’s vital to be straight up and honest with your
customers,?Tustison explains. “The best thing we
can do is say, ‘That’s similar to another [job] that
we’ve done, and we think we can do it; let’s go
try.’”
More than anything,
Tustison explains learning the technology takes time,
and it’s not a lifeboat to take on molders drowning in
other markets. “It was two years before we really made
a profit,?Tustison says. “It’s an investment of
time, it’s an investment of patience, and it’s not
something that if the computer market is in the dumps
right now, you’d want to transition your whole company
towards overmolding.?lt;br>
IMM - May 2003
Copyright?2003 Canon Communications LLC
Reprinted with permission from immnet.com. Contents
cannot be reprinted without permission from the publisher.
All Rights Reserved. www.immnet.com |
RETURN TO TOP
Click here for a PDF
version of this article.
Case Study
Pre-hardened Tool Steel
Saves Time and Money
Using NAK 55
standard mold bases allows moldmakers to focus on crucial
core and cavity work.
Sherry L.
Baranek
|
|
When
Tooling Express, Inc. (TEI) ?a Bellevue, ID-based mold
shop that specializes in sporting good molds ?branched
into the molding part of the business to further define
its niche and improve its moldmaking process, it soon
faced the challenge of finding a quality tool steel to
work with that also would shorten deliveries by reducing
machining times and post processes such as heat
treating.
Located right outside of
the ski resort area of Sun Valley, ID, this father/son
moldmaking/molding shop employs four full-time
toolmakers/mold designers. The shop is literally 15
minutes from the ski slopes,
and summertime fly-fishing is a 10-minute walk from the
shop’s back door. It seems only natural that the company
soon found its niche catering to the wide world of sports.
With a 10,000-square-foot facility containing six
International Mold Steel's
off-the-shelf NAK 55 MUD style bases allowed Tooling
Express to get it's customer's products ready on time.
injection molding machines ranging from 55 to 165 tons,
TEI also has second operation facilities such as pad
printing, ultrasonic welding, and minor assembly and
packaging of its customer's products.
The Overmolding
Challenge
According to Vice President Evan Downard,one of the
company’s earliest challenges involved building a mold
for over molded ski pole grips. “It had only been done
once before and our new customer wanted to get very
aggressive with the shut-off shapes that would show the
secondary color on the grip,?Downard explains. “We
quickly realized that the only way to ensure success with
the project was to also control the final injection
molding process. So, eight months into our endeavor as a
moldmaking shop, we also found ourselves as injection
molders. Our huge success with this particular over mold
job quickly lead to other jobs and helped us realize that
this is our niche in the industry.?lt;/font>
The object of overmolding
?or insert molding ?is to place either a metal or
plastic item into a mold and close on it. “This is
something that most injection molders try to avoid,?
Downard explains. “But here we are in our own private
Idaho, doing it all day long on purpose.
“A big problem with insert
molding is the fact that you are actually closing the mold
on pre-molded parts or some other insert material,?
Downard continues. “In the past, we have relied heavily
on heat treated tool steels to take on the task of
pinching off on insert material and still leave shut-off
surfaces intact. Taking the problem one step further,
there is often a need to do additional machining on mold
surfaces to fine-tune the pinch off areas.?lt;/font>
Standard Mold
Bases/Inserts Speed Delivery
Downard found the solution he was seeking at International
Mold Steel, a Florence, KY-based supplier of pre hardened
mold steels and a new line of MUD-style mold inserts. The
company’s off-the-shelf NAK 55 MUD style bases were the
best fit for TEI’s needs. “Since a large portion of
our molds are built in this style base, and the fact that
we can more efficiently cut NAK 55 over the other
available pre-hardened mold bases, this is what we were
looking for,?Downard comments. “The price may be a
bit higher, but we quickly make up for that additional
cost by having the ability to finish molds earlier due to
faster machining and less time spent on any unnecessary
heat treating. In addition, we don’t need to post-grind
the inserts.?nbsp;
Plus, the quick-change
inserts load in and out of a master frame that can be
reused over and over again, eliminating the need for each
mold to have its own “A?support plate and “B?
side ejection box or U-frame. “This obviously offers
some cost savings due to fewer materials being needed, but
more importantly, it allows the moldmaker to focus on the
more highly detailed core and cavity work,?Downard
explains.
The greatest challenge of
this type of work, he continues, is that most often there
is no real life part geometry to work from. A customer’s
only concern is that it works and achieves the desired
look when assembled. When components for the final
assembly are being made all around the world with no real
hard numbers to call law, quite often final “tweaking?
is necessary. For this reason, weldability of the mold
insert material is crucial, and Downard points out that it
can be welded without any evidence of the weld on the
part.
“In our latest endeavor
of overmolding plastic attachment points to the ends of
goggle straps, the NAK 55 mold bases have really shined,?
Downard adds. “Due to the perfect timing on delivery of
the mold bases and the ability to machine faster with
minimal polishing, we were able to get our customer’s
new concept products online in time for them to take
actual production parts with them to a recent trade show.?nbsp;
For more information
contact Paul Britton of International Mold Steel
(Florence, KY) at (859) 342-6000 or visit its website at www.imsteel.com.
MOLDMAKING TECHNOLOGY
ENGINEER, BUILD, REPAIR
Copyright?2001 Communication Technologies, ?001
Communication Technologies, Inc., All Rights Reserved.
Reprinted from MoldMaking Technology magazine. Contents
cannot be reprinted without permission from the publisher.
All Rights Reserved. www.moldmakingtechnology.com |
|
Tooling Express, Incorporated
680 South Main Street
Bellevue, Idaho 83313
Tel: 208/788-3242
Fax: 208/788-4602
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