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TOOLING: Solutions Start in the Mold
By:
Michelle Maniscalco
LeVic Plastics overcomes
challenges with its approach to tooling, including a creative way
to vent using porous mold steel.
Ron Knight became an owner at molder/moldmaker LeVic
Plastics in Grandview, MO in 1977, five years after it was
founded. From the start, it has been a comprehensive operation
offering not only molding and moldmaking, but also secondary
tooling and operations, assembly, and engineering. Markets served
include medical, aerospace, electronic, consumer, and industrial.
LeVic is a growing company today, despite the competition from
offshore moldmaking and molding companies. Knight believes its
growth is due to a strategic change in how the company approaches
manufacturing: LeVic has adopted a solution-oriented approach. As
a solution provider, it is open to, and regularly tests, different
manufacturing processes. This view has paid off, both in retaining
customers and acquiring new ones, especially those in important
growth markets. It is able to supply its customers with a
good-quality part out of a wide range of commodity and engineering
resins.
In aggressively going after production challenges, LeVic has found
a niche as a solution provider, a place where companies can bring
their challenges for review. Ron is not afraid to try new ways to
grow his business, which means educating existing and future
customers in a changing, growing market to ensure better part
quality at an affordable cost.
A new way to vent trapped gas
An example of turning its attention to solutions involves a change
in the way LeVic vents some of its molds. According to Knight,
certain mold geometries have one problem that plagues moldbuilders.
“They trap gas in the most difficult places, and this gas must be
released,” he says.
The most common and least expensive practice is to place inserts
and/or vent pins in the mold. While this method works for a
certain percentage of parts, it may be unacceptable to the
finished surface on others because of insert or pin lines that are
created.
LeVic solves this problem by
placing Porcerax II (International Mold Steel, Florence, KY)
inserts within some of its molds. This is a sintered, porous mold
steel that is 25% air by volume. The pores allow trapped gases to
escape directly through the steel. While this solution saves labor
in moldbuilding, it is also the only way to produce certain
medical and aerospace parts.
Knight comments on several benefits of using the porous inserts.
“We are able to use several fill speeds or ram speeds for
injection on our electric Toshiba machines, and the scrap rate
dropped to almost zero. There are no weldlines or gas trapped in
critical areas, and we also see a large increase in usable parts
per hour due to zero surface imperfections.”
In one case, a seemingly impossible part was tooled successfully.
“Medical parts often present the toughest molding challenges, as
many times they require sealed surfaces,” says Knight. “This
particular part is involved in bacterial analysis and can’t
tolerate a weldline, no matter how small. In tests using K-Resin,
we placed an insert inside the mold, and the result was a weldline.
Then we placed Porcerax II in the mold with no resulting weldline.”
Successful production of the part has brought additional medical
business to LeVic.
MM - June 2006
Reprinted with permission from
Canon Comunicaitons, LLC
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