|MEETINGS - BUSINESS - PEOPLE
The Ductile Iron Society Annual Meeting will be held May
11-13, 2010 at the Sheraton Vancouver Guildford Hotel in Surrey, B.C., Canada.
There will be visits to Century Pacific Foundry and Robar Industries, LTD, both
in Surrey, B.C. Canada.
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Find In-House Core Shops No Longer a “Core Necessity”
foundries outsource cores to gain significant benefits that far outweigh those
of producing cores in-house
sand core shop is an almost universal facility that can be found in foundries
around the world. At one time considered a vital part of the foundry for
constructing complex molds -particularly those with passages and cavities –
the foundry core shop may now be fading into the past due to higher costs,
overall core quality and production issues.
many foundries still maintain the classic in-house core shop, others are finding
conclusive evidence that core making is no longer a core necessity central to
their success, and is best outsourced from core specialists.
many foundries, in-house core production has been a sort of necessary evil that
for several reasons is no longer practical,” says Dick Holden, an industrial
consultant with Advanced Sales Dynamics, Cranberry Township, PA. “I think
it’s fair to say that in-house core production is often a deterrent to
productivity and profitability, and could be the source of considerable
that foundries are in the business of making and finishing castings, for them to
have core shops often creates a hidden source of overhead, Holden says. For
example, the core shop consumes energy, compressed air, air scrubbers, floor
space and other resources, yet often times labor is the only cost considered by
the foundry, when calculating core making costs.
you want to learn the true costs of cores, you can get those from an outside
core making specialist,” Holden adds. “Not only do they track overhead
completely and accurately, but they also help to keep the outsourcing of cores
competitive and affordable. Just considering the foundry’s unidentified
overhead, it is highly possible for them to lower core costs by going outside to
a core specialist.”
many in-house core makers are skilled craftsmen, their capabilities are
sometimes thwarted by foundry policies that inadvertently compromise casting
example, sourcing the optimum sand or silica used to make cores may be
unfamiliar or overlooked.
says core specialists such as Humtown Products (Columbiana, OH) use all virgin
sand that is consistent in quality and composition.
foundries recycle sand for use in making cores,” he explains. “So, there
might be a mixture of fine and coarse materials in it, or it might be coarse
this time and fine the next. Without consistency your core results, and possibly
casting results, will vary all over the place.”
adds that it is important to use special types of sand for certain types of
castings, including the many different kinds of iron and steel, steel alloys,
copper, brass, zinc. For example, for manganese steel a certain pH property is
required, such as olivine sand from Green Mountain, South Carolina.
you want the casting to chill faster in the mold, you should use a chromite
sand, which comes from Africa,” advises Don Covert, Humtown’s Technical
Sales Representative. “Zircon sand is more for steel castings, and much of
that material comes from Florida. Not only do the sand types and quality make a
difference, but also the types of powder additives. If you want to capture
nitrogen out of a certain kind of steel, you should add the black iron oxide,
spherox, or an appropriate powder additive to the sand and blend,” says
waste and machine time
cores that are used to make passages are often very intricate. For example, oil
pump passages for jet engines have very fine and small passages throughout the
casting. If the core is not prepared properly, such as with an incorrect sand
mix, flaws such as “burn in” can result.
can be very challenging to correct that kind of problem,” Covert says. “The
effect of burn-in is like metal spikes protruding into the casting passages.
These will restrict the flow of the pump, and when they do a flow test on the
casting, it will fail the test. Or, if you get something with too high of a
resin, you can have gas pockets in the casting, which can result in leakage. If
you have those types of defects in an internal passage, it can be difficult to
adds that many cores produce castings with excessive stock that require
unnecessary machine time. On the other hand, cores that produce castings with
too little clean-up stock for machining usually end up wasting valuable machine
time and the castings ultimately have to be re-melted.
those castings are tested after machining and the flaws are undetected, then
both the machine time and testing are wasted, plus delivery may be thrown off
schedule,” Holden says.
mentions that at Humtown core quality is checked very carefully, and because the
firm also has longtime pattern design and fabrication capabilities, worn or
out-of- spec tooling can be quickly and accurately corrected, a significant
value-added service to foundry and OEM customers.
of the main reasons foundries are outsourcing their cores is faster turnaround
time. While foundries are used to outsourcing cores with difficult
configurations, in many instances they inadvertently hold back production by
making simpler cores in-house.
foundries struggle to make 10 sets of cores per day,” Covert says, “where an
outside core specialist like Humtown can produce 100 sets of those same cores
every hour.” He adds that turnaround time for the outside core specialist may
be a matter of days to two or three weeks, compared to several weeks or even
months for the in-house core shop.
it comes to large volumes of cores, the capabilities of the outside specialists
are not lost on many foundries. But Holden says there are many instances when
the foundry should not be in the core business even for smaller volumes because
the real estate occupied by a core shop can be put to more profitable use,
whether making castings or for providing space for finishing equipment.
outside core specialists, foundry core shops are subject to EPA requirements,
some of which are very stringent. Core shops have to scrub all of the air within
the department or building because of the hazardous catalyst used to cure the
cores. In the case of outside core shops, the entire building must be sealed and
air scrubbed before it can be recycled. Foundries are held to even stricter
standards. Because the building cannot be sealed, air scrubbers are required for
every core-making machine – at very substantial cost. Even with this
equipment, cores continue to off-gas for periods up to 24 hours, exposing the
area to the catalyst, and subjecting the core facility to EPA compliance issues.
already have enough air quality issues to deal with,” says Holden. “When you
consider the capital investment required for air scrubbing equipment, the many
months it takes to get those systems installed, approved and permitted, plus the
tasks of dealing with continual monitoring, the already marginal benefits of
having an in-house core production facility become all the more problematic.”
more information, contact Humtown Products, 44708 Columbiana-Waterford Rd.,
Columbiana,OH; Phone 330-482-5555; Fax: 330-482-9307; Email email@example.com;
Humtown Products delivers quality cores to the 48 Continental United States and
Canada. Visit the web site www.humtown.com
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