WINTER 2016

166 THE DISTRIBUTOR’S LINK
DEL WILLIAMS ELIMINATING DEFECTIVE FASTENERS WITH HIGHER RESOLUTION, 3D INSPECTION EQUIPMENT from page 130
“A typical part today might have
10-30 dimensions checked, all
important to how it assembles and
functions,” adds Nygaard. “Any error
in measurement increases the odds
of falsely failing the part or falsely
passing it, either of which is bad for
profitability and quality control.”
According to Nygaard, to minimize
error and gain precision in fastener
inspection equipment it is important
to ask questions like: How well is
the part positioned in the mechanical
handling apparatus? How flat is the
surface that part riding on? Is there
any vibration distorting the image?
Is the part aligned with the optics
properly?
But he says this is the most
important question to ask: “Is the
sorting machine National Institute of
Standards and Technology (NIST)
traceable?”
Since many companies are ISO 17025 accredited,
their quality manual, in fact, requires any gauging system
they use to comply with NIST traceability. Calibration and
NIST traceability are actually mandatory, even though
many fastener companies do not realize this
requirement.
“A sorting machine is a gauge when you’re using it to
check dimensions on a part, but the dirty little secret in
the sorting industry is that most machines are not
traceable to NIST,” says Nygaard. “That can wreak
havoc on your production and quality control because
what you think you’re sorting for isn’t really what you’re
sorting for. It can be like using a mis-marked 13” ruler
to measure and sort for 12” parts.”
According to Nygaard, selecting a fastener sorting
system with intelligent software is also important in
eliminating defective parts.
“If the parts aren’t uniform, the algorithm needs
enough artificial intelligence to properly place fastener
feature start/stop positions,” says Nygaard. “To
improve lean manufacturing and process control, you
want to find and reject only the defects, and then use
that data to prevent defects, reduce scrap and variability
to increase yield.”
Despite the increased precision of today’s highresolution
fastener inspection equipment, they can be as
fast as or faster than traditional sorting machines.
“Fastener companies can expect to sort about 300-
1,000 parts per minute with the best fastener inspection
machines, but with better precision and coverage of the
part than typical sorting machines,” says Nygaard. “The
machine should be flexible enough to accommodate
thousands of different part numbers, but there’s a
tradeoff in flexibility and speed.”
While the cost of these fastener inspection systems
is higher than traditional sorting machines or cut-rate
overseas made equipment, over the course of a typical
5-7 year lifespan, the net cost is often just 1/10 a penny
or less per fastener in high-volume operations.
“If you’re making safety critical, lightweight parts or
will be functionally checked by auto-torquing
mechanisms, why roll the dice and play Russian roulette
with your company’s good name? Would you pay 50%
less for a life insurance policy that covered everything,
with the exception of cancer and heart attack?” asks
Nygaard. “Relying on the most precise 3D fastener
inspection systems for 100% sorting will help ensure
that fastener companies remain profitable, top-tier
suppliers.”
DEL WILLIAMS