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The Benefits of Process Monitoring in the Real World
By Peter Rucinski, Moldflow Corporation
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 You
cannot manage what you cannot measure. These words ring true
for all types of companies across all types of industries.
Imagine a gas station that was not measuring and tracking
the amount of gasoline it distributed, or an energy company
that was not monitoring the amount of energy produced versus
consumer requirements, or a soft drink producer that did not
measure how long it takes to fill and package 500,000 bottles
of its product. These companies would have no idea of when
they were going to run out of gasoline, energy, or soft drink.
Beyond that, they would not be able to manage and grow their
respective companies because they were not measuring key performance
indicators that are fundamental to their business operations.
Although it is hard to believe, today there are multitudes
of companies that do not measure key business performance
indicators, and the price they pay is lost market opportunity,
labor productivity losses, and costs associated with manufacturing
inefficiencies and unscheduled production downtime.
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Not so for one innovative US-based injection molder,
Vision Plastics, that uses the Moldflow Shotscope® process monitoring
and analysis system to measure and track key injection molding parameters,
allowing employees to work smarter and more productively and give
their company a strategic competitive advantage. The Moldflow Shotscope
process monitoring and analysis system is a comprehensive product
suite which collects critical data in real time injection molding
machines on the factory floor, then records, analyzes, reports, and
allows access to the information for use in
critical decision making. This article discusses how Vision Plastics
has implemented Moldflow's Shotscope system to monitor its injection
molding process and the value derived from measuring what it has to
manage in order to control and grow its business.
Eliminating
Guesswork and Downtime with Shotscope
Vision Plastics, Inc. started out in 1988 in Tualatin,
OR, with five molding presses and five employees. Today, the company
is relocated in a modern facility in Wilsonville, OR that houses
more than 38 machines and 150 employees. Vision Plastics is ISO
9002 certified and one of the most highly regarded custom injection
molding companies in the Pacific Northwest.
Today, Vision Plastics utilizes the Shotscope process
monitoring and analysis system from Moldflow to assure that the
very best parts are being manufactured. This system, installed directly
on each molding machine, is a real-time program designed to capture
a picture of each injection shot through predetermined parameters.
The data collected is available for review through a number of display
screens. Shotscope provides shot profiles, statistical process control
trend charts, shot-to-shot comparisons, and a number of other displays.
Each molding press is equipped with an analyzer to capture the data
and with a remote screen to display that data.
Each injection molding job has a set of predetermined
parameters that are input into the Shotscope system. Should any
of the parameters move outside the control limits, the machine alarms
and highlights the discrepancy for immediate appropriate action
by the mold technician.
Any changes to the established molding processes
that might be necessary are well documented through a Cause and
Effect system. This closed-loop system identifies the root cause
of any discrepancies in the process and documents changes that are
made to the injection molding machine settings to bring the operation
back within the pre-set limits.
Mike Olson is Vision Plastics' Shotscope coordinator.
It's his job to keep all 26 Shotscope-based plastic injection molding
machines running at peak performance. "Shotscope generates profiles
or overlays of what the machine is doing internally at all times,"
says Olson. "I save the overlays as references and as historical
data. I can pull any overlay up at any time and lay it on top of
another to see if there is any variation in the process. The overlays
tell us if the machine is varying from shot to shot, showing inconsistency."
| "We used Shotscope
at my previous place of employment and the software was considered
a valuable tool. I volunteered to get the system up and running
at Vision and we have been using it ever since to its full potential,"
said Olson. |
When Olson first joined Vision Plastics several
years ago, the company was not actively using Shotscope. "We used
it once or twice but that was only because one particular customer
wanted cavity pressure and mold temperatures from every shot. Once
we made the run, we downloaded the data to a diskette and sent it
to them with the parts. At that time, that was the extent of Shotscope
use here."
At that time, Olson approached the company owner
to find out why. "We used Shotscope at my previous place of employment
and the software was considered a valuable tool. I volunteered to
get the system up and running at Vision and we have been using it
ever since to its full potential." Shotscope monitors 26 machines,
although the software can monitor up to 32 machines at once. Olson
installed the Windows version of the software in August of 1997.
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Shotscope
Benefits
The software provides a graphical overview
of the Vision Plastics shop floor. Different colored icons
depicts each machine. Gray icons depict machines with no communication
between the machine and Shotscope. If the machine is not running,
the icon is red. A yellow icon represents an operating machine
that has exceeded one or more parameters. "Yellow signals
me to investigate what is causing the machine to go beyond
our set parameters," says Olson. A green icon indicates a
machine that is running within all parameters.
"Anytime something goes wrong, I can quickly
single out which machine needs attention," adds Olson. "Usually
a quick adjustment or two is all that is needed and we are
back in business. Shotscope saves a tremendous amount of time.
Traditionally, it would take several technicians and a lot
of time on the shop floor trying to figure out the problem
and how to remedy the situation. Shotscope eliminates all
that guesswork and down time."
Recently, Moldflow engineers from the company's
Oregon and Australia-based offices visited Olson. “I gave
them a tour of the facility and showed them how I use Shotscope.
I made some suggestions as to what I would like to see added
to the next version of the software such as pop up windows
that give the user information about what the machine is doing.
They seemed very pleased with the recommendations that we
provided," says Olson.
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During the visit with Moldflow, a Vision Plastics technician
made an adjustment to one of the molding machines without confiding
with Olson or Shotscope. The adjustment caused a yellow icon to appear
on Olson's monitor, indicating the highlighted machine's process had
been changed. Overlays were created to show before and after process
profiles. Upon comparison, it was clear that the new process would
cause an unstable process from shot to shot — an out-of-control condition
and questionable parts. The information proved that the technician
did not use Shotscope in his decision making. The process was subsequently
re-adjusted and the machine was brought back into a controlled condition.
Three overlays originate from a linear transducer
that measures the positioning and velocity of the screw. A pressure
transducer provides pressure overlays. These profiles can be downloaded
just seconds after the machine completes a shot and Shotscope analyzes
the data. "After a few shots, I know pretty much what is going on
with each machine's process. Whereas, out on the floor, it would
take me 20-30 minutes to gather the same data," Olson says.
It can be busy at times. However, Olson says that
once he and the technicians start the machine and a stable process
is established, his work is nearly complete for the whole run of
each particular machine. He adds, "If a heater band goes out, Shotscope
will alert me now before we start producing rejects. I can keep
my limits so tight that if the size of a part changes as minutely
as 1/1,000 of an inch, I will know about it. Or, if I lose temperature,
Shotscope highlights it and we can address the issue then, not when
the machine stops making parts, or when it starts making burned
parts, or when one of the zones overheats. Shotscope keeps a close
eye on all those areas that could become potential problems."
"In this competitive market, Shotscope is invaluable.
It helps Vision Plastics remain a viable contender in the industry
as a leading producer of high quality parts," Olson explains.
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| Shotscope profile analysis
revealed that the press was fighting to hit the transfer position,
resulting in inconsistent fill time and hold time from shot
to shot. |
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After the shot size was decreased,
a stable process was achieved. |
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Shotscope results showed that
the press was not holding a steady cushion length. Upon investigation,
it was discovered that the machine's check rings needed to be
replaced. |
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After check ring replacement,
Shotscope verified that the machine performed as expected. |
Conclusion
You cannot manage what you
cannot measure. These words ring especially true for injection molder
Vision Plastics, that relies on Moldflow's Shotscope system to measure
and track key business performance indicators so that they can control
and grow their business profitably and with a significant competitive
advantage.
To learn more about Moldflow's Shotscope product,
visit www.moldflow.com. To
learn more about Vision Plastics, visit www.visionplastics.com.
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