Modern Plastics Worldwide - October 2007 - dae uptlax

MODERN EXECUTIVE
Know your process to choose the
right runner
By Terry Schwenk
With the advancement of heater technology,
for the most part all hot
runner systems perform reasonably well
under moderate molding conditions. The
major differences between hot runner
suppliers seem to be in the area of service
and reliability.
To start your search for a hot runner
vendor, first make sure they are able to
reliably service their products. Ultimately
there will be issues, and what separates a
good supplier from a bad one is how well
and how quickly it responds to problems.
Ask about its service network and spare
part inventories. Make sure you understand
what “guaranteed” actually means.
This will give you a good indication about
the company’s capabilities at the beginning
of the process and reduce frustration
when you are in full production.
One of the biggest keys to successfully
select and specify the right hot runner
is to take ownership of your project.
Don’t expect hot runner suppliers to do
your job for you. Yes, you are paying
them to supply equipment for your
molding operation, but don’t expect
Selecting the correct hot runner system for your application is only possible if
you understand the complete manufacturing process.
them to know more about your operation
than you do. Be very open with
information relating to the application
and the production requirements. If you
think you have a difficult application,
make sure you relay that information.
Invest in education. The more your
employees know about processing with
hot runners, the better success you will
have. There are several sources for training
on hot runner technology and in
some cases they are free. The only cost to
you is the investment of time for you and
your staff. Take advantage of these educational
services and your production
will benefit.
Understand the requirements
What are the basic questions that need to
be answered first? Each hot runner application
can be addressed through an
understanding of the requirements related
to the project. So, here’s what you
need to know:
1. What is the resin being processed?
2. What are your experiences with this resin?
3. What are the part requirements?
4. How is the part used?
5. What molding equipment is being used?
6. How well are your employees trained on
the equipment?
As you can see, most of the questions
revolve around processing plastic. If your
hot runner supplier isn’t asking these
questions about your materials processing,
then what is the likelihood it will be
able to select the correct hot runner components
for your application?
Document the process
In my travels throughout the industry I
have observed on many occasions the
lack of process documentation. Whether
it was intentional because of trade secrets
or because the processor just didn’t think
it seemed important, to successfully
process plastic there is no substitute for
experience gained and lessons learned.
Less cost is not always less cost
Sometimes it seems the cheapest solution
is the best solution. But what is the cost
of not getting into production in a timely
manner or, worse yet, to have something
that’s not running at all? If you
don’t have a materials expert on staff,
there’s no shame in seeking out a professional
to assist you with your application.
I have always stated that I may not
have all the answers for a particular situation,
but I am the world’s foremost
expert on what not to do. A little money
spent up front to ensure smooth sailing
through the project is well worth it.
Selecting the right gating method
Now that you have found a supplier that
About the author:
Terry Schwenk is founder of Process and Design Technologies (Kenosha, WI),
providing plastics companies with complete optimized processing solutions
through efficiencies gained in engineering, manufacturing and processing. He
has more than 33 years of experience in the plastics industry, including more
than 22 years of specialized experience in hot runner technology and tooling.
Contact him at tschwenk@processdesigntech.com.
26 OCTOBER 2007 • MODERN PLASTICS WORLDWIDE modplas.com