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Scale Buildup In Waterlines
by Douglas M. Bryce
Although there have been dramatic
improvements over the years in all areas of plastic injection
molding (molds, machines, materials, etc.), little has been done to
improve mold cooling methods. Sure, the major suppliers have gone
digital, and with proper mold design you can hold the mold
temperature to +/- 1 degree F., but the major reason for increased
cycle times is still focused on inadequate cooling of the mold.
Even if your mold was designed
and built properly, and was able to sustain proper cycle times when
it was new, it may not be able to do so now.
What's the problem? Our studies
have shown that in most cases the waterlines contain scale or rust
buildup. And if the mold lines are clean the control units are
getting plugged due to the same scale buildup.
I am often called in to help fix
some defect problem, like warped parts or extremely long cycle
times, only to find the mold waterlines plugged solid. In many
cases, the "thermolators" are also plugged or close to it. In one
case I leaned on the edge of the "A" half mold mounting platen and
burned my hand because the mold was so hot and the heat transferred
to the platen after hours of running.
This is a very common problem.
What can be done about it? Simple. Descale the waterlines in the
mold. How? Read on.
A client of ours once asked if we
could design a portable descaling machine that he could run up to
his press, hook up to his mold, and clean the waterlines, without
shutting down the machine. His normal method required pulling the
mold and having the tool room route out the waterlines with a
special drill. His downtime amounted to 16 hours every time he did
that. And he had to do it on 22 molds once every month. We accepted
the challenge and came up with a very successful compromise. We call
it the RousterBout™.
On a "clean" mold, the
RousterBout™
can be used to keep the mold clean by using it
for 5 minutes every month. The secret is to GET the molds clean by
running the system until the scale is gone. This may take 48 hours,
but once it's gone the RousterBout™
can keep it gone, easily.
Our client found that he could
also use the RousterBout™
to keep his heat exchangers cleaned
out. That usually required a major overhaul and a downtime of 2
weeks for each machine.
On machine downtime alone, our
client was able to realize annual savings of over $45,000. Add that
to the $65,000 he saved annually on labor costs and you can see that
his initial investment of $975 paid for itself over and over again.
He has since purchased 5 more units and when his planned expansion
is complete he will buy 6 more.
If you wish to clean your lines
you'll need to use acid. We developed a special acid for the
RousterBout™
that is food acid based, and is safe to use and
even dump down the drain in places such as California which has the
strictest environmental laws of any state.
If you would like to see more
details on the RousterBout™
, please click
RousterBout. If you'd like to discuss the machine with
me by email please click
here. Ask whatever question you'd like and I'll reply by email.
If you leave your phone number I'll call you.
Every area of this country has
some type of water problem that causes scale buildup. As a rule of
thumb it is true that just 0.015" thick scale on a 1/4" waterline
will reduce the cooling efficiency of that waterline by 40%! Just
take a close look at the walls of your mold waterlines and see
what's there. It may surprise you.
(The chemicals we use in the
RousterBout™
can also be used in closed loop water systems and
in radiator systems to keep them scale free, )
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