Synventive
Molding Systems (Peabody MA), a manufacturer of advanced hot
runner feed systems for plastic injection molding, recently
expanded and upgraded its facility with the addition of 10
new CNC machines. With the installation of the new machines,
Synventive management reviewed all aspects of shop operations
to ensure that the new and the existing machines would be
operating at maximum efficiency. One of the first areas of
operations studied by Synventive was selection and maintenance
of the coolant. Michael Venable, Operations Supervisor, Milling
Department, explains, “The quality of the coolant in
the machines has a major effect on overall shop efficiency.
To maximize the return on our investment in machine tools,
we must ensure that the coolant we select has the combination
of properties best suited to help us achieve our throughput
and quality targets. Selecting a coolant based solely on lowest
price could be a very costly decision. Similarly, neglecting
to provide the operators with the equipment they need to keep
the coolant clean in their machines is a very short-sighted
‘cost saving’ measure. If the coolant in the machines
is loaded with tramp oil and chips, our machine throughput
suffers because operators must stop to make frequent adjustments,
surface finish suffers, and tool life is shortened. Another
problem resulting from running with contaminated coolant,
probably even more detrimental to our shop efficiency in the
long run, is the message we send to our operators that to
save the relatively small investment in coolant cleaning equipment
we are satisfied to have them deal with oily parts, dirty
machines, a smoky environment, and increased chance of contact
dermatitis. Keeping the coolant clean in the machines is clearly
an essential requirement for achieving maximum shop efficiency
and maintaining our excellent employee relations. Finding
a practical method to keep the coolant clean was a top priority
objective in our shop optimization program.” Synventive
management decided to have one coolant cleaning device stationed
permanently at each machine sump, rather than utilizing portable
units, so that each operator can maintain close control over
the quality of his own work environment. For this system to
work efficiently, it is essential that the coolant cleaning
devices require minimal operator attention. Venable tested
belt skimmers, but found that the
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skimmers
were ineffective for removing tramp oil from the relatively
large sumps. Venable also tested a few types of small pump/separator
units with electrically-operated pumps. He found that the
small pump/separators did not split out the tramp oil efficiently,
and maintenance problems with the pumps caused frequent shutdowns.
Venable then installed a Model #255 pump/separator unit from
Keller Products on one sump. The Model #255 has a number of
features which are particularly advantageous for his requirements—permanent
plastic oil separator elements which never need service or
replacement, a high capacity bag filter which removes all
suspended chips and fines from the coolant, and the rugged
air-operated diaphragm pump which has proven to be essentially
maintenance-free in thousands of Keller separator installations.
Venable found that the Model #255 effectively cleaned tramp
oil from the sump in a few hours, whether the machine tool
is operating or is idle. The unit requires little operator
attention: the separated tramp oil is drained from the separation
tank occasionally, usually once per day, by opening the oil
drain valve briefly, and the filter bag is changed about once
per month, a task of about 5 minutes, at a cost of $4.00 per
bag. The Model #255 is easily set up for operation in about
10 minutes. After Mike Venable operated the unit for about
one month, he decided that the Model #255 met all his requirements
for efficiently removing tramp oil with minimal operator attention.
In addition, Mike appreciated the fact that he could obtain
these results with a relatively inexpensive piece of equipment.
He proceeded to install one Model #255 on each of the 12 machine
sumps. When asked how he evaluates the performance of the
Model #255 separators, Mike says, “We are extremely pleased
with the significant cost savings we are getting as a result
of increased tooling life and coolant life. But we feel the
major benefit is that our operators can work with clean parts,
clean machines, in a clean shop, and take pride in their work.
As a result, we are maximizing the return on our investment
in machine tools. That’s the objective that we set for
ourselves when we started our program to evaluate coolants
and coolant maintenance, and the Model #255 has helped us
achieve that objective.”
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