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Marox Corporation
(Holyoke, MA) is a contract manufacturer specializing in
high precision machining of implants, external fixations, and
surgical
instruments for the medical industry, plus components with demanding
specifications
for the aerospace industry. Having celebrated its 50th year in
business last
year, Marox has 65 employees running two full shifts, 7 days per
week, in a
modern facility built in 2000. Brian Rosenkranz, Vice President,
attributes
Marox's success to their decision to stay at the cutting edge
of manufacturing
technology. They utilize up-to-date concepts such as lean manufacturing
and
high-tech integrated computer systems. To ensure total quality
control, Marox
performs most operations in house and jobs out very little. Their
products are
manufactured from stainless steel, titanium, aluminum, and other
specialty
metals and polymers on modern CNC equipment, such as palletized
horizontal
machining centers, five-axis vertical machining centers, and up
to twelve-axis swiss
type screw machines. Because Marox's customers rely on their "Dock-to-Stock"
deliveries, down-time of machines is not an option for them. Marox
makes a
point of maintaining an exceptionally clean shop to demonstrate
both to their
customers and their employees that meticulous work and total attention
to
cleanliness are essential elements of their products. In fact,
Brian Rosenkranz likes
to say that his customers would not feel out of place coming from
an
operating room into his shop.
Marox has
9 new CNC screw machines which utilize cutting oil as the working
fluid and 15 CNC millers with water-base coolant. Buildup of solids
in the
cutting oil in the screw machines was causing major problems in
shop
housekeeping, obviously a serious concern for Marox, as well as
generating significant
costs for unproductive labor and machine downtime. As described
by Michael
Consolmagno, Vice President of the Marox CNC Turning Unit, the
problems caused by
buildup of solids in the sumps of the screw machines, particularly
critical
with the new design machines, are:
•Chips and fines plug the coolant pump inlet screens, causing
the low
flow alarm to shut down the machine.
•A high concentration of fines in the coolant loop compromises
the finish
on precision parts.
•When the high pressure coolant pump is utilized, about 20%
of the time,
solids rapidly plug the filters in the high pressure loop, requiring
frequent
machine shutdowns to change the filter bag.
Until recently,
the only solution that Marox had to the problem of excessive
solids in the oil was to shut down the machine and manually rake
and shovel
the solids from the sump. The economic costs for this non-productive
(and
unpopular) function are the machine downtime and the use of skilled
labor. Even in
the new screw machines, the sumps are not readily accessible for
solids
raking or shoveling. Mike Consolmagno estimates three hours of
machine downtime
and labor to clean one sump. In addition to the economic costs,
the manual sump
cleaning and chip handling unavoidably produced oily deposits
that challenged
the Marox scrupulous housekeeping program.
The problem
of solids buildup in the sumps was solved literally overnight
when the salesman from Keller Products, Inc. (Lexington, MA) introduced
to Mike
Consolmagno the new portable pump/filter unit PFA-1002. The Keller
PFA-1002
can clean settled and suspended solids from a sump without the
need to drain the
sump or shovel the solids. The PFA-1002 contains a high capacity
bag filter
and a high flow rate air-operated pump, mounted on a compact (20”
x 30”)
cart. With the inlet and outlet hoses inserted in the sump, the
mixture of solids
and oil is pulled into the bag filter, which removes all solids
as fine as 5
microns, and the filtered oil is continuously returned to the
sump under pump
pressure at 20 gallons per minute. The force of the pressurized
liquid
discharge scours the bottom of the sump and keeps chips and sludge
suspended in the
sump for pickup by the inlet hose. The PFA-1002 can clean settled
and
suspended solids from a typical sump in 60 minutes or less. Requiring
only a 1/4”
compressed air line for operation (no electricals), the cart mounted
pump/filter
unit can be moved to another sump and set up to run in minutes.
The only
maintenance required is to empty or change the filter bag when
the pumping rate
slows or stops. Replacement filter bags cost $7.00 each. The self-priming
diaphragm pump has a suction lift of 15 feet and can be run dry
or dead-ended
without damage.
Marox now
utilizes one PFA-1002 to service all nine CNC screw machines.
Mike
Consolmagno says that treating each sump with the pump/filter
unit for about
one hour each week eliminates the screen plugging and parts finish
problems
associated with solids buildup in the sumps, and at the same time
completely
eliminates the messy and time consuming pump-out and shoveling
operations. Now
the machine tool is not taken off line for the sump cleaning.
Since Marox uses
two types of cutting oil, Mike particularly likes the feature
that the
self-priming pump on the PFA-1002 completely drains the bag filter
on the separator
after a sump is treated so that the next sump can be treated without
mixing
oils. He also points out that although on many of the machines
access to the
sumps is severely limited, the 8 foot lengths of both the inlet
and outlet hoses
and the fact that the pump on the PFA-1002 is self-priming permit
quickly
setting up and operating the unit on even the most difficult sumps,
without
significant sump modifications.
Marox also
uses the PFA-1002 to reduce the solids load on the high pressure
filter when the high pressure oil pump is operating. The PFA-1002
is set up
with the inlet hose positioned in the sump remote from the high
pressure pump
inlet and the outlet hose discharges filtered oil into the vicinity
of the pump
inlet. With the PFA-1002 operating in conjunction with the high
pressure
pump, the solids load in the high pressure pumping circuit is
greatly reduced, and
the time between bag changes on the high pressure filter is significantly
increased.
To sum up
the benefits of the Keller unit, Mike Consolmagno says, “The
PFA-1002 is rugged and easy to use. It works exactly as described,
with negligible
operating cost, and it has eliminated several costly problems.
No more
pumping out and shoveling out sumps, no more problems of fines
affecting parts
finishes, no more short runs with the high pressure coolant filter,
and with one
PFA-1002 it is far easier for us to maintain our high standards
of housekeeping
in the entire shop.”
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