Cleanliness, production efficiency and environmental
protection - All enhanced by MecWash Millennium component cleaning
system at IMI Norgen
The first installation of a MecWash Millennium parts washing
machine has now proven itself as central to the cleaning processes
at one of the world's leading pneumatic component manufacturers.
The unit is used intensively within one of the dedicated "focus"
facilities at IMI Norgren's Lichfield plant. It is located
ahead of assembly and storage areas and handles parts from
approaching 60 machines, 30 of which are high volume. Not
only is it achieving unprecedented levels of cleanliness -
to a level beyond the capabilities of small individual washing
units that have been attached to some of the machine tools
- but it is also helping to reduce the risk of mechanical
handling damage while increasing operational cost efficiency
and environmental protection.
The company's Fittings Division produces, in the main, brass
components, the majority of which are destined for the commercial
vehicle sector of the automotive industry for safety critical
braking and auxiliary applications which clearly calls for
the highest levels of component cleanliness and damage control.
The core machining processes leave components coated in mineral
oil and swarf or in some cases soluble oils - much of which,
with brass components, can be chipped and clogged. Until the
installation of the MecWash Millennium, this was mostly removed
using a multi stage process of spinning and riddling or by
subcontract cleaning. The installation of the Millennium has
significantly reduced in-house and sub-contract costs, component
handling requirements have been rationalised and both stock
level demands and production delays reduced.
At the heart of the Millennium installation is a rotating
drum within which the components are located and then subjected
to flood and spray wash then rinse and both hot air and vacuum
drying processes. The individual products are held in a series
of specially designed mesh baskets, themselves part of the
MecWash project, which are central to the efficiency of the
overall operation. Chris Jones, Manufacturing Engineer at
IMI Norgren, explains why -
"Components are collected at the machining stations
directly into the wash baskets submerged in machining oil
which provides an important degree of protection for the parts
as they exit down the chute into the basket," he says.
"From each location they are transported on special pallets
to the central wash area and hand loaded onto a roller conveyor
that feeds into the Millennium machine, although the installation
has been designed for adaptation to automatic loading if required.
The unit currently offers six programme sequences depending
upon component type at a typical throughput rate of just 2½
minutes per basket.
"Because the same baskets locate into the rotating drum
- in batches of eight - there is now no reason for components
to be tipped or removed from their containers at any point
between machining, washing and their eventual arrival at our
dedicated semi-automated wash basket to tote pan controlled
transfer installation where batch loads are created for onward
plating, assembly or storage. Significantly," he adds,
"the baskets themselves are cleaned as part of the operation,
removing the risk of cross-contamination."
The importance of the role played by the Norgren designed
basket is enhanced by an integral jetting system built into
the lid within the wash chamber. This allows the efficiency
of the cleaning process to be maximised - IMI Norgren estimate
up to a 40% improvement on previous methods - because the
basket mesh does not restrict the wash flow. Moreover, the
same manifold is then used to direct the hot air drying process
onto the components.
Further benefits of the basket design are noted through a
reduction in handling weight, better damage control by the
use of adjustable height lids and direct oil recovery at the
machining process compared with tote pans which collected
oil in the base. "The overall result sees components
cleaned to better than 20 microns. The Millennium machine
has been designed to be adapted for five microns if required,"
points out Chris Jones.
Collection of the high level of swarf that is removed from
each component is simplified in the MecWash Millennium machine
by the use of a multi strainer basket system and supporting
settlement tank - significantly, this also enables the components
to be cleaned without the need for spinning and riddling.
The damage caused by the previous processes had high associated
costs, scrap and re-work. The facility uses six removable
strainers which are simply emptied and cleaned each day to
protect the wash and rinse tanks from contamination. In turn,
this has led to a reduction in the need for regular dumping
of the cleaning solution tanks which itself has contributed
to operational efficiency. This is significantly enhanced
by the inline filtration and a MecWash Aqua-Save built into
the Millennium installation at IMI Norgren - designed to remove
machining oils that emulsify into the wash solution. This
allows clean water to be returned to the rinse tank and overflow
back to the wash tank, maximising the quality of both.
This is further endorsed by the use of an auto-dosing system
which ensures the optimum chemical content of the solution
is maintained - in this case MecWash supplies AC40 detergent
which also, importantly, helps to brighten the brass. The
system has run without a single requirement for solution dumping
during the first twelve months of operation with consequent
savings in downtime, water, energy and effluent disposal costs.
"Because this process also produces de-mineralised water,"
continues Chris Jones, "there is a marked reduction in
the risk of the brass components staining - always an aesthetic
consideration with this material. We are ISO 14000 accredited
so the use of this type of system is clearly important from
both environmental and production efficiency points of view."
The Lichfield Fittings Division operates a total of some
60 machining stations and the majority now feed directly into
the MecWash Millennium. The unit has been located centrally
within the premises alongside an existing MecWash Midi cleaning
system which has provided a highly effective centralised cleaning
process for selected machining operations over a number of
years. This latest investment, however, has now allowed the
organisation to deliver cleaning levels that match increasingly
stringent requirements both internally and from the company's
"From all points of view - efficiency, economy, the
environment and, ultimately, quality," concludes Chris
Jones, "the investment in the MecWash Millennium has
been highly successful and its versatility will allow it to
play a key role for many years to come. As an organisation,
we are committed to improving our performance and quality
standards on an ongoing basis and this installation is clearly
an important step in this direction."