MACHINERY LUBRICATION- INDIA NOVEMBER-DECEMBER 2019 | Page 20

Manoj Srivastava
WHAT IF..?
You observe rusted
products after use of
water miscible metal
working fluid
Machine:
• The fluid circuit was found to be OK.
The system had mesh installed to
trap debris before fluid was sent to
MWF sump.
• The nozzles during operation were in
good condition ensuring that the
components were properly wetted
thus avoiding chances of untreated
part of component liable to rusting.
(The customer had 23 operating
stations on their shop floor, each
with two nozzles – all in good
working condition).
It all started with our sales team
receiving a call from one of the
customers complaining about our
metal working fluid (MWF). Our MWF
was being used to produce mild steel
(MS) square pipes. The sales person
went to the customer’s site and sent us
this picture, showing components with
clear rusting.
Obviously something was wrong. One
of the expected functions of MWF is
that the components should be
protected against rust, which is not
possible if plain water was used. We
asked for sample of the undiluted MWF
from drum. The laboratory tests
showed the undiluted product meeting
18 | November - December 2019 |
all the specifications. So, off we went
with our team to understand the issue.
What better way to analyze the problem
than fish-bone diagram (Ishikawa
diagram).
Material:
• The MWF, itself, was OK. This was
confirmed by our quality control
(QC lab).
• Water being used for dilution was
tested in our lab and reported to
have hardness 650 ppm. This was
acceptable since our MWF was OK
up to 1000 ppm.
• The components were of MS and our
MWF was OK for MS.
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Man:
• The customer’s employee confirmed
that he was using 8% MWF + 92%
water, as specified by us.
• He also confirmed that this ratio was
being maintained even
during
top-up.
Method:
•
The
customer’s
representative
confirmed that MWF was added to
water and not vice-versa.
• It was also confirmed that all records
were maintained.
There must be a catch somewhere. So
we asked them to show us the records.
And we found an unintelligent mistake.