TECHNOLOGY FOCUS

METALWORKING FLUID FORMULATION

PART 7 -  THE END OR THE END USER?

by Dom Ruggeri

August 2001:

To me there is no greater challenge or pleasure then taking a young chemist and bringing them into the world of industry.  For some (such as myself) a new world of wonder is opened and the decision to remain in industry is confirmed, for others they return to academia or get out of the business altogether.  The first thing you need to learn is to sift through the salesmanship regarding chemicals and get to the heart of the matter. 

Back in the early nineties I was working for a large formulating house.  During a staff meeting we were informed of a big plant trial.  Normally the lab manager would ask for volunteers to attend the charge up and the subsequent monitoring of the system till we were satisfied that all was well.  This time the job was assigned to me.  I recommended that the new chemist accompany me.  Since this customer was within driving distance my recommendation was approved.  We arrived on site late Sunday night I noticed that one of the large coolant tanks had a guard posted by it.  I asked our salesman what was going on, he explained that the coolant in that tank was special, in that during it’s quiet time the goodie package would regenerate itself and the coolant would be good as new.  The new chemist was impressed.  I could only laugh. 

We charged the system and checked the concentration.  All was well and the night passed without a problem.  First shift checked in and the shop began full production.  Our system was running well and no coolant related problems were detected.  The other system, well, that was another story.  Nothing but problems.  Everything from flash rust to rancid odors.  In short, the coolant did not regenerate.  The site superintendent approached me and asked if we could get enough coolant there to recharge the problem system.  I called the salesman and of course the answer was ‘yes.’

Never being a person to let an opportunity slip by, I asked the superintendent about the problems he had with the other coolant.  His explanation surprised me.  From the beginning, the coolant did not perform as promised.  Samples were sent to the supplier and not a thing was found to be wrong.  It was the customer’s problem.  The customer was not controlling the coolant correctly; contaminants were getting into the system, the list went on till finally the supplier informed the customer that the coolant was being tampered with and they should post a guard at the tank.  The customer solved their problem by changing suppliers.  I didn’t mind.

If you kept up with the previous 6 articles, then you know as of now we have formulated a masterpiece of metalworking fluid technology.  Our fluid has passed all the necessary laboratory ASTM tests.  Now it is time to take our masterpiece to the customer for a full field trial.  As a formulator this part always worried me the most.  Why? Customers have their own criteria for pass-fail.  I remember one customer had a test where he would move a bottlebrush up and down in a fluid.  He watched how the fluid foamed from this test he determined the foaming tendencies of the fluid.  Tests such as these could determine the future of our fluid.  If luck is still with us, the fluid passed the entire battery of customer specific tests.

The customer agreed to a trial in one of their many central systems, and you will be on site for this fluid trial.  Everything goes according to plan and your masterpiece is performing as expected.  As always there are the normal problems associated with a new charge up of metalworking fluid.  These issues are quickly resolved and all is well.

After a week of being bored out of your mind (a good thing) you return to the office to celebrate your success.  But no sooner do you arrive than your customer calls, and your fluid has gone to pot.  Problems such as poor tool life, Monday morning odor, and of course foam.  What happened?  First and foremost, remember your fluid was the only change that customer made, so any problems will be your fault no matter what.  Second your fluid probably is not the problem.  If it were your coolant, the above problems would have manifested within the first days of the trial, not weeks later.

It is a good practice to recheck the retained sample of the fluid.  One never knows what could happen.  Next request a sample of the diluted coolant, since this sample will tell you if the fluid is being maintained properly or if other factors are at work.  Let’s look at a real life example.

A customer had a particularly difficult machining center.  Using a semi-synthetic, they changed alloys and the center went belly up; tool life went down and scrap went up.  The coolant did not have the guts to work that alloy.  The customer wanted a change, and they opted for a chlorinated soluble oil.  A good choice since they were machining a harder alloy.

The charge up went fine, but as weeks progressed they began to notice that again tool life was trending down, scrap was trending upward and the product was foaming.  What changed? An analysis revealed that by alkalinity the concentration was at 5%, the recommended level.  However, an acid split revealed that the lubrication package was only at about 2%.  Further it was known that this customer used a coolant reclamation system consisting of a centrifuge and subsequent make up with fresh coolant.  No one thought to check into the reclamation system before the charge up.  A follow up investigation showed that the operators were in fact measuring the coolant concentration as it passed through the centrifuge, however, they were using alkalinity as their control.  That’s great, but alkalinity measures the water-soluble part of the coolant, so according to the alkalinity the concentration was going up and so they added water rather then fresh coolant.  Also the centrifuge was still set for the semi-synthetic.  Way more power than soluble oil needs.

In conclusion always look at the whole system before, during, and after a charge up.  You will cave yourself countless headaches by doing your work up front.  As always, feel free to e-mail any questions to Email Dom.

All Best

Dom