TECHNOLOGY FOCUS

METALWORKING FLUID FORMULATION

PART II - THE CUSTOMER WANTS WHAT?

by Dom Ruggeri

December 2000:

Back in the very early 1980’s I began my career working for a small formulating house.  At that point in time I never dreamed that I would choose formulating as my life’s work, but stranger things have happened.  The project was to formulate a metalworking fluid that would machine steel.  At that time, this was a big challenge.  I was a novice.  How could I possibly develop that type of product. 

My Dad always taught me that if a long-standing colleague ever gives you some advice it is best to take it to heart.  I was working with a Senior Chemist, he felt we should call on the customer, get a feel for his needs, and from there I would know where to begin.  The call was cordial, however, I came away from it more confused then before the meeting.  First the customer wanted a semi-synthetic, since this was the most difficult job in the shop, and whatever would work there should work everywhere else.  Further, the customer had sales and technical support issues.  The Senior Chemist then advised me that the company coming in, is always held to a higher standard then the incumbent.  And I thought life was fair…

We found a product in the line that had a good chance of meeting the customer’s needs.  We submitted a sample.  I was certain the sample would pass the laboratory screening, but it fell short in the system tests.  After a modification and another round of lab tests we were confident that the product would pass the system tests.  Yeah right, the report read: “almost but not quite.”  I was stunned.  Every result I generated indicated that this masterpiece should pass with no problem. 

The salesman had a different idea.  He requested we resubmit the product using three samples.  The first to be dyed red, the second to be dyed amber, and the third dyed green.  He also wanted a new product name reflecting the various colors of the product.  Certainly we complied, but I was curious and quizzed the salesman on his strategy.  His reply was quick, “The green one will work.”  I laughed and bet him a dinner that he was wrong he took the bet.  Three weeks later I got a call report from this salesman he wrote: “The green one worked”. 

When I first entered this business there were four major classifications of metalworking fluids:
Red, Amber, Green…just kidding.  Actually, there was:

Straight Oils: Oil based product used as received
Soluble Oils:  Oil Based product that can be diluted with water
Semi-Synthetics: Oil/water based product that can be diluted with water
Synthetics: Water based product that can be diluted with water

The raw materials in each class may be very different or quite the same depending on the properties the customer wants.

Straight Oils:

To formulate this type of product one needs oil, parafinic or napthenic depending on the customer’s desire.  Further, formulating depends on the customers operation, so we will say it is a severe machining operation requiring the lubrication properties provided by straight oils.  This type of product should contain the following:

1.  Oil this will be the main lubricant and carrier for our product
2.  Some lubricity / extreme pressure additive:
    a.  Sulfurized fat 
    b.  Phosphorous as a Phosphate Ester
    c.  Chlorine as a Chlorinated Molecule
3. Various esters or other molecules    
4. Antioxidant: There are many on the market
5. Water scavenger: Once again there are many on the market

Depending on the operation there can be many other additives to enhance product performance.  What will depend on the customer’s needs and system requirements.  The biggest drawback of using straight oil is disposal.  Disposing straight oil is expensive and in many states, waste oil is considered a hazardous waste.

Soluble Oil:

Once again, to formulate this type of product one needs oil.  However, here we have the added dimension of taking a substance we know does not mix with water, and using various chemical substances we can render this mineral oil dispersible in water.  I must confess the first time I saw a soluble oil bloom in water I was impressed. 

The emulsions made from soluble oils will vary from milky white to translucent.  This is determined by the emulsion particle size.  The larger the emulsion particle size, the more milky the emulsion.  The smaller the emulsion particle size, the more translucent the solution will be.  The type and amount of emulsifier package present in the product will determine the particle size.  Once again let’s look at a typical formulation:

1. Oil: Either Parafinic or Napthenic
2. Emulsifier: Petroleum Sulfonate
3. Emulsifier: Fatty Acid Soap
4. Co-emulsifier: Surfactant HLB=8
5. Coupler: Glycol ether
6. Biocide
7. Fungicide

Now this is a simple formulation.  There are others that are far more complex depending on the type of job.  These could contain extreme pressure additives, corrosion preventives, or non-ferrous inhibitors to name a few.  The list is endless and I will be talking about these other additives in future articles.  Many companies use soluble oils because they waste treat easier than other types of fluids, and in today’s metalworking market, waste treatment is a major consideration. 

Until next month, I wish all a very happy and joyous holiday season and a happy, healthy, and prosperous 2001
As always, if I can be of any help, feel free to e-mail me at the magazine.


Dom