MWF FORMULATION - PART 1
METALWORKING FLUID FORMULATION
PART I - WHAT DOES THE CUSTOMER REALLY NEED?
by Dom Ruggeri
In the late eighties I began working for a rather large metalworking-formulating house. I was on the job for about 3 months; during that time I was asked to formulate a semi-synthetic metalworking fluid using a material called a PAO (poly alpha olefin) rather than mineral oil. I quickly found out that a PAO emulsified quite differently than did a mineral oil; further, formulating the standard additive package into this particular formulation was a nightmare. The old reliable package was not stable and what was stable was not effective. After about 3 weeks of trial and error I finally stabilized a package that was as effective as the standard.
The next step was to evaluate the performance properties of my latest creation. Once again I used such tests as the Modified Herbert Rust Test, Falex Lubrication Test, Four Ball Lubrication Test, and of course Tramp Oil Rejection. These were all ASTM procedures and of course should have been the definitive answer to my fluid’s fitness for sale. My manager decided that we should test my creation at a place in Ohio called Tipp City. There we could see how the fluid would perform under typical manufacturing operations, while still having the controls of a laboratory. Needles to say my perfectly formulated fluid fell flat on its face.
Back in the late 1980’s ISO 9001 was a monumental undertaking it still is quite a challenge. That is the down side; the up side is if a company’s ISO procedures reflect what that company really does selecting the right product for the customer’s application is a scientific undertaking as opposed to a lucky guess. Here’s how it should work:
1. Sales calls on a customer, ascertains the customer’s needs, and determines what the customer wants.
2. The salesman transmits the customer’s feedback to the formulating chemist.
3. The chemist checks the product line to see if there is a direct replacement (there normally is not).
4. The chemist will then run a series of performance tests on the competitive fluid and select the best performance fit from the product line.
5. Should no performance match exist in the product line, the chemist begins a development project to meet the customer’s need.
Yeah, right. Maybe in a perfect ISO 9000 world, but in reality there are many other factors to consider. Factors like: sales volume, cost, personnel issues, manufacturing, and the most critical; is the salesman willing to sponsor a project for this customer? Assuming all of the above parameters are met the chemist sets to work developing a product. Depending on the chemist’s level of experience, their area of expertise, and the company’s formulating philosophy, this process may take a few weeks to a few months.
So how does a formulating chemist formulate a metalworking fluid? First the chemist ascertains what type of fluid the customer needs, second pick the raw material combinations that will yield the performance properties desired by the customer, third test and tweak the formulation until the desired performance properties are achieved. So far it sounds easy, well let’s look at a typical formulating project:
Salesman visits a typical machine shop consisting of three fifty thousand gallon central systems. This shop makes automotive parts using 308 aluminum a typical automotive alloy. The customer wants to improve tool life. Currently he is getting 500 parts before he needs to replace inserts. They want 750 parts or more before changing inserts. Sales answer: “Sure we can do that.” The customer wants the coolant to last for one full year with minimum maintenance. Sales answer: “No problem.” They want the coolant to be low foam and low misting. Sales answer: “We can handle that.” Currently they are paying $8.00 per gallon, they want cost reduction to $5.00 per gallon. Sales answer: "Now that's a tough one. We'll have to look into that."
The above will appear in the sales call report. The chemist will get a listing of the formulation parameters based on that call report. Now we go to work. Assuming that the competitive fluid is a soluble oil we will begin formulating using these steps:
1. Select the base oil; normally this would be 100sus napthenic oil, however in today’s market place parafinic base oils are gaining popularity so we will use a 100sus parafinic base oil.
2. Select the emulsifier package; one can use a many combinations of emulsifiers from surfactants to fatty acid/amine soaps to petroleum sulfonate or any combination of the above. Further, many additive companies offer packaged emulsifier bases - just add oil.
3. Since your machining aluminum you need to choose an EP package. There are many to chose from among them esters, chlorinated parafins, phosphate esters, and many non-traditional EP additives.
4. Next the biocide package. I was always partial to Grotan and Sodium Olmadine. This combination never failed me. However, like most biocide packages, it needs to be maintained and replenished by post additions.
5. Cost: Assuming we selected our raw materials with care and cost in mind we should have met the customer’s price requirements.
The next step is testing the product. Certainly we can use a series if ASTM tests comparing our product to the customer’s current product. Once again, if we kept the customer’s goals in mind, the product should perform as good or better than his current fluid. The final test is at the customer’s site. Unfortunately, no ASTM tests exist there and the new product sinks or swims on it’s own merit.
A broad brush approach, yes but it is intended to give the you, the consumer, a flavor of the product development process. Every company will work differently, however, what I stated above will be the done in some way or another. Future articles in this series will present raw material functions, synergistic interactions and how the formulator uses these to get the performance properties he desires.
As always any questions or if I can help out in any way please feel free to e-mail me at the magazine. Good Luck