problems with foaming in coolanttank

[frank l]

i have problems with foaming in coolanttank of miilingmachine
who cant help me i dont want to use anti foam additives i think it dont solve this problem

[frank l]

i dont want
to use anti foam additives

[MMICKELS]

Frank, it could be due to having soft water and new coolant. We had the same problem at my work and switched to a type of coolant that doesn't foam as much. I don't remember the exact name, but the product is made by Trim. HTH

[frank l]

yes we have also tried demi water and we switch to a other type of coolant but after a several weeks it start again may be the problems is the machine run 24/7 a week sorry my english is very bad

[MMICKELS]

Frank, what is demi water? Don't worry about your English, it's actually pretty good!

[MMICKELS]

OK, got a line on demineralized water. That is part of the problem. Demi water is "soft" and the detergent in the coolant will tend to foam even more with soft or demi water. Try just regular water out of the tap.

[frank l]

i tried this monday and think about why we started with demi water for a few years we hat a other problem with a other type of coolant

gr of holland

[PixMan]

The two most common causes of foaming are related to each other. One is is you are using a small tank and high-volume pump(s). The other reason is coolant concentration. If the pumps are cavitating (sucking air) you can be getting too much air into the coolant.

Coolant concentration being too high (too much water has evaporated) is the leading cause of foaming. High pressure and/or high volume pumps can introduce much heat into the coolant/cutting fluid. This evaporates water and makes concentration too high.

Have you been using a calibrated refractometer to check the water/coolant ratio to see if it's within the recommended specifications? Does the temperature of the cutting fluid rise to high levels? If so, you may need to add a chiller but this is something usually reserved for systems using high pressure pumps.

[fizzissist]

Originally Posted by MMICKELS OK, got a line on demineralized water. That is part of the problem. Demi water is "soft" and the detergent in the coolant will tend to foam even more with soft or demi water. Try just regular water out of the tap.

Regular tap water isn't a good idea because it contains minerals, chemicals, bacteria, and whatever else your municipality is selling you. In and of itself that's not a bad thing, but....

What happens over time is that you get evaporation from the heating of the coolant and all that circulation, which you have to replenish to keep the level up. Therein lies the rub. The minerals and other stuff doesn't all evaporate out too, and gradually your water becomes harder, and harder, and harder, until it starts to compromise the coolant's chemistry.

One of my machines alone went through about 3 gallons a day, and we set up a reverse osmosis system for replenishment water. Worked out great.

We're using Master Chemical's Trim E206 at 10:1 with reasonably good success. I'm not a huge fan of it, but it works well enough, and we really abuse the stated sump life. I mean really.

My complaint with it, and it may be our application, is some rusting between the vise and the table....and some attendant stink...and it tends to foam in the Mazak chucker. They sell an anti-foam which I tried but without a lot of luck.

I'd like to hear some good anti-foam solutions, especially with the high pressure coolant systems.

[PixMan]

Originally Posted by fizzissist I'd like to hear some good anti-foam solutions, especially with the high pressure coolant systems.

For starters, use a larger reservoir. The Chip Blaster units carry their own 45-50 gallon reservoir that adds to the total from the machine sump. This helps dissipate ingested air bubbles within the coolant/cutting fluid and may also be more stable because it takes longer for the overall process temperature (machine, tooling, workpiece and coolant) to rise and fall.

MP Systems also came out with such a system, and others have followed suit. Other solutions are:

Use a coolant made specifically for HP systems, because most semi-synthetic coolants aren't engineered for high pressure pumps and small orifice output. The nodules of emulsified oils are often broken down under high pressures so you lose the solution and get product separation.

Keep the concentration within spec. Too rich and separation is easier because mixing can't get more coolant to disperse into the water. Too lean and the coolant loses it's lubricity and/or rust prevention capabilities. The pH level is also important and can have an effect on foaming. Most often, if the coolant is too alkaline you'll get foaming. Correction is usually just getting the concentration right.

Pressure! One of the most-common mistakes is to run it too high. Instead of choosing the proper tooling to break and/or otherwise control chips, we just dial up the coolant pressure. More pressure equals more heat. More heat breaks down the coolant's emulsification and other features. The balance between pressure and volume is the key to successful application of HP systems.

[miniz98]

We use water soluble coolant and we have noticed if the mixture is not rich enough it will foam. Purchase a refractometer and check you're mixture if your using water soluble. It should read around 4-6.







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[PixMan]

Originally Posted by miniz98 We use water soluble coolant and we have noticed if the mixture is not rich enough it will foam. Purchase a refractometer and check you're mixture if your using water soluble. It should read around 4-6.

Be careful with blanket statements like that.

A water soluble coolant may be soluble oil, semi-synthetic, or fully synthetic. Each has different degrees of light diffraction and that is why the coolant makers publish a correction factor for each product.

In general, most soluble oils are a 1:1 or 1:1.2 correction factor. Semi-synthetics tend to be 1:1.6 to 1:1.9, fully synthetic coolants can be over 1:2 (though most are similar to semi-synthetics.)