best fluids forever

How do I choose my new BFF?  Or the best cutting fluid / coolant / oil for my machine?

Selecting the proper metalworking fluid is probably already know that!


First, let's discuss solubles (fluids you mix with water). There are synthetics, semi-synthetics, and soluble mineral oil based fluids.


If you've used these fluids in the past, and I mean more than 5 years ago, especially more than 10 years ago, things have changed drastically! 


Solubles used to be the go-to product. Tried and true. They had their issues, but not like the others. Some people still swear by them...and that's okay, as long as it really is the best choice for the application.


Semi-synthetics didn't have a great start to life. Back in the day they were plagued with problems - essentially they shared some of the problems of synthetics AND solubles combined. This is no longer the case with many semi-synthetic coolants.


Synthetics had their own unique issues. Leaking seals on your machines, sticky prox sensors, cost, etc.


Now, fast forward to the modern era of machine tool soluble coolants. Synthetics are great, stable, long lasting. And they don't eat your machine's paint or seals. These problems were addressed. 


Machine tool seals also got more modern, and don't suck up oils - which used to make them fat. After years of soaking up oil, people tried a synthetic oil-rejecting coolant and guess what? Yes, that oil-rejecting synthetic eliminated that fat, bloated, oil-soaked seal's thirst for oil...which made the seal shrink and shrivel (and leak). 


And machine tools have different paint now. Back in the day your chips would fly off the spindle or workpiece and inevitably scratch the inside of your machine, thousands of tiny scratches. With soluble oils, no problem. But then you tried synethics, and they got underneath the paint wherever there were scratches. That would magically peel your paint away; and running back to soluble oils you would go - thinking synthetics are the devil in disguise!


And at proper concentrations, prox switches and sensors aren't an issue for synthetics anymore.


So, what should you use? No good answer yet but we're getting there. We will start by saying that 99% of our customers use a synthetic or semi-synthetic for their metalworking coolants and grinding fluids.


Tool life - that's gotta be at the top. Choosing the wrong coolant can cost you thousands of dollars a month in tool life. There's high end fluids, there's the middle of the road, and there's the cheap ones. Who cares what it costs? We've seen coolants from $600-1900 per 55gal drum. Forget about cost. Go with tool life. Even at $1900/drum you're better off saving the tooling if that "expensive" coolant gives you more tool life. It doesn't take many wasted carbide inserts and indexable drills to pay for more drums of coolant. Show your buyer the cost differences of "saving money" on cheap coolants while spending far more on carbide - and "saving money" on expensive coolants while spending a lot less on carbide. It'll blow them away.


Surface finish - another top of the lister! Because as any machinist will tell you, surface finish is a great indicator of reduced stress on the tools, less heat being generated, less load on the machine tool, less tool chatter, less built-up-edge, less burnishing, less thermal cracking of inserts, less fracturing, LESS EVERYTHING! Choose a coolant that provides great surface finishes. You can even benefit by less scrap and rework in cases where you have an Ra profile callout. Less investment in profilometers!


Rust prevention (RP) - a good metalworking fluid will provide a light film of corrosion preventative. Not a thick, sticky film, but a clean, thin, slick film. This is essential for in-process protection (i.e. roughing a part on one machine, throwing it on a pallet and having it sit a few days before it gets set up on a finishing machine). The RP additives also help with finished goods. A quality coolant can prevent many man-hours of rework to remove flash rust and corrosion. Customers are happier too - as you're delivering rust-free parts to them!


Foaming - whatever coolant you select, be sure it doesn't foam. Especially under high pressure and coolant-thru-tooling applications.


Well, we're not sure if any of this is helping your choice but we hope you're getting closer. After the above considerations, it really comes down to a few things:


·      Metallurgy (aerospace aluminum, mild steel, hardened alloys, aluminum, yellow metals, titanium, cast iron, cobalt chromes, etc. 


·      Machining characteristics will be a factor. Are you only roughing, or finishing, or both? Speeds & feeds, deep hole drilling, tools hanging way out, interrupted cuts, work hardening, ejector and gun drilling, trepanning, high speed milling.


·      Other considerations include FDA (medical device manufacturing) approvals, Boeing / aerospace approvals, non-chlorinated, boron free, formaldehyde free, sulfur free, non-staining aluminum work.


For neat cutting oils, the principals are the same as above - only you don't have to worry about mixing water and making so many choices. But the fundamentals are there.


Finally, the most important component, your preferences! Do you want a trouble free, well-rounded, all purpose coolant that has great sump life, doesn't smell or go rancid, works on most metals and cutting operations, doesn't give operators skin issues, and provides excellent machining attributes? If so, call us and we can help you decide based on your exact situation and goals.