Little-Known Facts About Cryogenic Machining

As crowds gathered around the cryogenic machining demonstration at Okuma’s Manufacturing Excellence event last December, a sense of amazement prevailed. Mike Judge, EVP Business Development for 5ME, described a staggering list of benefits such as faster processing speeds, reductions in cycle time and increased tool life…all using 5ME’s Internal Liquid Nitrogen (LN2) instead of coolant. Since coolant has been the lifeblood of our industry for so long, this is obviously a revolutionary concept. We asked 5ME to answer some questions that arise when people first encounter this technology, and following are some little-known facts about cryogenic machining.

Is it dangerous to use nitrogen instead of coolant?

Nitrogen is an inert gas, and it’s very safe for user interaction. Nitrogen is 78% of the air we breathe. Because there is a cold factor, there are small safety measures that should be put in place, such as handling tools using gloves or aprons. But it’s quite easy to handle overall. Liquid nitrogen is probably a much less dangerous material to use than the relatively complex chemistries found in things like coolant.

Is LN2 a new development for industrial use?

Liquid nitrogen has been used very successfully in other industries. For example, it’s commonly used in the food processing industry. Flash freezing food has been going on for decades. For example, fishing industries use liquid nitrogen to flash freeze fish while out at sea.

Sounds fairly common. Can you think of any other examples?

Many high-end restaurants actually use liquid nitrogen for a type of cuisine called molecular gastronomy. While we were at IMTS 2014 we dined at a Chicago restaurant called Moto where they did tableside cooking using liquid nitrogen. They created several meals and desserts for us. The photo above was taken at the restaurant, and you can see George Georgiou, one of 5ME’s cryogenic engineers, sampling the cryo delicacies.

Are there any advantages for operators?

Operators who run cryogenic machines are relieved because they no longer have to suffer with dermatitis issues, or with coolant smell being ingrained into their clothes and body. There are also bronchitis and lung-related problems that come from the mist in the air, and these are alleviated by using nitrogen. “Quality of life” is an excellent benefit that makes for a happier workforce and may even help with attracting and keeping highly skilled workers.

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Are there any other hazards in the machine shop that cryogenic machining can solve?

A common accident-related issue in plants today is “slip-and-fall.” This is especially dangerous on large machines where the operators have to go out on the machine to get something set up or clear chips out. With traditional coolants you get oily residue all over the machine, so slip-and-falls are a problem. When using cryo this is completely eliminated.

How does the operator manage chips?

When you take cutting fluids out of a machine there’s a huge benefit regarding chip management. Now your chips are dry and not sticky. They’re lighter, and therefore much easier to manage and move. So what we do is simply manage chips using air assist. You might be shocked at how easy it is to move titanium and steel chips around at a machine when there’s no coolant on the chips.

If someone transitioned to using cryogenic machining, what if they wanted to revert back to coolant machining? Is cryo an irreversible change?

We’ve had a few customers who’ve chosen to leave external flood coolant on a machine as kind of a safety net while they bridged the gap into 100% cryogenic machining. If for some reason that customer wants to run through-spindle coolant again, taking the hardware back off of the machine is not a very difficult task.

What about cost? Isn’t cryogenic machining expensive?

If you look at it as a one-to-one comparison, purchased by the liter, liquid nitrogen is actually less expensive than water. There are a lot of commercial suppliers to purchase liquid nitrogen from, so it’s very competitively priced. The way liquid nitrogen is produced is its simply taken from the atmosphere and compressed under very high pressures into liquid form, and then we’re simply sending it right back to the atmosphere. So when you do the math and look at cost-per-piece, it’s a very inexpensive, readily available, sustainable way to machine parts.

What is the typical ROI?

Our goal is to have no more than a 12-month ROI on our cryogenic machining kit. This is compared to an industry average for capital equipment purchases of 2-3 years. Our customers find our ROI very favorable.

How would someone go about putting this technology to use?

First, 5ME can help shops identify which materials and parts are best suited for cryo. (It’s especially useful when machining tough materials.) We can also let them know which builders have the right culture and expertise to embrace this technology. Okuma has always done an extraordinary job being on the leading edge of developing new cutting methodologies. Today, as a result of vision and leadership from Jim King, everyone at Okuma America is 100% onboard with the cryo solutions 5ME provides. There are currently 12 Okuma machine models that can be ordered with 5ME cryogenic machining technology, including both VMCs and HMCs.

Thanks to Mike Judge, Pete Tecos and Will Gruber of 5ME for their answers and insights. Feel free to comment below with any further questions you may have.

More: Watch 5ME’s video to learn about the many benefits of cryogenic machining. And take a look at Fun With Liquid Nitrogen for some quick science demos (kids will love these too), and to see how safe this material is to work with.