Coolant change

At what point do shops usually change coolant? When it smells like a dead animal? When operators get physically sick? When operators get rashes? When someone dies? Or, before it is grossly obvious that it needs to be changed?

When Mastercam Verify quits working.

Much less frequently now that we have colasers (works better than skimmers) . 18 -24 months average, smell is one factor, contamination from plastic is a big factor for us. Keep tanks full and keep concentration correct helps. PM is well worth it.

I cannot speak for other shops...only here.

It used to be when the coolant went from coolant to hmmm, that's not right. Skim the top add some fresh and hope for the best we knew it had to be changed. So out it came, cleaned the sump, machine recharged with a fresh batch and away we went for some time.

Then the formulation changed... and this became the every few months unless machine was used daily. This was about the time we got into CNC from the old conventional s.

The one then two CNC's were used daily, but coolant only lasted a couple months. Yes I was skimming and cleaning sump, staying on top of concentration. Just one day it didn't feel right, a bit of an off smell and it was time to change.

The search was on from that time...had to be a better coolant. It took a few years and a willingness to spend dumb money on what used to be cheap. Also a willingness to constantly clean out the machines to try a new. Some seemed ok at first, but stained material, others went rancid in weeks, some leached stuff from materials leaving clogged lines and filthy machines. Some didn't play nice with us operators...I was usually to first to break out. With each fail it was pull it from the machine, clean clean and recharge.

Finally found the one we are using and I only have one machine it turns sour in. I have cleaned that one from top to bottom and if its let to go even a tad low on concentration it goes rancid. Aside from that machine, keep it skimmed, pull crud from sump and concentration right it last for years.

So to answer your question...we change as needed. Luckily that is kinda rare these days, but if an odor is picked up we try to tackle it within a few days, when machine is between jobs and have several hours to clean and recharge.

It is cheaper to buy good stuff, stay on top of concentration, keep clean and skimmed then pull it out fill a big drum to have hauled off as hazardous waste, waste time cleaning and refilling. As to letting it go till ill health effects...no. I if I won;t put my hands in there or run the machine...nobody working under me will either. If it gets that bad...I am also the one pulling and cleaning as its the dirtiest nastiest job I won't let others do.

LockNut said:

When Mastercam Verify quits working.

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So, daily?

For us using castrol semi synthetic its once a year or close to it.

Smell is a good indicator of the bacteria level and a telltale sign of when it's getting out of hand. Oil that mixes into the coolant is basically food for bacteria. Good pm habits are essential to keeping the coolant as safe as possible. Remember- the coolant aerates and you breath it in and gets on your skin so how clean you keep your coolant impacts your health.
I'm sure we all know tank and coolant maintenance but if you're getting rashes and bad odors I'd recommend changing brands to something better suited to your shops needs. Material, usage, way lube oil type and such are things to consider when talking to the coolant rep.

Using Hangsterfers 5080D. Current batch has been in the machine for over two years, plus regular topping up, no hint of bad smell. No skimmer needed. The Haas doesn't pee way oil into the coolant though like most machines, I'm sure that helps.

depends what coolant, how you are topping it up, water hardness and mineral content, tramp oils and other contaminants. if you keep it clean and up to spec, ive had some last years with maintinence. even checked the ph etc.

CORONA VIRUS said:

At what point do shops usually change coolant?

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Where I used to work, it was when the operator called me out to look at something on the machine...and I said "Holy Hell! When was the last time this coolant was changed????" and then went and bitched to his supervisor....who then allowed the operator time to change it.

Yeah, I have a DI system for my coolant water. That helps a lot.

locknut said:

when mastercam verify quits working.

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hahahahahahahahahahahaha!!!!
Bwahahahahaaha!!

CORONA VIRUS said:

At what point do shops usually change coolant? When it smells like a dead animal? When operators get physically sick? When operators get rashes? When someone dies? Or, before it is grossly obvious that it needs to be changed?

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Depends on whose coolant and the water used.
Keep it clean, and good quality coolant can last years before being changed.
Also, depends on what you're machining. Cutting a lot of cast iron? You're gonna be flushing tanks every 6 months.

CORONA VIRUS said:

At what point do shops usually change coolant? When it smells like a dead animal? When operators get physically sick? When operators get rashes? When someone dies? Or, before it is grossly obvious that it needs to be changed?

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I wait until at least 4 people die. Any less than 4 and how can you be sure of the cause of death?

A few gallons of carry off/mist/loss a day seem to be plenty to keep a 300 gal sump good continuously.

About 3-4 years ago I switched to creative chemistry c-cool 720, and started using reverse osmosis water and havent changed coolant since. This stuff is amazing! Lasts forever. Even in my lathe that sometimes sits for long time with huge slick of way oil on top.

Hardplates said:

I wait until at least 4 people die. Any less than 4 and how can you be sure of the cause of death?

A few gallons of carry off/mist/loss a day seem to be plenty to keep a 300 gal sump good continuously.

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Ah, so the key is to hire 3 or fewer people so you'll never need to change coolant.

Our evaporation + carryoff on the horizontals is more like 30-40 gallons per day, per machine. And that's after reclaiming coolant from the chip bins. I think the last time we did a full coolant changeout on the NHX6300 was when we moved in 2016.

My lathe is more picky on coolant %. I get about 2 years, and what I do is slowly move it to the Mill which is boxway/oil where I can get 3-4 years.
The mill was starting to stink on a lot sooner before (1yr) but since changing to Fuchs 7830C, this coolant has barely any smell to begin with(best I tried so far anyway). I think its mostly the way oil in the mill that mixes in a bit over time that has a bit of a smell.

When the mill gets too bad, it goes in my evaporator and turns back to a pail of syrup thick oil.

Picture of this evaporator ???
Gw

*laughs in Swisslube*

Greg White said:

Picture of this evaporator ???
Gw

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It can be seen behind the doosan lathe in the last page of my shop pictures in that section.
Just a top an bottom catch tank/tub, a drip hose, valve and a bath towel on an old cart I wasn't using anymore. Eventually maybe I'll make something fancier and more compact, but this works and it works surprisingly fast in winters dry air. In a hot weather area it'd be easy to set up something outside and likely evaporate even faster in 100° sun.