Changing coolant is not a glamorous task. End of story.
It's a messy, unpleasant job that's often pushed to the bottom of the to-do list. But in the world of machine shops and steel fabrication, understanding how often coolant should be changed is more important than you might think.
For people who are new to the industry, when and why they should change their cutting oil is a common question.
People start thinking about changing their coolant for a few reasons. It might be that there’s an unpleasant odour in the shop, or the metal working fluid is aging. Commonly it’s because Christmas is just around the corner, making it a perfect time for a fresh start.
In this article, we'll dive into the essential aspects of coolant maintenance and answer the question: "How often should I change my coolant?"
Coolant Change Frequency
The perfect cutting fluid change schedule isn't etched in stone, but some general rules can steer you in the right direction.
For mineral coolants and semi-synthetics, an annual change is a pretty good benchmark. It’s often done at the end of the year when you're giving the entire machine shop a thorough clean-out. This way, everything gets a fresh start in one go. That being said, some people opt for more frequent changes, especially if their machines are grubbier or if they plan to clean the tank and cutting fluid simultaneously.
In the majority of cases, a well-maintained coolant can comfortably last for 12 months. If it doesn't, it might signal an issue with the coolant itself. Here at Excision, we're confident that the majority of our metal working fluids can last a full year in the sump.
Factors That Can Shorten Coolant Lifespan
The lifespan of your coolant can be influenced by various factors, not all of which are directly related to the fluid's quality.
For example, prolonged stagnation, especially in hot and humid conditions, can accelerate degradation. If this is the case you'll probably have smelly coolant. And then there are external factors such as machine breakdowns, excessive tramp oil, incorrect concentration levels, or leaks that can all play a part in shortening your coolant's life.
When it comes to full synthetics, the story changes a bit. They're generally more stable and can last longer in the sump. While it's tough to pinpoint an exact timeframe, there are some incredible stories of fully synthetic fluids lasting up to 7 years in the sump. You still need favourable conditions for this but it is possible.
Consequences of Neglected Coolant
Well, what are the consequences if I don’t change my coolant frequently enough?
Postponing or neglecting metal working fluid changes can take a toll on your machines and the quality of your workpieces, not to mention the people who are working around it.
Over time, coolants can lose their lubricating, anti-foam, and anti-bacterial properties. This is where you might get decreased tool life, because the cutting fluid isn’t doing its job, or extreme foaming meaning you can’t see your workpiece. If you’re anti-bacterial isn’t working properly you’re probably also going to get smelly coolant, which isn’t fun.
Long story short, your coolant isn’t going to do its job very well.
Extending Coolant Life
However, fret not. There are definitely strategies you can use to extend your coolant's life. This includes:
- Implementing fluid management and periodic coolant checks, adding additives if necessary
- Doing an annual cleaning and filtration of the fluid
- Removing tramp oil with a skimmer
- Using tap or demineralized water instead of bore water or rainwater
- Maintaining recommended concentration levels
- Considering recirculating the coolant during weekends when there's no operation
We’ve got another blog with more details on how to extend the life of your coolant.
I Don’t Want To Change My Coolant
If you’re not interested in changing your coolant at the minute, you’ve got a couple of options.
If you think you just need a bit more cutting fluid to keep you going, we recommend using our website’s top-up calculator to work out your ratios. (However, we don’t recommend this if your coolant is degraded). You should also be regularly monitoring concentration levels to ensure you’ve got enough additives to fight bacteria and fungi.
If you’re maintaining your metal working fluid correctly, you can significantly prolong your coolant's sump life.
In Short
There’s no one-size-fits-all answer to the question of how often coolant should be changed.
Instead, by understanding what to look for (bad performance, smelly coolant, etc) you’ll know when to change your metal working fluid.
Maybe you have a schedule of every 12 months. Maybe you need to do it more often because of high usage. Nonetheless, as a guide:
Mineral / Semi-Synthetic Coolant: 3-12 months
Fully-Synthetic Coolant: 12-24 months
If you’re still not sure when to change your coolants, reach out to our team!
