If you're the recent owner of a CNC machine, you're likely excited about all the machining and metalworking possibilities available to you. From milling throwing knives, hatchets, or even axes to constructing metal patio furniture or other larger items for extra income, the sky is the limit when it comes to what this handy machine can do. However, choosing the right coolant and learning how this coolant can impact your machine is crucial when it comes to maintaining it and ensuring a long mechanical lifespan. Read on to learn more about the coolant options available to you, as well as which options may be best for your needs, uses, and budget. 

What are your choices when it comes to CNC machine coolants?

There are three basic types of CNC coolant available, although each type is available in a wide range of brands and prices. 

Soluble OIls

This coolant tends to look like milk and includes soluble oil, emulsifier (to keep the oils mixed), and additives like chlorine. These oils are highly rust-resistant, which can be a boon to any machine with a lot of metal components or that is being used to cut or mill metal. However, this resistance to rust doesn't extend to bacteria, and you'll need to be meticulous about cleaning your coolant receptacle and flushing it when it's been a few days since you last used the machine. Failure to do so could leave you with a smelly, sludgy mess that impacts the functionality of your machine.

Soluble oil can also be less efficient at evenly distributing heat than semi-synthetic or synthetic coolants, which is something you'll want to keep in mind if you're planning a project that requires ultra-fine work. While soluble oil is ideal for most types of CNC projects, most CNC professionals tend to gravitate toward a more synthetic option.

Semi-Synthetic Coolant

This type of coolant bridges the gap between synthetics and soluble oil, combining the two to take advantage of synthetic's heat dissipation and distribution while benefiting from oil's resistance to rust and corrosion. 

Synthetic Coolant 

Synthetic or artificial coolants contain a variety of ingredients, including polymers and additives designed to reduce bacteria growth, minimize corrosion, and improve performance. Unless the label on your synthetic coolant specifies "oil-free," this coolant may even contain small amounts of emulsified oils.

Which coolant type is right for you? 

Each coolant for CNC machines operates and performs a bit differently, so the perfect choice can be different for each individual depending upon the age and condition of their CNC machine, the types of projects being milled, and the frequency of use. These coolants also require some additives to prevent bacteria growth and maintain stability through weather changes, so you'll want to factor this in when considering your project costs. 

In general, those who have the budget for synthetics, who want to enjoy a minimal maintenance schedule, or who don't plan to use their machines on a daily or even necessarily weekly basis may want to opt for semi-synthetics or synthetics. These options are usually a bit more expensive than soluble oil, but the high quality of the additives used can enhance performance and ensure that your machine is doing exactly what it's capable of. 

On the other hand, those who plan to use these machines regularly or who can't stomach the cost of synthetic coolant may opt for soluble oil instead. As long as you stay up on your cleaning and ensure that you're adding enough additives to eliminate bacteria growth (storing your CNC machine in a cool, dry place can help), you should be able to successfully create many projects with the use of your soluble oil coolant.