Air-Cooled Spindle vs. Water-Cooled Spindle in CNC Work

By scribe

CNC routers and plasmas are loaded with parts and components that can have a tremendous impact on the performance of the machine and on the outcome of the job – and few are as important as the spindle.

The spindle, located at the center of the machine tool’s rotating axis, determines the speed and cutting force of the machine based on inputs from the CNC controller. And when it rotates at exceptionally high speeds, it generates a lot of heat and must be cooled in an efficient manner to avoid a decline in its condition, performance, and service life.

There are two primary methods when it comes to cooling the spindle – water cooling and air cooling (also sometimes referred to as fan cooling). Here is a closer look at the key differences between the two to help determine which might be the better option for your specific CNC machine and operating environment.

How does each method work?

The methods of water cooling and air cooling are somewhat self-explanatory by name, but it helps to understand the specifics before getting to the advantages of each.

Water cooling uses water circulation to cool the spindle as it rotates at high speeds, circulating water via an external pump into and out of the spindle’s internal shell. As water exits the spindle, it is pumped into a vat of water that is then cooled by the surrounding air.

Air cooling, on the other hand, uses air from a fan to cool the spindle during operation. Machines that leverage air cooling have two real solutions – shaft-driven or electric fan-driven. With shaft-driven, a cooling turbine attaches to the shaft of the spindle. As the spindle rotates, it causes the turbine to do the same, drawing ambient air into and through the interior of the spindle.

With electric fan-driven, an electric fan is attached to the top of the spindle and uses an electric motor to draw ambient air into and through the interior of the spindle, helping reduce internal operating temperatures. The benefit of electric fan-driven is that they can continue to cool while the spindle isn’t running, thus allowing for higher duty cycles and higher spindle cutting torque.

Given the differences in how air-cooled spindles and water-cooled spindles operate, there are several distinct pros and cons attributed to each.

Convenience

Because water-cooled spindles have to find a way to apply and dispose of water to cool the spindle, they do require a bit of external equipment, such as water tanks, pumps, and chillers. This can all be a lot to deal with if you’re looking for speed and efficiency, whereas air-cooled spindles can be used without any external equipment. Simply turn on the machine and start working.

Maintenance

Because water breaks down over time, water-cooled spindles have a series of maintenance items to contend with, including replacement of water, refilling the system, and worrying about air pockets developing in the system over time.

Additionally, water-cooled systems must contend with seals breaking down over time and with water pumps that will eventually need maintenance. On an air-cooled solution, you will have to consider cleaning the fan fits and blowing them out occasionally to maintain good air movement, similar to what you would do with a ceiling fan.

Environment

The additional equipment required for water-cooled spindles also means they take up more space in the shop than air-cooled spindles (which only require a small fan/turbine attached to the machine). This can make them a less-than-desirable option in smaller shops or at-home environments.

Water-cooled spindles are also not great in areas with colder temperatures. During the winter, cold weather can cause the water tank and pipes to freeze, which can end up causing damage to the spindle. Air-cooled spindles are less restrictive and can be used in most environments regardless of outside factors.

Cutting Force

When it comes to cutting force, air cooling offers greater torque when compared to water cooling, making it the superior choice in this area. Additionally, when comparing shaft fan vs. electric fan, the electric fan solutions increase cutting torque by reducing the draw against the spindle shaft, thus concentrating more HP and torque onto your cutter.

Noise Level

Due to the operation of the fan, air-cooled spindles can in some instances be a bit noisier than water-cooled spindles. However, the electric fan-cooled spindle can often be quieter due to their small electric motor. If noise is a key concern due to shop size, location, or other factors, this should be taken into consideration during the purchasing process.

Experience CNC the Way It Was Meant to Be

ShopSabre’s industry-best and American-made CNC routers, plasmas, and accessories leverage air-cooled spindles and are designed to help both shop owners and hobbyists grow their production through unmatched precision, repeatability, and automation – all at an affordable price.

Our machines are easy to purchase, set up, and operate, even without any formal training. Our team of dedicated experts offers one-on-one support to help you find the right machine and to make sure it works the way you and your business need it to – both on day one and on day 1,000.

Here are a few of the reasons ShopSabre can develop and produce such revolutionary CNC technology at an affordable price point:

• Experienced and dedicated in-house engineering talent.
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