Spindles are a key component of CNC machining. A spindle is the rotating axis inside a machine that holds and spins the cutting tool. It usually consists of a motor/driver, bearings, shafts, and other components.
Understanding spindle lubrication is essential for getting the best performance and longevity from a spindle. With proper lubrication, spindles can run for years without any issues.
There are two types of lubrication systems – manual and automatic. Spindle bearings play a crucial role in determining the efficiency of your machine.
Inadequate lubrication can result in premature failure of your spindle bearings, which is why manufacturers should understand the different types of lubricants, the different methods, and their pros and cons when choosing a lube for your specific application. Whatever type of machine spindles you need, the professionals at Fischer Precision Spindles, Inc. can help.
What is a Spindle Bearing?
A spindle bearing is a series of rollers placed inside a spindle housing that supports the rotating shaft. The rollers consist of a material that is resistant to wear and tear and are designed to withstand the fluctuations in heat and stress that accompany the process of machining parts.
Spindle bearings are typically found in CNC machines, drill presses, lathes, mills, and grinders. The bearings ensure that the spindle rotates smoothly and without jamming, resulting in more consistent and accurate cuts and a longer life span for the machine.
Manual Lubrication System
In a manual lubrication system, one fills the spindle bearings with liquid lubricant via a filling hole, a pipe, or a manual pump. The lubricant feeds into the bearings via a series of channels, or grooves, through the spindle housing.
Due to the fact that the spindle bearings become completely submerged in the lubricant, it is crucial to use the correct amount of lubrication. Too much lubricant can cause the spindle bearings to become over-pressurized and cause leakage.
On the other hand, too little lubricant can result in premature failure. The manual lubrication system generally uses a mineral-based lubricant, such as grease or synthetic oil. Mineral-based lubricants are generally more economical but tend to become runny in high-temperature environments.
Automatic Lubrication System
An automatic lubrication system uses a pump to deliver lubricant to the spindle bearings. The pump connects to a reservoir filled with the appropriate liquid for lubrication.
There are two types of lubrication systems – oil-based and grease-based systems. Both systems deliver a controlled amount of lubricant, which reduces the risk of leakage and over-pressurization.
Lubrication systems with a manual shut-off valve are ideal for switching between manual and automatic modes. It’s helpful when switching from a high-temperature environment to a lower-temperature one, as one must change the type of lubricant. For example, a grease-based lubrication system is the lubricant of choice when machining with stainless steel, whereas machinists use an oil-based lubrication system when machining with aluminum.
Types of Lubricants for Spindle Bearings
There are several types of lubricants that can be used for spindle bearings. However, not all of these types of lubricants are suitable for all types of applications.
Hydraulic Oil
One of the most commonly used lubricants for spindle bearings is hydraulic oil, which people use in a wide range of applications. Hydraulic oil is widely available in most hardware stores and is relatively cheap. However, it is not the best choice for dry environments.
Synthetic Oil
Synthetic oils are the most common lubricants used in high-performance applications. They’re generally made of synthetic or organic oils or synthetic ester-based fluids. They are highly suitable for high-temperature environments and are often a synthetic alternative to mineral oils.
Graphite-Based Lubricant
This lubricant comes in handy for precision machining, such as in the medical industry. Someone applies it via a graphite spray. However, one applies it before the part is cut to minimize the risk of heat build-up.
Silicone Grease
When water is a concern, silicone grease is useful. It is an ideal lubricant for use in places where high temperatures and water are a concern.
Pros and Cons of Manual Lubrication
Advantages
When it comes to choosing the best type of lubrication system, manual lubrication systems are generally considered to be the best choice. A manual lubrication system is a cost-effective option that allows you to apply lubrication to your spindle bearings on demand.
Disadvantages
The main disadvantage of manual lubrication is that it requires you to manually apply the lubricant to the bearings when needed. So, workers must be mindful of keeping track of when it’s time for more lubrication. If you forget to add lubricant to the spindle bearings, they can easily overheat and become damaged.
Pros and Cons of Automatic Lubrication Systems
Advantages
A pump controls automatic lubrication systems, which can be programmed to apply the correct amount of lubricant to your spindle bearings at the appropriate time.
Automatic lubrication systems are particularly helpful with high-precision applications.
Disadvantages
Automatic lubrication systems are significantly more expensive than manual lubrication systems. Depending on the type of system you choose, you may have to install an entire pump system to your machine.
Conclusion
Spindle bearings play a crucial role in determining the efficiency of your machine. Inadequate lubrication can result in premature failure of your spindle bearings, which is why it’s vital to understand the different types of lubricants, the different methods, and their pros and cons when it comes to choosing a lube for your specific application. A manual lubrication system is a cost-effective option that allows you to apply lubrication to your spindle bearings on demand, while the automatic lubrication system is helpful in high-precision applications. For professional spindle sales, design, and repair, contact the professionals at Fischer Precision Spindles, Inc. today.