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Have you ever wondered how to keep your CNC machine running smoothly? The answer is: proper lubrication. Applying the right amount of oil or grease to sliding surfaces and moving parts helps eliminate friction and wear. It also prevents heat and corrosion that can damage precision machining parts over time.

Oiling CNC machines correctly takes some practice. There are a few main areas that need oil or grease, including the joints that allow the machine to move back and forth, the places where the arm slides or turns, and gears and belts that power the machine. Bearings deep inside the machine that spin parts need lubrication too.

We’ll explain the basics of how to lubricate a CNC machine and the dos and don’ts of applying lubrication. 

How Does Oil or Lubrication Work?

Lubrication plays a crucial part in many mechanical processes, like machining. It works by reducing friction between moving parts, lowering temperatures, and preventing damage.

The ways oiling or lubrication keeps machines operating smoothly are:

Friction reduction. When various metal parts move against each other during machining, lubrication creates a coating on the surfaces. That coating allows the parts to slide past each other with less force resisting their movement. Less friction means less energy loss to heat and wear.

Cooling surfaces that generate heat from friction. Metalworking processes generate a lot of heat during cutting and shaping materials. The lubricant absorbs this excess heat and carries it away from the surfaces. So, the temperatures stay at safe levels that prevent damage from occurring.

Protecting surfaces from corrosion and helping dissolve metal chips. Without the barrier a oil provides, surfaces could rust or oxidize over time from exposure to air and moisture. Oils also dissolve metal chips created during cutting, preventing chips from sticking to tools and interfering with the process.

In short, the specific ways oiling or lubrication benefits machining include:

• Lowering tool wear by reducing friction on tool surfaces
• Extending tool life by minimizing temperature increases
• Preventing rust and corrosion on tools and materials
• Improving surface finish quality by chip removal

How to Lubricate a CNC Machine: All the Steps Explained

Regular lubrication is important for any machine with moving parts. When a CNC machine runs, it has plenty of large and small components that move and all that moving means these parts need lubrication. 

The rails that guide the cutting tool need oil. The motors that provide power need grease. Even the small gears and screws need a coating of lubricant. When these parts aren’t lubricated, they can get noisy and stiff, leading to breakdown eventually. 

We’ll explain how to lubricate a CNC machine, or a typical 3 axis CNC machine to be precise. 

Materials Needed

Before starting the lubrication, gather the necessary supplies. Don’t worry as you need only a few items:

• A high-performance general purpose machine oil (like Mobil Vactra) for lubricating the rails and bearing blocks
• A high-quality, synthetic lubricant (like Super Lube) for the lead screw
• Allen key set

Optional items include: 

• A light scouring pad (like Scotch Brite pad) to clean the rails 
• Clean rags for wiping
• A pair of gloves
• A pair of safety goggles 

Now, follow these steps for the oiling process: 

a. Oil the X-axis and Y-Axis

The first step of oiling CNC machines is to lubricate the X-axis rails, which are the ones that guide the cutting tool left and right. We’ll also do the same for Y-axis rails that move the tool back and forth.

Disconnect the belts that connect the rails to the motors, so the rails can slide freely without the motors running. Look for where the belts attach at each end of the rails. Once off, the rails can smoothly glide back and forth when we push or pull them.

Take a Scotch-Brite pad and wipe down the length of each rail to clean off any debris or rust buildup. Be gentle so as not to roughen the surface. A clean rail allows the oil to coat it fully.

Squeeze a few drops of a lightweight machine oil (Mobil Vactra, for example) into the groove running along the top and bottom of each rail. Rub it in with your finger, so it coats the entire groove.

Then, grab the rail carriage and slide it from one end to the other for about 20 to 30 times. Push and pull swiftly between your hands, so the oil goes deep into where the rails make contact. After several passes, take a look. If any spots appear dry, add a little more oil.

b. Oil the Z-axis Bearing Blocks

After working on the X-axis and Y-axis rails, we’ll move to oil the Z-axis rails that move the tool up and down. Look for the bearing blocks with a screw hole in the center on each side of these rails. 

First, unscrew the center screw on one bearing block to reveal an opening that leads inside the block. Squeeze a few drops of oil straight into this hole. Re-attach the screw once the oil is added. Do the same for the bearing block opposite to it.

The next step is moving to the bearing blocks above. Again, remove their center screws and add oil through the holes. Then, re-attach the screws.

By lubricating both the top and bottom bearing blocks, the entire vertical length of the Z-axis rail is coated, which will keep it sliding smoothly. To prevent wear, add oil to each block during raising and lowering the tool.

c. Lubricate the Z-axis Lead Screw

One last part that needs lubrication is the lead screw that lifts the tool. This screw must turn smoothly as the tool moves up and down.

Find the long threaded shaft attached to the bottom of the Z-axis assembly. Carefully wipe it down if needed.

Squeeze a small string of a synthetic lubricant (such as Super Lube) onto your finger and rub the finger along the full length of the screw, coating the metal thoroughly. This special lubricant clings tightly and resists being flung off as the screw rotates. 

d. Reassembling the Machine 

Once you’ve done all the steps of how to lubricate a CNC machine, it’s time to put everything back together.

• First, reattach the belts that drive the rails. Check that each belt is tight but not overly strained. The rails should move smoothly when the motors run.
• Examine every screw and connection point. Make sure all components are securely in place. Nothing should rattle or wobble.
• Pay attention where the gantry rails meet the machine body. These joints experience a lot of stress, so confirm that they are fitted tightly.

Run the machine to see if you’ve done the lubrication correctly. A properly lubricated CNC machine should run as quietly and precisely as when it was new. 

Maintenance and Safety Tips

Regular lubrication will keep your CNC machines operating at their best. They’ll perform even better if you follow these tips: 

• As a rule, lubricate the machine every 50 hours of use. But if you notice parts feeling dry, go ahead and oil sooner.
• Flip the power switch off before performing any maintenance. Moving parts can cause injury when the machine is plugged in. 

Dos and Don’ts for Oil or Lubrication on a CNC Machine

By paying attention to these basic best practices, you can ensure your CNC machine stays protected with proper lubrication. That translates to longer life, better performance, and safer operation too.

The Dos for Lubrication on a CNC Machine

Here are some important things to do for lubrication:

Clean the lubrication system parts. The pumps, pipes, filters, and some other parts that distribute lubricant around the machine need to stay clean internally. 

Following the owner’s manual to do the cleaning the right way. Flush out old lubricant and scrub or swap any dirty parts like screens. Also, replace any worn seals or tubes.

Keep work areas tidy. Whether lubricating or doing maintenance, try to avoid spills and leaks. A messy workbench leads to poor cleaning and higher chances of slipping in lubricants. 

Ensure your safety. Use protective gear like gloves, goggles, and aprons. Getting slippery lubricants on your bare skin or in your eyes could cause irritation and more serious problems. 

Keep lubricants stored safely. When not in use, store your lubricating oils, greases, and other products somewhere cool, dry, and protected from sunlight and heat. It helps them last longer without going bad. Don’t leave lubricants exposed where they could spill or get contaminated by dirt.

The Don’ts for Lubrication on a CNC Machine

There are some things you should not do to make the oiling process safer and more effective:

Don’t use the wrong lubricant. The lubricant is important for the machine to work properly and last a long time. Use only the ones recommended by the manufacturer. Check the specific qualities it needs, like the viscosity, performance in high and low temperatures, etc. 

Be careful of using too much or too little lubricant. Using too much oil can cause leaking or make a mess. But you can’t use less than the recommended amount because it’ll cause friction and overheat the components. 

Never mix different lubricants. If you use the wrong type of oil, it’ll wear things out faster because the mixed liquid’s thickness and other properties are different. So, keep the lubricants separate.

Never use old or dirty lubricants. Store lubricants safely away from heat, light, and dirt. Dirty lubricant is never as effective as the fresh one and can spread grime inside the machine.

Don’t throw away used lubricants anywhere outdoors. Follow local rules for disposing of waste lubricants, so they don’t pollute the environment. You may also get fined for just throwing it away somewhere.

Conclusion

Following these steps of how to lubricate a CNC machine will keep it running smoothly for many more production hours. Remember, using the right lubricant, applying the correct amount, and keeping things clean will extend the life of your machine and ensure workplace safety.

Contact Zintilon for all your precision machining needs. We have experts to provide any sheet metal fabrication and custom CNC machining services. 

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