Knowing how to do maintenance of CNC machine is necessary if you want the equipment to last. Regular maintenance also ensures optimum performance under varying conditions. Whether you use it regularly on only occasionally, you’ve got to keep your CNC in good condition, otherwise it could negatively affect performance.
Daily Care and Maintenance of CNC Machines
A CNC machine is complex, and if one component isn’t working could affect the final output. Here are some of the parts you should check daily after each activity.
- Look over the hydraulic pressure and make certain the pressure is set at 4.5 MPa. The hydraulic fluids also have to be at the appropriate level before operation.
- The chuck needs to be at the appropriate pressure level. If it’s below what’s required for operation, problems could occur. While you’re looking over the chuck, make certain the lube level is correct and add more if necessary.
- Heavy duty CNC machines need a coolant to prevent overheating, but it needs to be at the appropriate level to be effective. The right level is stated in the operator’s handbook or with the coolant’s guide.
Your CNC machine needs regular cleaning. At least once a week is the minimum, preferably daily if you use it heavily. Remove all the chips in the chip pan. If the machine isn’t running as smoothly as before, some components may require greasing. If you’re having trouble seeing the machine’s interior, clean the door and windows thoroughly.
For the best results you should wipe clean the stainless steel and apply hydraulic oil in the appropriate parts. Every week or so, remove the CNC control cabinet filter and clean it. By keeping the filter clean, air flows in more smoothly, helping cool the machine.
More Intensive Cleaning and Maintenance
Every three months / 500 hours, an operator should perform a more thorough maintenance. Here are some suggestions.
- Examine the chip conveyor chain and grease it. This is necessary to ensure the machine runs smoothly.
- Examine the coolant tank filters and clean them thoroughly.
You can do the following every six months or so. However if you use the CNC machine extensively, it won’t hurt to have a professional engineer examine it every 4 or 5 months. The following should be looked into:
- Have the tank examined and the oil, chips and sludge removed. These accumulate over time and affect performance, so regular cleanup is necessary.
- Drain the hydraulic tank and replace the fluid with fresh, new oil. Replace the suction filter and line filter as well.
- A heavily used CNC machine needs to have the radiator cleaned. The fins have to be straight up.
- Drain the lubrication unit, clean it and add new lube. If the CNC machine is equipped with a cooling mechanism, have it refilled and drained.
One of the keys to running a CNC machine is proper leveling. Have it check periodically and make the proper adjustments. You or an engineer should have the wipers checked for damage and replaced immediately.
Yearly Maintenance Duties
Every year you should have the following areas in the CNC machine examined:
- Look for signs of taper in the headstock and tailstock.
- Examine the turret inclination and parallelism for any problems.
- Look for signs of run out on the chuck cylinder.
- Examine the spindle and look for signs of radial play.
If the axis seems off, ask your CNC machine distributor to prepare a backlash program and make adjustments to the X and Z axis.
These steps are preventive in nature, and these should keep your CNC machine in good condition. Running a maintenance program is not difficult, and you will never be caught flat footed in case something falters in the machine.
- Ohm Meter: buy a quality meter, and it only costs a few hundred dollars. With this you’ll get precise readings, essential for maintenance.
- You should also get a megohm meter that tests cables, motors and servo motors. With this you’ll be able to check if those cables or plugs are not working properly.
A megohm meter measures megohm resistance over 1,000,000,000 ohms or 1000 megaohms. There are many types of megaohms, with the most common having a range of 1 meg to 30 megaohms.
- Phase Rotation Meter: this device is ideal for companies which add or move CNC equipment in the facility. A phase rotation meter makes certain phasing is done right. As a CNC operator will tell you, cooler pumps, hydraulic pumps and coolant pumps could get damaged if phasing is not done right.
- Fused Jumper: a fused jumper is used for testing output and input from CNC machines and other devices. This is a critical tool for CNC maintenance.
- Proximity Switch Tester: this tool evaluates proximity switches, and it also tells you if a proxy switch is PNP or NPN. You can use this to test the system and to check stock compatibility. You will also find this tool useful for wiring if the prints aren’t available.
- Drawbar clamp force dynamometer: this tool is not cheap, but it’s one you’ll want to have for troubleshooting.
Tips and Suggestions
- Set a Schedule: your CNC machine comes with an operator’s handbook with instructions for maintenance. Follow the maintenance schedule given there.
- If you’re overseeing several CNC machines, designate the maintenance to someone. It is not necessarily the person’s job to do the maintenance work, but it is his/her responsibility to make sure it takes place as scheduled.
- Train yourself in DIY maintenance if you’re the only one who’ll do it. Read the guide, follow the instructions and buy good quality maintenance tools.
- Don’t use a CNC machine for projects it is not intended for, as that increases the possibility of damage.
The information presented here is meant as a general guideline for maintaining a CNC machine. Of course there are many types of CNC machines so the precise method will vary. Your operator’s handbook should have all the details for maintenance and troubleshooting, and you should use that for reference.