Preventive Maintenance for CNC Routers

This article offers guidelines for maintaining a CNC router machine.  Well-built CNC routers can potentially operate for many years, but only if they are properly cared for. A disciplined approach to preventive maintenance can extend the useful life of any CNC router, reduce repair costs, and improve cut quality.  Most preventive maintenance tasks listed in this article can be performed by the end user, but there are times when it is important to call the CNC router dealer for help, and those are addressed later in this article.

Daily Maintenance

The following maintenance tasks should be performed daily:

1.      Check the machine’s air pressure regulator

Some CNC routers, including MultiCam routers, feature an air pressure regulator that helps to control incoming air pressure.  On a MultiCam machine, the air pressure regulator is located at either the back of the machine on the right frame rail or in the middle of the right side of the machine’s frame.  The regulator should be adjusted so the incoming pressure to the machine is within the manufacturer’s specification (between 110 to 120 psi for a MultiCam).  To adjust the regulator, pull up on the center cap and rotate to set the desired pressure.  After pressure is adjusted push down on center cap to lock in place.

2.      Purge water and oil separators

Some CNC routers, including MultiCam routers, feature water and oil separators on the incoming air line.  The water and oil separators need to be checked and purged daily to make sure that no contaminates get through the air supply to the machine.  To purge the oil and water separators turn the knobs at the bottom of each unit until clean air flows out. Some of these units have red push buttons to purge instead of knobs that turn.

3.      Check heat exchanger (if spindle is liquid-cooled)

The coolant reservoir in the heat exchanger should be checked once or twice a week to make sure that the coolant level is full. If coolant is need, use a 50/50 mixture of distilled water and ethylene glycol.  Always make sure that the heat exchanger is on and running at the start of each day. If the spindle is run for an extended amount of time without cooling it will damage the bearings in the spindle.

4.      Clean the spindle fan (if spindle is air-cooled)

Dust accumulates on the spindle’s cooling fan and can cause it to become out of balance.  Use compressed air to blow off the fan daily.

5.      Check computer connections

6.      Sweep work area

7.      Examine tools before cutting

8.      Check dust collector bins/bags (if equipped) and empty if needed

Weekly Maintenance

The following maintenance tasks should be performed weekly:

1.      Lubricate bearings and screws

CNC routers can use a combination of rack-and-pinion, ball screw, and lead screw devices to create motion.  Each of these requires regular lubrication, and end users should find out from their dealer how many of each of these devices are on the machine and where they are located.

On a standard MultiCam machine configuration there are 13 linear bearings that need to be lubricated once a week. The X-Axis has 4, the Y-Axis has 4, the Z-Axis has 4 and the dust hood has 1.  The Z-Axis of the machine has a ball screw or lead screw that needs to be cleaned and re-lubricated once a week.  This is very important!

2.      Clean vacuum pump filters

Vacuum pump filters should be checked and cleaned each week and replaced when necessary. Take great care when removing and cleaning the filters not to let any debris enter the vacuum pump inlet.

3.      Clean air filter in heat exchanger (if spindle is liquid-cooled)

The air filter on the heat exchanger should be cleaned with compressed air once a week and replaced as needed.

4.      Clean tool holders and collets

Tool holders, collets, and collet nuts must be rust-free and clean.  Use a mild scotch-bright pad to clean any rust.  Apply a very light oil to prevent oxidation, and then remove excess oil with a clean, soft rag.  Never use abundant oil or grease.  Typically these components need to be cleaned weekly, but frequency really depends on the amount of moisture in the air and how quickly rust develops.  Components should look like they are new at all times.

5.      Clean the spindle taper

Cleaning the spindle taper should be done once a week.  Wipe the taper very well with a green scotch bright pad, use compressed air to blow the taper out, and then wipe with a clean dry cloth.

6.      Wipe off excess grease

7.      Double check all connections

Monthly Maintenance

The following maintenance tasks should be performed monthly:

1.      Check and change heat exchanger coolant filter

Once a month the heat exchanger coolant filter should be inspected and changed if needed.

2.      Lubricate racks

If the machine features any rack-and-pinion devices, the racks should be lubricated monthly.  A typical MultiCam machine has 3 gear racks, 2 on the X-Axis and 1 on the Y-Axis.

3.      Check for loose bolts on machine and tighten as needed

4.      Wipe rails with a scotch bright pad

Quarterly Maintenance

The following maintenance tasks should be performed quarterly:

1.      Clean or replace relief valve filter on the vacuum pump

2.      Change vacuum pump oil, if applicable

3.      Change grease cartridges, if applicable

4.      Clean rack-and-pinion and re-lubricate

5.      Clean overall machine

When to Call an Expert

Most preventive maintenance tasks listed in this article can be performed by the end user, but there are times when it is important to call the CNC router dealer for help.  Your dealer should have a staff of factory-trained technicians that can maintain your machine, repair it as needed, and train your staff.  At Advanced Machine Tools (a MultiCam distributor), our customers have told us that our help is valuable in these situations, among others:

• Some end users do not have the mechanical skills in-house to perform all of the preventive maintenance procedures.  In these situations, they may perform some of the steps listed above, but also call their dealer for periodic preventive maintenance visits to perform the more difficult tasks.
• Some end users may have the skill but do not want to spend any time worrying about preventive maintenance, because they want to focus on their business.  In these cases, they can work with their dealer to set up a schedule of regular preventive maintenance visits.
• When new operators are hired, it is important for them to be trained in machine operations, maintenance, and safety.  Your dealer can provide training for your new employees.

Beyond the above situations, there are also procedures that the end user should not attempt to do on their own.  End users can benefit from improved machine performance and longevity if they call their dealer for a periodic “tune-up”.  During a tune-up visit, the dealer technician can perform the following procedures in addition to preventive maintenance:

1.      Check and adjust the square of the machine to make sure that parts are being cut accurately.

2.      Check and adjust the spindle to make sure that the spindle is perpendicular to the table surface.

3.      Check and adjust alignment of tool changer.

4.      Check and adjust electrical components.

5.      Check and adjust the motors to the gear racks and inspect for wear.

6.      Check and adjust all drive belts.

7.      Update the machine operating files and or communication software to take advantage of new features or enhancements.

8.      Make recommendations to the operators on what they can do better to keep the machine in proper working order.

9.      Answer specific application questions to help increase productivity and return on investment.

 

Copyright © 2008 AMT Op Co, LLC d/b/a Advanced Machine Tools

Date Last Updated: June 2, 2008.