Comprehensive CNC Maintenance Checklist for All Machine Types

CNC-equipped machines come in a variety of shapes and sizes, from routers to lathes, mills to wire EDMs. Finding a detailed checklist which works equally well for all of them can be difficult.

In this list, we’ve pared away some of the minute details, which vary from machine to machine, and left you with a maintenance checklist which will work across the board for CNC machines.

What is CNC?

First off, a brief definition. Computer Numerical Control, or CNC, refers to machines which can be programmed to perform a series of cuts and maneuvers without an operator. CNC technology enables the automation of many steps in the manufacturing process. It also offers vastly improved quality control and uniformity of the parts produced. CNC technology has been around since the 1950s, but with the advent of computers and robotics, CNC machines can tackle increasingly complicated operations, moving on multiple axis and switching between different tools and cutting heads within the same machine.

Despite the growing automation of CNC machines, they still require a human operator for programming and maintenance. A machinist may be responsible for multiple CNC machines at the same time. Having a quality checklist can make maintenance easier, quicker, and more efficient.

Basic CNC Checklist

Maintenance tasks for CNC machines fall into three general categories: daily inspections, jobs that need to be performed every 500 hours or every six months, and additional inspections to be done every 1000 hours or every year. The daily checklist will of course be the longest one, and the one you’ll use most often. Don’t forget the other checks, however, especially if your machine is running around-the-clock or for extended shifts. Five 24-hour days is 121 hours, meaning that machines which are in nearly constant use could require a 500-hour inspection almost every month.

Daily

• Check pressure – Verify that your machine is maintaining hydraulic pressure at the recommended level. Also check the pressure on the chuck.
• Check fluids – Check the hydraulic fluid levels. Also inspect oil or lubrication levels, and ensure that there’s adequate cooling fluid.
• Clear away built-up grime – Many CNC machines employ a cooling system, sometimes water-based; if one is used, be sure that the drains are clear. Wipe down the machine heads if needed.
• Empty chip pan – On a CNC lathe or mill, excess trimmings frequently simply fall to the floor of the machine. Clear these away to minimise the potential of any debris interfering with the operation.
• Clean glass and viewports – An EDM or metal lathe may include a viewport for the operator to verify the progress of the machining process. Make sure these viewports are cleaned on a daily basis.

500 Hours

• Inspect and lubricate the chain (usually on the chip conveyer) – If your machine has a chip conveyer.
• Inspect and clean filters on the cooling tank – Keep your cooling fluid useful for longer by regularly cleaning the filters on the coolant tank. 

1000 Hours

• Maintenance by a certified technician

Every six months to a year, you should have your CNC machines thoroughly inspected by a trained technician, often one sent from the original manufacturer of the machine. That person can completely drain and replace the hydraulic fluid, clean the coolant tank itself, and perform an inspection of the chuck, jaws, and clamps of the machine heads.

Final Considerations

Much of the necessary maintenance for a CNC machine boils down to common sense. Make sure your machine is clean, or at least clear from any unnecessary buildup or clutter. Check to be sure any dials or pressure gauges are within the machine’s recommended limits. Get in the habit of performing these checks daily. Not only will you preserve your machine for longer, but you’ll also catch any problems quicker.

CNC maintenance doesn’t need to be hard; it does need to be performed thoroughly and regularly to get the most out of your machines.