by Robbie Williams
A preventive maintenance checklist reduces downtime
When you purchase a new car, you are probably diligent about regular maintenance, especially at the beginning. Most of us understand this type of maintenance is required to keep the vehicle running smoothly so it can get us where we need to go. However, that same mindset is not always true for high end CNC equipment.
Reactive maintenance costs
The idea of stopping production on your machine for the small amount of time it takes to perform regularly scheduled maintenance–and the costs involved–might make you cringe. However, studies show reactive maintenance programs on average cost 12 to 18per cent more than preventive maintenance programs.
Preventive maintenance also gives you the flexibility to choose when your machine will be shut down.
Preventive maintenance controls potential costs
The overall cost of maintenance in your business can be a sizable budget item. So the overall goal and benefit of planning maintenance proactively through a preventive maintenance program is to reduce these costs and maximize productivity.
A good preventive maintenance program for your CNC machine includes a system of cleaning, checking and replacing various components on a regular schedule. There are many preventive maintenance activities that should be performed by shop employees on a daily basis, while other more extensive operations are carried out over longer time frames by a certified service engineer, which are typically available through your service provider or distributor.
Following are some guidelines to effective preventive machine tool maintenance.
Daily preventive maintenance activities
• Check hydraulic pressure, hydraulic fluids, chuck pressure, lube levels; and, if you have a cooling system, check the cooling unit level
• Clean out chips, grease parts as needed, clean off windows and doors, and wipe down and lubricate way covers so they move smoothly
Every three months or 500 hours
• Check and grease the chain on the chip conveyor
• Check and clean the filters on the coolant tank
Every six months or 1,000 hours
Have the following preventive maintenance performed by a certified engineer:
• Clean the coolant tank of sludge, chips and oil
• Clean the chuck and jaws
• Drain the hydraulic tank and replace the hydraulic oil, and change the line filter and suction filter
• Clean the radiator and make sure the radiator fins are straight
• Drain and clean the lubrication unit and add fresh way lube
• Drain and refill the cooling unit
• Check the leveling of your machine and adjust if necessary
• Clean and inspect way wipers and replace any wipers that are damaged
Once a year or every 2,000 hours
Have your certified engineer perform the following inspections:
• Check the headstock for taper
• Check the spindle for radial and end play
• Check the chuck cylinder for run out
• Check the tailstock for taper
• Check turret parallelism and inclination
• Run a backlash program to check the backlash in X and Z axis
• Check the X and Z axis gibs
Three take-action tips
There are ways you can take action with a planned preventive maintenance program while minimizing disruptions to your workflow and productivity. Consider the following:
1. Schedule preventive maintenance during known shutdown times, such as holiday breaks. During a known shutdown period, productivity is already reduced.
2. Order your preventive maintenance kit early. This minimizes variables in leadtime and ensures you can take advantage of that opportune window of time during a scheduled shutdown.
3. During a preventive maintenance service, inspect your machine for unseen or potential issues. When you’ve slid back the covers on your machine, you may see areas of wear that couldn’t be detected on a daily basis, and this gives you a chance to make repairs before an expensive failure occurs.
Preventive maintenance is about more than just protecting your CNC machine tool investment. A proactive preventive maintenance plan ensures you maximize productivity and helps reduce overall, long-term costs. To help you keep up with your maintenance needs, refer to your owner’s manuals, contact your local distributor or download Okuma’s Scheduled Maintenance app from the Okuma App Store. Protect your investment, protect your business. SMT
Robbie Williams is a junior applications engineer, Okuma America Corp.
