CNC Machining Preventive maintenance routines that actually reduce scrap

[Alan]

End of January 2026 check in for the CNC Machining Forum. I want to start a practical preventive maintenance thread for the benefit of anyone trying to reduce scrap and keep machines consistent. A lot of shops have “PM” on paper, but the routines that actually move the needle tend to be the simple ones that get done every week or month.

What checks do you genuinely see results from, and how often do you do them? Things like way covers, lubrication, coolant concentration, chip management, backlash checks, spindle warmup habits, probe verification, tool setter checks, or anything that helps accuracy stay predictable. Share your routine and what problem it prevented, because that’s the kind of info people can copy immediately.

 

[TovalRandonneur]

Coolant concentration checks have helped more than I expected. I started doing a quick refractometer check weekly and topping up correctly instead of guessing. Fewer weird finish changes and fewer mystery tool life swings.

 

[JudeRanster]

doing a short spindle warmup every morning and then verifying the probe or tool setter repeatability before trusting offsets. When I skip that, I feel like I’m guessing and the machine eventually proves me wrong.