--- title: "CNC Preventive Maintenance: Build a Schedule From Data" description: "Learn how to build a CNC preventive maintenance schedule from machine data: production hours, part counts and alarms, with a worked example and FAQ." image: https://www.jitbase.com/hubfs/preventive-maintenance-cnc-machines-data-driven-schedule.webp --- [+1 438 942-8501](tel:+1%20438%20942-8501) [Log In](https://app.jitbase.com/) - [English](https://www.jitbase.com/blog/preventive-maintenance-cnc-machines-data-driven-schedule) - [Français](https://www.jitbase.com/fr/blog/maintenance-preventive-cnc-plan-donnees-machine) [![JITbase black logo](https://www.jitbase.com/hs-fs/hubfs/Logos/jitbase-logo-black-horiz.webp?width=175&height=88&name=jitbase-logo-black-horiz.webp)](https://www.jitbase.com) - Solutions Back ##### [Machine Monitoring](https://www.jitbase.com/machine-monitoring) - ##### [Machine Monitoring](https://www.jitbase.com/machine-monitoring) Back - [Live Dashboard](https://www.jitbase.com/machine-monitoring) - 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[English](https://www.jitbase.com/blog/preventive-maintenance-cnc-machines-data-driven-schedule) - [Français](https://www.jitbase.com/fr/blog/maintenance-preventive-cnc-plan-donnees-machine)   [Book a demo](https://www.jitbase.com/demo) [Connect Machines for Free](https://sso.jitbase.com/realms/webapp/protocol/openid-connect/registrations?client_id=website-registration&response_type=code&scope=openid&redirect_uri=https://admin.jitbase.com) ![Two CNC shop workers reviewing a paper maintenance schedule next to a machine tool](https://www.jitbase.com/hubfs/preventive-maintenance-cnc-machines-data-driven-schedule.webp) Blog [Machine monitoring](https://www.jitbase.com/blog/tag/machine-monitoring) # CNC Preventive Maintenance: Build a Schedule From Data [*written by* Judicael Deguenon on October 28, 2026](https://www.jitbase.com/blog/author/judicael-deguenon) Preventive maintenance on a CNC machine means doing planned work before the machine fails: lubrication, cleaning, inspections and the replacement of wear parts. Most shops run it on a calendar, for example every quarter, whatever the machine has actually done in that time. That is where a schedule goes wrong. A machine that runs two shifts and a machine that runs a few hours a day do not wear at the same rate, so one gets serviced too late and the other too early. This guide shows how to build a preventive maintenance schedule from machine data, with a worked example and the signals that should trigger an inspection. ## What Is Preventive Maintenance for CNC Machines? Preventive maintenance is planned work done at set points to reduce the chance of an unplanned stop. On a CNC machine it covers lubrication, coolant, filters, way covers, the chip conveyor, air supply, the tool changer and the checks of spindle and axes recommended by the manufacturer. It differs from reactive maintenance, which waits for a breakdown, and from predictive maintenance, which forecasts failures from continuous condition monitoring. Preventive maintenance sits in the middle: you act on a rule, based on time, usage or condition, before something fails. The real question is which rule to use. ## Calendar-Based vs Usage-Based vs Condition-Based Maintenance | Approach | Trigger | Strength | Weakness | | --- | --- | --- | --- | | **Calendar-based** | A fixed date, such as every month or quarter | Simple to plan and easy to explain | Ignores how much the machine was used | | **Usage-based** | Production hours or parts or cycles since the last service | Follows real wear and adapts to heavy and light months | Needs reliable production hours or counts per machine | | **Condition-based** | A signal such as a rising alarm count or a drifting cycle time | Targets the machine that needs attention now | Needs a way to see and compare those signals | In practice, a solid schedule mixes all three. Tasks that depend on use follow production hours, tasks that depend on time follow the calendar, and condition signals add an inspection between two planned services when something changes. ## What Should a CNC Preventive Maintenance Schedule Include? The manufacturer's manual is the reference for each task and interval. As a general structure, tasks fall into three rhythms: - **Every day or every shift:** check lubricant and coolant levels, clear chips, wipe the machine, and look for leaks or unusual noise. - **Every week or month:** clean or replace filters, check coolant concentration, inspect way covers and the chip conveyor, and check air pressure. - **Every several hundred production hours, or every season:** deeper inspections and replacement of wear parts according to the manual, such as the lubrication system, the tool changer and the spindle and axes checks. Treat these as a structure, not as intervals to copy. Take the exact tasks and hours from your machine's documentation, and adjust them with your own failure history. ## How to Build a Preventive Maintenance Schedule From Machine Data 1. **List your machines and their manufacturer intervals.** Note which tasks are tied to operating hours and which to time. 2. **Measure real use.** Get the production hours per machine over the last months, not the hours the machine was powered on. A machine can be on all day and produce for only part of it. 3. **Convert intervals into your own calendar.** Divide the hour interval by the daily production hours of each machine. The result is the real number of working days between two services. 4. **Add usage and condition triggers.** Part counts, cycles, alarms and repeated stop reasons give you reasons to inspect between two planned services. 5. **Schedule the work in low-load windows.** Put planned maintenance where it disturbs the fewest jobs, and record it as planned time so it does not count as a failure. 6. **Record each task with the production hours at that moment.** That record is what lets you shorten or lengthen an interval with evidence. **Know your production hours per machine.** JITbase shows how long each machine actually runs in production, so you can trigger maintenance on real use instead of the calendar. [See machine monitoring](https://www.jitbase.com/machine-monitoring) ## Worked Example: Two Machines on the Same Calendar Schedule Suppose the manual calls for a lubrication and filter service every 500 production hours. The shop services every machine every 3 months, about 63 working days. | | Machine A (two shifts) | Machine B (light use) | | --- | --- | --- | | Production hours per working day | 14 h | 5 h | | Hours reached after 63 working days | 14 × 63 = 882 h | 5 × 63 = 315 h | | Compared with the 500-hour interval | 76% over: serviced too late | 37% under: serviced too early | | Working days to reach 500 hours | 500 ÷ 14 = about 36 days | 500 ÷ 5 = 100 days | The same quarterly calendar leaves Machine A running almost twice the recommended interval and has Machine B serviced when it still has more than a third of its interval left. A usage-based rule fixes both: service A about every 36 working days, and B about every 100. The numbers are an illustration. Replace the 500 hours with your manufacturer's value, and the daily hours with the production hours measured on each machine. ## Which Machine Data Should Trigger an Inspection? | Signal | What to watch | Typical action | | --- | --- | --- | | **Production hours** | Hours in production since the last service reach the interval | Do the planned service | | **Part or cycle count** | Parts or cycles since the last tool, fixture or tool changer service | Inspect the wear item tied to the count | | **Alarm frequency** | The same alarm type rising on one machine over several weeks | Inspect the related component before it stops the machine | | **Unplanned stops** | A falling time between failures or a stop reason that keeps coming back | Review the plan for that machine and shorten the interval if needed | | **Cycle time drift** | A rising cycle time on the same program and material | Check tool wear, lubrication and axis condition | These signals are triggers for a person to look, not automatic diagnoses. A rising alarm count tells you where to look first. Counting finished parts reliably is covered in our guide to [part counting in CNC shops](https://www.jitbase.com/blog/part-counting-cnc-shops), and the stops themselves in [automated downtime detection](https://www.jitbase.com/blog/automated-downtime-detection-cnc-setup). In JITbase, the data behind these triggers is available per machine: production time, part counts, alarms by type and machine, and the stop reasons entered by operators at the machine screen. Operators can also tell a breakdown apart from a planned stop, so planned maintenance does not pollute your failure data. JITbase does not replace your maintenance log or maintenance software: your team still sets the interval and records the task. **Separate planned maintenance from real breakdowns.** Operators select the stop reason at the machine screen, so planned maintenance stays out of your failure data. [See production monitoring](https://www.jitbase.com/production-monitoring) ## How Do You Know Your Preventive Maintenance Is Working? Check the plan against the data every few months. Four measures are enough to start: - **Share of unplanned stops.** It should fall as preventive work takes over from emergency repairs. The method to rank stop causes is in [downtime root cause analysis with Pareto charts](https://www.jitbase.com/blog/downtime-root-cause-analysis-pareto-charts). - **Time between failures.** A rising MTBF per machine means the plan is working. See [how to calculate MTBF from shop-floor data](https://www.jitbase.com/blog/mtbf-cnc-machines-calculate-shop-floor-data). - **Repair time.** MTTR shows how long a failure takes when it does happen. See [how to measure MTTR](https://www.jitbase.com/blog/mttr-cnc-machines-measure-repair-time). Planned maintenance is excluded from both MTBF and MTTR, so record it as planned time. - **Compliance.** The share of planned tasks done on time. A good plan that is not followed shows up here, not in the failure data. For the bigger picture, fewer unplanned stops raise availability, one of the three factors in [overall equipment effectiveness (OEE)](https://www.jitbase.com/blog/complete-guide-overall-equipment-effectiveness-oee). ## Common Preventive Maintenance Mistakes - **Copying a calendar for every machine.** Use differs by machine, so intervals should too. - **Counting power-on time as use.** A machine can be on all day and produce for only part of it. Use production hours. - **Over-maintaining.** Every planned service takes production time. If the failure data does not improve, the interval may be too short. - **Ignoring the manual.** Intervals from the manufacturer are the baseline. Change them with evidence, not by feel. - **Not recording the work.** Without the date and production hours of each task you cannot tell whether an interval is right. - **Mixing planned and unplanned stops.** Planned maintenance recorded as a failure distorts MTBF and MTTR. ## Key Takeaways - A calendar-based schedule ignores how much each machine was used. Production hours and part counts follow real wear more closely. - Divide the manufacturer's hour interval by each machine's daily production hours to get its real service interval in working days. - Use alarms, repeated stop reasons and cycle time drift as triggers to inspect between planned services. - Record every task with the date and production hours, and track MTBF, MTTR, the unplanned share and compliance. - Machine data supports the decision. The team still sets the interval and does the work. **See what fewer unplanned stops are worth.** Estimate the return of tracking production hours, stops and alarms on your own machines. [Calculate your return on investment](https://www.jitbase.com/return-on-investment) ## Frequently Asked Questions ### What is preventive maintenance on a CNC machine? Preventive maintenance is planned work done on a CNC machine before it fails: lubrication, cleaning, filter changes, coolant checks, inspections and the replacement of wear parts. The goal is to avoid unplanned stops, which interrupt jobs already in progress and are harder to schedule around than planned work. It sits between two other approaches. Reactive maintenance waits for a breakdown, and predictive maintenance forecasts failures from continuous condition monitoring. Preventive maintenance is the planned middle: you act on a rule, based on time, usage or condition, before the failure. ### How often should CNC machines receive preventive maintenance? The machine manufacturer's manual sets the baseline intervals for each task, and your schedule should start there. Daily tasks usually cover levels, chips and visual checks, while heavier tasks are tied to a number of operating hours or a longer calendar period. Two machines on the same calendar do not wear at the same rate. A machine that runs two shifts reaches an hour-based interval far sooner than one used a few hours a day, so tying tasks to production hours often matches real wear better than a fixed date. ### What is the difference between preventive and predictive maintenance? Preventive maintenance follows a rule you set in advance, such as every 500 production hours or after a given number of cycles. Predictive maintenance estimates when a failure is likely from continuous measurements, such as vibration or temperature, and usually needs dedicated sensors and analysis. A usage-based schedule built from machine data is still preventive maintenance, not predictive. It gets you much of the benefit with data most shops already have, and it can be refined over time as you see which signals really precede a stop. ### Is usage-based maintenance better than calendar-based maintenance? For most CNC shops, usage-based is closer to real wear because it follows production hours or part counts instead of the date. It avoids servicing a lightly used machine too early and servicing a heavily used machine too late. Calendar-based maintenance still has a place for tasks that depend on time rather than use, such as checking batteries, safety devices or fluids that age even when the machine is idle. Most good schedules mix the two. ### What data do you need to build a preventive maintenance schedule? Start with the manufacturer's intervals, then add what your machines actually do: production hours per machine, part or cycle counts, alarms by type, and the stop reasons entered by operators. Together they show how much each machine is used and which problems keep returning. You also need a record of each maintenance task, with the date and the production hours at that moment. Without that record you cannot tell whether an interval is too short or too long. ### How do you know if your preventive maintenance is working? Track the share of stops that are unplanned, the time between failures (MTBF) and the repair time (MTTR) for each machine. If preventive maintenance works, unplanned stops become less frequent and the time between failures grows. Also track how many planned tasks were done on time. A good plan that is not followed shows up as a low compliance rate, and a plan that is followed but does not change the failure data needs shorter intervals or different tasks. #### SHARE [mailto:email@example.com?subject=Mail%20from%20our%20Website](mailto:email@example.com?subject=Mail%20from%20our%20Website) ## Related Articles [![Tablet mounted next to a CNC machine control showing production status and planned stop buttons: recording stops for MTBF with JITbase](https://www.jitbase.com/hs-fs/hubfs/mtbf-cnc-machines-calculate-shop-floor-data.webp?width=352&name=mtbf-cnc-machines-calculate-shop-floor-data.webp)](https://www.jitbase.com/blog/mtbf-cnc-machines-calculate-shop-floor-data) [Machine monitoring](https://www.jitbase.com/blog/tag/machine-monitoring) ### [MTBF for CNC Machines: How to Calculate Mean Time Between Failures from Shop-Floor Data](https://www.jitbase.com/blog/mtbf-cnc-machines-calculate-shop-floor-data) Read more [![Technician repairing a CNC lathe while an operator logs the stop on a tablet: MTTR for CNC machines with JITbase](https://www.jitbase.com/hs-fs/hubfs/mttr-cnc-machines-measure-repair-time.webp?width=352&name=mttr-cnc-machines-measure-repair-time.webp)](https://www.jitbase.com/blog/mttr-cnc-machines-measure-repair-time) [Machine monitoring](https://www.jitbase.com/blog/tag/machine-monitoring) ### [MTTR for CNC Machines: How to Measure Repair Time](https://www.jitbase.com/blog/mttr-cnc-machines-measure-repair-time) Read more [![CNC shop floor team reviewing machine operations and production throughput KPIs in a manufacturing workshop.](https://www.jitbase.com/hs-fs/hubfs/blog-images/throughput-kpis-cnc-shop-hero-1.jpg?width=352&name=throughput-kpis-cnc-shop-hero-1.jpg)](https://www.jitbase.com/blog/throughput-kpis-cnc-shop) [Machine monitoring](https://www.jitbase.com/blog/tag/machine-monitoring) ### [5 KPIs Every Shop Manager Should Track to Increase Throughput Without Hiring (Includes Dashboard Templates)](https://www.jitbase.com/blog/throughput-kpis-cnc-shop) Read more [![Machinist measuring a part at an inspection bench while a CNC machining center runs behind him: hidden-time operator tasks with JITbase](https://www.jitbase.com/hs-fs/hubfs/hidden-time-operator-tasks-cnc-shops.webp?width=352&name=hidden-time-operator-tasks-cnc-shops.webp)](https://www.jitbase.com/blog/hidden-time-operator-tasks-cnc-shops) [Machine monitoring](https://www.jitbase.com/blog/tag/machine-monitoring) ### [Hidden-Time Operator Tasks: How to Schedule Them in CNC Shops](https://www.jitbase.com/blog/hidden-time-operator-tasks-cnc-shops) Read more [![JITbase block logo](https://www.jitbase.com/hs-fs/hubfs/eca01011d7169e8c6395a8d7eebe802d.webp?width=317&height=158&name=eca01011d7169e8c6395a8d7eebe802d.webp)](https://www.jitbase.com) ![image-2](https://www.jitbase.com/hs-fs/hubfs/image-2.webp?width=156&height=78&name=image-2.webp) Solutions - 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[Privacy Policy](https://www.jitbase.com/privacy-policy) ```json { "@context" : "https://schema.org", "@type" : "BlogPosting", "author" : { "@type" : "Person", "name" : "Judicael Deguenon", "url" : "https://www.jitbase.com/blog/author/judicael-deguenon" }, "dateModified" : "2026-10-28T19:27:16.209Z", "datePublished" : "2026-10-28T19:27:16.000Z", "headline" : "CNC Preventive Maintenance: Build a Schedule From Data", "image" : [ "https://www.jitbase.com/hubfs/preventive-maintenance-cnc-machines-data-driven-schedule.webp" ], "mainEntityOfPage" : { "@id" : "https://www.jitbase.com/blog/preventive-maintenance-cnc-machines-data-driven-schedule", "@type" : "WebPage" }, "publisher" : { "@type" : "Organization", "logo" : { "@type" : "ImageObject", "url" : "https://www.jitbase.com/hubfs/logo%20jitbase%201.svg" }, "name" : "JITbase" } } ``` ```json { "@context" : "https://schema.org", "@type" : "FAQPage", "mainEntity" : [ { "@type" : "Question", "acceptedAnswer" : { "@type" : "Answer", "text" : "Preventive maintenance is planned work done on a CNC machine before it fails: lubrication, cleaning, filter changes, coolant checks, inspections and the replacement of wear parts. The goal is to avoid unplanned stops, which interrupt jobs already in progress and are harder to schedule around than planned work. It sits between two other approaches. Reactive maintenance waits for a breakdown, and predictive maintenance forecasts failures from continuous condition monitoring. Preventive maintenance is the planned middle: you act on a rule, based on time, usage or condition, before the failure." }, "name" : "What is preventive maintenance on a CNC machine?" }, { "@type" : "Question", "acceptedAnswer" : { "@type" : "Answer", "text" : "The machine manufacturer's manual sets the baseline intervals for each task, and your schedule should start there. Daily tasks usually cover levels, chips and visual checks, while heavier tasks are tied to a number of operating hours or a longer calendar period. Two machines on the same calendar do not wear at the same rate. A machine that runs two shifts reaches an hour-based interval far sooner than one used a few hours a day, so tying tasks to production hours often matches real wear better than a fixed date." }, "name" : "How often should CNC machines receive preventive maintenance?" }, { "@type" : "Question", "acceptedAnswer" : { "@type" : "Answer", "text" : "Preventive maintenance follows a rule you set in advance, such as every 500 production hours or after a given number of cycles. Predictive maintenance estimates when a failure is likely from continuous measurements, such as vibration or temperature, and usually needs dedicated sensors and analysis. A usage-based schedule built from machine data is still preventive maintenance, not predictive. It gets you much of the benefit with data most shops already have, and it can be refined over time as you see which signals really precede a stop." }, "name" : "What is the difference between preventive and predictive maintenance?" }, { "@type" : "Question", "acceptedAnswer" : { "@type" : "Answer", "text" : "For most CNC shops, usage-based is closer to real wear because it follows production hours or part counts instead of the date. It avoids servicing a lightly used machine too early and servicing a heavily used machine too late. Calendar-based maintenance still has a place for tasks that depend on time rather than use, such as checking batteries, safety devices or fluids that age even when the machine is idle. Most good schedules mix the two." }, "name" : "Is usage-based maintenance better than calendar-based maintenance?" }, { "@type" : "Question", "acceptedAnswer" : { "@type" : "Answer", "text" : "Start with the manufacturer's intervals, then add what your machines actually do: production hours per machine, part or cycle counts, alarms by type, and the stop reasons entered by operators. Together they show how much each machine is used and which problems keep returning. You also need a record of each maintenance task, with the date and the production hours at that moment. Without that record you cannot tell whether an interval is too short or too long." }, "name" : "What data do you need to build a preventive maintenance schedule?" }, { "@type" : "Question", "acceptedAnswer" : { "@type" : "Answer", "text" : "Track the share of stops that are unplanned, the time between failures (MTBF) and the repair time (MTTR) for each machine. If preventive maintenance works, unplanned stops become less frequent and the time between failures grows. Also track how many planned tasks were done on time. A good plan that is not followed shows up as a low compliance rate, and a plan that is followed but does not change the failure data needs shorter intervals or different tasks." }, "name" : "How do you know if your preventive maintenance is working?" } ] } ```