How To Schedule Maintenance Without Hurting OEE

Planned downtime is the safest moment to perform preventive maintenance, but coordinating it without disrupting production is harder than it looks. The goal is simple: keep machines healthy while protecting throughput and OEE. 

What Is the Best Time to Perform Preventive Maintenance in a Factory?

The best maintenance windows are the ones that create no impact on production flow. In practice this means:

Non production hours

• Night shift
• Weekends
• Holidays
• End of shift periods when operators clean up or run warm down routines

Micro breaks in the schedule

• Tool change blocks
• Setup change windows
• Material delivery gaps
• Lunch breaks on manual or semi automated lines

Full planned stops

• Weekly cleaning blocks
• Monthly shutdowns
• Quarterly electrical inspections

Factories with stable schedules can set recurring maintenance slots. High mix factories need more dynamic planning based on real time data.

How Do Production and Maintenance Teams Coordinate Planned Downtime?

Coordination fails when both teams guess instead of using data. A clean coordination method includes a single calendar where planners publish production commitments and maintenance publishes required intervals.

Priority rules:

• Safety critical tasks always come first.
• Regulatory and calibration tasks follow.
• Condition based and preventive tasks come next.

Confirmation process:

• Maintenance proposes a slot.
• Production verifies WIP, material availability and target output.
• Both sides approve the final window.

The fastest way to remove conflict is to plan all maintenance windows at the same granularity as production schedules.

How Do You Use Real Time Data to Pick the Right Maintenance Window?

Modern machine monitoring systems help teams decide based on facts instead of estimates. If the machine provides states and counters, you can optimize:

Cycle time variation: growing variation shows increasing friction, spindle wear or tool load issues. Plan maintenance during the next natural break.

Spindle or motor load spikes: if load trends climb shift by shift, schedule inspection during the next planned stop instead of waiting for a failure.

Unoccupied machine states: a machine that sits idle for short periods is a perfect candidate for micro maintenance. Operators already expect downtime and can help coordinate access.

Downtime Pareto charts: if a line loses most time to predictable issues, you schedule targeted preventive tasks during the least impactful window.

Should Planned Maintenance Count as Downtime in OEE?

For standard OEE, planned maintenance does not count against availability because the line is intentionally stopped. Two rules keep reporting clean: count it as planned loss, not downtime. You still track the hours, but you do not penalize the production team. Also, make sure to separate maintenance hours from production hours.

This allows planners to forecast required blocks and understand the cost of maintenance, without losing OEE trends.

Maintenance Scheduling Checklist Table

How Do You Reduce Unplanned Downtime with Better Maintenance Scheduling?

Unplanned downtime drops sharply when plants shift from reactive to predictable scheduling. The core steps are:

1. Align PM frequency to machine age and workload

Older machines require tighter intervals. High torque operations need earlier checks.

2. Use simple condition indicators

• Spindle temperature
• Motor current
• Run hours
• Alarm frequency trends

These indicators help trigger maintenance during low impact windows.

3. Break large tasks into smaller ones

Instead of one four hour intervention, perform four one hour tasks across the week. This reduces schedule collisions.

4. Validate impact weekly

Track whether the planned maintenance actually prevented failures. Adjust intervals as needed.

A Practical Maintenance Scheduling Routine for Production Plants

You can apply this workflow in any CNC or automated environment.

Step 1. Identify non production windows

List breaks, shift transitions and routine pauses.

Step 2. Map maintenance tasks by criticality

Safety, quality, performance and cosmetic tasks.

Step 3. Assign default windows for repetitive tasks

Lubrication, cleaning, alignments, inspections.

Step 4. Map dynamic tasks to real time data

Schedule based on load, hours, alarms or cycle variation.

Step 5. Publish a shared schedule

Maintenance and production approve blocks in advance.

Step 6. Review performance weekly

Confirm impact on downtime and OEE.

Scheduling maintenance during planned downtime is one of the most effective ways to protect OEE, avoid schedule slippage and reduce unplanned stops. The key is coordinating production and maintenance through shared schedules, real time machine data and clear prioritization rules. When both teams plan together at the same level of detail, maintenance stops being a disruption and becomes a competitive advantage.

About MDCplus

Our key features are real-time machine monitoring for swift issue resolution, power consumption tracking to promote sustainability, computerized maintenance management to reduce downtime, and vibration diagnostics for predictive maintenance. MDCplus's solutions are tailored for diverse industries, including aerospace, automotive, precision machining, and heavy industry. By delivering actionable insights and fostering seamless integration, we empower manufacturers to boost Overall Equipment Effectiveness (OEE), reduce operational costs, and achieve sustainable growth along with future planning.