Preventive maintenance issues in manufacturing rarely arise due to missing schedules or poorly defined tasks. Most plants know what needs to be done and when. Problems arise when planned work reaches execution and cannot be completed because the required spare parts are unavailable, incorrect, or not accessible at the time of work. When this happens repeatedly, planned maintenance is missed, and reactive work increases.
In practice, spare parts planning determines whether preventive maintenance can be executed consistently. That said, maintenance teams must focus on stabilizing parts availability before considering broader changes, including reviewing the best preventive maintenance software for manufacturing. Without alignment between the maintenance plan and parts availability, preventive work becomes unreliable regardless of how well it is documented or planned.
Scheduling And Execution Are Not The Same
Preventive maintenance tasks are scheduled based on asset requirements and operating hours. Execution depends on whether the job can be completed as planned. The two are related but not interchangeable.
When parts readiness is not verified before work reaches the floor, common outcomes include:
- The job is deferred after the technician arrives
- The job is closed without completing all steps
- A substitute part is used without updating records
These are not deliberate decisions. These are execution issues that distort maintenance history and inventory data.
When these execution shortcuts repeat, planning data becomes unreliable. Deferred work is not visible, part consumption is understated, and task durations appear shorter than reality. Over time, planners schedule more work than teams can complete. This leads to overloaded weeks, rushed closeouts, and growing gaps between the schedule and what actually happens on the floor.
Basic Readiness Checks Improve Execution
Plants with stable PM execution apply simple readiness checks before work starts. These checks confirm that the job can be completed without interruption.
A few key checks for a successful PM execution include:
- Confirmation of the correct part number
- Verification that the part is available or has a confirmed delivery date
- Confirmation of quantity
- Clarity on approved substitutes
- Clarity on who can approve changes if needed
Applying these checks consistently reduces last-minute deferrals and incomplete work.
Without these checks, technicians arrive ready to work but spend time searching, waiting, or improvising. They may close the task, but key steps are skipped. Over time, this normalizes partial completion, masks recurring shortages, and makes it difficult to distinguish planning errors from execution failures during reviews.
Bills Of Materials Must Match Actual Use
Bills of materials (BOMs) link preventive tasks to spare parts planning. When BOMs are inaccurate, technicians make adjustments to complete the job. These adjustments include parts being borrowed, substituted, or taken from emergency stock. While the equipment may be serviced, inventory records no longer reflect reality.
These changes over time lead to:
- Recurring shortages of the same items
- Inconsistent usage records
- Reduced confidence in inventory data
Teams that maintain reliable PM execution treat BOMs as operational records. When substitutes are used repeatedly, the BOM is reviewed and corrected. High-impact assets are checked regularly to keep parts lists aligned with actual usage.
Spare Parts Should Be Prioritized By Impact
Applying the same inventory rules across all spare parts creates unnecessary risk. Some parts cause immediate production loss if unavailable. Others can be sourced quickly with minimal impact.
A practical approach is to prioritize parts based on the following key aspects:
- Production impact
- Supplier lead time
- Replacement difficulty
- Usage frequency
Critical spares with long lead times should be managed differently from routine preventive consumables. Low-use insurance spares should also be reviewed periodically to avoid obsolescence. This will keep inventory focused on supporting production continuity rather than simply increasing stock levels.
Kitting Supports Planned Maintenance
For repeat preventive tasks, kitting improves execution consistency. Parts are pulled in advance and staged for the job, reducing delays and interruptions.
Kitting is most effective when applied selectively:
- High-volume preventive tasks
- Jobs with a history of delays
- Assets that directly affect production output
Clear rules are needed for what happens to unused parts and pre-picked kits when work is postponed, so inventory records stay accurate. When kitting is informal or unmanaged, parts are staged but not consumed, returned late, or reassigned without record updates. This creates false availability, complicates reordering decisions, and increases last-minute shortages for future preventive jobs.
Reorder Levels Should Reflect Preventive Demand
Preventive maintenance creates predictable parts demand. Reorder points should reflect actual PM usage rather than historical purchasing patterns or emergency orders.
This requires:
- Issuing PM parts against the work order
- Reviewing usage during planning cycles
- Reviewing and updating supplier lead times regularly
When PM consumption is tracked accurately, inventory stabilizes and emergency purchasing declines.
Maintenance And Procurement Must Stay Aligned
Spare parts planning falls between maintenance and procurement. When these teams operate independently, preventive maintenance execution suffers.
Effective coordination involves:
- Agreed lead-time categories
- Clear escalation thresholds
- Approved alternate suppliers
- Regular review of slow-moving and obsolete stock
Final Thoughts
When spare parts planning supports preventive maintenance, planned work can be completed as scheduled. Technicians spend less time waiting for parts, inventory decisions become more predictable, and downtime risk is reduced. In turn, preventive maintenance remains effective as manufacturing operations grow.
