Planned Maintenance

Planned maintenance is the second TPM pillar most shops put in place, after autonomous maintenance, and the one that gives the maintenance department its actual structure. The pillar exists in opposition to a maintenance team that lives entirely in firefighting mode. A shop where every breakdown is an emergency cannot run planned maintenance, because there is no time for the schedule. The first step of building the pillar is, paradoxically, creating enough operator capability through autonomous maintenance that the maintenance team has time to plan.

"If the maintenance team only ever shows up to a fire, the calendar is fiction."

How planned maintenance works

Planned maintenance combines three kinds of work into one schedule. Preventive tasks run on time or usage intervals: change the hydraulic filter every 2,000 hours, rebuild the spindle every 18 months. Predictive tasks run on condition data: replace the bearing when vibration crosses a threshold, change oil when particulate count exceeds a limit. Corrective and improvement projects address known weaknesses on a planned timeline: redesign the guard that keeps getting damaged, upgrade the controller before it becomes obsolete.

The schedule starts with the manufacturer's recommendations and the maintenance team's institutional knowledge of what each machine has actually needed. Tasks get sequenced into a weekly or monthly rhythm. A typical small shop schedule has heavier work in the week with the lowest production demand and lighter work distributed across the rest. The schedule is reviewed weekly: what is due, who is doing it, when will the machine be available. Findings from each task get logged and feed adjustments to the next cycle of work.

The interface between planned maintenance and autonomous maintenance is critical. Operators surface issues through their daily checks; the maintenance lead triages those findings into either immediate work or a planned task at the next interval. Without the operator input, planned maintenance becomes blind to what is actually happening on the floor. Without the planned response, operator findings pile up and nothing gets fixed.

Where planned maintenance fits on the shop floor

Picture a 30 person contract manufacturer running CNC, sheet metal, and assembly. The maintenance team is two people. The shop has a binder of preventive tasks from when the equipment was new but has not opened it in two years; everyone is too busy with breakdowns. Average unplanned downtime is around 14 percent across the floor.

A planned maintenance reboot would start by carving out time. Operators take on autonomous tasks (cleaning, light inspection, basic lubrication) so the maintenance team can claw back four to six hours a week per person for scheduled work. The binder gets pulled out, the tasks get refreshed with what the team actually knows about the equipment now, and the schedule moves onto a printed weekly grid posted near the maintenance bench. The first eight weeks are mostly catch up: bearings that should have been changed 1,500 hours ago, hydraulic lines that should have been replaced last year. By the end of the first quarter, unplanned downtime is closer to 8 percent and the schedule is sticking. The maintenance team's day looks different. It is plan, not panic.

Common mistakes with planned maintenance

• Letting reactive work displace planned work. A maintenance team in constant firefight mode never executes the schedule. Carve out planned hours and protect them.
• Keeping the schedule in one person's head. A schedule that lives in memory disappears when that person leaves. Print it, file it, version it.
• Not adjusting intervals. Tasks set up three years ago are no longer calibrated to current usage. Quarterly schedule review prevents drift.
• Owning planned maintenance only in the maintenance department. The production schedule has to make machine time available. Without operations buy in, the team can plan all day and never execute.
• Treating planned maintenance as separate from autonomous maintenance. The two pillars share data. Without the operator findings, planned tasks are guesses.

Planned maintenance and related Lean tools

Planned maintenance is one of the TPM pillars and the structured counterpart to operator owned autonomous maintenance. It usually contains both preventive maintenance (calendar or usage based work) and predictive maintenance (condition based work). It exists in opposition to breakdown maintenance, the unplanned firefighting mode that planned work is designed to replace.