This page explains how to lay out a maintenance schedule, listing what gets checked and how often, and calculate its yearly cost by formula. This matters to a production manager who wrote a schedule but never checks whether it is followed, and to a factory owner who wants a maintenance budget that reflects reality.
Delta Garments, the export factory used throughout this course, shares one illustrative machine across an export order and a domestic order, a hybrid use this lesson uses to show a schedule's structure does not change with who the output goes to. Karim, its production manager, wrote a schedule calling for a monthly visit, but has to check whether the floor team is actually following it.
Without this skill, a schedule exists on paper while nobody tracks whether its cost matches what the factory really spends, or how often visits really happen. A schedule that has quietly drifted from its written interval looks the same as a well-run one, while the machine's real breakdown risk rises unnoticed. This lesson gives you the method for tracked, formula-driven cost, and for catching drift before it becomes a breakdown.
You need: lesson 6.2's preventive-versus-breakdown comparison is useful background, since this lesson's schedule produces the preventive-maintenance figure that comparison uses.
By the end of this lesson you can:
Not covered here: calculating a new machine's payback period (lesson 6.1), comparing preventive and breakdown maintenance cost for a machine already owned (lesson 6.2), and combining an old machine's rising maintenance cost with a new machine's payback period to decide whether to replace it (lesson 6.4).
| Term | Meaning |
|---|---|
| Preventive maintenance | Scheduled inspection and parts replacement done before a machine breaks down, on a fixed timetable. |
| Breakdown maintenance | Repair work done only after a machine has already stopped working, usually more costly than preventive maintenance. |
| Downtime cost | The value of production lost while a machine is stopped, whether for a scheduled visit or an unplanned breakdown. |
| Payback period | The time it takes for a machine's total monthly savings to add up to its total investment cost. |
| Depreciation | Spreading a machine's purchase cost over its useful working life instead of counting it all in the year it was bought. |
A maintenance schedule lists every scheduled task with its own interval and its own cost. A single task's yearly cost is calculated as its number of visits per year multiplied by its cost per visit, never typed as one number. A schedule's total scheduled cost sums every task's yearly cost. A schedule that is never checked against what the factory actually spends, or how often visits actually happen, cannot tell anyone whether it is being followed or quietly skipped.
*A single task's yearly cost multiplies how often it happens by what each visit costs. Twelve monthly visits at USD 20 each give USD 240 a year, the figure this lesson traces back to its own schedule.*
What you meet in real life| What can differ | The shapes you meet | Why it matters |
|---|---|---|
| A schedule with no cost tracking | A maintenance calendar exists, listing what should happen and when, but nobody records what each visit actually cost. | The factory cannot tell whether the schedule is worth its price or being skipped to save money. |
| A schedule with tracked, formula-driven cost | Each task's interval and per-visit cost are entered once, and the yearly cost is calculated by formula, matching or explaining any difference from a separate comparison. | Shows plainly whether the schedule's real cost matches what was planned. |
| A schedule that drifts from what actually happens | The written schedule says monthly, but the floor only manages it every six weeks. | The tracked cost should reflect what is actually done, not what was planned, or any comparison built on it becomes meaningless. |
| Different machines needing different intervals | A fusing press and an automated cutting machine do not need the same maintenance interval. | The schedule structure is the same, but each machine's own interval and cost are entered separately. |
| A machine used only for export production | A machine dedicated to one export order's deadline has its maintenance timed around that order's own delivery pressure. | The schedule method does not change, but the cost of a missed interval is judged against a specific buyer's date. |
| A hybrid machine shared across export and domestic work | A machine running both an export order and a domestic order cannot be taken offline for maintenance without affecting both. | The same schedule and cost-tracking method applies, but a missed maintenance window now risks two different deliveries at once. |
Delta Garments runs its illustrative machine across two kinds of work: an export order for its usual export buyer, and a domestic order it also produces on the same equipment, a hybrid use of one machine. Karim, the production manager, writes a maintenance schedule with two illustrative tasks: a monthly scheduled visit at USD 20 (illustrative) per visit, 12 times a year, and a quarterly parts-replacement visit at USD 40 (illustrative) per visit, 4 times a year. These are the same two components lesson 6.2 used as the preventive-maintenance total, USD 240 and USD 160, and this lesson shows exactly where those two numbers come from.
Using the workbook's own formulas, each task's yearly cost multiplies its interval by its per-visit cost, and the schedule's total sums both tasks.
A common mistake is treating a written schedule as complete once it exists on paper, without checking whether the floor is actually following its stated intervals. A schedule that looks complete but is quietly being skipped, to save short-term time or cash, will not show up as a problem until a breakdown happens, by which point the factory has already lost the preventive-maintenance saving it thought it had.
This lesson is about writing down exactly what maintenance work should happen and when, then working out what that plan actually costs in a year. Multiply how often each task happens by what one visit of that task costs, and add all the tasks together to get the year's total. That total only means something if the schedule is actually being followed. If a machine is supposed to get a monthly check but the floor only manages one every six weeks, the sheet's cost figure is describing a plan, not reality, and the real risk of a breakdown is higher than the unchanged, reassuring number on the sheet suggests.
Karim, the production manager at Delta Garments, wrote a maintenance schedule for the illustrative machine shared between an export order and a domestic order.
The note Karim finds when he checks the floor log against the schedule sheet:
Does the schedule's calculated yearly cost of USD 240 still describe what is actually happening on the floor? Decide before opening the answer.
No. The schedule sheet still assumes an interval the floor is no longer following.
First fact. If visits are actually happening every six weeks instead of monthly, the real number of visits is closer to 8 or 9 a year, not 12, so the real tracked cost is lower than USD 240 (illustrative).
Second fact. More importantly, the machine is now going longer between checks than the schedule assumes, which raises its breakdown risk even though the cost sheet still shows the original, unchanged figure.
The formula is only as accurate as the interval entered into it; a formula calculating the wrong interval is still wrong. Karim needs to update the schedule sheet's interval to match the floor's real practice, and separately decide whether stretching to six weeks is an acceptable risk or a drift that should be corrected back to monthly, given that both an export and a domestic delivery now depend on this one machine.
Framed qualitatively, since the specific dollar figures in this course are illustrative teaching numbers, not fixed facts: a maintenance schedule that has drifted from its written interval, while its cost sheet still reports the original planned figure, hides a rising breakdown risk behind an unchanged, reassuring-looking number. On a machine shared between an export order and a domestic order, a breakdown from a missed maintenance window can delay two different deliveries at once, a cost this lesson avoids by insisting the schedule's tracked interval match what is actually done on the floor, not what was originally planned.
Open the Machine investment payback calculator and go to its "Maintenance cost" sheet. The illustrative preventive-maintenance total of USD 400 a year traces back to this lesson's own schedule: 12 monthly visits at USD 20 each, plus 4 quarterly visits at USD 40 each. In the "Your machine" columns, enter your own equipment's tasks, their real intervals, and their per-visit costs, and check the resulting total against what your factory actually spends. Download link: `templates/T08-C06-machine-investment-payback-calculator.xlsx`.
1. Why must a maintenance task's yearly cost be calculated as interval times cost per visit, rather than typed as a single number?
2. In the illustrative example, what is the yearly cost of a monthly visit at USD 20 per visit?
3. If a factory's floor team stretches a monthly schedule to every six weeks without updating the schedule sheet, what happens?
| EN | AR | FR | TR | Meaning |
|---|---|---|---|---|
| Payback period | فترة استرداد الاستثمار | Délai de récupération | Geri ödeme süresi | The time it takes for a machine's total monthly savings to add up to its total investment cost. |
| Preventive maintenance | الصيانة الوقائية | Maintenance préventive | Önleyici bakım | Scheduled inspection and parts replacement done before a machine breaks down, on a fixed timetable. |
| Breakdown maintenance | صيانة العطل | Maintenance corrective | Arıza bakımı | Repair work done only after a machine has already stopped working, usually more costly than preventive maintenance. |
| Downtime cost | تكلفة وقت التوقف | Coût des temps d'arrêt | Duruş maliyeti | The value of production lost while a machine is stopped, whether for a scheduled visit or an unplanned breakdown. |
| Depreciation | الإهلاك | Amortissement | Amortisman | Spreading a machine's purchase cost over its useful working life instead of counting it all in the year it was bought. |
You now know how to build a maintenance schedule and check that its tracked cost matches what is actually happening on the floor. The final lesson combines a new machine's payback period with an old machine's avoidable maintenance cost to decide, by calculation, whether replacing it now is worth the investment. Back to the course map