Calculation purpose and formula
Baseline hours = printers × hours/day × days. Lost hours = baseline × downtime rate. Lost cycles = lost hours ÷ cycle time. Lost units = lost cycles × parts per cycle.
Interpret the result
Use it to put an operational buffer around a production plan and to show the economic effect of recurring repairs, failed starts, or unplanned holds.
Worked example
Ten printers run 20 hours/day for 30 days create 6,000 baseline hours. At 15% downtime, the loss is 900 hours, or about 180 five-hour cycles and 360 two-part cycles.
Assumptions and limitations
Downtime is spread across the schedule and the average cycle represents the mix of work. Lost cycles and units are approximate; a downtime event that interrupts a long job can have a different outcome.
Common planning mistake
Do not subtract downtime from yield. Downtime reduces available time; yield describes how much attempted output becomes good output.