Throughput

Throughput can be measured at multiple levels: individual workstation, production line, manufacturing cell, or entire factory. At each level, the calculation is straightforward: Throughput = Good units produced / Time period. For meaningful analysis, measure throughput consistently across shifts and days to identify trends, patterns, and anomalies. Important nuances include: count only units that pass final quality inspection (not units produced before rework), measure over consistent time periods (comparing an 8-hour shift to a 12-hour shift requires normalizing to hourly rates), and distinguish between gross throughput (including rework) and net throughput (first-pass good units only). For mixed-model production lines, throughput can be expressed in standard hours produced (each product weighted by its standard cycle time) to enable meaningful comparison across different product mixes. Track throughput alongside OEE to understand whether throughput changes are driven by availability, performance, or quality shifts.

Throughput is limited by the bottleneck — the process step with the lowest capacity in the production system. Even if every other station can produce 100 units per hour, if one station can only handle 60 units per hour, system throughput is capped at 60. Beyond the bottleneck constraint, several factors reduce throughput below its potential: Unplanned downtime from equipment breakdowns halts production entirely. Long changeovers consume time that could be producing units. Quality defects reduce net throughput even if gross output is high. Material shortages cause starvation at workstations that are ready to produce. Absenteeism reduces throughput on manual or semi-automated lines. Schedule instability causes confusion, incorrect setups, and lost time. Each of these factors can be addressed through targeted improvement: TPM for downtime, SMED for changeovers, quality at the source for defects, better scheduling for material flow and schedule stability. The Theory of Constraints provides a systematic approach to prioritizing these improvements based on their impact on the bottleneck.

Production scheduling significantly impacts throughput through several mechanisms. Bottleneck utilization: the schedule should ensure the bottleneck is never idle — schedule a buffer of work ahead of the bottleneck so it always has the next job ready. Changeover optimization: sequence products to minimize changeover time on the bottleneck (e.g., scheduling from light to dark colors in painting, or from small to large sizes in machining). Balanced loading: distribute work evenly across parallel resources to prevent some from being overloaded while others are idle. Preventive maintenance scheduling: schedule maintenance during low-demand periods rather than during peak production. In LinePlanner, these principles translate to practical scheduling actions: identify which production lines are constraints, prioritize their scheduling, minimize changeovers on those lines through intelligent product sequencing, and use the visual calendar to verify that the bottleneck has continuous work across every shift. The result is measurably higher throughput from the same equipment and workforce.