同样三道工序，为什么单件流先交货？Same three operations — why does one-piece flow deliver first?
年，亨利·福特在海兰帕克让汽车沿移动装配线经过工人；到 年前后，丰田的大野耐一面对小市场、多车型的真实现场，把连续移动推进成“单件流”：每做完一件就马上交给下一道工序。下面让相同设备、相同 8 秒节拍、相同 12 件订单，只改变传递批量。 In , Henry Ford's Highland Park line moved cars past workers. Around , Taiichi Ohno faced Toyota's real constraint—a small market demanding many models—and pushed continuous movement toward “one-piece flow”: hand off each part as soon as it is finished. Below, both lines use the same equipment, the same 8-second cycle, and the same 12-part order. Only the transfer batch changes.
💡 跑完看数据：差距全在等待上💡 Run it, then read the numbers: the gap is all waiting
赛后由两线 stats() 自动填充Auto-filled from both lines' stats() after the race| 指标Metric | 批量流Batch flow | 单件流One-piece flow |
|---|---|---|
| 首件产出First piece out | — | — |
| 全部完成All 12 complete | — | — |
| 最大 WIPMaximum WIP | — | — |
Little 定律：WIP = 产出率 × 流动时间。批量不改变每站动作，却把更多时间变成排队。打开 F49 推导 → Little's Law: WIP = throughput × flow time. Batching changes no operation, yet converts more elapsed time into queueing. Open the F49 derivation →
批量攒得越多，客户等得越久。The bigger the batch, the longer the customer waits.