SIM05 · 起源 / 把停机作业搬到机外SIM05 · Origin / Move setup work outside machine downtime
换模慢，就只能一直做大批量吗？Does a slow changeover force you into large batches?
年，新乡重夫把丰田一台千吨压机的换模从 4 小时压到 3 分钟。关键不是催人快干，而是先分清：机器非停不可才能做的是内部作业，机器不停也能准备的是外部作业。把 40 秒外部作业提前做好，真正的换模停机就从 60 秒降到 20 秒。In , Shigeo Shingo cut changeover on a 1,000-ton Toyota press from four hours to three minutes. The breakthrough was not asking people to hurry. It was separating internal setup, which requires the machine to stop, from external setup, which can be prepared while the machine is still running. Move 40 seconds of external work out of downtime and the actual stop falls from 60 seconds to 20.
🎬 盯住灰色机床：停机换模时一件也不出🎬 Watch the gray machine: output stops completely during changeover
0
0s
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A 蓝件A · blue
B 橙件B · orange
灰=换模停机Gray = down for changeover
💡 跑完看数据：换模越短，小批量越敢切💡 Run it, then read the numbers: shorter changeover makes small batches viable
全部由同一 DES 的 stats() 计算Every value comes from the same DES stats()| 批量Batch | 换模 60s60s changeover | 换模 20s20s changeover | 多出Gain |
|---|---|---|---|
| B=2 | — | — | — |
| B=4 | — | — | — |
| B=8 | — | — | — |
🎯 现场规则🎯 Shop-floor rule
先把换模变快，再把批量降下来；别拿大批量替慢换模打掩护。Shorten changeover first, then bring the batch down. Do not use large lots to hide slow setup.
⚠ 常见误区⚠ Common mistakes
✗ 换模慢，所以批量要大✗ Slow changeover means the batch must stay large
✓ 先把换模变快，批量自然能变小。✓ Shorten changeover first; smaller batches then become practical.
✗ 换模就是换那一下模具✗ Changeover is only the moment the die is swapped
✓ 从上一件合格品到下一件合格品，才是完整换模时间。✓ Measure from the last good part of the old run to the first good part of the next.
✗ 内外作业分不清✗ Internal and external setup are hard to tell apart
✓ 机器不停也能干的，都算外部作业。✓ If it can be done while the machine runs, it is external setup.