Kanban WIP‑Limit Lab — CONWIP cards, flow time, and service
💡
Idea:
WIP limits trade off throughput vs. lead time. Use cards to hit service targets with minimal WIP.
Arrival rate λ (orders/hr)
12
Service rate μ (orders/hr)
14
Arrival variability c
a
(0–1)
0.30
Service variability c
s
(0–1)
0.20
Kanban cards (WIP cap K)
20
SLA target (hrs, 90th pct)
2.0
Holding cost ($/order·hr)
0.50
Late penalty ($/SLA miss)
20
Revenue per order ($)
40
Tight K (fast LT)
Generous K (high TP)
High variability
Balanced to SLA
Reset
Instructor notes
Show Little’s Law: WIP ≈ TH × Lead. Increase K → WIP↑ → Lead↑, even if TH barely changes.
Use the 90th‑percentile SLA line to tune K. Aim for ≥90% on‑time with minimal WIP.
Discuss pull (CONWIP) vs. push: arrival backlog grows if λ>TH and K is tight.
Arrivals
Completions
WIP level
Throughput
–
Avg WIP
–
Avg Lead (hr)
–
P90 Lead (hr)
–
On‑time (≤SLA)
–
Revenue (H)
–
Cost (H)
–
Profit / Hr
–
Little’s Law check: Lead ≈ WIP / TH. Pull with K cards caps WIP → caps lead time.
Self‑tests
— quick checks
Running…