We'd rather you know the boundary before you buy than discover it after. RASQI is a focused discrete-event simulator for serial and assembly production lines, engineered for accuracy with simplicity. Chasing every feature of a general-purpose platform would make it complex and slow — and still not out-power the specialists. So some things are in, and some are deliberately out of scope. Here's the honest map.
| Configuration / capability | Status | Why / our stance |
|---|---|---|
| What RASQI models | ||
| Serial flow line | Included | Core. |
| Parallel identical machines (M/M/c) — PLC-style dispatch | Included | Each finished part goes to ONE of the parallel machines, chosen the way a real line PLC would — by committed load (buffer + parts already on their way): a starving machine still short of a full cycle is fed first (the one closest to completing a cycle), then a running machine still short of a cycle, then the lowest-load machine; stopped or idle machines only when there's nothing better. Full buffers are skipped; ties go to the shortest conveyor. Net effect: feeding rotates, completing one machine at a time instead of piling parts on one. |
| Synchronized assembly · multi-BOM feeders | Included | The assembly waits when a component line can't keep up — a real merge, not just costing. |
| Finite buffers + blocking & starvation | Included | The core Factory-Physics coupling most spreadsheets miss. |
| 7 statistical distributions (fit to data) | Included | Normal, lognormal, triangular, uniform, exponential, gamma, Weibull — with auto-fit. |
| Breakdowns — MTBF/MTTR, per cycle or per time | Included | Interval and duration are both distributional; failures accrue with usage, not idle time. |
| Scrap & at-station rework | Included | Rework re-runs the cycle where the defect happens — the common case. |
| Setups & multi-product campaigns | Included | Product and material setups; campaign sequencing. |
| Conveyors with transit time | Included | Length ÷ speed delays material and acts as a moving buffer. |
| Batch / container transport between stations | Included | A finite, shared fleet of returnable carts carries parts in batches (capacity, min-load, reorder point / kanban overlap); the cart is the buffer, so transfer-batch size and fleet limits both affect flow — not just one-piece movement. |
| Branched conveyors (fork & merge) | Included | Shared trunk with exclusive branches, fork and merge, with documented modeling recipes. (Mid-trunk accumulation is approximated — see the beta notes below.) |
| Replications · 95% CI · CRN · warm-up | Included | Statistical discipline — a run is not an anecdote. |
| Full-factorial DOE & constraint-elevation study | Included | Up to 3 factors, effects Pareto and optimum — plus an auto-DOE that cuts the constraint's cycle and shows the cascade of gains as the bottleneck moves. |
| Financials — payback · ROI · ROIC · NPV · IRR · EVA | Included | A line decision becomes a financial one, down to value creation vs. cost of capital. |
| Validated vs M/M/1 · Little's Law | Included | Engine checked against closed-form queueing theory (~2%). |
| Runs in the browser — no specialist, no install | Included | The whole point: anyone who knows the line can run it. |
| WIP cap / CONWIP (pull) — "Max WIP" | Included | A line-level WIP cap: a new part is released only while WIP is below the cap (pull). Per-stage kanban stays out of scope. |
| Shared / mobile operators with walk time | Included | One operator serves several stations and walks between them at a set speed — the machine waits for them to arrive, and walking is counted as waste, so tightening the layout shows a real gain. |
| Shift calendar & break stops | Included | The whole line pauses between shifts and during breaks (real availability), separate from the labor-cost side. |
| Sequence-dependent setup (from→to) | Included | An optional sparse from→to changeover matrix, consulted when a station switches product in a campaign. |
| Accumulating conveyor | Included | Set a product size and each belt gets a real capacity (length ÷ size); parts accumulate when blocked — toggle synchronous vs accumulating. |
| Advanced stochastic reliability (optional) | Included | An optional engine adds Weibull time-to-failure, micro-stops, imperfect repair and wear/learning curves — off by default, labeled experimental. |
| Flow view over a plant photo (digital-twin layout) | Included | Lay your stations over a plant photo or drawing, draw the conveyor paths, and watch per-product markers, buffer queues and the live bottleneck. |
| Automated diagnosis + executive report | Included | Ranked findings with cause, $/year value and Lean/TOC/6σ/TPM actions; a print-ready one-page executive summary; and a Check-line configuration validator. |
| Deliberately out of scope | ||
| Queue priority (non-FIFO · SPT / EDD) | FIFO | It doesn't move throughput, OEE or $/year — any work-conserving discipline yields the same throughput and mean WIP (Little's Law). It only changes per-order lateness, a scheduling concern outside our money-first purpose. |
| Rework routed to another station / repair area | At-station | At-station rework (the common case) is fully modeled and hits the bottleneck correctly. Routing defects back upstream is a rarer topology; leaving it out keeps the model simple without changing the throughput logic where rework actually bites. |
| Re-entrant flows (loops) | Out of scope | Semiconductor, PCB and plating lines are a specialist vertical; supporting a part that revisits a station would complicate the router for every other user. |
| Job-shop / arbitrary routing | Out of scope | A different tool class. RASQI is a flow-line simulator; arbitrary routing belongs to general-purpose platforms and would trade away the simplicity that lets anyone run it. |
| Disassembly / split (1 → N) | Out of scope | Not our market (meat, primary cutting, recycling). It inverts the part model and adds user-facing complexity for a vertical we don't target. |
| Probabilistic / conditional routing | Out of scope | Rare in the serial and assembly SME lines we serve; branch logic would complicate modeling for the majority who don't need it. |
| AGV fleets / detailed material handling | Out of scope | We model the material handling that actually drives flow — conveyor transit time and parts moving between stations in batches (containers). What we leave out is full AGV-fleet dispatch and routing: a heavy modeling layer that's uncommon in the SME lines we serve. |
| Secondary constrained resources (tools / fixtures / molds) | Out of scope | Out of scope to preserve simplicity; multi-cavity capacity covers the common case. |
Current limitations that aren't design decisions — the honest state of the beta, being worked on.
No accounts, cloud storage or multi-user yet — your lines, products and backups live in your browser. Portability is via JSON export/import.
Interface and the built-in 26-section manual in English and Português (beta); Español · 中文 · Русский planned.
Access is behind a one-time email PIN, and builds carry an expiry date; a running copy auto-detects a newer build and offers to update.
A shared conveyor trunk is modeled as the receiver's input buffer — exact for capacity and blocking; mid-trunk accumulation and junction re-routing aren't physically modeled.
RASQI runs in a browser tab; there's no public API or headless batch runner yet.
Answer 8 short questions about how material flows through your line and get an honest verdict — RASQI is a flow-line simulator, not a fit for every layout, and we'll tell you straight.
Check compatibility →Between the OEE spreadsheet and the $15k general-purpose simulators: the rigor of Factory Physics — finite buffers, real variability, blocking, 95% confidence intervals, validation vs queueing theory — and a money-first answer, for serial and assembly SME lines, at a fraction of the price and with no specialist. It gives up job-shop routing, re-entrant flows and AGV-level material handling on purpose, so it stays simple enough for anyone who knows the line.