Which resource limits a small robot-printer-inspection cell, and does the busiest one tell you what to upgrade?
research/robofab-cell
Discrete-event twin of an arm, printers and an inspection station: printers have the highest utilisation at every size, yet at 6 printers an extra arm saves 10.9 min vs 2.3 for an extra inspection station; dispatch rules trade makespan for flow time; a mean-value twin is optimistic. Stylised, illustrative parameters.
What it found
A discrete-event twin of one arm, 1–8 printers and one inspection station (30 parts, 200 replications, illustrative times). Printers have the highest utilisation at every size, yet at 6 printers an extra arm saves 10.9 min of makespan against 2.3 for an extra inspection station, because a printer is held while it waits for the arm. Dispatch rules trade makespan for mean flow time as textbook scheduling predicts, and a mean-value twin underestimates the stochastic makespan by 1–133 min. Stylised; parameters are invented, not measured.
A figure from its own output
Paper, code and results
More in Robot manufacturing loops
- Where is the bottleneck of an arm, printer and inspection cell?Discrete-event twin of an arm, 3D printers and an inspection station: a utilisation bound names the bottleneck (printers to 10, the arm from 12, ~12.7 good parts/h) and the simulation sits 10–11% below it near the switch; a 25% faster arm lifts 11.34 to 12.68 parts/h at 12 printers, a second inspector nothing (stylised).
- Does exact queueing analysis predict a robot-printer cell's throughput better than a utilisation bound?Exact mean value analysis of the arm, printers and inspection network against a discrete-event twin: a few per cent off for exponential times, up to 11% low for less variable ones, better than the utilisation bound in most real-semantics rows, and it overshoots saturation at high work in process. Stylised.
- Where does exact queueing analysis of a robot-printer cell stop working?Coefficient-of-variation sweep and a measured printer stall share for the arm-printer-inspection queueing model: MVA's error crosses zero near cv 1 while the utilisation bound stays high, and held-printer capacity times (1 − stall) reproduces the saturated rate at 4 and 8 printers. Stylised.
- Is a print-failure camera worth it in a robot-arm 3D-printer cell?Is a print-failure camera worth it in a robot-arm printer cell? Blind printing against abort-on-failure: +6 to 10% good parts per hour at 2 to 10 printers, none once the arm limits the cell; break-even false-stop rate. Stylised.
- Where should a print-failure detector's alarm threshold go in a robot-arm 3D-printer cell?Where should a print-failure detector's alarm threshold go in a robot-arm printer cell? A look every 2 min makes a z = 2 threshold 19 to 23% worse than blind printing; the best z is 3 to 3.5, worth +6% (d' = 2) to +11% (d' = 4). Stylised.
- Where does a flow-equivalent-server decomposition of a robot-printer cell go wrong as the inspector speeds up or slows down?Where does the flow-equivalent-server decomposition of a robot-printer cell err as the inspector speed varies? Error is 0 for fast and slow inspectors but peaks at −2% to −5% just below the knee where inspector and subsystem rates match, ten times the earlier 0.3% mean. Stylised.
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Proper scoring & elicitation28Effort & peer prediction9Verification games & slashing19Detection & tolerances14Markets as routers13Prediction-market design9Paying contributors8Decentralised training systems23Digital twins & sim-to-real164LLM chip design loops40Robot manufacturing loops53Ambient AI assistant46Self-replicating manufacturing34Simulation-first design64Engineered clothing45Task-specific AI accelerators40Algorithmic chip-design loops42Open-source purpose-built robots44The software-engineering loop43Adversarial human imitation41Open-source residential construction41Autonomous multi-angle capture34Sensing, imaging and 3D31Energy supply and dense energy storage39Robot societies among people31Agentic co-design of low-cost robots27Laundry-hanging robots25Machine learning on qualitative data23Robots on the building site27Civilizations & group psychology1History & human sciences1
Produced with AI assistance (Claude). Results are from the code in this repository and are simulated or stylised unless the abstract says otherwise; nothing here implies affiliation with or endorsement by any lab, researcher or company cited. MIT licensed.