How much do the RepRap closure numbers depend on which parts a shop is judged able to make?
research/selfrep-judgement
How much the RepRap closure numbers depend on which parts a shop is judged able to make (stylised, assumed inputs): buying all optimistic lines cuts mass closure from 22% to 17%; making the motors in-house would add 22 points.
What it found
Flips the make-or-buy judgements behind selfrep-closure. Buying all five optimistic lines (washers, GT2 pulley, MDF bed, brass bushing) cuts the largest shop to 17% mass and 11% cost closure, the printer-alone level, and no single line moves mass closure by more than 2.4 points. Granting a missing capability matters far more: making the NEMA17 motors in-house would add 22 points of mass closure, the 370 mm threaded rods 10. Monte Carlo (judged lines kept with probability 0.5, arguable vitamins granted with 0.1; arbitrary): mass closure 18–35% (5–95%). Stylised; masses and costs are assumed placeholders.
A figure from its own output
Paper, code and results
More in Self-replicating manufacturing
- Does sharing part jobs across printers make a replicating printer shop double faster than one copy per printer?Does sharing part jobs across printers beat one copy per printer (stylised, assumed inputs): a pool serving the oldest copy first doubles in 43.2 h against 51.1 h with no import limit, about half the gap to the fluid 34.7 h; with imports binding all policies agree.
- How many parts should a replicating printer print per plate to double its shop fastest?How many parts per print plate double a replicating printer shop fastest (stylised, assumed inputs): with no changeover one part per plate wins (43.2 h doubling), with 0.25 h per plate four parts (46.4 h), with 0.5 to 1 h eleven parts; pooled fleets stay 7.6 to 15.5% ahead of one copy per printer.
- How much of a RepRap printer can a growing seed shop make itself?Part, mass and cost closure of the RepRap Prusa Mendel (iteration 2) for three seed shops: printer alone makes 18 of 51 part lines (35%), plus router and laser 43%, assumed-mass closure 22%; casting helps only with brass bushings. Mass and cost inputs assumed. Stylised.
- Which machine should a seed shop add next, and does a greedy rule find it?Which machine a printer-only seed shop should add next under a budget: greedy closure-per-price vs exhaustive search; same choice on the real 3-machine instance, optimal in 72–94% of 500 synthetic instances. Machine prices assumed. Stylised.
- How fast does a replicating printer shop grow when its vitamins must be bought?Discrete-event and fluid growth of a replicating printer shop with imported vitamins: doubling time falls roughly as 1/budget until machine time binds (about 53 h in the simulation), failed builds cost about 1/(1-f), and closure helps most when imports bind. All inputs assumed; Lackner and Wendt comparison not done. Stylised.
- When should a replicating shop stop copying itself and start making goods?Optimal split of a replicating printer shop's time between copies and goods: copy flat out, then switch one e-folding time (about 50 h) before the horizon; constant splits get 9–27% of that value, smooth ramps no better. Cash-limited cases switch about 50 h from the end. All inputs assumed. Stylised.
All 34 Self-replicating manufacturing projects →
Other research topics
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.