How much imported material can recycling save a self-replicating printer shop?

research/selfrep-materials

Mass and energy balance of plastic and aluminium recycling for one RepRap copy (stylised, assumed process parameters): vitamins stay about 75% of imported mass, recycling the shop's own scrap cuts imports a median 3%, and only retired-machine plastic changes the plastic import much.

10 tests

What it found

Builds on the selfrep-closure part list. A stylised steady-state mass and energy balance for building one more RepRap Prusa Mendel, with shredding and re-extrusion of plastic and remelting of aluminium offcuts. With assumed process parameters, vitamins stay about 75% of imported mass for the largest shop (82% for the printer alone), and recycling the shop’s own scrap cuts imports by a median 3% (5–95% over parameter draws: 1–6%). Only plastic from retired machines changes the filament import much, and then the assumed recycled-share cap decides the result. Limitations: every yield, loss and energy figure is an assumption, recycling machines are not counted, and recycled-plastic quality is not modelled.

A figure from its own output

Figure produced by research/selfrep-materials: figure — selfrep-materials/experiments/figure.png, written by the project's own experiment code.

Paper, code and results

More in Self-replicating manufacturing

How many printer copies does it take for a shop's recycling machines to repay their own imports?Payback of recycling machines with their own assumed part lists (stylised): about 100 printer copies on the shop's own scrap, 12–31 if retired machines' plastic is recycled.
Does pricing a shop’s imports, instead of weighing them, change when its recycling machines repay themselves?Recycler payback priced instead of weighed (stylised, assumed prices): plastic pair 98–111 printer copies on own scrap, furnace 203, 10–26 with retired plastic.
What is the closed form of a replicating shop’s smooth switch from copying to goods, and does it match dynamic programming?Closed-form optimal copy share for a replicating printer shop with a saturating goods market (Pontryagin singular arc: goods output grows linearly, last 1/k hours all goods); earns 99.96–100% of the dynamic-programming policy's value. Necessary conditions only; all inputs assumed. Stylised.
When the goods market saturates, does a replicating shop’s bang-bang switch turn smooth?Reinvestment of a replicating printer shop when the goods market saturates, checked by dynamic programming: bang-bang is optimal with linear revenue, but with market capacity below about 10^4 machine-hours per hour the optimum ramps the copy share down over 90–300 h and bang-bang loses 4.5–7%. All inputs assumed. Stylised.
What fleet can a replicating printer shop sustain when its machines wear out?Fleet a replicating printer shop sustains when machines wear out (stylised, assumed inputs): short-lived machines die out from one seed; recycling gains need a correction for builds cut short.
Can an exactly solvable birth-death chain explain why short-lived printer fleets die out?Exact mean extinction time of a wearing-out printer fleet as a birth-death chain (stylised, assumed inputs): explains the die-outs in kind, within about 35% only after a post-hoc fix.

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Other research topics

Proper scoring & elicitation28 Effort & peer prediction9 Verification games & slashing19 Detection & tolerances14 Markets as routers13 Prediction-market design9 Paying contributors8 Decentralised training systems23 Digital twins & sim-to-real164 LLM chip design loops40 Robot manufacturing loops53 Ambient AI assistant46 Self-replicating manufacturing34 Simulation-first design64 Engineered clothing45 Task-specific AI accelerators40 Algorithmic chip-design loops42 Open-source purpose-built robots44 The software-engineering loop43 Adversarial human imitation41 Open-source residential construction41 Autonomous multi-angle capture34 Sensing, imaging and 3D31 Energy supply and dense energy storage39 Robot societies among people31 Agentic co-design of low-cost robots27 Laundry-hanging robots25 Machine learning on qualitative data23 Robots on the building site27 Civilizations & group psychology1 History & 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.