How wide are the budget bands where mass weighting changes the machine choice when prices are uncertain?

What it found

Follow-up to simdesign-flipseeds, whose count-vs-mass machine-choice flips sat exactly on thresholds set by assumed round prices. Machine prices (800, 600, 300) are scaled by independent U(1−s, 1+s) factors, 400 draws over 8 samples of 20 000 sampled brackets. For family log the flip band widens from budgets 600–800 to 500–1000, but its edges soften to about one half; large's single nominal flip at 800 appears in 44% of draws at s = 0.2 and spills to 700 and 900; small never flips. Near-tie flips never lose more than 0.5 points. Stylised: assumed prices and rules, uniform independent noise, arbitrary 0.5-point materiality threshold.

A figure from its own output

Paper, code and results

• README and method
• Experiments and results
• Code
• Tests

More in Simulation-first design

• Which share of a bracket family can each shop process make, and which machine should a shop add next?Share of a sampled bracket family each shop process can make under the simdesign-dfm rules: geometry alone adds nothing beyond FDM (negative), with a tip-load requirement the processes separate (FDM alone 30%, +casting +laser 41%) and the best next machine depends on budget and part size, where greedy sometimes loses 1–2 points to exhaustive search (stylised, assumed rules).
• Does a mesh-aware stress margin change what manufacturing rules cost a sized bracket?Re-runs simdesign-dfm with a stress knock-down and a finer search mesh, checking designs at h = 0.7 mm: the price ordering (casting ~1.4, CNC ~1.23, FDM 1.0) survives the mesh, the laser-cutting price does not (1.01–1.22, noisy), and a 1.3 margin leaves designs at 0.88–1.02 of the limit (stylised, assumed rule values).
• Does a patch-averaged stress converge under mesh refinement where the peak element stress does not?Compares peak and patch-averaged von Mises stress under mesh refinement on the L-bracket: the peak rises 18–41% from h = 2.5 to 0.55 mm while a 3 mm patch average moves 1–6%, but it reads only 0.45–0.69 of the peak so needs its own limit (stylised, assumed values).
• Does a patch-averaged stress change what manufacturing rules cost a sized bracket?Repeats the process-rule bracket search with a 3 mm patch-averaged stress instead of the peak: the ordering of mass prices (casting > CNC > laser ≈ FDM) holds, the laser price spread across seeds shrinks from 0.16 to under 0.005, and designs overshoot their limit by 2–12% on a fine mesh against 19–34% for the peak (stylised, assumed values, uncalibrated limit).
• Is the shrinking laser-cutting price scatter under the patch stress caused by the near-sharp fillet floor?Tests whether a near-sharp fillet floor explains the laser-cutting price scatter seen in simdesign-patchsearch: it does not (peak-stress designs already use 7.6–14.3 mm fillets, so floors of 0.2 and 1 mm give identical designs); the patch-stress price is steady (sd 0.006–0.011) at every floor, and the cause of the peak scatter is not identified (negative, five seeds, stylised).
• Where does the peak-stress price scatter of laser-cutting rules come from?Follow-up to simdesign-filletfloor: the peak-stress price scatter of laser-cutting rules (sd 0.063) sits in the 2 mm gauge sub-search, not the fillet floor; a four-times search budget cuts it to 0.025 but not monotonically, so several nearby optima are plausible but not shown (five seeds, stylised).

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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.