What do manufacturing rules cost a sized bracket on FDM, CNC routing, laser cutting and casting?

What it found

The L-bracket of simdesign-bracket is sized for minimum mass under a stress and a deflection limit with and without each process’s rules (tool radius, plate or sheet gauges, minimum walls, draft, an even-section rule), in the same material, so the ratio isolates the rules. Sand casting pays +43% (best of three seeds), driven by its wall-ratio rule rather than draft; CNC routing +24%, from the thinnest plate on the stock list; laser cutting and FDM about nothing, within optimiser noise (three seeds spread over 20%). Re-solved on a fine mesh, every chosen design exceeds its stress limit by 17–26%. Stylised: rule values and materials are assumed, the model is 2D, nothing was built. Exports an STL and DXF profiles.

A figure from its own output

Paper, code and results

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

More in Simulation-first design

• How much does a bolt hole cost a tension plate, and which rule sets its width?Tension plate with a required bolt hole sized under net-section, Kt = 3 and finite-element stress models and per-process hole rules (stylised).
• Does weighting parts by mass change which shop process, and which machine, matters?Does weighting parts by mass change which shop process, and which machine, matters? With a tip load FDM covers 0.30 of parts by count and 0.58 by mass, the laser-versus-CNC order flips, and at budgets 600–800 exhaustive search picks the laser cutter by count but the casting setup by mass (one seed). Stylised, assumed rules and prices, simulated only.
• Do the mass-weighting machine-choice flips of simdesign-coverweight survive across seeds?Do the mass-weighting machine-choice flips of simdesign-coverweight survive across seeds? Over 20 seeds, log flips from the laser cutter (count) to the casting setup (mass) in 20/20 at budgets 600–800, large only at 800, small never; the 1100–1400 flips are near-ties (≤0.26 points). Stylised, assumed rules and prices, simulated only.
• How wide are the budget bands where mass weighting changes the machine choice when prices are uncertain?How wide are the budget bands where mass weighting changes the machine choice when prices are uncertain? With ±20% independent price noise the log flip band widens from budgets 600–800 to 500–1000 but softens at its edges (about one half), and large's single nominal flip at 800 shows up in only 44% of price draws. Stylised, assumed rules and prices, simulated only.
• 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).

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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.