Inputs & Validation

Public industrial input limits

The current public model accepts the following supported ranges.

Input	Supported range
Nominal press size	6–16 in, integer
Configurable billet minimum	100–3000 mm
Configurable billet maximum	100–3000 mm
Table length	10–100 m
Cut length	1000–15000 mm
Exit / extrusion speed	1–100 m/min
Technical dead time	5–30 s
Saw kerf	0 mm, or 3–10 mm

Additional relational checks apply, for example:

• canonical trim_total_per_billet_m must be finite and nonnegative; booleans and numeric strings are rejected;
• any non-null legacy front_scrap_m or multi_billet_front_scrap_m alongside canonical trim is an ambiguity error (including legacy zero); absent/null means unspecified;
• legacy trim values must be nonnegative and strictly less than table length; the canonical total is not directly subjected to that per-pull limit;
• canonical total trim is distributed before geometric feasibility checks; legacy p=2 inputs retain their per-pull meaning, with explicit migration;
• billet minimum cannot exceed billet maximum;
• cut length cannot exceed the available table length;
• container bore must be larger than the actual billet diameter when both are explicitly supplied;
• exits, explicit cuts, requested bars and requested billets must be whole positive integers.

These ranges define the current supported software domain. They should not be interpreted as universal physical limits of the aluminium extrusion industry.

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Numerical behaviour and input validation

PyExtrusion is designed for deterministic software integration.

Public inputs follow these rules:

• numerical values must be finite;
• NaN, positive infinity and negative infinity are rejected;
• numeric strings are not silently converted;
• Python booleans are not accepted as substitute integers;
• structural counts such as exits, bars and billets must be integral;
• JSON input is treated strictly;
• predictable input errors are reported through controlled PyExtrusion errors.

This is particularly important when PyExtrusion is used behind a GUI, web service, ERP or MES integration.

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