Calculate a sequence of production orders

PyExtrusion can calculate a user-supplied list of production orders in sequence.

This feature is intentionally simple and deterministic:

You supply the order. PyExtrusion returns the same order calculated in line.

It does not decide what should run first.

Create production orders

from pyextrusion import ProductionOrder, PlanningRequest

orders = [
    ProductionOrder(
        "OF-001",
        case_a,
        PlanningRequest.bars(300),
    ),
    ProductionOrder(
        "OF-002",
        case_b,
        PlanningRequest.billets(20),
    ),
    ProductionOrder(
        "OF-003",
        case_c,
        PlanningRequest.kg(2500),
    ),
]

Calculate the sequence

from pyextrusion import calculate_production_sequence

sequence = calculate_production_sequence(
    press,
    orders,
)

What PyExtrusion does

For each order it:

1. calculates the order using the normal planning engine;
2. stores its technical press duration;
3. starts the next supplied order immediately after the previous calculated order;
4. accumulates totals.

Useful outputs include:

sequence.total_planned_billets
sequence.total_planned_bars
sequence.total_planned_good_kg
sequence.total_scrap_kg
sequence.total_press_time_min
sequence.all_orders_fulfilled
sequence.unresolved_order_ids

Per order:

sequence.orders[0].order_id
sequence.orders[0].duration_min
sequence.orders[0].cumulative_start_min
sequence.orders[0].cumulative_end_min
sequence.orders[0].planning

Optional theoretical clock time

You can provide a starting date/time:

from datetime import datetime

sequence = calculate_production_sequence(
    press,
    orders,
    start_at=datetime(2026, 9, 7, 5, 0),
)

PyExtrusion can then expose theoretical clock timestamps for each order.

These timestamps are not an industrial schedule. They assume continuous technical press time.

No setup or waiting time is invented

PyExtrusion does not insert time for:

• die change;
• die caustic cleaning / soda treatment;
• die correction;
• die heating;
• billet waiting;
• operator breaks;
• shift changes;
• maintenance;
• plant stoppages.

This is deliberate. Such events can vary from minutes to hours or days and cannot be safely guessed from the information available to the calculation engine.

No automatic reordering

If you send:

OF-001
OF-002
OF-003

PyExtrusion returns the sequence in exactly that order.

It does not move OF-003 ahead of OF-001, even if another ordering might appear faster.

Quantity request restriction

Sequence orders should represent production quantities. Use:

• bars;
• kg;
• metres;
• billets.

Time-window requests (minutes, hours) are intended for standalone capacity calculations, not as normal production orders inside a sequence.

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