Worked example
Extrusion scheduling case study: one week across four lines
This illustrative worked example uses representative extrusion orders and the same simulated four-line schedule shown on RunMark's homepage. It is not a customer testimonial, a claim about a named plant, or a promise of guaranteed results.
The purpose is to make the scheduling workflow concrete: start with real line and product constraints, reserve the time that production and changeovers consume, and produce a weekly plan the floor can inspect.
The plant and the week's order mix
The example plant has four lines with different size ranges, downstream equipment, and configured planning rates. Seven runs are due between Wednesday and Friday. The schedule cannot treat those lines as interchangeable.
| Production line | Configured rate | Representative work |
|---|---|---|
| Line 1 · 6–18 in | 1,150 lb/hr | 8 in and 12 in HDPE pipe |
| Line 2 · 2–6 in | 86 ft/min | 4 in PVC conduit and 3 in irrigation tubing |
| Line 3 · Profile | 18 ft/min | Gray PVC extruded profile |
| Line 4 · 1–4 in | 74 ft/min | 2 in PVC conduit and 3 in irrigation tubing |
Constraints the schedule has to honor
- Each product can run only on lines with compatible size range, tooling, and downstream equipment.
- Production time uses the configured product-and-line rate rather than a single plant-wide speed.
- Each line has its own available shift calendar, and two runs cannot occupy the same line at the same time.
- The transition into selected runs reserves 75 minutes for a die-and-resin change, 45 minutes for tooling, or 60 minutes for a color-and-die change.
- Due dates remain visible while the planner evaluates the sequence.
- Order SO-1849 can be split between two eligible lines when that produces a workable plan.
The resulting four-line schedule
The schedule produces seven visible runs. Three modeled changeovers reserve 180 minutes—three hours—that would otherwise be easy to hide inside a spreadsheet note or optimistic run-time estimate.
| Line | Run sequence | Due-date signal |
|---|---|---|
| Line 1 | 75-minute die-and-resin change → HDPE pipe · 8 in SDR 11 → HDPE pipe · 12 in SDR 17 | Thursday, then Friday |
| Line 2 | 45-minute tooling change → PVC conduit · 4 in → 120 reels of 3 in irrigation tubing | Wednesday, then Friday |
| Line 3 | Gray PVC extruded profile with a 60-minute color-and-die change reserved before the run | Thursday |
| Line 4 | PVC conduit · 2 in → 80 reels of 3 in irrigation tubing | Friday |
What changes compared with a flat spreadsheet list
| Planning question | Flat order list | Constraint-aware schedule |
|---|---|---|
| Can this line make the product? | Planner checks from memory or notes | Product-to-line eligibility is part of the scheduling input |
| How long will the run take? | One average or manually copied rate | Rate can differ by product and by line |
| Where is setup time? | Often hidden in a buffer or omitted | Three hours of entered changeover time appears on the schedule |
| Can a large order use two lines? | Planner manually divides quantity and timing | The example splits SO-1849 across Lines 2 and 4 |
| What reaches the floor? | A grid whose rules may be implicit | A shared line-by-line sequence with due dates and visible setup time |
What the example demonstrates
- Seven runs can be evaluated as one connected weekly plan instead of seven independent due dates.
- Line eligibility prevents an apparently open but incompatible line from becoming a false solution.
- The same order can use more than one eligible line when the order is deliberately split.
- Entered changeover minutes consume real capacity before the team commits to the plan.
- Schedule-derived PDF labels can carry the run and unit sequence into the traceability workflow.
What this example does not claim
- It is simulated data, not measured results from a named customer.
- It does not prove that RunMark found the globally lowest possible changeover total.
- It does not model BOM-driven material requirements, purchasing, accounting, or multi-step routings.
- A real schedule is only as reliable as the line calendars, eligibility rules, rates, changeover minutes, quantities, and due dates entered by the plant.
How to run the same pilot with your own orders
- Choose one representative week with real due dates and at least one difficult changeover or line-eligibility decision.
- Enter each production line's available shifts and the products it can actually run.
- Use demonstrated shop-floor rates for each product-and-line combination, starting conservatively where the data is uncertain.
- Enter the transition times that materially affect the week, then import or enter the open orders.
- Build the schedule, review every exception with the planner and floor lead, and correct any input that does not match reality.
Frequently asked questions
Is this an actual RunMark customer case study?
No. It is a transparent, illustrative worked example using representative extrusion constraints and the same simulated schedule shown on RunMark's homepage.
How many production runs are in the example?
Seven runs are placed across four production lines. The schedule includes three entered changeovers totaling 180 minutes.
Why is one order split across two lines?
SO-1849 is divided into 120 reels on Line 2 and 80 reels on Line 4 to demonstrate how a sufficiently large order can be split across eligible lines when the planner chooses that approach.
Does RunMark automatically minimize every changeover?
No. RunMark reserves the entered transition time and considers changeovers while choosing slots, but it does not claim to search every possible sequence for the absolute minimum total.
What information would my plant need for a pilot?
Start with production lines, shift availability, product-to-line eligibility, demonstrated production rates, important changeover times, order quantities, and due dates for one representative week.
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