Production Scheduling for Flexible Packaging Converting

This guide is for production planners and operations managers at mid-market flexible packaging converters who want a practical, model-based approach to scheduling multi-stage print-to-pouch production. It shows how to configure Schantt for the four-stage converting process — printing, lamination, slitting, and pouching — with parallel machines, sequence-dependent changeovers, divergent rollstock-versus-pouch routing, and 24-hour curing holds.

This guide follows a fictional composite company built from industry research on flexible packaging converting; all names, parameters, and figures are illustrative.

Industry context

Flexible packaging converting — the process of turning raw film, foil, and paper substrates into printed laminate rolls or finished pouches — is one of the most scheduling-intensive production environments in mid-market manufacturing. Converters operate at the intersection of long material lead times, rapidly shifting customer orders, and high fixed-capital equipment. A typical mid-market converter employs 50 to 200 people and manages 200 to over 1,000 active SKUs, with a planning team of one to three people working across four sequential production stages.

The pressroom is where the scheduling pressure starts. Printing presses — flexographic and gravure — run at 150 to 600 metres per minute, but changeovers between jobs consume 10 to 25 percent of available press time. A same-ink-family colour change takes 30 to 60 minutes; a full chemistry change (solvent to water-based, or dark to light) can take 90 minutes or more. With two to five presses, a converter might run 30 to 60 print jobs per week, of which 15 to 25 percent arrive as rushes — disrupting any carefully built sequence. The challenge is compounded downstream: lamination (one to three machines) adds a second pass with its own adhesive-system changeovers, slitting (two to five machines) turns wide reels into finished rolls at 300 to 800 metres per minute, and pouching (three to eight machines) converts slit rolls into stand-up pouches, three-side seal bags, or spouted pouches at 40 to 200 pouches per minute. The curing hold between lamination and slitting introduces a 12- to 48-hour passive delay that is invisible in most planning tools. Every stage has its own shift pattern, its own changeover discipline, and its own bottleneck dynamics.

Pacific Flex Packaging runs approximately 150 people at a 5,500 square metre facility, making three product classes across four production stages, scheduled by a two-person planning team.

Process overview

flowchart LR
    P["Printing"] -->|"30 min"| L["Lamination"]
    L["Lamination"] -->|"1,440 min<br/>(24 h cure)"| S["Slitting"]
    S["Slitting"] -->|"60 min"| D["Pouching"]

Substrate travels through up to four production stages — Printing, Lamination, Slitting, and Pouching — with curing between Lamination and Slitting modelled as a wall-clock transfer time.

Unprinted rollstock skips Printing entirely, entering at Lamination via a bridging transfer time. Rollstock classes end at Slitting; pouch classes continue through Pouching.

Scheduling challenges and how Schantt handles them

The scheduling problem at a flexible packaging converter is driven by customer orders — a mix of repeat business, new designs, and rush requests — that arrive as jobs for specific print-and-pouch specifications. Each job enters the schedule as a product and quantity at the stage where its product class enters production. The optimizer in Schantt minimises total production time (the overall span across all jobs) and schedules forward from a start date, respecting every machine's calendar, every changeover, and every inter-stage transfer time. This guide assumes a weekly planning horizon of 30 to 60 jobs across three presses; converters whose order book or equipment scale differs can adapt the same model by adjusting the job list. In Auto mode, Schantt decides job sequence, machine assignments, and timing from scratch — the best choice when sequencing freedom is available and the planner wants the algorithm to find an efficient order. In Semi-Auto mode, you supply the production order and Schantt optimises machine assignments within that fixed sequence — useful when customer pickup dates, material availability, or committed delivery windows constrain the run order and the planner needs to preserve an existing sequence while improving machine utilisation.

What Schantt handles well

• Multi-stage sequential routing with divergent paths. Schantt chains production through ordered stages with transfer times between them, so each job flows Print → Laminate → Slit (→ Pouch) in the correct order. Product classes that skip stages — unprinted rollstock bypasses printing — use a bridging transfer time that routes material directly from substrate stores to lamination.
• Parallel-machine assignment at every stage. With multiple presses, laminators, slitters, and pouch machines, Schantt explores which machine handles each job and chooses the combination that minimises total production time. A job on the gravure press, for example, might leave the flexo press free for a rush order that arrives the same day.
• Directional changeover times between product classes. Changeovers are sequence-dependent and asymmetric — switching from rollstock to pouches on a press may take 30 minutes, while the reverse takes 45. Schantt accounts for these directional times and sequences jobs to minimise cumulative changeover duration across all machines.
• Wall-clock curing holds as inter-stage delays. The 24-hour cure after lamination is not a production stage — it is passive elapsed time that runs through nights and weekends. Schantt models it as a transfer time, so the downstream slitting stage automatically sees the correct earliest-start time for each job without the planner needing to schedule a hold operation.
• Dual calendars for pressroom versus finishing. Printing and lamination follow a two-shift pattern (06:00 to 22:00, Monday through Saturday); slitting and pouching follow a reduced 1.5-shift pattern (06:00 to 18:00). Schantt applies each calendar to its stage's machines, so finishing operations start and end within finishing hours even when the pressroom runs later.

How Schantt handles each challenge

1. Print-job sequencing across three presses with differing ink systems.

• Three presses share a pool of 30 to 60 weekly jobs, but Press 1 (solvent flexo, 1,321 mm, 8-colour) and Press 3 (gravure, 1,321 mm, 8-colour) can run the standard rollstock and pouch classes, while Press 2 (water-based flexo, 1,118 mm, 6-colour) is dedicated to water-based ink work not covered by this guide's scope. The planner must decide which jobs go to which press and in what order, with changeovers that differ by press and product class.
• In Auto mode, the algorithm considers every capable press for each job. Press 1 and Press 3 each have directional changeover entries between Standard Rollstock and Standard SUP, so the system sequences the job list to minimise cumulative changeover duration across the full pressroom load. The planner reviews the resulting assignment on the Gantt chart — each press's lane shows its job sequence, changeover gaps, and any overlap with finishing downstream.

2. Curing-hold delay between lamination and slitting.

• Solventless lamination requires a 24-hour cure before slit rolls can be handled. This hold is pure waiting time — no machine, no operator — but it blocks the downstream schedule. In a spreadsheet, a planner must manually offset every slit job 24 hours from its lamination completion, and the delay is invisible until someone checks the calendar.
• The laminate-to-slit transfer time is set to 1,440 minutes (24 hours). The schedule automatically shifts each slitting operation to begin after that wall-clock delay, and the curing window appears as a visible gap between the lamination and slitting bars on the Gantt chart. Unprinted rollstock, which uses extrusion lamination and requires no cure, uses a bridging transfer time of 0 minutes so it proceeds to slitting immediately.

3. Divergent routing — rollstock versus pouches at the slitting handoff.

• After slitting, roughly 40 to 60 percent of production ships as finished rolls, while the remainder proceeds to pouch making. Each path uses different downstream machines and has different changeover profiles. A schedule that treats all jobs as the same route will either miss the pouching capacity constraint or under-utilise the slitters.
• Each product class defines its own routing. Standard Rollstock ends at slitting. Standard SUP continues through pouching with its own transfer time (60 minutes from slitter to pouch machine staging area) and its own set of capable pouch machines and directional changeovers. The algorithm routes each job through exactly its class's stages, so slitter demand and pouch-machine demand are sized independently — and the Gantt chart shows both the rollstock and pouch work centres in their own calendar bands.

4. Conflicting calendars between pressroom and finishing.

• Presses and laminators run 06:00 to 22:00, while slitters and pouch machines run 06:00 to 18:00. If a job finishes lamination at 20:00, the downstream slitting operation cannot start until 06:00 the next day — but a manual schedule might incorrectly assume it starts immediately.
• Machines on the printing and lamination stages use the Press Calendar (06:00 to 22:00, Monday through Saturday); machines on the slitting and pouching stages use the Finishing Calendar (06:00 to 18:00). Calendar exceptions — a maintenance shutdown, a public holiday, an overtime Saturday — are entered once and apply to all machines on their respective calendars. The schedule respects each stage's working hours, so finishing operations clamp to finishing hours automatically and no manual shift-boundary adjustment is needed.

What to model in Schantt

The flexible packaging converter scenario maps to five first-class entities. Each count below is the number of objects a planner creates to represent this production environment.

Sub-configuration details — 8 per-class routings, 17 machine throughput entries, 16 directional changeover pairs, 3 transfer times (plus a bridging entry for unprinted rollstock), 4 calendar exceptions, and 8 machine downtimes — are set on the respective entity detail pages.

Step-by-step setup

1. Create the four stages. Add Printing (position 1), Lamination (position 2), Slitting (position 3), and Pouching (position 4). Set each stage's type to flow. Then, on each stage's detail page, enter the transfer times:
- Printing → Lamination: 30 minutes (physical roll transfer plus QA sample check)
- Lamination → Slitting: 1,440 minutes (24-hour curing hold for solventless adhesive; unprinted rollstock uses a 0-minute bridging transfer)
- Slitting → Pouching: 60 minutes (slit roll transfer to pouching staging area; Standard Rollstock and Unprinted Rollstock skip this entry as they do not route through pouching)

2. Add the machines to each stage. Each machine belongs to its stage:
- Printing: Press 1 (solvent flexo, 1,321 mm, 8-colour), Press 2 (water-based flexo, 1,118 mm, 6-colour — dedicated to water-based ink work), Press 3 (gravure, 1,321 mm, 8-colour)
- Lamination: Laminator 1 (solventless adhesive, 1,321 mm), Laminator 2 (solvent-borne adhesive, 1,118 mm)
- Slitting: Slitter 1 (duplex, auto knife, 1,321 mm), Slitter 2 (duplex, manual knife, 1,118 mm), Slitter 3 (centre-surface rewinder, heavy-gauge, 1,321 mm)
- Pouching: Pouch Machine 1 (SUP with zipper, 350 mm), Pouch Machine 2 (3-side-seal, 450 mm), Pouch Machine 3 (SUP no zipper, 300 mm), Pouch Machine 4 (spouted pouch, 400 mm)

3. Create the three product classes and define each class's routing. On each product class's detail page, toggle the stages the class passes through:
- Standard Rollstock: Printing → Lamination → Slitting. Partial transfers are off.
- Standard SUP: Printing → Lamination → Slitting → Pouching. Partial transfers are off.
- Unprinted Rollstock: Lamination → Slitting (skips printing). Partial transfers are off.

4. Add one representative product per class. Create a product that belongs to each class:
- Standard Rollstock: Printed Laminate Roll, 610 mm × 3,048 m
- Standard SUP: Stand-up Pouch with Zipper, 203 mm × 305 mm
- Unprinted Rollstock: Unprinted White PE Roll, 914 mm × 4,572 m

Each product's display colour differentiates it on the Gantt chart.

5. Set machine throughput and changeover times on each machine's detail page. Enter the throughput for each product class and stage combination that the machine can run:
- Press 1: 15,000 units/hour for Standard Rollstock and Standard SUP
- Press 3: 24,000 units/hour for Standard Rollstock and Standard SUP
- Laminator 1: 21,000 units/hour for all three classes
- Laminator 2: 12,000 units/hour for Unprinted Rollstock
- Slitter 1: 30,000 units/hour for all three classes
- Slitter 2: 24,000 units/hour for Unprinted Rollstock
- Slitter 3: 18,000 units/hour for Standard Rollstock
- Pouch Machine 1: 4,800 pouches/hour for Standard SUP
- Pouch Machine 3: 6,000 pouches/hour for Standard SUP

For each machine that handles two or more product classes, enter the directional changeover time between classes — for example, Press 1 requires 30 minutes changing from Standard Rollstock to Standard SUP and 45 minutes in the reverse direction. Enter values based on your plant's measured durations; Schantt uses these as-is without validation. Verify that every capable machine has a throughput entry for each class it should run — machines without an entry are treated as ineligible.

6. Configure calendars, exceptions, and downtimes. Create two calendars:
- Press Calendar: 06:00 to 22:00, Monday through Saturday — assigned to the three presses and two laminators
- Finishing Calendar: 06:00 to 18:00, Monday through Saturday — assigned to the three slitters and four pouch machines

Add calendar exceptions for planned non-working days (e.g. maintenance shutdown, public holiday) and overtime days (e.g. a Saturday that extends finishing hours to match the pressroom pattern). Enter scheduled machine downtimes — weekly anilox roll cleaning rotation across the three presses, monthly preventive maintenance for a laminator, a slitter, and a pouch machine — as recurring windows on their respective machine detail pages.

For step-by-step instructions on configuring each of these in Schantt, see the Schantt documentation.

Common mistakes

1. Entering a single blanket changeover for all transitions. A single changeover time cannot capture the difference between a same-ink-family colour swap (30 minutes) and a full chemistry change (90 minutes or more). The schedule will overestimate or underestimate every transition, producing an infeasible sequence. Fix: enter at least the directional changeover times between product classes on every machine that handles two or more classes; add finer-grained entries where the same class has significantly different setup durations.

2. Modelling the curing hold as a production stage. Adding a "Curing" stage with a machine and zero throughput creates a phantom bottleneck and forces the algorithm to find a curing-machine assignment where none is needed. Fix: model the curing hold as a transfer time on the Stage detail page — 1,440 minutes from Lamination to Slitting. The delay appears as an inter-stage gap on the schedule without consuming a stage slot or a machine.

3. Merging all pouch types into a single product class. A stand-up pouch with zipper, a three-side-seal bag, and a spouted pouch have different changeover profiles on different machines. A single class ignores those differences and prevents the system from routing each type to its most capable machine. Fix: create separate product classes for pouch families that differ in machine eligibility or changeover duration; the guide's three-class model is a scoping choice, and real converters may need six to ten classes to capture changeover-time differentiation.

4. Expecting Schantt to optimise knife layout or trim waste. Slitter knife positioning and trim-optimisation is a separate combinatorial problem that the scheduling algorithm does not solve. If the schedule groups jobs with incompatible slit-width patterns on the same slitter, the planned order may be unusable. Fix: plan your slitter knife layout separately and enter the resulting roll configuration as the slitting job. Schantt schedules the slitting operation but does not optimise trim patterns.

5. Ignoring the calendar mismatch between pressroom and finishing. When all machines share one calendar, a job that finishes lamination at 20:00 is treated as ready for slitting immediately — but the slitting crew leaves at 18:00. Fix: assign the Press Calendar to printing and lamination machines and the Finishing Calendar to slitting and pouch machines. The schedule then honours each stage's working hours, and slitting operations clamp to finishing hours automatically.

What a good schedule looks like

A well-configured schedule resolves the four most persistent pain points of flexible packaging converting into a clear, machine-by-machine plan that a planner can review, adjust, and communicate in minutes rather than hours.

Before (spreadsheet or ERP dispatch): The pressroom sequence groups jobs by customer rather than by ink system or changeover duration, so the three presses collectively lose 2 to 4 hours per shift to avoidable changeovers. The 24-hour curing hold is a mental offset — the planner adds a day to every lamination completion date, but the downstream schedule has no visible gap, so slit rolls pile up at the staging area waiting for curing clearance. The slitting schedule is built without regard to pouch-machine availability, so pouch machines periodically sit idle while slit rolls of the right specification are still in the curing area or queued behind unrelated work on the slitter.

After (Schantt Auto mode): The three presses run sequenced by product class transition, recovering 4 to 10 hours of changeover time per week across the pressroom. The curing hold is visible as an explicit gap between each job's lamination completion and its earliest slitting start — the planner can see at a glance which jobs are cleared for finishing and which are still curing. Slitter and pouch-machine demand are sized independently because each product class follows its own routing, so pouch machines receive a steady supply of slit rolls that are ready for pouching. The dual-calendar setup ensures that every finishing operation respects the shorter finishing shift without manual end-of-day adjustments. Overall, optimised press assignment across the two capable presses reduces the total production span by an estimated 5 to 15 percent compared to a manual or first-come-first-served sequence.