Production Scheduling for Ceramic Tiles

Production planners and operations managers at ceramic tile plants face a unique scheduling challenge: batch pressing must synchronise with continuous-flow kilns that never stop, while glaze colour changes and mold swaps consume hours of productive time. Schantt models the complete tile production flow — pressing, drying, glazing, kiln firing, and sorting and packaging — as a mixed batch-and-flow pipeline with sequence-dependent changeovers, letting you optimise sequences that keep the kiln fed and reduce total production time. This guide walks through configuring your tile plant in Schantt and setting up a schedule that matches how your floor actually runs.

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

Industry context

Ceramic tile manufacturing is a hybrid flowshop process that combines discrete batch operations with continuous flow. Raw clays, feldspar, and quartz are ball-milled into slurry and spray-dried into atomised powder with approximately 5–7% residual moisture. This powder is then hydraulically pressed into green tile, dried to below 1% moisture, glazed and decorated (for surface-finished products), fired in a roller kiln at temperatures exceeding 1,000°C, and finally sorted, graded, and packaged. The dominant modern process is single-fire (monoporosa), where the dried green tile is glazed and fired in a single kiln pass. An SMB or mid-market tile plant typically produces between 3,000 and 10,000 m² per day across one to five million square metres annually.

The critical equipment chain includes hydraulic presses (6–24 strokes per minute, 1,500–4,500 ton force), multi-level vertical dryers (20–60 minutes residence time at 100–200°C), digital inkjet glazing lines (up to eight colours, 30–70 m/min), and roller kilns (60–150 m long, 1,100–1,250°C peak temperature, 40–70 minute firing cycle). The kiln is the most constrained asset: it runs 24/7, cannot be stopped for short periods, and a full controlled shutdown requires 3–5 days. Glaze colour changeovers are directional and sequence-dependent, ranging from 10 minutes for a same-family light-colour switch to 60 minutes for a dark-to-light full cleaning circuit. Press mold changes add 15–45 minutes per format swap. Drying residence time varies by tile thickness — wall tiles dry in approximately 25 minutes, while thicker terracotta tiles require up to 40 minutes. The inter-stage buffer between pressing and the kiln holds approximately 30–90 minutes of production.

Scheduling complexity arises from three-to-five product classes with distinct firing temperatures, pressing forces, and routings — some skip the glazing stage entirely. Product-class switches on the kiln carry a 2–6 hour temperature stabilisation penalty, and the calendar mismatch between 24/7 kilns and shift-based sorting creates an overnight production accumulation. Yield is probabilistic: A-grade output typically ranges from 82 to 92% after firing, so planners schedule an overproduction buffer to meet grade targets.

Crestone Ceramics runs approximately 140 people at a 28,000 m² facility, making three product classes (wall tile, decorative mosaic tile, rustic terracotta tile) across five production stages, scheduled by a three-person planning team.

Process overview

flowchart LR
  P["Pressing<br/>(Batch)"]
  D["Drying<br/>(Flow)"]
  G["Glazing<br/>(Flow)"]
  K["Kiln Firing<br/>(Flow)"]
  S["Sorting and Packaging<br/>(Flow)"]
  P --> D
  D --> G
  D --> K
  G --> K
  K --> S

The five-stage ceramic tile production flow. Drying branches to either glazing (wall tile) or directly to the kiln (unglazed classes).

Skip-routing note: Decorative mosaic tile and rustic terracotta tile bypass the glazing stage entirely. Their routings connect drying directly to kiln firing through a bridging transfer time.

Scheduling challenges and how Schantt handles them

The schedule in this scenario is driven by planned production quantities per product class for a weekly horizon — make-to-stock is the primary demand assumption. Most tile plants produce standard sizes and colours against inventory targets, with the kiln dictating the sequence through its thermal profile requirements. For plants with significant make-to-order volume, urgent custom orders can be sequenced early in Semi-Auto mode, but this guide assumes a weekly production plan rather than due-date-driven scheduling.

Schantt minimises total production time, scheduling forward from a start date. The practical horizon assumed here is one week with daily adjustments — long enough to plan kiln runs and colour sequences but short enough to accommodate mold availability and raw material changes. In Auto mode, the scheduler reorders jobs and assigns machines to minimise total production time. In Semi-Auto mode, the job sequence is held fixed and machine assignment is optimised within it — the recommended starting mode for tile plants where kiln temperature grouping constrains the sequence and planners need to lock in a specific order.

What Schantt handles well

• Sequential multi-stage production — Model the ordered tile production flow — pressing, drying, glazing, kiln firing, and sorting and packaging — as stages with per-class routing and material-handoff delays between them.

• Multi-machine stages — Configure multiple presses at the pressing stage, multiple kilns at the firing stage, and multiple sorting lines at the sorting stage. The scheduler explores which machine each job runs on and chooses the assignment that minimises total production time.

• Mixed batch-and-flow pipelines — Model pressing as a batch stage (cycle per press stroke times number of strokes) and drying, glazing, and kiln firing as flow stages (throughput per hour). The simulation feeds downstream flow stages from upstream batch completions and flags supply gaps when material starves a stage.

• Multi-product routing with stage skipping — Define per-class routings so unglazed products (decorative mosaic, rustic terracotta) follow their own path through shared stages without adding stages they never touch. Bridging transfer times connect the stage before the skipped span to the stage after it.

• Sequence-dependent changeovers — Enter directional changeover times for glaze colour switches, press mold changes, kiln temperature transitions, and any other per-pair setup. The scheduler favours sequences that cluster similar products to reduce total changeover time.

• Calendar exceptions and downtimes — Add planned kiln refractory maintenance or holiday shutdowns as downtime windows and calendar exceptions. Schantt subtracts these from working capacity before scheduling and renders them as shaded overlays on the schedule.

How Schantt handles each challenge

1. Kiln starvation from upstream coordination gaps.

• Kilns run 24/7 and cannot be stopped mid-schedule. When a press mold change runs late or a glazing colour changeover takes longer than planned, the inter-stage buffer empties and the kiln starves — typically within 40 minutes. Crestone estimates that 60–70% of kiln idle time stems from upstream coordination failures, with kiln utilisation averaging 85% against a target of 93–95%.
• Schantt models the kiln as a flow stage on a continuous calendar and links it to upstream pressing and glazing through transfer times. The scheduler sequences jobs so upstream completions arrive at the kiln just in time; any supply gap appears as an idle segment on the schedule. Planners see exactly when the kiln is at risk and can adjust batch sizes or press assignments before the week begins.

2. Glaze colour changeover overhead eroding productive glazing time.

• Glaze colour changes are directional and sequence-dependent: a dark-to-light changeover (such as black to white) requires a full cleaning circuit taking 45–60 minutes, while light-to-dark takes 15–25 minutes. Crestone's two glazing lines average approximately 3.5 hours of changeover time per day, roughly 22% of available glazing shift time. A poorly sequenced colour run can add 45 minutes of avoidable cleaning daily.
• Schantt captures each glaze changeover as a directional per-pair duration on the glazing machine. The scheduler naturally clusters same-colour-family runs and sequences colours from lightest to darkest — the direction with the shorter changeover time — reducing total cleaning time. The changeover penalty is visible on the schedule as setup blocks between jobs.

3. Press mold change sequencing and availability conflicts.

• Each tile format requires a specific mold set. Crestone averages 6–8 mold changes across three presses per day, each taking 15–45 minutes. Mold-change sequencing is driven by the planned kiln sequence, but shared molds and tooling workshop turnaround create availability conflicts that the current spreadsheet schedule misses, causing approximately 90 minutes of press idle time per day.
• Schantt models the changeover duration for each press mold swap as a directional per-pair time between product classes. The scheduler sequences press jobs to minimise total changeover time, clustering same-format runs where possible. Mold-slot availability is a manual planner check — Schantt schedules the changeover duration but does not track finite tooling slots.

4. Batch-press-to-continuous-kiln asynchrony.

• Presses produce green tiles in discrete batches while the kiln consumes fired tiles continuously. Crestone's inter-stage buffer can hold approximately 45 minutes of production; once that empties, the kiln runs on residual material. Press-to-kiln coordination failures account for an estimated 30–40% of unscheduled kiln throughput dips.
• Schantt models the pressing stage as batch (cycle time times quantity per stroke) and the kiln as flow with a fixed hourly throughput. Transfer times between stages capture the forklift handoff. The simulation feeds the flow kiln from batch press completions and emits idle gaps when press supply cannot keep pace. Planners see the buffer window and can adjust batch quantities or press assignments to match kiln consumption.

5. Kiln and sorting shift mismatch creating an overnight accumulation backlog.

• Kilns run 24/7 while sorting and packaging operates on fewer shifts. At Crestone, approximately 1,500 m² of fired tile exits the kilns overnight and accumulates at the sorting entry. The first two hours of each sorting shift are consumed processing this backlog rather than keeping pace with current kiln output. Any unplanned sorting downtime compounds the backlog.
• Schantt models the sorting stage with its own calendar — fewer working hours than the kiln. Tiles exiting the kiln during non-sorting hours accumulate as work-in-progress; when the sorting shift starts, the schedule shows the backlog as queued material. Planners see the buildup and can decide whether to add a sorting shift or adjust kiln throughput during accumulation windows.

What to model in Schantt

Before setting up the schedule, configure the following entities in Schantt to represent your tile plant's production model.

Step-by-step setup

1. Create the stages in order. Add Pressing (batch), Drying (flow), Glazing (flow), Kiln Firing (flow), and Sorting and Packaging (flow) in sequence. Then set the transfer times between consecutive stages on each Stage's detail page.

• Transfer times (forklift and conveyor flow): Pressing to Drying: 15 min; Drying to Glazing: 15 min; Drying to Kiln Firing: 15 min (bridging transfer for unglazed classes); Glazing to Kiln Firing: 15 min; Kiln Firing to Sorting and Packaging: 15 min.

2. Add the machines to each stage. Assign the presses, dryers, glazing lines, kilns, and sorting and packaging lines to their respective stages.

• Pressing: Press 1 (2,000 t, dedicated to wall tile), Press 2 (1,500 t, handles mosaic), Press 3 (1,800 t, handles terracotta)
• Drying: Dryer 1 (150 m roller path), Dryer 2 (120 m roller path, overflow and thick tiles)
• Glazing: Glazing Line 1 (digital inkjet, six colours), Glazing Line 2 (digital inkjet, four colours)
• Kiln Firing: Kiln A (85 m, dedicated to wall tile), Kiln B (75 m, handles mosaic and terracotta)
• Sorting and Packaging: Sorting Line 1, Sorting Line 2, Packaging Line 3 (shared palletising)

3. Create the product classes and define their routings. Add three classes: wall tile (full route), decorative mosaic tile (skips glazing), and rustic terracotta tile (skips glazing). On each Product Class detail page, define the stage sequence and set partial-transfer toggles where material moves in batches rather than continuously.

• Wall tile routing: Pressing to Drying to Glazing to Kiln Firing to Sorting and Packaging
• Decorative mosaic routing: Pressing to Drying to Kiln Firing to Sorting and Packaging
• Rustic terracotta routing: Pressing to Drying to Kiln Firing to Sorting and Packaging

4. Add one product per class. Create a representative product for each class: Wall tile 300×450 mm, Mosaic tile 100×100 mm, Terracotta tile 250×250 mm. Each inherits its class's routing and changeover matrices.

5. Set machine capacity parameters and changeovers. On each Machine detail page, enter the batch or flow parameters per product class, then add per-pair changeover durations. This step requires the product classes from step 3.

• Pressing (batch) — cycle duration per stroke / batch size: 0.07 min / 2.8 m² for wall tile on any press; 0.06 min / 1.4 m² for mosaic; 0.06 min / 1.5 m² for terracotta
• Drying (flow) — throughput in m²/h: Dryer 1: 110 (wall), 45 (mosaic), 55 (terracotta); Dryer 2: 85, 35, 45 respectively
• Glazing (flow) — throughput: 700 m²/h on both lines (wall tile only)
• Kiln Firing (flow) — throughput: Kiln A: 146 m²/h (wall tile); Kiln B: 117 m²/h (mosaic and terracotta)
• Sorting and Packaging (flow) — throughput: 800 m²/h on Sorting Lines 1 and 2, 600 m²/h on Packaging Line 3
• Changeovers: Press mold changes (15–45 min per direction between classes), glaze colour changes (10–60 min per direction — light-to-dark fast, dark-to-light slow), kiln temperature transition between mosaic and terracotta on Kiln B (120 min each direction)

6. Configure calendars, exceptions, and downtimes (optional, last). Set the working-time patterns for each stage, add annual holiday exceptions, and schedule planned maintenance windows.

• Calendars: Standard shift for pressing, drying, and glazing — three shifts Monday to Friday plus one shift Saturday; sorting shift for sorting and packaging — two shifts Monday to Friday plus one shift Saturday; continuous for kiln firing — 24/7
• Exceptions: New Year's Day (non-working), International Workers' Day (non-working), Christmas Eve (half-day), New Year's Eve (half-day)
• Downtimes: Kiln A annual refractory maintenance from January 5 to 10; Kiln B annual refractory maintenance from January 12 to 17; factory-wide summer shutdown from August 1 to 14

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

Common mistakes

1. Modeling the kiln as a batch stage. The roller kiln is a continuous-flow tunnel, not a batch furnace. Configuring it with a cycle duration and batch size instead of hourly throughput produces a schedule where the kiln can stop between batches — entirely unrealistic for a machine that takes 3–5 days to shut down. Fix: Set the kiln as a flow stage with throughput in m²/h, never as batch.

2. Using a single blanket changeover time for all glaze colour changes. Glaze changeovers are directional and asymmetric: dark-to-light cleaning takes 45–60 minutes, while light-to-dark takes 15–25 minutes. A single average changeover time prevents the scheduler from clustering light colours together to minimise total cleaning time. Fix: Enter each direction as a separate per-pair duration on the glazing machine's changeover matrix.

3. Creating one product class for both glazed and unglazed tiles. Product classes with different routings — one that passes through glazing, one that skips it — cannot share a single class because the routing is defined at the class level. Fix: Create separate product classes for wall tile (full route) and for each unglazed class (decorative mosaic, rustic terracotta) with glazing omitted from their stage sequences.

4. Assigning the same calendar to the kiln and to sorting. Kilns run 24/7; sorting and packaging typically run fewer shifts. Using the same calendar for both hides the overnight tile accumulation that is a critical real-world dynamic. Fix: Give the sorting stage its own calendar with fewer working hours, and review the overnight backlog on the schedule before the sorting shift starts.

5. Omitting bridging transfer times for stage-skipping routings. When decorative mosaic tile skips the glazing stage, material moves from drying directly to the kiln. Without a transfer time covering that span, the handoff delay is silently zeroed. Fix: Add a bridging transfer time from Drying to Kiln Firing for the two unglazed product classes, matching the forklift travel time.

What a good schedule looks like

A well-configured Schantt schedule transforms a reactive whiteboard plan into a predictable, optimised production sequence. Here is what the shift looks like before and after.

Before (whiteboard and spreadsheet at the ~85% kiln utilisation baseline):

• Glaze colour changes sequenced reactively — dark-to-light transitions cluster poorly, consuming approximately 3.5 hours of changeover time per day across both glazing lines
• Press mold changes driven by kiln sequence but blind to mold availability, causing approximately 90 minutes of press idle time daily
• Kiln starved one to three times per shift as press and glazing completions drift out of sync with continuous consumption
• Sorting backlog of approximately 1,500 m² accumulated overnight, consuming the first two hours of each sorting shift

After (Schantt Semi-Auto mode with optimised sequencing):

• Glaze changeover time reduced by clustering light-colour runs and sequencing lightest-to-darkest — the scheduler naturally follows the shorter changeover direction, producing a colour sequence that a manual planner would need hours to optimise
• Press mold changes minimised by grouping same-format production blocks, reducing mold-change frequency and associated idle time across all three presses
• Kiln supply gaps visible and preventable — the schedule shows exactly when the inter-stage buffer empties, letting planners adjust press quantities or batch sizes before the week starts rather than reacting mid-shift
• Sorting backlog visible on the schedule as overnight accumulation between the 24/7 kiln and the shift-based sorting stage, enabling informed decisions about adding sorting capacity or adjusting kiln throughput during those hours
• Total changeover time across glazing lines and presses reduced, translating directly into more productive hours per week without adding shifts