A UV flatbed does not lose time in the print. It loses time between prints, when the fixture changes, the file changes, the ink layers change and the operator runs a sample to prove the restart. A schedule built from the headline speed figure will be late by the amount of that stop, repeated once per job.

This guide covers how to sequence mixed-material work so the changeovers cost the least: how to group jobs before ordering them, what a changeover actually involves, how small parts and large sheets share one machine, how personalised versions are ordered, what to record at each change and how to protect colour across a schedule that changes the material under the head.

Why does a mixed-material schedule lose time?

Because the changeover is not in the estimate.

Most mixed-material schedules lose time at the changeover rather than at the print, and the changeover is usually the step missing from the time plan.

The published production guidance for this range is unusual in naming the changeover as a required input. The container workflow asks for the required quantity, the changeover frequency, the quality level and the deadline as one group, and the small-part workflow asks for the quantity by blank and artwork, the personalisation fields, the loading sequence, the changeovers and the inspection reference for every version. Where a schedule is built on print speed alone, none of those inputs appear, and the plan fails at the first job that is not the same as the last.

The cost is not only idle time. A changeover that is rushed is a changeover that is not proved, and an unproved restart produces the scrap that a proper sample print would have caught. The published workflow for bottle work is explicit that a change of size or shape can require the correct fixture, artwork resized to the new circumference, height and focus checks, rotation calibration and a sample print. That is a defined sequence, and it takes as long as it takes.

How should jobs be grouped before they are sequenced?

By ink configuration, substrate family and quality mode.

Jobs that share all three run with the least interruption, so the sequence should cross as few of those boundaries as it can.

Three axes decide how much a changeover costs. The first is the ink configuration, because a job needing white and varnish behaves differently from a four-colour job on the same file. The second is the substrate family, because preparation and setting change between a rigid panel, a board, a coated metal blank and a cylindrical container. The third is the quality mode, because moving between a draft mode and a premium mode changes the pass count and therefore the time per piece.

The grouping rule is to sort the work into families on those three axes, then sequence inside each family and finally order the families to minimise the number of transitions. The published guidance for standard sheets makes the same point from the other direction, asking a buyer to review the largest panel, the most frequent panel and the changeover pattern rather than selecting a bed around one unusual job. The changeover pattern is a production input, not an afterthought.

What does a changeover actually involve?

Fixture, artwork, focus, calibration and a sample print.

A changeover is a defined sequence rather than a pause, and skipping a step in it moves the cost from setup time into scrap.

The sample print is the step most often dropped under time pressure, and it is the step that protects the batch. A changeover that has been proved is a changeover that can be repeated; one that has not is a guess that will be repeated differently next time.

How do you sequence small parts against large sheets?

Separate the beds and protect the schedule.

Large sheets and small parts compete for the same machine, so they should be sequenced as separate groups unless the small-part job has its own approved fixture and loading pattern.

A small-part tray can be nested into the unused edge of a large-sheet bed, and the published guidance for small flat parts supports that approach where the loading pattern is controlled. The risk is the opposite of the saving: a large-format run broken by a small-part tray loses the sheet setup, and the published comparison for standard sheets warns that a bed larger than the sheet does not by itself make the material printable. Nesting is only useful when the fixtures are approved and the loading is repeatable, not when it is improvised to fill space.

The practical rule is to give small parts a dedicated block and a dedicated fixture, and to let large sheets run in their own block. Where the two must share a bed, the small-part fixture should be treated as a fixed item that does not disturb the sheet setup, and the sequence should keep that fixture in place across the whole block rather than removing and refitting it between sheets.

How should personalised versions be ordered?

From a position-to-file matrix.

Personalised work should be sequenced from a matrix that connects each loaded pocket to the correct artwork and order identifier, so a version change stays a file change.

The published guidance for medals, coins and buttons is the clearest version of this idea: map each blank position to the correct artwork, colour reference and order record so that personalisation and multiple designs remain traceable. Where the plate carries many versions, the published workflow asks for a file matrix, a quantity by design and a loading sequence with the changeovers and the inspection reference for every version. That is what allows a single tray to carry a dozen designs without a dozen restarts.

Ordering then becomes a sorting exercise. Group versions that share an ink construction and a colour reference, sequence them within the tray position they occupy, and treat a change of ink layer as a real changeover rather than a file swap. Where the version count is high, the published guidance for personalised workflows still asks for the file source, the part mapping and the verification step to be reviewed before production, because traceability is the part that cannot be improvised.

What belongs on a changeover record?

What changed, and what proved the restart.

A changeover record should state the job, the fixture, the file, the ink layers and the sample print that approved the restart, so the next run can be set up from the record.

The record turns a changeover from an event into a procedure. The published process fields for this range cover the approved artwork version, the RIP and ink-layer settings, the substrate and pretreatment, the fixture or loading method, the bed position, the environmental conditions and the inspection result. Recorded at the changeover, those fields capture exactly the variables that the change introduced, which is why the changeover is the natural moment to write them down.

Two fields are specific to mixed work. The first is the job that ran before the change, because a fixture or setting that worked well before the transition is a clue when the next job misbehaves. The second is the reason for the change, whether it was a new substrate, a new version or a different quality mode, because the reason determines how much of the setup has to be rebuilt next time.

How do you protect colour across a mixed schedule?

With a fixed reference and a recorded profile.

Colour should be judged against an approved physical reference rather than a screen, with the profile and density settings recorded, because a mixed schedule changes the material under the head.

A schedule that moves between a white acrylic panel, a coated metal blank and a dark container changes the substrate on which the same brand colour is built, and every one of those changes affects the result. The published position for this range is a controlling application plus RIP software with ICC-based profiles, curves and density adjustment, and the published guidance for canvas and art panels asks for a control target and representative artwork to be approved together before production. The control target is what keeps the colour honest when the substrate changes underneath it.

The environmental conditions belong in the same control. This range is published to run between 20 and 30 degrees Celsius and 40 to 60 percent relative humidity, and a schedule that runs through a shift of changing temperature will see the ink behave differently at the end from the start. Recording the conditions with the result is what allows a colour drift to be explained rather than argued about.

When should a job be split into two batches?

When the changeover costs more than the delay.

Split a job when a mid-batch changeover would cost more than a second pass, or when a single run would hold up a deadline that matters more than the extra setup.

The calculation is a comparison of two costs. Running the job in one block minimises setup but ties the machine up for the whole quantity, whereas splitting it releases the machine between passes and adds a changeover. For large quantities of one design, one block usually wins. For a rush order that has to reach a customer before a longer job can finish, the split is the better answer even though it costs a setup.

The published scheduling guidance for this range supports both patterns by treating the changeover as a countable cost. The bottle workflow asks for the changeover frequency alongside the quantity and the deadline, and the small-part workflow asks for the quantity by design so the version count is visible before the sequence is fixed. Where a schedule cannot answer how many changeovers it contains, it cannot tell whether a job should be split, and the decision is then made under pressure rather than in advance.

One further input belongs in any mixed schedule. The ink cost published for this range is roughly 0.80 to 1.20 US dollars per square metre, which is what turns a changeover from a loss of time into a number a planner can weigh against a deadline.

What the decision comes down to

A mixed-material schedule is decided at the changeover. Group the work by ink configuration, substrate family and quality mode, give each changeover a defined sequence and a record, and sequence personalised versions from a position-to-file matrix so a version change stays a file change.

Then treat the changeover as a countable cost when deciding whether to split a job. The published changeover, loading and version guidance for this range sits with the promotional products, bottles and tumblers and cosmetic container collections, and the compact platform that carries the fixture and optional CCD route is described on the AJ1206 page.

Process control practice for mixed production is covered by the industry bodies that publish it, including colour management guidance from the International Color Consortium and process standards from Fogra and PRINTING United Alliance. Chemical and material obligations for inks and substrates follow the applicable regulations (REACH), occupational exposure guidance for print workshops is set out by the relevant authority (HSE printing), and international trade requirements for exported printed goods are summarised by trade.gov.