Packaging is the one print market where the product is not the print. A box has to fold, close, hold weight and survive a journey, and a bag has to carry a purchase without the handle failing. The print is part of that structure rather than the point of it.

This guide covers how packaging work behaves on a UV flatbed: why a rigid box differs from a carton, how the board and paper are chosen, what folding does to a print, how a paper bag is handled, how coatings change the surface, how short a run can be, what to test, and what records keep a packaging job repeatable.

Why does a rigid box behave differently from a carton?

Because it is assembled, not folded.

A rigid box is built from several pieces of board, so the print has to sit on the piece that will be visible after assembly rather than on a flat sheet.

The published board guidance for this range treats packaging as a sequence rather than a sheet. It asks for the loading and converting stage, covering the printed sheets, the pieces per bed, the cutting, scoring, folding, gluing and assembly, and it asks for the order and approval target to be recorded with it. That framing is accurate for a carton and it is even more accurate for a rigid box, where the wrap and the base are separate components.

The practical consequence is that the printable piece is defined by the assembly drawing. Printing the wrong panel of a wrap is not a small error; it is a component that cannot be used, and on a small run there is no spare board to recover it.

How should the board or paper be chosen?

By the construction and the finish.

The published board guidance asks for the sheet, the pieces per bed and the converting sequence, and a coated or laminated face changes what the ink sits on.

The published material guidance for this range is consistent across substrates: identify the construction, the supplier and the batch rather than testing an unspecified sample. On packaging that means the board grade and the finish, because two boards of the same nominal thickness can behave differently once the surface treatment differs.

What does folding do to a printed surface?

It stresses the film along the crease.

A crease bends the board and the printed layer together, so the published guidance is to test the converting sequence on the real material rather than after printing.

Scoring and folding put a concentrated strain on a narrow line. Where the printed film is stiff, the fold can crack the ink along the crease, and the failure appears as a light line on a dark background or a broken graphic across the panel. That is why the published packaging workflow asks whether the board can be cut, scored or folded after printing and answers that the complete sequence has to be tested.

The fix is usually in the design or the construction rather than the ink. Keeping a heavy ink area away from the fold line, choosing a board that creases more cleanly, or scoring before printing are all decisions that remove the problem, and all of them are cheaper when they are made at the artwork stage.

How should a paper bag be handled?

As a flat blank with a forming step.

A bag is printed flat and formed afterwards, so the printable area and the no-print zones follow the blank rather than the finished shape.

Three zones matter on a bag. The fold lines, which become edges and gussets, because ink across a fold is stressed in the same way as on a carton. The handle area, because a handle is either punched or glued and both operations need a clean surface. And the base, because the bottom of the bag takes the load.

The published artwork guidance for this range asks for cutouts, openings and clearances to be taken from the current drawing and built into the file, and on a bag the fold and handle positions are exactly those zones. Building them into the artwork means the second order of the same bag is printed correctly without the operator reconstructing the layout.

How does a coating or lamination change the job?

It decides the surface the ink meets.

A varnished, laminated or coated board presents a different surface from an uncoated one, which is why the published approach is to identify the finish and test it.

The published guidance for coated surfaces is to record the coating or finish and to clean the surface before printing, removing oil, fingerprints and residue that would otherwise sit between the ink and the board. On packaging that step is easy to skip, because the board arrives looking clean and the surface treatment is invisible.

Lamination adds a second consideration, which is the order of operations. A board that will be laminated after printing presents the ink to a laminating film rather than to the customer, while a board laminated before printing presents a sealed surface to the ink. The two are different jobs, and the choice belongs in the specification rather than in the schedule.

How short can a packaging run be?

One box, at the page level.

Direct printing suits prototypes and short runs because it needs no plate, which is the same advantage the published packaging guidance describes for prototyping.

The published comparison for packaging is explicit that longer volumes of established graphics can suit a conventional process, where plates and setup steps are justified by the quantity, while short and variable work suits direct printing. The crossover is a commercial calculation rather than a technical one, and it moves with the amount of versioning in the job.

Where a project involves several versions, prototypes or a changing design, the direct route avoids the fixed cost of a plate per version. That is the same logic that applies to retail campaign work, where the published guidance asks for version control and release status to be recorded so that a single version can be reprinted without reprinting a set. The campaign workflow is described in the article on retail displays and POP.

What should be tested before delivery?

Adhesion, folding and the assembled look.

The published packaging checks cover the printed piece and the converted result, and folding and handling belong in the same test as adhesion.

Four checks cover most of the risk. Adhesion on the real board, because the surface treatment decides it. The fold, because a crease is where a film fails. The assembly, because a box is judged as a closed object rather than as a flat panel. And the handling, because a packed box is stacked, carried and unpacked before the print is ever seen as a design.

Two published methods support the technical checks. Adhesion is assessed with the cross-cut tape test under ASTM D3359 and wear under ASTM D4060. Where the packaging will meet food or a food-adjacent product, the contact question belongs in the specification as well, and the framework for materials intended to come into contact with food is published by the relevant authority (EU food contact materials).

What records keep a packaging job repeatable?

The board, the finish, the file and the result.

The published process record covers the substrate, the settings and the inspection result, and a packaging job adds the construction and the converting sequence.

Four entries make the record usable. The board grade, the finish and the batch, so a change of material is visible. The converting sequence, because printing before or after lamination changes the job. The artwork version, because packaging carries version and language changes more often than most work. And the inspection result, including the fold and assembly checks rather than only the printed appearance.

The published approach is to keep the approved sample with its record so a repeat order is checked against the same physical piece. That matters more in packaging than in most markets, because the customer often reorders the same box months later for a new product, and the board may have changed in between. Material and chemical obligations for the inks and the board follow the applicable regulations (REACH), occupational guidance for the workshop is published by the relevant authority (HSE printing), and process practice is published by the bodies in the field (PRINTING United Alliance). The workflow itself is covered in the guide to short-run packaging.

What the decision comes down to

Packaging is judged after it is folded. Define the printable piece from the assembly drawing, record the board and the finish, keep heavy ink away from the creases, test the converting sequence on the real material, and check the assembled box rather than the flat sheet.

The published board and packaging guidance for this range sits with the cardboard and corrugated collection and the AJ3220EX page, and the adjacent workflows are covered in the guides to short-run packaging and retail displays and POP.