Dieline File Formats: Should You Send PDF, AI or DXF?

Vector vs raster: why a dieline must be vector

A dieline is a set of mathematically defined paths: straight lines, arcs and curves with exact coordinates. Vector formats (AI, PDF, EPS, DXF) keep those paths sharp and measurable at any size, so a die maker can read a 2 mm tuck-flap radius or a 150 mm panel exactly. A raster image (JPG, PNG, TIFF, a phone photo or a screenshot) stores pixels, not lines. It cannot be turned into a cutting path without redrawing, and redrawing introduces errors.

Artwork can contain raster elements such as product photography, but the structural lines themselves should always stay vector. If the only dieline you have is a scan or a picture, treat it as a reference sketch and ask for a redrawn vector structure before any artwork is placed on it.

Keep cut, crease and finish lines on separate spot-colour layers

Prepress teams and CAD operators commonly ask for each line type to sit on its own layer and use its own named spot colour, for example swatches called CUT, CREASE and PERF. Common practice is:

1. Put the structure on a top layer named “Dieline”, locked while the artwork is edited.
2. Use 100% spot colours for the lines, never a CMYK mix, so they separate cleanly and cannot accidentally print as a visible colour.
3. Set dieline strokes to overprint so they do not knock holes in the artwork beneath.
4. Give special finishes (foil, spot UV, embossing, window patches) their own spot-colour layers, aligned to the same structure.
5. Leave a legend in the file stating which colour means cut, crease, perforation and bleed.

Colour conventions differ by supplier, so match the legend on the template you were given rather than assuming a colour.

Why the cutting table wants DXF

DXF (Drawing Exchange Format) was created by Autodesk as a way to move drawings between CAD programs, and it is read by most packaging CAD software, die-making systems and digital sample-cutting tables. These machines follow the vector paths with a knife, a creasing wheel or a perforating tool, so the file needs to describe geometry only.

When exporting a DXF from a design program, check that units are millimetres and the scale is 1:1, that connected segments are joined into continuous paths, that curves have not been broken into visibly faceted segments, and that line types are separated by layer or colour so the operator can assign the correct tool. Remove artwork, text, crop marks and dimension labels from the DXF version, or keep dimensions on a clearly separate non-cutting layer.

Why the printer wants PDF/X

PDF/X is a family of ISO-standardised PDF subsets (ISO 15930) designed for reliable exchange of print files. Two variants are common in packaging:

• PDF/X-1a: CMYK and spot colours only, transparency flattened, all fonts embedded. Very predictable on older or conservative workflows.
• PDF/X-4: allows live transparency and colour-managed (ICC-based) workflows, which suits modern prepress systems and complex effects.

Ask your printer which variant and output intent they want before exporting. Whichever is chosen, the dieline layer should still be present as a non-printing spot colour so prepress can check artwork position against the structure.

Decision rules

• Choose AI (or editable layered PDF) when the file is going to a designer who will build or revise artwork.
• Choose PDF/X when the artwork is final and going to prepress for plates or digital printing.
• Choose DXF when a structural engineer, die maker or sample-cutting table needs to cut a white sample or make a cutting die.
• Send all three for a new structure: it avoids a round of “please resend in another format” and lets each team check the same geometry.

Start from a correct structure

Most format problems begin with a dieline that was redrawn by hand or rescaled. Downloading a structure and then editing dimensions is usually safer. The BestPackFactory dieline library lists common structures, including the mailer box dieline, the tuck end box dieline, the stand-up pouch dieline, the paper bag dieline and the magnetic rigid box dieline. Treat any template as a starting point: the final dimensions, board thickness allowances and seal widths are confirmed in the quotation and on the approved proof.

What to send with your RFQ

1. The structure type and internal dimensions (length × width × depth in mm).
2. Your dieline in AI or PDF, plus DXF if you already have one from a structural designer.
3. Artwork status: not started, in progress, or final PDF/X.
4. A list of special finishes and which spot-colour layer holds each one.
5. Material and thickness, if known, because board caliper changes crease and panel allowances.

Common mistakes

• Sending a JPG or screenshot as the “dieline”.
• Cut and crease lines in the same colour, or on the artwork layer.
• Dieline strokes in CMYK black that end up printed on the box.
• A DXF exported in inches or at the wrong scale.
• Outlining fonts in the only copy of the file, so later text edits become difficult.
• Resizing a template proportionally instead of changing each panel to the real product size.

For bleed, safe-zone and colour-mode requirements in more detail, see the packaging artwork and dieline preparation guide.

Related pages

• Packaging dieline library
• Packaging artwork and dieline preparation guide
• Contact BestPackFactory for a quotation