What to Send a Carton Factory for a Quote: ID, Die-Line, Artwork

You wrote 300 × 200 × 150 mm in the enquiry. Six weeks later the cartons land and the inside measures 292 × 192 × 141. Nothing was mis-made. The factory read your figure as the outside of the box, subtracted board thickness on every face, and built exactly what it thought you asked for. Your product no longer fits, the die is cut, and the argument is unwinnable because neither party ever wrote down which surface the number referred to.

Knowing what to send a carton factory for a quote is mostly about closing that class of ambiguity before it becomes tooling. A corrugated RFQ has maybe a dozen fields. Half of them change the price, and three of them change whether the box works at all. Below is what each one has to contain, in the form a Chinese box plant can actually quote from, and what the common failure looks like when it is missing.

The dimension block, and the one word that prevents most disputes

Corrugated dimensions are quoted internal by default across most of the industry, in the order length × width × depth, where length is the longer of the two open-top dimensions and depth is measured from the inside of the bottom flaps to the top edge. That is the convention, but conventions are what you argue about later. Write the word out.

A dimension block that cannot be misread looks like this:

• Product size (the thing going in): 296 × 196 × 138 mm, rigid, no compressible packaging
• Required carton internal dimensions (ID): 300 × 200 × 145 mm
• Fit allowance already included: 4 mm on L and W, 7 mm on depth
• External dimensions (OD): factory to calculate and confirm, must not exceed 312 × 212 × 158 mm for pallet fit
• Units: millimetres throughout

Four things are doing work there. First, the letters ID and OD appear beside numbers, so no one guesses. Second, the product size is given separately, so the plant can sanity-check your allowance instead of silently trusting it. Third, the allowance is stated, because a box built to exactly the product's dimensions will not accept the product — board has thickness on the inside too, flaps bow inward, and a filled carton needs clearance to load. Fourth, the OD is given as a ceiling rather than a value, because the OD depends on the board, and the board is the factory's job to confirm.

That last point is the one buyers most often get wrong. Change the flute and the OD moves while the ID stays put — a single-wall C board and a BC double wall differ by three or four millimetres per wall, which is enough to lose a box per pallet layer. If your pallet pattern is fixed, say so as a hard constraint in the RFQ, and give the pallet size and the target cartons per layer. The board decision then has to live inside your cube, which is exactly the discipline that flute selection demands.

The die-line: what makes a drawing quotable

"Send us your drawing" and "send us a die-line" are different requests. A quotable die-line is a 1:1 vector file, drawn flat as the blank, with the following separated so a pre-press operator can read it without phoning you:

Two file formats do this job well: a layered vector PDF, or a DXF/CF2 for the structural side with the artwork supplied separately. A JPEG of a hand sketch is not a die-line, but it is still worth sending alongside — plants build to sample and to drawing all the time, and a photo of the current box with a ruler in frame resolves more ambiguity than another paragraph of email. Ask which formats the factory's pre-press actually accepts before you export anything; it is a one-line question that saves a re-issue.

If your structure is standard, name the FEFCO style code in the title block rather than describing it in words. If it is not standard, send the physical sample. A plant working ODM on a full-material basis, sourcing its own board and building to your drawing or sample, is in a position to redraw a structure for manufacture — but only if it can see what you mean.

The two specs that decide what you actually get

The board specification, written as papers not adjectives

"Strong 3-ply" is not a specification, and it is the single most common reason quotes for the same spec come back different. A board spec that binds has four parts:

1. Ply count and flute: 3-ply C, 5-ply BC, and so on.
2. Grammage of every layer, in g/m²: outer liner / medium / inner liner, and all five for double wall.
3. A strength target: an edge crush value in kN/m or lb/in, or a burst grade — and say which test method, because the two are not convertible. The distinction is worked through in ECT versus bursting strength.
4. Liner surface: kraft, white-top, mottled white, or coated — this decides what your artwork will look like more than your ink choice does.

Add the environment the box lives in: stack height, warehouse humidity, ocean leg or air, how long it sits palletised. A plant that knows the box will sit six high in a humid warehouse for eight weeks will quote a different board than one that assumes a 48-hour parcel journey, and both quotes will be honest.

Artwork: what corrugated printing will and will not hold

Most disappointment with printed cartons comes from artwork designed for a folding-carton press being sent to a flexo printer-slotter running post-print on corrugated. The board is not flat at a microscopic level — the liner dips slightly between flute tips, which produces washboarding — and flexo on kraft spreads ink. Design around it:

• Vector, fonts outlined, live text supplied separately. Raster art should be at least 300 dpi at final size, and line art higher.
• Specify colours as Pantone, and ask for a drawdown on your actual liner. A Pantone coated chip and the same ink on brown kraft are two different colours. On unbleached kraft, ask for the uncoated reference and expect a shift regardless.
• Minimum line weight and reversed type. Fine positive lines and small reversed-out text fill in on flexo-printed corrugated. Keep reverses generous and test anything under about 8 pt on a real drawdown before approving.
• Keep solids off creases and the joint. Ink on a crease cracks when it folds; ink on the glue tab weakens the bond.
• Barcodes: orientation matters. Print shipping barcodes with the bars running parallel to the flutes so that washboard shadows do not fall across the bars, keep the quiet zones, and state the symbology and magnification — ITF-14 and GS1-128 have different rules and different bearer-bar requirements.
• Say how many colours you expect. A two-colour printer-slotter is a different proposition from a multi-colour press or a litho-laminated construction, and finishes such as lamination, spot UV or foil may be in-house at one plant and subcontracted at the next. Ask which of your artwork's features are produced in the building and which go outside; that answer moves both the price and the lead time.

The commercial fields that quietly move the number

One more field worth adding: who owns the die and the plates, and what the charge is. Ask at RFQ stage, before tooling exists, because the answer is far more negotiable then.

Common questions

The factory redrew my die-line. Do I have to accept their version?

You should expect it. Plants adjust blanks for their own tooling, board caliper and machine allowances, and a redraw is usually a sign someone competent read your file. What matters is that the returned die-line comes back to you for written approval, at 1:1, with dimensions called out, and that you check the ID, the flute arrow and the joint position before signing.

How precise can carton dimensions actually be?

Corrugated is a paper product with tolerances measured in millimetres, not tenths. Ask the factory to state its slot and score tolerance and its squareness tolerance in the quotation rather than assuming a number, and design your fit allowance so that the box still works at the loose end of that band.

Can I send a physical sample instead of drawings?

Yes, and for an unusual structure it is often faster. Send the sample flat and unglued if you can, mark the panels, and include a note stating which dimensions are critical and which are free. Then still write the dimension block — the sample tells the plant what shape you want; the block tells it what has to be held.

What to send a carton supplier next

Package the RFQ as one email with one attachment set, and include all of this:

1. Dimension block — product size, required ID, allowance stated, OD ceiling, units in mm.
2. Die-line at 1:1 with cut, crease, perf, joint, flute arrow, bleed and title block on separate layers — plus a photo of the current box with a rule in frame.
3. Board spec — ply, flute, grammage per layer, ECT or burst target with test method, liner surface.
4. Use case — stack height, warehouse conditions, transport mode, time palletised.
5. Artwork — vector, fonts outlined, Pantone references, barcode symbology and orientation, and a question asking which file formats and colour system their pre-press wants.
6. Quantities at three tiers, annual volume, call-off pattern, overs/unders band.
7. Delivery — Incoterms 2020 rule and named port, packing and pallet spec, in-warehouse date.
8. Sample request, stated as what it must prove.
9. Tooling question — die and plate charges, and who retains them.

If you want a live example to send that package to, the CMH listing for Jindong Packaging describes a Shenzhen paper-packaging manufacturer founded in 2007 that works ODM on a full-material basis — sourcing the board and materials itself and manufacturing to your drawing or sample, with almost everything made to drawing rather than pulled from a catalogue — quoting sampling at about seven days and bulk production at about fifteen working days after artwork and sample approval, from 1,000 pieces with tiers at 3,000 and 5,000, on T/T terms. Its listed equipment includes two-colour high-speed printer-slotters, slotting and creasing machines and gluing and stitching machines. Which artwork file formats and colour system its pre-press prefers, and which print finishes are produced in the building versus subcontracted, are not stated in that listing — so put both on the same email. A supplier's answer to the pre-press question, more than its answer to the price question, tells you how the next six weeks will go. For the wider discipline of writing a spec a Chinese plant can build to, see how to write a product spec sheet, and for realistic MOQ and lead-time expectations, the sourcing data guide.