Three technologies at a glance
- Die-cut paperboard — Holds by geometry — a punched hole with relief tabs, on a folded deck. Cheapest, ships flat, recycles with the carton, does not absorb impact.
- EVA foam — Holds by interference — a cavity cut slightly smaller than the vial. Absorbs impact, tolerates repeated removal, costs several times paperboard, is not paper.
- Formed tray — Holds by moulded pocket. Identical every time, machine-loadable, needs vial-specific tooling that is fixed cost regardless of quantity.
A fourth option exists and is often overlooked: moulded pulp, which forms like plastic and recycles like paper. It is opaque, so it cannot be used where the product must be visible through the tray.
Cost, honestly
Rather than quote figures that would be misleading without a specification, here is how the three behave against each other.
- At low volume — Paperboard is cheapest by a wide margin. Tray tooling dominates the unit price on a short run, sometimes overwhelmingly.
- At high volume — Tray tooling amortises to almost nothing and trays can undercut foam. Paperboard stays cheapest on material.
- Labour — A one-piece foam block or tray is one placement per box. A partition grid has to be assembled, and a twenty-five cell grid takes disproportionately longer than a ten cell one.
- Freight — Paperboard ships flat. Foam and formed trays take real volume, which is a recurring cost worth modelling.
Tooling behaves very differently at low and high volume, and the crossover is worth modelling rather than assuming — the detail sits on the formed tray and blister page.
Protection compared
These are different kinds of protection and it is worth separating them.
- Against vibration — All three work, provided the fit is right. Vibration damage is a fit problem, not a material problem.
- Against impact — Foam by a clear margin. Paperboard locates but transmits; a tray sits between the two.
- Against glass-on-glass contact — Any of them, so long as there is a physical wall between cavities rather than just distance.
- Against repeated removal — Foam. Paperboard relief tabs widen with each cycle and eventually stop gripping.
- Against inconsistent presentation — Formed tray. Every pocket is identical, which is what a window box needs.
Structures we cut in paperboard
- Raised platform — A single blank folded into a deck with punched holes. The default single- and low-count insert.
- Folded partitions — Interlocking strips forming a grid of cells, each vial walled on four sides.
- Twin-wall partitions — Double-thickness cells for heavier vials, which also stiffen the carton itself.
- Wrap-around cradle — A folded shape supporting a vial lying on its side, for flatter packs.
- Laminated platform — Two bonded layers where a single sheet would flex.
Grain direction matters more on inserts than on cartons: a fold running across the grain cracks, and a fold running with it does not. It is one reason we cut inserts rather than adapting generic ones — the detail is on the packaging materials page.
Cavity shapes we cut in foam
- Straight round cavity — For standard crimp-sealed vials.
- Stepped cavity — A wider mouth for the closure and a narrower body section below, giving grip without forcing the cap.
- Syringe channel — A long slot with a widened section at the plunger flange.
- Ampoule cradle — A curved trough for components with no flat base.
- Finger relief — A scallop beside each cavity so vials lift out without tools.
- Lid pad — A thin foam layer in the lid removing the last of the vertical movement.
Density, cavity depth and how the interference fit is set are covered in full on the EVA foam insert page.
Finger relief is the detail most often omitted and most often complained about. An insert the end user cannot unload easily has failed, however well it protects.
End of life
If recyclability is a requirement, this is the section that decides the specification.
- Paperboard — Same stream as the carton, provided it is uncoated or aqueous-coated rather than laminated.
- Moulded pulp — Also paper. Formed protection without plastic, at the cost of transparency.
- PET and RPET trays — Widely accepted in plastic streams, but must be separated from the carton.
- EVA foam — Not paper and not widely recycled. It must be removed before the carton goes in a paper stream.
We will tell you exactly what a given build means for recycling rather than describing a pack as recyclable in general terms.
How to choose in under a minute
- Box ships on its own? — Foam.
- Vial 10ml or heavier? — Foam, or twin-wall paperboard if it travels inside a case.
- Behind a window, or machine-loaded? — Formed tray.
- Must recycle in one stream? — Paperboard or moulded pulp.
- Opened repeatedly? — Foam.
- None of the above? — Paperboard, and spend the saving on the printing.
Questions about this
Can one insert hold several different components?
Yes. A single foam block can carry a round vial cavity, a syringe channel and an ampoule cradle, each cut to its own item. Send us all of the components rather than the main one.
How do you decide foam density?
Against the vial weight and how often the pack is opened, then confirmed on a physical sample. A foam that suits a presentation box opened once would be frustrating on a pack opened weekly.
Do inserts arrive assembled?
Paperboard platforms and partitions arrive flat and are folded during packing. Foam arrives cut, loose or pre-fitted. Formed trays arrive nested.
Are partitions cheaper than a tray?
Cheaper to buy, more expensive to use. The crossover depends on your volume and labour cost, which is why we quote both against your actual quantity rather than recommending one in the abstract.
Why does my paperboard insert crack when folded?
Almost always grain direction. Board folds cleanly along the grain and cracks across it, and it is far worse in very dry conditions. We specify grain when cutting.
Can inserts be printed?
Paperboard inserts, yes — position numbering and short labels cost very little and are the clearest way to tell a user which cavity is which. Foam takes simple marking or a laminated top layer, not detailed artwork.
Do I need an insert at all?
For a glass vial, yes. Without one the vial slides and rotates, which chips glass, scuffs labels and can work a crimp seal loose. Void fill is not a substitute, because it moves too.
How do you test that an insert works?
Load a sample with your actual vials, close it, invert it, shake it, and check for movement marks inside the cavity. If it makes a noise the specification changes. For documented transit performance you would need an accredited laboratory testing your final packed configuration.