Secondary packaging is where a filling line stops producing individual containers and starts producing shippable units. Tray shrink wrap packing equipment sits at that transition point, grouping bottles, cans, jars, or pouches into a collated set, supporting them with a tray or pad, wrapping the group in polyethylene film, and passing the bundle through a heat shrink wrapper that pulls the film tight around the load.
For producers moving beverages, food products, household chemicals, or nutritional goods to retail and distribution, this format has stayed popular for a straightforward reason: it uses less corrugated than a full case, it presents product clearly on a shelf, and it produces a stable pallet load. Since 1988 we’ve handled used tray shrink packing systems and heat shrink tunnels across every one of those industries, and the questions buyers ask tend to circle back to the same place — which bundle format do I actually need, and what does that mean for the machine I’m shopping for?
Almost every tray shrink packer on the market builds one of three output formats. Knowing which one your product and your customers require narrows the equipment search considerably, because the format dictates how much of the machine is dedicated to board handling.
A formed corrugated or chipboard tray cradles the product on the bottom and up all four sides, and shrink film wraps over the top and around the whole assembly. This is the sturdiest of the three and the usual choice for heavier glass, tall or top-heavy containers, and products that will be stacked several layers high on a pallet. Machines producing this format need a tray erecting section — either forming trays from flat blanks or setting up pre-glued trays — which adds width, complexity, and a magazine to the footprint.
Instead of a formed tray with walls, a flat corrugated pad sits under the product and the film does the rest of the work. Pad-and-shrink bundles use less board than trays while still giving the load a flat, rigid base that handles conveyor transfers and pallet stacking better than film alone. Machines running this format need only a pad magazine and a placement mechanism rather than a full erecting section, which usually makes them simpler to operate and maintain.
The lightest format skips board entirely. Film-only bundles work well for lighter containers, plastic bottles, and shorter-run distribution where the pack won’t see rough handling. Some plants use film-only for warehouse-club packs or for bundles that go straight into a shipper. These machines are the least complicated of the three, and they’re often the fastest, since there’s no board feeding step to synchronize.
Plenty of used machines can run more than one of these formats with a change part kit, and that flexibility is worth asking about when you’re evaluating a specific piece of equipment.
Whichever format you’re producing, the machine breaks down into the same functional zones.
Containers arrive from the filler, capper, and labeler on a mass or single-file conveyor and get organized into the pack pattern — a 4×6 arrangement, a 3×4, whatever the customer spec calls for. Lane dividers, timing screws, or servo-driven flight bars separate the product into rows and then push a complete group forward. This zone is where most format changeover time lives, so look closely at how change parts are held and how much of the adjustment is tool-free.
On tray and pad machines, blanks pull from a magazine, get transferred into position, and — for trays — fold up at the corners with glue or a mechanical lock. Hot melt glue systems are common here. When inspecting used equipment, check the vacuum cups, the magazine rails, and the condition of the glue system, since those are the wear points that get the most attention.
A film unwind station feeds polyethylene shrink film around the grouped product. Most machines use a side-seal or lap-seal arrangement, with a heated sealing bar or wire cutting and joining the film into a loose sleeve around the bundle. Film tension control matters here, and it’s worth watching the machine run if you can, because sloppy tension shows up as wrinkles downstream that no tunnel will fix.
The bundle passes through a heated chamber on a conveyor, the film contracts, and it emerges as a tight, unitized pack. Tunnels differ mostly in how they deliver heat and how they move product through the chamber. Belt type matters more than buyers expect — roller conveyors, mesh belts, and slat conveyors each behave differently with heavy loads and with film that needs to shrink cleanly underneath the bundle.
Hot air recirculating tunnels are the most common in tray and bundle applications. Fans circulate heated air around the pack, and adjustable baffles or nozzles direct airflow toward the areas that need the most shrink, typically the bullseyes on the ends of the bundle.
Radiant and infrared tunnels apply heat from elements without heavy air movement, which suits lighter film and lighter loads but gives less control on large bundles.
Steam tunnels appear in sleeve label applications far more often than in tray packing, but they occasionally show up in mixed lines.
Chamber length, conveyor speed, and temperature all interact to determine dwell time. Rather than quoting general speed or temperature figures here, we’d rather talk through the specifics of a given machine against your film and container — those numbers should always be verified against the actual unit and your material.
Semi-automatic systems rely on an operator to place product and board, with the machine handling wrapping and shrinking. These suit craft producers, low-volume co-packers, and plants running many short jobs.
Automatic inline machines take collated product straight off the conveyor and run continuously with minimal operator involvement beyond film and board replenishment. This is the bulk of what moves through our inventory.
High-speed continuous motion systems keep product moving through the collation and wrapping stages rather than indexing and stopping, and they’re built for the volumes you see in large beverage and food operations.
Start with the format and pack pattern you need, then work backward. Ask whether the change parts for your container size are included, since sourcing them separately can take time. Look at the condition of the sealing bar or wire, the tunnel’s heating elements and insulation, the conveyor belt, and the drive components. Confirm the control platform and whether the HMI and PLC are still supported. Check that guarding and safety circuits are intact. And match the machine’s rated output to your filler’s — a tray packer that outpaces or lags your line by a wide margin creates backup problems either way.
A tray shrink packer usually lands after labeling and before palletizing, with accumulation ahead of it to buffer against short stoppages. If you’re adding one to an existing line, the conveyor height, discharge direction, and available floor length are the first three specs to nail down.
We’ve been sourcing used tray shrink packing equipment and heat shrink wrappers since 1988, and our inventory spans semi-automatic units through high-speed continuous motion systems across beverage, food, dairy, brewing, spirits, wine, pharmaceutical, nutritional, household, and chemical applications. Financing is available on qualifying equipment.
Tell us your container, your pack pattern, and your target rate, and we’ll point you toward the machines in inventory that fit — and tell you honestly which ones don’t.
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